M. Kulmala

Publication List Details

Period

1143 - 2009

Number

492

Co-Authors

European Geosciences Union A look at aerosol formation using data mining techniques Atmospheric Chemistry and Physics (2009)

T. Pohja, S. Launiainen, P. Hari, H. Mannila, M. Kulmala

Abstract. Atmospheric aerosol particle formation is frequently observed throughout the atmosphere, but despite various attempts of explanation, the processes behind it remain unclear. In this study...

Sensitivity of aerosol concentrations and cloud properties to nucleation and secondary organic distribution in ECHAM5-HAM global circulation model (2009)

Makkonen, R., Asmi, A., Korhonen, H., Kokkola, H., Järvenoja, S., Räisänen, P., ...

The global aerosol-climate model ECHAM5-HAM was modified to improve the representation of new particle formation in the boundary layer. Activation-type nucleation mechanism was introduced to produce...

Results of the first air ion spectrometer calibration and intercomparison workshop (2009)

E. Asmi, M. Sipilä, H. E. Manninen, J. Vanhanen, K. Lehtipalo, S. Gagné, ...

The Air Ion Spectrometer (AIS) measures mobility and size distributions of atmospheric ions. The Neutral cluster and Air Ion Spectrometer (NAIS) can additionally measure neutral particles. The number...

Negatively charged nanoparticles produced by splashing of water (2009)

H. Tammet, U. Hõrrak, M. Kulmala

The production of splashing-generated balloelectric intermediate ions was studied by means of mobility spectrometry in the atmosphere during the rain and in a laboratory experiment simulating the...

Classifying previously undefined days from eleven years of aerosol-particle-size distribution data from the SMEAR II station, Hyytiälä, Finland (2009)

S. Buenrostro Mazon, I. Riipinen, D. M. Schultz, M. Valtanen, M. Dal Maso, L. Sogacheva, ...

Studies of secondary aerosol-particle formation depend on identifying days in which new particle formation occurs and, by comparing them to days with no signs of particle formation, identifying the...

Airborne measurements of nucleation mode particles II: boreal forest nucleation events (2009)

C. D. O'Dowd, Y. J. Yoon, W. Junkermann, P. Aalto, M. Kulmala, H. Lihavainen, ...

Airborne measurements of nucleation mode aerosol concentrations during nucleation events over the boreal forest of southern Finland are reported. Three case studies are analyzed in an attempt to...

Sensitivity of aerosol concentrations and cloud properties to nucleation and secondary organic distribution in ECHAM5-HAM global circulation model (2009)

R. Makkonen, A. Asmi, H. Korhonen, H. Kokkola, S. Järvenoja, P. Räisänen, ...

The global aerosol-climate model ECHAM5-HAM was modified to improve the representation of new particle formation in the boundary layer. Activation-type nucleation mechanism was introduced to produce...

Homogeneous vs. heterogeneous nucleation in water-dicarboxylic acid systems (2009)

A. I. Hienola, H. Vehkamäki, I. Riipinen, M. Kulmala

Binary heterogeneous nucleation of water-succinic/glutaric/malonic/adipic acid on nanometer-sized particles is investigated within the frame of classical heterogeneous nucleation theory. Homogeneous...

Introduction: European Integrated Project on Aerosol Cloud Climate and Air Quality interactions (EUCAARI) – integrating aerosol research from nano to global scales (2009)

M. Kulmala, A. Asmi, H. K. Lappalainen, K. S. Carslaw, U. Pöschl, U. Baltensperger, ...

The European Aerosol Cloud Climate and Air Quality Interactions project EUCAARI is an EU Research Framework 6 integrated project focusing on understanding the interactions of climate and air...

Aerosol dynamics simulations on the connection of sulphuric acid and new particle formation (2009)

H. Vuollekoski, J. Leppä, I. Riipinen, H. Korhonen, ...

We have performed a series of simulations with an aerosol dynamics box model to study the connection between new particle formation and sulphuric acid concentration. For nucleation either activation...

Applying the Condensation Particle Counter Battery (CPCB) to study the water-affinity of freshly-formed 2–9 nm particles in boreal forest (2009)

I. Riipinen, H. E. Manninen, T. Yli-Juuti, M. Boy, M. Sipilä, M. Ehn, ...

Measurements on the composition of nanometer-sized atmospheric particles are the key to understand which vapors participate in the secondary aerosol formation processes. Knowledge on these processes...

Charged and total particle formation and growth rates during EUCAARI 2007 campaign in Hyytiälä (2009)

H. E. Manninen, T. Nieminen, I. Riipinen, T. Yli-Juuti, S. Gagné, E. Asmi, ...

Despite the fact that frequent aerosol formation has been observed in various locations in the atmosphere, the overall magnitude of the new particle formation as a particle source is still unclear....

Analysis of atmospheric neutral and charged molecular clusters in boreal forest using pulse-height CPC (2009)

K. Lehtipalo, M. Sipilä, I. Riipinen, T. Nieminen, M. Kulmala

We measured the size distribution of atmospheric neutral and charged clusters and particles down to mobility diameter around 1.5 nm by applying pulse-height CPC technique at SMEAR II station in...

Time span and spatial scale of regional new particle formation events over Finland and Southern Sweden (2009)

T. Hussein, H. Junninen, P. Tunved, A. Kristensson, M. Dal Maso, I. Riipinen, ...

We investigated the time span and spatial scale of regional new particle formation (NPF) events in Finland and Southern Sweden using measured particle number size distributions at five background...

Quantitative long-term measurements of VOC concentrations by PTR-MS: annual cycle at a boreal forest site (2009)

T. M. Ruuskanen, R. Taipale, J. Rinne, M. K. Kajos, H. Hakola, M. Kulmala

Atmospheric concentrations of volatile organic compounds (VOCs) vary diurnally, seasonally and annually. Therefore continuous long-term measurements are needed to properly describe the atmospheric...

Time-span and spatial-scale of regional new particle formation events over Finland and Southern Sweden (2009)

T. Hussein, H. Junninen, P. Tunved, A. Kristensson, M. Dal Maso, I. Riipinen, ...

We investigated the time-span and spatial-scale of regional new particle formation (NPF) events in Finland and Southern Sweden using measured particle number size distributions at five background...

Ambient new particle formation parameter indicates potential rise in future events (2009)

B. Bonn, M. Boy, M. Kulmala, A. Groth, K. Trawny, S. Borchert, ...

Atmospheric new particle formation is a general phenomenon observed over coniferous forests. So far nucleation is described as a function of gaseous sulfuric acid concentration only, which is unable...

Long term particle size distribution measurements at Mount Waliguan, a high-altitude site in inland China (2009)

N. Kivekäs, J. Sun, M. Zhan, A. Hyvärinen, M. Komppula, ...

Particle number size distributions in size range 12–570nm were measured continuously at Mount Waliguan, a remote mountain-top station in inland China. The station is located at the altitude of 3816...

Charged and total particle formation and growth rates during EUCAARI 2007 campaign in Hyytiälä (2009)

H. E. Manninen, T. Nieminen, I. Riipinen, T. Yli-Juuti, S. Gagné, E. Asmi, ...

Despite the fact that frequent aerosol formation has been observed in various locations in the atmosphere, the overall magnitude of the new particle formation as a particle source is still unclear....

Day-time concentrations of biogenic volatile organic compounds in a boreal forest canopy and their relation to environmental and biological factors (2009)

H. K. Lappalainen, S. Sevanto, J. Bäck, T. M. Ruuskanen, P. Kolari, R. Taipale, ...

Atmospheric concentrations of methanol, acetaldehyde, acetone, isoprene and monoterpenes were measured using a PTR-MS (proton transfer reaction mass spectrometry) in a boreal forest site in...

Atmospheric aerosols in the earth system: a review of interactions and feedbacks (2009)

K. S. Carslaw, O. Boucher, D. V. Spracklen, G. W. Mann, S. Woodward, ...

The natural environment is a major source of atmospheric aerosols, including dust, secondary organic material from terrestrial biogenic emissions, carbonaceous particles from wildfires, and sulphate...

New particle formation and growth at a remote, sub-tropical coastal location (2009)

R. L. Modini, Z. D. Ristovski, G. R. Johnson, C. He, N. Surawski, L. Morawska, ...

A month-long intensive measurement campaign was conducted in March/April 2007 at Agnes Water, a remote coastal site just south of the Great Barrier Reef on the east coast of Australia. Particle and...

VOC measurements within a boreal forest during spring 2005: the role of monoterpenes and sulphuric acid in selected intense nucleation events (2009)

G. Eerdekens, N. Yassaa, V. Sinha, P. P. Aalto, V. Fiedler, H. Aufmhoff, ...

In this study we present measurements of selected trace gases and aerosol made in a boreal forest during the BACCI-QUEST IV intensive field campaign in Hyytiälä, Finland in April 2005. Several...

Cold oceans enhance terrestrial new-particle formation in near-coastal forests (2009)

T. Suni, L. Sogacheva, J. Lauros, H. Hakola, J. Bäck, T. Kurtén, ...

The world's forests produce atmospheric aerosol by emitting volatile organic compounds (VOC) which, after being oxidized in the atmosphere, readily condense on the omnipresent nanometer-sized...

Annual particle flux observations over a heterogeneous urban area (2009)

L. Järvi, Ü. Rannik, I. Mammarella, A. Sogachev, P. P. Aalto, P. Keronen, ...

Long-term eddy covariance (EC) particle number flux measurements for the size range 6 nm to 5 μm were performed at the SMEAR III station over urban area in Helsinki, Finland. Heterogeneous urban...

Measuring condensation sink and ion sink of atmospheric aerosols with the electrical low pressure impactor (ELPI) (2009)

H. Kuuluvainen, J. Kannosto, A. Virtanen, J. M. Mäkelä, M. Kulmala, P. Aalto, ...

We investigate the suitability of ELPI for condensation sink and ion sink measurements. The aim is to find the simple calibration factors by which the measured ELPI currents can be converted to...

Day-time concentrations of biogenic volatile organic compounds in a boreal forest canopy and their relation to environmental and biological factors (2009)

H. K. Lappalainen, S. Sevanto, J. Bäck, T. M. Ruuskanen, P. Kolari, R. Taipale, ...

Atmospheric concentrations of methanol, acetaldehyde, acetone, isoprene and monoterpenes were measured using PTR-MS (proton transfer reaction mass spectrometry) in a boreal forest site in Hyytiälä,...

Long term particle size distribution measurements at Mount Waliguan, a high-altitude site in inland China (2009)

N. Kivekäs, J. Sun, M. Zhan, A. Hyvärinen, M. Komppula, ...

Particle number size distributions in size range 12–570 nm were measured continuously at Mount Waliguan, a remote mountain-top station in inland China. The station is located at the altitude of...

The role of sulphates and organic vapours in new particle formation in a eucalypt forest (2009)

Z. D. Ristovski, T. Suni, M. Kulmala, M. Boy, N. K. Meyer, J. Duplissy, ...

The influence of biogenic particle formation on climate is a well recognized phenomenon. To understand the mechanisms underlying the biogenic particle formation, determining the chemical composition...

Sulfuric acid and OH concentrations in a boreal forest site (2009)

T. Petäjä, R. L. Mauldin, III, E. Kosciuch, J. McGrath, T. Nieminen, P. Paasonen, ...

As demonstrated in a number of investigations, gaseous sulfuric acid plays a central role in atmospheric aerosol formation. Using chemical ionization mass spectrometer the gas-phase sulfuric acid and...

New particle formation and growth at a remote, sub-tropical coastal location (2009)

R. L. Modini, Z. D. Ristovski, G. R. Johnson, C. He, N. Surawski, L. Morawska, ...

A month-long intensive measurement campaign was conducted in March/April 2007 at Agnes Water, a remote coastal site just south of the Great Barrier Reef on the east coast of Australia. Particle and...

Annual particle flux observations over a heterogeneous urban area (2009)

L. Järvi, Ü. Rannik, I. Mammarella, A. Sogachev, P. P. Aalto, P. Keronen, ...

Long-term eddy covariance particle number flux measurements for the diameter range 6 nm to 5 μm were performed at the SMEAR III station over an urban area in Helsinki, Finland. The heterogeneity of...

A new parametrization for ambient particle formation over coniferous forests and its potential implications for the future (2009)

B. Bonn, M. Boy, M. Kulmala, A. Groth, K. Trawny, S. Borchert, ...

Atmospheric new particle formation is a general phenomenon observed over coniferous forests. So far nucleation is either parameterised as a function of gaseous sulphuric acid concentration only,...

New particle formation from the oxidation of direct emissions of pine seedlings (2009)

L. Q. Hao, P. Yli-Pirilä, P. Tiitta, S. Romakkaniemi, P. Vaattovaara, M. K. Kajos, ...

Measurements of particle formation following the gas phase oxidation of volatile organic compounds (VOCs) emitted by Scots pine (<i>Pinus sylvestris</i> L.) seedlings are reported....

Results from the CERN pilot CLOUD experiment (2009)

J. Duplissy, M. B. Enghoff, K. L. Aplin, F. Arnold, H. Aufmhoff, M. Avngaard, ...

During a 4-week run in October–November 2006, a pilot experiment was performed at the CERN Proton Synchrotron in preparation for the CLOUD<sup>1</sup> experiment, whose aim is to study...

Atmospheric sub-3 nm particles at high altitudes (2009)

S. Mirme, A. Mirme, A. Minikin, A. Petzold, U. Hõrrak, ...

Formation of new atmospheric aerosol particles is known to occur almost all over the world and the importance of these particles to climate and air quality has been recognized. Recently, it was found...

Atmospheric data over a solar cycle: no connection between galactic cosmic rays and new particle formation (2009)

M. Kulmala, I. Riipinen, T. Nieminen, M. Hulkkonen, L. Sogacheva, H. E. Manninen, ...

Aerosol particles affect the Earth's radiative balance by directly scattering and absorbing solar radiation and, indirectly, through their activation into cloud droplets. Both effects are known with...

Physicochemical properties and origin of organic groups detected in boreal forest using an aerosol mass spectrometer (2009)

T. Raatikainen, P. Vaattovaara, P. Tiitta, P. Miettinen, J. Rautiainen, M. Ehn, ...

An Aerodyne quadrupole aerosol mass spectrometer (Q-AMS) was deployed in Hyytiälä, a forested rural measurement site in southern Finland, during a 2-week measurement campaign in spring 2005. Q-AMS...

Aerosol dynamics simulations on the connection of sulphuric acid and new particle formation (2008)

Vuollekoski, H., Leppä, J., Riipinen, I., Korhonen, H., ...

We have performed a series of simulations with an aerosol dynamics box model to study the connection between new particle formation and sulphuric acid concentration. For nucleation either activation...

Sensitivity of aerosol concentrations and cloud properties to nucleation and secondary organic distribution in ECHAM5-HAM global circulation model (2008)

Makkonen, R., Asmi, A., Korhonen, H., Kokkola, H., Järvenoja, S., Räisänen, P., ...

The global aerosol-climate model ECHAM5-HAM was modified to improve the representation of new particle formation in the boundary layer. Activation-type nucleation mechanism was introduced to produce...

SO2 oxidation products other than H2SO4 as a trigger of new particle formation ? Part 1: Laboratory investigations (2008)

Berndt, T., Stratmann, F., Bräsel, S., Heintzenberg, J., Laaksonen, A., Kulmala, M.

Mechanistic investigations of atmospheric H2SO4 particle formation have been performed in a laboratory study taking either H2SO4 from a liquid reservoir or using the gas-phase reaction of OH radicals...

SO2 oxidation products other than H2SO4 as a trigger of new particle formation ? Part 2: Comparison of ambient and laboratory measurements, and atmospheric implications (2008)

Laaksonen, A., Kulmala, M., Berndt, T., Stratmann, F., Mikkonen, S., Ruuskanen, A., ...

Atmospheric new particle formation is generally thought to occur due to homogeneous or ion-induced nucleation of sulphuric acid. We compare ambient nucleation rates with laboratory data from...

Technical Note: Quantitative long-term measurements of VOC concentrations by PTR-MS ? measurement, calibration, and volume mixing ratio calculation methods (2008)

Taipale, R., Ruuskanen, T. M., Rinne, J., Kajos, M. K., Hakola, H., Pohja, T., ...

Proton transfer reaction mass spectrometry (PTR-MS) is a technique for online measurements of atmospheric concentrations, or volume mixing ratios, of volatile organic compounds (VOCs). The aim of...

Size distributions, sources and source areas of water-soluble organic carbon in urban background air (2008)

Timonen, H., Saarikoski, S., Tolonen-Kivimäki, O., Aurela, M., Saarnio, K., Petäjä, T., ...

This paper represents the results of one year long measurement period of the size distributions of water-soluble organic carbon (WSOC), inorganic ions and gravimetric mass of particulate matter....

Amines are likely to enhance neutral and ion-induced sulfuric acid-water nucleation in the atmosphere more effectively than ammonia (2008)

Kurtén, T., Loukonen, V., Vehkamäki, H., Kulmala, M.

We have studied the structure and formation thermodynamics of dimer clusters containing H2SO4 or HSO4? together with ammonia and seven different amines possibly present in the atmosphere, using the...

Mode resolved density of atmospheric aerosol particles (2008)

Kannosto, J., Lemmetty, M., Virtanen, A., Mäkelä, J. M., Keskinen, J., Junninen, H., ...

In this study, we investigate the mode resolved density of ultrafine atmospheric particles measured in boreal forest environment. The method used here enables us to find the distinct density...

Basic characteristics of atmospheric particles, trace gases and meteorology in a relatively clean Southern African Savannah environment (2008)

Laakso, L., Laakso, H., Aalto, P. P., Keronen, P., Petäjä, T., Nieminen, T., ...

We have analyzed one year (July 2006?July 2007) of measurement data from a relatively clean background site located in dry savannah in South Africa. The annual-median trace gas concentrations were...

The role of ammonia in sulfuric acid ion induced nucleation (2008)

Ortega, I. K., Kurtén, T., Vehkamäki, H., Kulmala, M.

We have developed a new multi-step strategy for quantum chemical calculations on atmospherically relevant cluster structures that makes calculation for large clusters affordable with a good...

Airborne measurements of nucleation mode particles II: boreal forest nucleation events (2008)

O'Dowd, C. D., Yoon, Y. J., Junkerman, W., Aalto, P., Kulmala, M., Lihavainen, H., ...

Airborne measurements of nucleation mode aerosol concentrations during nucleation events over the boreal forest of southern Finland are reported. Three case studies are analysis in an attempt to...

Applicability of condensation particle counters to measure atmospheric clusters (2008)

Sipilä, M., Lehtipalo, K., Kulmala, M., Petäjä, T., Junninen, H., Aalto, P. P., ...

The ambient and laboratory molecular and ion clusters were investigated. Here we present data on the ambient concentrations of both charged and uncharged molecular clusters as well as the performance...

The role of ammonia in sulfuric acid ion induced nucleation (2008)

Ortega, I. K., Kurtén, T., Vehkamäki, H., Kulmala, M.

We have developed a new multi-step strategy for quantum chemical calculations on atmospherically relevant cluster structures that makes calculation for large clusters affordable with a good...

The role of VOC oxidation products in continental new particle formation (2008)

Laaksonen, A., Kulmala, M., O'Dowd, C. D., Joutsensaari, J., Vaattovaara, P., Mikkonen, S., ...

Aerosol physical and chemical properties and trace gas concentrations were measured during the QUEST field campaign in March?April 2003, in Hyytiälä, Finland. Our aim was to understand the role of...

SALSA ? a Sectional Aerosol module for Large Scale Applications (2008)

Kokkola, H., Korhonen, H., Lehtinen, K. E. J., Makkonen, R., Asmi, A., Järvenoja, S., ...

The sectional aerosol module SALSA is introduced. The model has been designed to be implemented in large scale climate models, which require both accuracy and computational efficiency. We have used...

New particle formation in the Front Range of the Colorado Rocky Mountains (2008)

Boy, M., Karl, T., Turnipseed, A., Mauldin, R. L., Kosciuch, E., Greenberg, J., ...

New particle formation is of interest because of its influence on the properties of aerosol population, and due to the possible contribution of newly formed particles to cloud condensation nuclei....

Temporal variations in black carbon concentrations with different time scales in Helsinki during 1996?2005 (2008)

Järvi, L., Junninen, H., Karppinen, A., Hillamo, R., Virkkula, A., Mäkelä, T., ...

Variations in black carbon (BC) concentrations over different timescales, including annual, weekly and diurnal changes, were studied during ten years in Helsinki, Finland. Measurements were made in...

Variation and balance of positive air ion concentrations in a boreal forest (2008)

Hõrrak, U., Aalto, P. P., Salm, J., Komsaare, K., Tammet, H., Mäkelä, J. M., ...

Air ions are characterized on the basis of measurements carried out in a boreal forest at the Hyytiälä SMEAR station, Finland, during the BIOFOR III campaign in spring 1999. The air ions were...

Formation and characteristics of ions and charged aerosol particles in a native Australian Eucalypt forest (2008)

Suni, T., Kulmala, M., Hirsikko, A., Bergman, T., Laakso, L., Aalto, P. P., ...

Biogenic aerosol formation is likely to contribute significantly to the global aerosol load. In recent years, new-particle formation has been observed in various ecosystems around the world but...

Aerosol dynamics simulations on the connection of sulphuric acid and new particle formation (2008)

Vuollekoski, H., Leppä, J., Riipinen, I., Korhonen, H., ...

We have performed a series of simulations with an aerosol dynamics box model to study the connection between new particle formation and sulphuric acid concentration. For nucleation either activation...

Sensitivity of aerosol concentrations and cloud properties to nucleation and secondary organic distribution in ECHAM5-HAM global circulation model (2008)

Makkonen, R., Asmi, A., Korhonen, H., Kokkola, H., Järvenoja, S., Räisänen, P., ...

The global aerosol-climate model ECHAM5-HAM was modified to improve the representation of new particle formation in the boundary layer. Activation-type nucleation mechanism was introduced to produce...

SO2 oxidation products other than H2SO4 as a trigger of new particle formation ? Part 1: Laboratory investigations (2008)

Berndt, T., Stratmann, F., Bräsel, S., Heintzenberg, J., Laaksonen, A., Kulmala, M.

Mechanistic investigations of atmospheric H2SO4 particle formation have been performed in a laboratory study taking either H2SO4 from a liquid reservoir or using the gas-phase reaction of OH radicals...

SO2 oxidation products other than H2SO4 as a trigger of new particle formation ? Part 2: Comparison of ambient and laboratory measurements, and atmospheric implications (2008)

Laaksonen, A., Kulmala, M., Berndt, T., Stratmann, F., Mikkonen, S., Ruuskanen, A., ...

Atmospheric new particle formation is generally thought to occur due to homogeneous or ion-induced nucleation of sulphuric acid. We compare ambient nucleation rates with laboratory data from...

Technical Note: Quantitative long-term measurements of VOC concentrations by PTR-MS ? measurement, calibration, and volume mixing ratio calculation methods (2008)

Taipale, R., Ruuskanen, T. M., Rinne, J., Kajos, M. K., Hakola, H., Pohja, T., ...

Proton transfer reaction mass spectrometry (PTR-MS) is a technique for online measurements of atmospheric concentrations, or volume mixing ratios, of volatile organic compounds (VOCs). The aim of...

Size distributions, sources and source areas of water-soluble organic carbon in urban background air (2008)

Timonen, H., Saarikoski, S., Tolonen-Kivimäki, O., Aurela, M., Saarnio, K., Petäjä, T., ...

This paper represents the results of one year long measurement period of the size distributions of water-soluble organic carbon (WSOC), inorganic ions and gravimetric mass of particulate matter....

Amines are likely to enhance neutral and ion-induced sulfuric acid-water nucleation in the atmosphere more effectively than ammonia (2008)

Kurtén, T., Loukonen, V., Vehkamäki, H., Kulmala, M.

We have studied the structure and formation thermodynamics of dimer clusters containing H2SO4 or HSO4? together with ammonia and seven different amines possibly present in the atmosphere, using the...

Mode resolved density of atmospheric aerosol particles (2008)

Kannosto, J., Lemmetty, M., Virtanen, A., Mäkelä, J. M., Keskinen, J., Junninen, H., ...

In this study, we investigate the mode resolved density of ultrafine atmospheric particles measured in boreal forest environment. The method used here enables us to find the distinct density...

Basic characteristics of atmospheric particles, trace gases and meteorology in a relatively clean Southern African Savannah environment (2008)

Laakso, L., Laakso, H., Aalto, P. P., Keronen, P., Petäjä, T., Nieminen, T., ...

We have analyzed one year (July 2006?July 2007) of measurement data from a relatively clean background site located in dry savannah in South Africa. The annual-median trace gas concentrations were...

The role of ammonia in sulfuric acid ion induced nucleation (2008)

Ortega, I. K., Kurtén, T., Vehkamäki, H., Kulmala, M.

We have developed a new multi-step strategy for quantum chemical calculations on atmospherically relevant cluster structures that makes calculation for large clusters affordable with a good...

Airborne measurements of nucleation mode particles II: boreal forest nucleation events (2008)

O'Dowd, C. D., Yoon, Y. J., Junkerman, W., Aalto, P., Kulmala, M., Lihavainen, H., ...

Airborne measurements of nucleation mode aerosol concentrations during nucleation events over the boreal forest of southern Finland are reported. Three case studies are analysis in an attempt to...

Applicability of condensation particle counters to measure atmospheric clusters (2008)

Sipilä, M., Lehtipalo, K., Kulmala, M., Petäjä, T., Junninen, H., Aalto, P. P., ...

The ambient and laboratory molecular and ion clusters were investigated. Here we present data on the ambient concentrations of both charged and uncharged molecular clusters as well as the performance...

The role of ammonia in sulfuric acid ion induced nucleation (2008)

Ortega, I. K., Kurtén, T., Vehkamäki, H., Kulmala, M.

We have developed a new multi-step strategy for quantum chemical calculations on atmospherically relevant cluster structures that makes calculation for large clusters affordable with a good...

The role of VOC oxidation products in continental new particle formation (2008)

Laaksonen, A., Kulmala, M., O'Dowd, C. D., Joutsensaari, J., Vaattovaara, P., Mikkonen, S., ...

Aerosol physical and chemical properties and trace gas concentrations were measured during the QUEST field campaign in March?April 2003, in Hyytiälä, Finland. Our aim was to understand the role of...

SALSA ? a Sectional Aerosol module for Large Scale Applications (2008)

Kokkola, H., Korhonen, H., Lehtinen, K. E. J., Makkonen, R., Asmi, A., Järvenoja, S., ...

The sectional aerosol module SALSA is introduced. The model has been designed to be implemented in large scale climate models, which require both accuracy and computational efficiency. We have used...

New particle formation in the Front Range of the Colorado Rocky Mountains (2008)

Boy, M., Karl, T., Turnipseed, A., Mauldin, R. L., Kosciuch, E., Greenberg, J., ...

New particle formation is of interest because of its influence on the properties of aerosol population, and due to the possible contribution of newly formed particles to cloud condensation nuclei....

Temporal variations in black carbon concentrations with different time scales in Helsinki during 1996?2005 (2008)

Järvi, L., Junninen, H., Karppinen, A., Hillamo, R., Virkkula, A., Mäkelä, T., ...

Variations in black carbon (BC) concentrations over different timescales, including annual, weekly and diurnal changes, were studied during ten years in Helsinki, Finland. Measurements were made in...

Variation and balance of positive air ion concentrations in a boreal forest (2008)

Hõrrak, U., Aalto, P. P., Salm, J., Komsaare, K., Tammet, H., Mäkelä, J. M., ...

Air ions are characterized on the basis of measurements carried out in a boreal forest at the Hyytiälä SMEAR station, Finland, during the BIOFOR III campaign in spring 1999. The air ions were...

Formation and characteristics of ions and charged aerosol particles in a native Australian Eucalypt forest (2008)

Suni, T., Kulmala, M., Hirsikko, A., Bergman, T., Laakso, L., Aalto, P. P., ...

Biogenic aerosol formation is likely to contribute significantly to the global aerosol load. In recent years, new-particle formation has been observed in various ecosystems around the world but...

Formation and characteristics of ions and charged aerosol particles in a native Australian Eucalypt forest (2008)

T. Suni, M. Kulmala, A. Hirsikko, T. Bergman, L. Laakso, P. P. Aalto, ...

Biogenic aerosol formation is likely to contribute significantly to the global aerosol load. In recent years, new-particle formation has been observed in various ecosystems around the world but...

Variation and balance of positive air ion concentrations in a boreal forest (2008)

U. Hõrrak, P. P. Aalto, J. Salm, K. Komsaare, H. Tammet, J. M. Mäkelä, ...

Air ions are characterized on the basis of measurements carried out in a boreal forest at the Hyytiälä SMEAR station, Finland, during the BIOFOR III campaign in spring 1999. The air ions were...

Temporal variations in black carbon concentrations with different time scales in Helsinki during 1996─2005 (2008)

L. Järvi, H. Junninen, A. Karppinen, R. Hillamo, A. Virkkula, T. Mäkelä, ...

Variations in black carbon (BC) concentrations over different timescales, including annual, weekly and diurnal changes, were studied during ten years in Helsinki, Finland. Measurements were made in...

New particle formation in the Front Range of the Colorado Rocky Mountains (2008)

M. Boy, T. Karl, A. Turnipseed, R. L. Mauldin, E. Kosciuch, J. Greenberg, ...

New particle formation is of interest because of its influence on the properties of aerosol population, and due to the possible contribution of newly formed particles to cloud condensation nuclei....

SALSA ─ a Sectional Aerosol module for Large Scale Applications (2008)

H. Kokkola, H. Korhonen, R. Makkonen, A. Asmi, S. Järvenoja, ...

The sectional aerosol module SALSA is introduced. The model has been designed to be implemented in large scale climate models, which require both accuracy and computational efficiency. We have used...

The role of VOC oxidation products in continental new particle formation (2008)

A. Laaksonen, M. Kulmala, C. D. O'Dowd, J. Joutsensaari, P. Vaattovaara, S. Mikkonen, ...

Aerosol physical and chemical properties and trace gas concentrations were measured during the QUEST field campaign in March–April 2003, in Hyytiälä, Finland. Our aim was to understand the...

The role of ammonia in sulfuric acid ion induced nucleation (2008)

I. K. Ortega, T. Kurtén, H. Vehkamäki, M. Kulmala

We have developed a new multi-step strategy for quantum chemical calculations on atmospherically relevant cluster structures that makes calculation for large clusters affordable with a good...

Applicability of condensation particle counters to measure atmospheric clusters (2008)

M. Sipilä, K. Lehtipalo, M. Kulmala, T. Petäjä, H. Junninen, P. P. Aalto, ...

This study presents an evaluation of a pulse height condensation particle counter (PH-CPC) and an expansion condensation particle counter (E-CPC) in terms of measuring ambient and...

Amines are likely to enhance neutral and ion-induced sulfuric acid-water nucleation in the atmosphere more effectively than ammonia (2008)

T. Kurtén, V. Loukonen, H. Vehkamäki, M. Kulmala

We have studied the structure and formation thermodynamics of dimer clusters containing H<sub>2</sub>SO<sub>4</sub> or...

Basic characteristics of atmospheric particles, trace gases and meteorology in a relatively clean Southern African Savannah environment (2008)

L. Laakso, H. Laakso, P. P. Aalto, P. Keronen, T. Petäjä, T. Nieminen, ...

We have analyzed one year (July 2006–July 2007) of measurement data from a relatively clean background site located in dry savannah in South Africa. The annual-median trace gas concentrations were...

Laboratory studies of H2SO4/H2O binary homogeneous nucleation from the SO2+OH reaction: evaluation of the experimental setup and preliminary results (2008)

L. H. Young, D. R. Benson, F. R. Kameel, J. R. Pierce, H. Junninen, M. Kulmala, ...

Binary homogeneous nucleation (BHN) of sulphuric acid and water (H2SO4/H2O) is one of the most important atmospheric nucleation processes, but laboratory observations of this nucleation process are...

Mode resolved density of atmospheric aerosol particles (2008)

J. Kannosto, A. Virtanen, M. Lemmetty, J. M. Mäkelä, J. Keskinen, H. Junninen, ...

In this study, we investigate the mode resolved density of ultrafine atmospheric particles measured in boreal forest environment. The method used here enables us to find the distinct density...

Size distributions, sources and source areas of water-soluble organic carbon in urban background air (2008)

H. Timonen, S. Saarikoski, O. Tolonen-Kivimäki, M. Aurela, K. Saarnio, T. Petäjä, ...

This paper represents the results of one year long measurement period of the size distributions of water-soluble organic carbon (WSOC), inorganic ions and gravimetric mass of particulate matter....

SO<sub>2</sub> oxidation products other than H<sub>2</sub>SO<sub>4</sub> as a trigger of new particle formation. Part 1: Laboratory investigations (2008)

T. Berndt, F. Stratmann, S. Bräsel, J. Heintzenberg, A. Laaksonen, M. Kulmala

Mechanistic investigations of atmospheric H<sub>2</sub>SO<sub>4</sub> particle formation have been performed in a laboratory study taking either...

Technical Note: Quantitative long-term measurements of VOC concentrations by PTR-MS – measurement, calibration, and volume mixing ratio calculation methods (2008)

R. Taipale, T. M. Ruuskanen, J. Rinne, M. K. Kajos, H. Hakola, T. Pohja, ...

Proton transfer reaction mass spectrometry (PTR-MS) is a technique for online measurements of atmospheric concentrations, or volume mixing ratios, of volatile organic compounds (VOCs). This paper...

Measurements of the relation between aerosol properties and microphysics and chemistry of low level liquid water clouds in Northern Finland (2008)

H. Lihavainen, M. Komppula, J. Laakia, S. Saarikoski, ...

Physical and chemical properties of boundary layer clouds, together with relevant aerosol properties, were investigated during the first Pallas Cloud Experiment (First Pace) conducted in northern...

SO<sub>2</sub> oxidation products other than H<sub>2</sub>SO<sub>4</sub> as a trigger of new particle formation. Part 2: Comparison of ambient and laboratory measurements, and atmospheric implications (2008)

A. Laaksonen, M. Kulmala, T. Berndt, F. Stratmann, S. Mikkonen, A. Ruuskanen, ...

Atmospheric new particle formation is generally thought to occur due to homogeneous or ion-induced nucleation of sulphuric acid. We compare ambient nucleation rates with laboratory data from...

SO2 oxidation products other than H2SO4 as a trigger of new particle formation. Part 1: Laboratory investigations (2008)

T. Berndt, F. Stratmann, S. Bräsel, J. Heintzenberg, A. Laaksonen, M. Kulmala

Mechanistic investigations of atmospheric H2SO4 particle formation have been performed in a laboratory study taking either H2SO4 from a liquid reservoir or using the gas-phase reaction of OH radicals...

Technical Note: Quantitative long-term measurements of VOC concentrations by PTR-MS ─ measurement, calibration, and volume mixing ratio calculation methods (2008)

R. Taipale, T. M. Ruuskanen, J. Rinne, M. K. Kajos, H. Hakola, T. Pohja, ...

Proton transfer reaction mass spectrometry (PTR-MS) is a technique for online measurements of atmospheric concentrations, or volume mixing ratios, of volatile organic compounds (VOCs). This paper...

SO2 oxidation products other than H2SO4 as a trigger of new particle formation. Part 2: Comparison of ambient and laboratory measurements, and atmospheric implications (2008)

A. Laaksonen, M. Kulmala, T. Berndt, F. Stratmann, S. Mikkonen, A. Ruuskanen, ...

Atmospheric new particle formation is generally thought to occur due to homogeneous or ion-induced nucleation of sulphuric acid. We compare ambient nucleation rates with laboratory data from...

Airborne measurements of nucleation mode particles II: boreal forest nucleation events (2008)

C. D. O'Dowd, Y. J. Yoon, W. Junkerman, P. Aalto, M. Kulmala, H. Lihavainen, ...

Airborne measurements of nucleation mode aerosol concentrations during nucleation events over the boreal forest of southern Finland are reported. Three case studies are analysis in an attempt to...

Applicability of condensation particle counters to measure atmospheric clusters (2008)

M. Sipilä, K. Lehtipalo, M. Kulmala, T. Petäjä, H. Junninen, P. P. Aalto, ...

The ambient and laboratory molecular and ion clusters were investigated. Here we present data on the ambient concentrations of both charged and uncharged molecular clusters as well as the performance...

The role of ammonia in sulfuric acid ion induced nucleation (2008)

I. K. Ortega, T. Kurtén, H. Vehkamäki, M. Kulmala

We have developed a new multi-step strategy for quantum chemical calculations on atmospherically relevant cluster structures that makes calculation for large clusters affordable with a good...

Basic characteristics of atmospheric particles, trace gases and meteorology in a relatively clean Southern African Savannah environment (2008)

L. Laakso, H. Laakso, P. P. Aalto, P. Keronen, T. Petäjä, T. Nieminen, ...

We have analyzed one year (July 2006–July 2007) of measurement data from a relatively clean background site located in dry savannah in South Africa. The annual-median trace gas concentrations...

Mode resolved density of atmospheric aerosol particles (2008)

J. Kannosto, M. Lemmetty, A. Virtanen, J. M. Mäkelä, J. Keskinen, H. Junninen, ...

In this study, we investigate the mode resolved density of ultrafine atmospheric particles measured in boreal forest environment. The method used here enables us to find the distinct density...

Amines are likely to enhance neutral and ion-induced sulfuric acid-water nucleation in the atmosphere more effectively than ammonia (2008)

T. Kurtén, V. Loukonen, H. Vehkamäki, M. Kulmala

We have studied the structure and formation thermodynamics of dimer clusters containing H<sub>2</sub>SO<sub>4</sub> or...

Size distributions, sources and source areas of water-soluble organic carbon in urban background air (2008)

H. Timonen, S. Saarikoski, O. Tolonen-Kivimäki, M. Aurela, K. Saarnio, T. Petäjä, ...

This paper represents the results of one year long measurement period of the size distributions of water-soluble organic carbon (WSOC), inorganic ions and gravimetric mass of particulate matter....

Technical Note: Quantitative long-term measurements of VOC concentrations by PTR-MS – measurement, calibration, and volume mixing ratio calculation methods (2008)

R. Taipale, T. M. Ruuskanen, J. Rinne, M. K. Kajos, H. Hakola, T. Pohja, ...

Proton transfer reaction mass spectrometry (PTR-MS) is a technique for online measurements of atmospheric concentrations, or volume mixing ratios, of volatile organic compounds (VOCs). The aim of...

SO<sub>2</sub> oxidation products other than H<sub>2</sub>SO<sub>4</sub> as a trigger of new particle formation – Part 2: Comparison of ambient and laboratory measurements, and atmospheric implications (2008)

A. Laaksonen, M. Kulmala, T. Berndt, F. Stratmann, S. Mikkonen, A. Ruuskanen, ...

Atmospheric new particle formation is generally thought to occur due to homogeneous or ion-induced nucleation of sulphuric acid. We compare ambient nucleation rates with laboratory data from...

SO<sub>2</sub> oxidation products other than H<sub>2</sub>SO<sub>4</sub> as a trigger of new particle formation – Part 1: Laboratory investigations (2008)

T. Berndt, F. Stratmann, S. Bräsel, J. Heintzenberg, A. Laaksonen, M. Kulmala

Mechanistic investigations of atmospheric H<sub>2</sub>SO<sub>4</sub> particle formation have been performed in a laboratory study taking either...

Sensitivity of aerosol concentrations and cloud properties to nucleation and secondary organic distribution in ECHAM5-HAM global circulation model (2008)

R. Makkonen, A. Asmi, H. Korhonen, H. Kokkola, S. Järvenoja, P. Räisänen, ...

The global aerosol-climate model ECHAM5-HAM was modified to improve the representation of new particle formation in the boundary layer. Activation-type nucleation mechanism was introduced to produce...

Aerosol dynamics simulations on the connection of sulphuric acid and new particle formation (2008)

H. Vuollekoski, J. Leppä, I. Riipinen, H. Korhonen, ...

We have performed a series of simulations with an aerosol dynamics box model to study the connection between new particle formation and sulphuric acid concentration. For nucleation either activation...

Classifying previously undefined days from eleven years of aerosol-particle-size distribution data from the SMEAR II station, Hyytiälä, Finland (2008)

S. Buenrostro Mazon, I. Riipinen, D. M. Schultz, M. Valtanen, M. Dal Maso, L. Sogacheva, ...

Studies of secondary aerosol-particle formation depend on identifying days in which new particle formation occurs and, by comparing them to days with no signs of particle formation, identifying the...

Measurements of the relation between aerosol properties and microphysics and chemistry of low clouds in northern Finland (2008)

H. Lihavainen, M. Komppula, J. Laakia, S. Saarikoski, ...

Physical and chemical properties of boundary layer clouds, together with relevant aerosol properties, were investigated during the first Pallas Cloud Experiment (First PaCE) conducted in northern...

Applying the CPCB setup to study the hygroscopicity and composition of freshly-formed 2–9 nm particles in boreal forest (2008)

I. Riipinen, H. E. Manninen, T. Yli-Juuti, M. Boy, M. Sipilä, M. Ehn, ...

Measurements on the composition of nanometer-sized atmospheric particles are the key to understand which vapors participate in the secondary aerosol formation processes. Knowledge on these processes...

Negatively charged nanoparticles produced by splashing of water (2008)

H. Tammet, U. Hõrrak, M. Kulmala

The production of splashing-generated balloelectric intermediate ions was studied by means of mobility spectrometry in the atmosphere during the rain and in a laboratory experiment simulating the...

Results of the first air ion spectrometer calibration and intercomparison workshop (2008)

E. Asmi, M. Sipilä, H. E. Manninen, J. Vanhanen, K. Lehtipalo, S. Gagné, ...

The air ion spectrometer (AIS) measures mobility and size distributions of atmospheric ions. The neutral air ion spectrometer (NAIS) can additionally measure neutral particles. The number of the...

Homogeneous vs. heterogeneous nucleation in water-dicarboxylic acid systems (2008)

A. I. Hienola, H. Vehkamäki, I. Riipinen, M. Kulmala

Binary heterogeneous nucleation of water-succinic/glutaric/malonic/adipic acid on nanometer-sized particles is investigated within the frame of classical heterogeneous nucleation theory. Homogeneous...

Coastal and open ocean aerosol characteristics: investigating the representativeness of coastal aerosol sampling over the North-East Atlantic Ocean (2008)

M. Rinaldi, M. C. Facchini, S. Decesari, C. Carbone, E. Finessi, M. Mircea, ...

In order to achieve a better understanding of the modifications of the physical and chemical properties of marine aerosol particles during transport from offshore to the coast, size distribution and...

Introduction: European Integrated project on Aerosol Cloud Climate and Air Quality interactions (EUCAARI) – integrating aerosol research from nano to global scales (2008)

M. Kulmala, A. Asmi, H. K. Lappalainen, K. S. Carslaw, U. Pöschl, U. Baltensperger, ...

The European Aerosol Cloud Climate and Air Quality Interactions project EUCAARI is an EU Research Framework 6 integrated project focusing on understanding the interactions of climate and air...

Sulfuric acid and OH concentrations in a boreal forest site (2008)

T. Petäjä, R. L. Mauldin, III, E. Kosciuch, J. McGrath, T. Nieminen, M. Boy, ...

As demonstrated in a number of investigations, gaseous sulfuric acid plays a central role in atmospheric aerosol formation. Using chemical ionization mass spectrometer the gas-phase sulfuric acid and...

Analysis of atmospheric neutral and charged molecular clusters in boreal forest using pulse-height CPC (2008)

K. Lehtipalo, M. Sipilä, I. Riipinen, T. Nieminen, M. Kulmala

We measured the size distribution of atmospheric neutral and charged clusters and particles down to mobility diameter around 1.5 nm by applying pulse-height CPC technique at SMEAR II station in...

Technical Note: Quantitative long-term measurements of VOC concentrations by PTR-MS – measurement, calibration, and volume mixing ratio calculation methods (2008)

R. Taipale, T. M. Ruuskanen, J. Rinne, M. K. Kajos, H. Hakola, T. Pohja, ...

Proton transfer reaction mass spectrometry (PTR-MS) is a technique for online measurements of atmospheric concentrations, or volume mixing ratios, of volatile organic compounds (VOCs). The aim of...

SO2 oxidation products other than H2SO4 as a trigger of new particle formation – Part 2: Comparison of ambient and laboratory measurements, and atmospheric implications (2008)

A. Laaksonen, M. Kulmala, T. Berndt, F. Stratmann, S. Mikkonen, A. Ruuskanen, ...

Atmospheric new particle formation is generally thought to occur due to homogeneous or ion-induced nucleation of sulphuric acid. We compare ambient nucleation rates with laboratory data from...

SO2 oxidation products other than H2SO4 as a trigger of new particle formation – Part 1: Laboratory investigations (2008)

T. Berndt, F. Stratmann, S. Bräsel, J. Heintzenberg, A. Laaksonen, M. Kulmala

Mechanistic investigations of atmospheric H2SO4 particle formation have been performed in a laboratory study taking either H2SO4 from a liquid reservoir or using the gas-phase reaction of OH radicals...

Evaluation and modeling of the size fractionated aerosol particle number concentration measurements nearby a major road in Helsinki – Part II: Aerosol measurements within the SAPPHIRE project (2007)

Hussein, T., Kukkonen, J., Korhonen, H., Pohjola, M., Pirjola, L., Wraith, Darren, ...

This study presents an evaluation and modeling exercise of the size fractionated aerosol particle number concentrations measured nearby a major road in Helsinki during 23 August–19 September 2003...

Hygroscopic properties of ultrafine aerosol particles in the boreal forest: diurnal variation, solubility and the influence of sulfuric acid (2007)

Ehn, Mikael, Petäjä, T., Aufmhoff, Heinfried, Aalto, Pasi, Hämeri, K., Arnold, Frank, ...

The hygroscopic growth of aerosol particles present in a boreal forest was measured at a relative humidity of 88%. Simultaneously the gas phase concentration of sulfuric acid, a very hygroscopic...

Connections between atmospheric sulphuric acid and new particle formation during QUEST III–IV campaigns in Heidelberg and Hyytiälä (2007)

Riipinen, I., Kulmala, M., Arnold, Frank, Dal Maso, M., Birmili, W., ...

This study investigates the connections between atmospheric sulphuric acid and new particle formation during QUEST III and BACCI/QUEST IV campaigns. The campaigns have been conducted in Heidelberg...

Sub-micron atmospheric aerosols in the surroundings of Marseille and Athens: physical characterization and new particle formation (2007)

T. Petäjä, M. Dal Maso, H. Junninen, I. K. Koponen, T. Hussein, ...

The properties of atmospheric aerosol particles in Marseille and Athens were investigated. The studies were performed in Marseille, France, during July 2002 and in Athens, Greece, during June 2003....

Estimating the NH3:H2SO4 ratio of nucleating clusters in atmospheric conditions using quantum chemical methods (2007)

T. Kurtén, L. Torpo, M. R. Sundberg, H. Vehkamäki, M. Kulmala

We study the ammonia addition reactions of H2SO4·NH3 molecular clusters containing up to four ammonia and two sulfuric acid molecules using the ab initio method RI-MP2 (Resolution of Identity...

SALSA ? a Sectional Aerosol module for Large Scale Applications (2007)

Kokkola, H., Korhonen, H., Lehtinen, K. E. J., Makkonen, R., Asmi, A., Järvenoja, S., ...

The sectional aerosol module SALSA is introduced. The model has been designed to be implemented in large scale climate models, which require both accuracy and computational efficiency. We have used...

New particle formation in the front range of the Colorado Rocky Mountains (2007)

Boy, M., Karl, T., Turnipseed, A., Mauldin, R. L., Kosciuch, E., Greenberg, J., ...

New particle formation is of interest because of its influence on the properties of aerosol population, and due to the possible contribution of newly formed particles to cloud condensation nuclei....

Black carbon concentration trends in Helsinki during 1996?2005 (2007)

Järvi, L., Junninen, H., Karppinen, A., Hillamo, R., Virkkula, A., Mäkelä, T., ...

The black carbon (BC) concentration trends were studied during ten years in Helsinki, Finland. Measurements were made in three campaigns between 1996 and 2005 at an urban area locating two kilometres...

Formation and characteristics of ions and charged aerosol particles in a native Australian Eucalypt forest (2007)

Suni, T., Kulmala, M., Hirsikko, A., Bergman, T., Laakso, L., Aalto, P. P., ...

Biogenic aerosol formation is likely to contribute significantly to the global aerosol load. In recent years, new-particle formation (NPF) has been observed in various ecosystems around the world but...

Characterization of positive air ions in boreal forest air at the Hyytiälä SMEAR station (2007)

Hõrrak, U., Aalto, P. P., Salm, J., Komsaare, K., Tammet, H., Mäkelä, J. M., ...

The behavior of the concentration of positive small (or cluster) air ions and naturally charged nanometer aerosol particles (aerosol ions) has been studied on the basis of measurements carried out in...

The role of VOC oxidation products in continental new particle formation (2007)

Laaksonen, A., Kulmala, M., O'Dowd, C. D., Joutsensaari, J., Vaattovaara, P., Mikkonen, S., ...

Aerosol physical and chemical properties and trace gas concentrations were measured during the QUEST field campaign in March?April, 2003, in Hyytiälä, Finland. Our aim was to understand the role of...

Contribution of mixing in the ABL to new particle formation based on some observations (2007)

Lauros, J., Nilsson, E. D., Dal Maso, M., Kulmala, M.

The connection between new particle formation and micro- and mesoscale meteorology was studied based on measurements at SMEAR II station in Southern Finland. We analyzed turbulent conditions...

Chemical composition of atmospheric aerosols between Moscow and Vladivostok (2007)

Kuokka, S., Teinilä, K., Saarnio, K., Aurela, M., Sillanpää, M., Hillamo, R., ...

The TROICA-9 expedition (Trans-Siberian Observations Into the Chemistry of the Atmosphere) was carried out at the Trans-Siberian railway between Moscow and Vladivostok in October 2005. Measurements...

Evaluation and modeling of the size fractionated aerosol number concentration measurements near a major road in Helsinki (2007)

Hussein, T., Kukkonen, J., Korhonen, H., Pohjola, M., Pirjola, L., Wraith, D., ...

This study presents an evaluation and modeling of the size fractionated aerosol number concentrations that were measured near a major road of Itäväylä in Helsinki, during 23 August ? 19 September...

Understanding the formation of biogenic secondary organic aerosol from ?-pinene in smog chamber studies: role of organic peroxy radicals (2007)

Bonn, B., Korhonen, H., Petäjä, T., Boy, M., Kulmala, M.

This study focusses on the description of the nucleation process observed during the ozone reaction of the biogenic monoterpene ?-pinene in smog chambers. Therefore, a detailed aerosol dynamics model...

Estimating the NH3:H2SO4ratio of nucleating clusters in atmospheric conditions using quantum chemical methods (2007)

Kurtén, T., Torpo, L., Sundberg, M. R., Vehkamäki, H., Kulmala, M.

We study the ammonia addition reactions of H2SO4·NH3 molecular clusters containing up to four ammonia and two sulfuric acid molecules using the ab initio method RI-MP2 (Resolution of Identity 2nd...

Hydrocarbon fluxes above a Scots pine forest canopy: Measurements and modeling (2007)

Rinne, J., Taipale, R., Markkanen, T., Ruuskanen, T. M., Hellén, H., Kajos, M. K., ...

We measured the fluxes of several hydrocarbon species above a Scots pine (Pinus sylvestris) stand using disjunct eddy covariance technique with proton transfer reaction ? mass spectrometry. The...

A chemistry-transport model simulation of middle atmospheric ozone from 1980 to 2019 using coupled chemistry GCM winds and temperatures (2007)

Damski, J., Thölix, L., Backman, L., Kaurola, J., Taalas, P., Austin, J., ...

A Global 40-year simulation from 1980 to 2019 was performed with the FinROSE chemistry-transport model based on the use of coupled chemistry GCM-data. The main focus of our analysis is on...

Concentrations and fluxes of aerosol particles during the LAPBIAT measurement campaign in Värriö field station (2007)

Ruuskanen, T. M., Kaasik, M., Aalto, P. P., Hõrrak, U., Vana, M., Mårtensson, M., ...

The LAPBIAT measurement campaign took place in the SMEAR I measurement station located in Eastern Lapland in the spring of 2003 between 26 April and 11 May. In this paper we describe the measurement...

Using a moving measurement platform for determining the chemical composition of atmospheric aerosols between Moscow and Vladivostok (2007)

Kuokka, S., Teinilä, K., Saarnio, K., Aurela, M., Sillanpää, M., Hillamo, R., ...

The TROICA-9 expedition (Trans-Siberian Observations Into the Chemistry of the Atmosphere) was carried out at the Trans-Siberian railway between Moscow and Vladivostok in October 2005. Measurements...

Contribution of mixing in the ABL to new particle formation based on observations (2007)

Lauros, J., Nilsson, E. D., Dal Maso, M., Kulmala, M.

The connection between new particle formation and micro- and mesoscale meteorology was studied based on measurements at SMEAR II station in Southern Finland. We analyzed turbulent conditions...

Evaluation and modeling of the size fractionated aerosol particle number concentration measurements nearby a major road in Helsinki ? Part II: Aerosol measurements within the SAPPHIRE project (2007)

Hussein, T., Kukkonen, J., Korhonen, H., Pohjola, M., Pirjola, L., Wraith, D., ...

This study presents an evaluation and modeling exercise of the size fractionated aerosol particle number concentrations measured nearby a major road in Helsinki during 23 August?19 September 2003 and...

Concentrations and fluxes of aerosol particles during the LAPBIAT measurement campaign at Värriö field station (2007)

Ruuskanen, T. M., Kaasik, M., Aalto, P. P., Hõrrak, U., Vana, M., Mårtensson, M., ...

The LAPBIAT measurement campaign took place in the Värriö SMEAR I measurement station located in Eastern Lapland in the spring of 2003 between 26 April and 11 May. In this paper we describe the...

Hydrocarbon fluxes above a Scots pine forest canopy: measurements and modeling (2007)

Rinne, J., Taipale, R., Markkanen, T., Ruuskanen, T. M., Hellén, H., Kajos, M. K., ...

We measured the fluxes of several hydrocarbon species above a Scots pine (Pinus sylvestris) stand using disjunct eddy covariance technique with proton transfer reaction ? mass spectrometry. The...

Ambient sesquiterpene concentration and its link to air ion measurements (2007)

Bonn, B., Hirsikko, A., Hakola, H., Kurtén, T., Laakso, L., Boy, M., ...

Ambient air ion size distributions have been measured continuously at the Finnish boreal forest site in Hyytiälä since spring 2003. In general, these measurements show a maximum of air ions below...

Estimating the NH3:H2SO4 ratio of nucleating clusters in atmospheric conditions using quantum chemical methods (2007)

Kurtén, T., Torpo, L., Sundberg, M. R., Vehkamäki, H., Kulmala, M.

We study the ammonia addition reactions of H2SO4·NH3 molecular clusters containing up to four ammonia and two sulfuric acid molecules using the ab initio method RI-MP2 (Resolution of Identity 2nd...

Waterfalls as sources of small charged aerosol particles (2007)

Laakso, L., Hirsikko, A., Grönholm, T., Kulmala, M., Luts, A.

In this study, we measured the mobility distributions of cluster and intermediate ions with an ion spectrometer near a waterfall. We observed that the concentration of negative 1.5?10 nm ions was...

A chemistry-transport model simulation of middle atmospheric ozone from 1980 to 2019 using coupled chemistry GCM winds and temperatures (2007)

Damski, J., Thölix, L., Backman, L., Kaurola, J., Taalas, P., Austin, J., ...

A global 40-year simulation from 1980 to 2019 was performed with the FinROSE chemistry-transport model based on the use of coupled chemistry GCM-data. The main focus of our analysis is on...

Connections between atmospheric sulphuric acid and new particle formation during QUEST III?IV campaigns in Heidelberg and Hyytiälä (2007)

Riipinen, I., Kulmala, M., Arnold, F., Dal Maso, M., Birmili, W., ...

This study investigates the connections between atmospheric sulphuric acid and new particle formation during QUEST III and BACCI/QUEST IV campaigns. The campaigns have been conducted in Heidelberg...

Boundary layer concentrations and landscape scale emissions of volatile organic compounds in early spring (2007)

Haapanala, S., Rinne, J., Hakola, H., Hellén, H., Laakso, L., Lihavainen, H., ...

Boundary layer concentrations of several volatile organic compounds (VOC) were measured during two campaigns in springs of 2003 and 2006. The measurements were conducted over boreal landscapes near...

Airborne measurements of nucleation mode particles I: coastal nucleation and growth rates (2007)

O'Dowd, C. D., Yoon, Y. J., Junkerman, W., Aalto, P., Kulmala, M., Lihavainen, H., ...

A light aircraft was equipped with a bank of Condensation Particle Counters (CPCs) (50% cut from 3?5.4?9.6 nm) and a nano-Scanning Mobility Particle Sizer (nSMPS) and deployed along the west coast of...

Detecting charging state of ultra-fine particles: instrumental development and ambient measurements (2007)

Laakso, L., Gagné, S., Petäjä, T., Hirsikko, A., Aalto, P. P., Kulmala, M., ...

The importance of ion-induced nucleation in the lower atmosphere has been discussed for a long time. In this article we describe a new instrumental setup ? Ion-DMPS ? which can be used to detect...

Relation of air mass history to nucleation events in Po Valley, Italy, using back trajectories analysis (2007)

Sogacheva, L., Hamed, A., Facchini, M. C., Kulmala, M., Laaksonen, A.

In this paper, we study the transport of air masses to San Pietro Capofiume (SPC) in Po Valley, Italy, by means of back trajectories analysis. Our main aim is to investigate whether air masses...

Non-volatile residuals of newly formed atmospheric particles in the boreal forest (2007)

Ehn, M., Petäjä, T., Birmili, W., Junninen, H., Aalto, P., Kulmala, M.

The volatility of sub-micrometer atmospheric aerosol particles was studied in a rural background environment in Finland using a combination of a heating tube and a scanning mobility particle sizer....

Nucleation and growth of new particles in Po Valley, Italy (2007)

Hamed, A., Joutsensaari, J., Mikkonen, S., Sogacheva, L., Dal Maso, M., Kulmala, M., ...

Aerosol number distribution measurements are reported at San Pietro Capofiume (SPC) station (44°39' N, 11°37' E) for the time period 2002?2005. The station is located in Po Valley, the largest...

Technical Note: The heterogeneous Zeldovich factor (2007)

Vehkamäki, H., Määttänen, A., Lauri, A., Napari, I., Kulmala, M.

In this technical note we present the exact form of the Zeldovich factor for heterogeneous nucleation on spherical pre-existing particles. We study the error caused by planar pre-existing surface...

Hygroscopic properties of ultrafine aerosol particles in the boreal forest: diurnal variation, solubility and the influence of sulfuric acid (2007)

Ehn, M., Petäjä, T., Aufmhoff, H., Aalto, P., Hämeri, K., Arnold, F., ...

The hygroscopic growth of aerosol particles present in a boreal forest was measured at a relative humidity of 88%. Simultaneously the gas phase concentration of sulfuric acid, a very hygroscopic...

Identification and classification of the formation of intermediate ions measured in boreal forest (2007)

Hirsikko, A., Bergman, T., Laakso, L., Dal Maso, M., Riipinen, I., Hõrrak, U., ...

We have measured the size distributions of air ions (0.42?7.5 nm in diameter) with the Balanced Scanning Mobility Analyzer in boreal forest, in Southern Finland since spring 2003. The size range...

SALSA ? a Sectional Aerosol module for Large Scale Applications (2007)

Kokkola, H., Korhonen, H., Lehtinen, K. E. J., Makkonen, R., Asmi, A., Järvenoja, S., ...

The sectional aerosol module SALSA is introduced. The model has been designed to be implemented in large scale climate models, which require both accuracy and computational efficiency. We have used...

New particle formation in the front range of the Colorado Rocky Mountains (2007)

Boy, M., Karl, T., Turnipseed, A., Mauldin, R. L., Kosciuch, E., Greenberg, J., ...

New particle formation is of interest because of its influence on the properties of aerosol population, and due to the possible contribution of newly formed particles to cloud condensation nuclei....

Black carbon concentration trends in Helsinki during 1996?2005 (2007)

Järvi, L., Junninen, H., Karppinen, A., Hillamo, R., Virkkula, A., Mäkelä, T., ...

The black carbon (BC) concentration trends were studied during ten years in Helsinki, Finland. Measurements were made in three campaigns between 1996 and 2005 at an urban area locating two kilometres...

Formation and characteristics of ions and charged aerosol particles in a native Australian Eucalypt forest (2007)

Suni, T., Kulmala, M., Hirsikko, A., Bergman, T., Laakso, L., Aalto, P. P., ...

Biogenic aerosol formation is likely to contribute significantly to the global aerosol load. In recent years, new-particle formation (NPF) has been observed in various ecosystems around the world but...

Characterization of positive air ions in boreal forest air at the Hyytiälä SMEAR station (2007)

Hõrrak, U., Aalto, P. P., Salm, J., Komsaare, K., Tammet, H., Mäkelä, J. M., ...

The behavior of the concentration of positive small (or cluster) air ions and naturally charged nanometer aerosol particles (aerosol ions) has been studied on the basis of measurements carried out in...

The role of VOC oxidation products in continental new particle formation (2007)

Laaksonen, A., Kulmala, M., O'Dowd, C. D., Joutsensaari, J., Vaattovaara, P., Mikkonen, S., ...

Aerosol physical and chemical properties and trace gas concentrations were measured during the QUEST field campaign in March?April, 2003, in Hyytiälä, Finland. Our aim was to understand the role of...

Contribution of mixing in the ABL to new particle formation based on some observations (2007)

Lauros, J., Nilsson, E. D., Dal Maso, M., Kulmala, M.

The connection between new particle formation and micro- and mesoscale meteorology was studied based on measurements at SMEAR II station in Southern Finland. We analyzed turbulent conditions...

Chemical composition of atmospheric aerosols between Moscow and Vladivostok (2007)

Kuokka, S., Teinilä, K., Saarnio, K., Aurela, M., Sillanpää, M., Hillamo, R., ...

The TROICA-9 expedition (Trans-Siberian Observations Into the Chemistry of the Atmosphere) was carried out at the Trans-Siberian railway between Moscow and Vladivostok in October 2005. Measurements...

Evaluation and modeling of the size fractionated aerosol number concentration measurements near a major road in Helsinki (2007)

Hussein, T., Kukkonen, J., Korhonen, H., Pohjola, M., Pirjola, L., Wraith, D., ...

This study presents an evaluation and modeling of the size fractionated aerosol number concentrations that were measured near a major road of Itäväylä in Helsinki, during 23 August ? 19 September...

Understanding the formation of biogenic secondary organic aerosol from ?-pinene in smog chamber studies: role of organic peroxy radicals (2007)

Bonn, B., Korhonen, H., Petäjä, T., Boy, M., Kulmala, M.

This study focusses on the description of the nucleation process observed during the ozone reaction of the biogenic monoterpene ?-pinene in smog chambers. Therefore, a detailed aerosol dynamics model...

Estimating the NH3:H2SO4ratio of nucleating clusters in atmospheric conditions using quantum chemical methods (2007)

Kurtén, T., Torpo, L., Sundberg, M. R., Vehkamäki, H., Kulmala, M.

We study the ammonia addition reactions of H2SO4·NH3 molecular clusters containing up to four ammonia and two sulfuric acid molecules using the ab initio method RI-MP2 (Resolution of Identity 2nd...

Hydrocarbon fluxes above a Scots pine forest canopy: Measurements and modeling (2007)

Rinne, J., Taipale, R., Markkanen, T., Ruuskanen, T. M., Hellén, H., Kajos, M. K., ...

We measured the fluxes of several hydrocarbon species above a Scots pine (Pinus sylvestris) stand using disjunct eddy covariance technique with proton transfer reaction ? mass spectrometry. The...

A chemistry-transport model simulation of middle atmospheric ozone from 1980 to 2019 using coupled chemistry GCM winds and temperatures (2007)

Damski, J., Thölix, L., Backman, L., Kaurola, J., Taalas, P., Austin, J., ...

A Global 40-year simulation from 1980 to 2019 was performed with the FinROSE chemistry-transport model based on the use of coupled chemistry GCM-data. The main focus of our analysis is on...

Concentrations and fluxes of aerosol particles during the LAPBIAT measurement campaign in Värriö field station (2007)

Ruuskanen, T. M., Kaasik, M., Aalto, P. P., Hõrrak, U., Vana, M., Mårtensson, M., ...

The LAPBIAT measurement campaign took place in the SMEAR I measurement station located in Eastern Lapland in the spring of 2003 between 26 April and 11 May. In this paper we describe the measurement...

Using a moving measurement platform for determining the chemical composition of atmospheric aerosols between Moscow and Vladivostok (2007)

Kuokka, S., Teinilä, K., Saarnio, K., Aurela, M., Sillanpää, M., Hillamo, R., ...

The TROICA-9 expedition (Trans-Siberian Observations Into the Chemistry of the Atmosphere) was carried out at the Trans-Siberian railway between Moscow and Vladivostok in October 2005. Measurements...

Contribution of mixing in the ABL to new particle formation based on observations (2007)

Lauros, J., Nilsson, E. D., Dal Maso, M., Kulmala, M.

The connection between new particle formation and micro- and mesoscale meteorology was studied based on measurements at SMEAR II station in Southern Finland. We analyzed turbulent conditions...

Evaluation and modeling of the size fractionated aerosol particle number concentration measurements nearby a major road in Helsinki ? Part II: Aerosol measurements within the SAPPHIRE project (2007)

Hussein, T., Kukkonen, J., Korhonen, H., Pohjola, M., Pirjola, L., Wraith, D., ...

This study presents an evaluation and modeling exercise of the size fractionated aerosol particle number concentrations measured nearby a major road in Helsinki during 23 August?19 September 2003 and...

Concentrations and fluxes of aerosol particles during the LAPBIAT measurement campaign at Värriö field station (2007)

Ruuskanen, T. M., Kaasik, M., Aalto, P. P., Hõrrak, U., Vana, M., Mårtensson, M., ...

The LAPBIAT measurement campaign took place in the Värriö SMEAR I measurement station located in Eastern Lapland in the spring of 2003 between 26 April and 11 May. In this paper we describe the...

Hydrocarbon fluxes above a Scots pine forest canopy: measurements and modeling (2007)

Rinne, J., Taipale, R., Markkanen, T., Ruuskanen, T. M., Hellén, H., Kajos, M. K., ...

We measured the fluxes of several hydrocarbon species above a Scots pine (Pinus sylvestris) stand using disjunct eddy covariance technique with proton transfer reaction ? mass spectrometry. The...

Ambient sesquiterpene concentration and its link to air ion measurements (2007)

Bonn, B., Hirsikko, A., Hakola, H., Kurtén, T., Laakso, L., Boy, M., ...

Ambient air ion size distributions have been measured continuously at the Finnish boreal forest site in Hyytiälä since spring 2003. In general, these measurements show a maximum of air ions below...

Estimating the NH3:H2SO4 ratio of nucleating clusters in atmospheric conditions using quantum chemical methods (2007)

Kurtén, T., Torpo, L., Sundberg, M. R., Vehkamäki, H., Kulmala, M.

We study the ammonia addition reactions of H2SO4·NH3 molecular clusters containing up to four ammonia and two sulfuric acid molecules using the ab initio method RI-MP2 (Resolution of Identity 2nd...

Waterfalls as sources of small charged aerosol particles (2007)

Laakso, L., Hirsikko, A., Grönholm, T., Kulmala, M., Luts, A.

In this study, we measured the mobility distributions of cluster and intermediate ions with an ion spectrometer near a waterfall. We observed that the concentration of negative 1.5?10 nm ions was...

A chemistry-transport model simulation of middle atmospheric ozone from 1980 to 2019 using coupled chemistry GCM winds and temperatures (2007)

Damski, J., Thölix, L., Backman, L., Kaurola, J., Taalas, P., Austin, J., ...

A global 40-year simulation from 1980 to 2019 was performed with the FinROSE chemistry-transport model based on the use of coupled chemistry GCM-data. The main focus of our analysis is on...

Connections between atmospheric sulphuric acid and new particle formation during QUEST III?IV campaigns in Heidelberg and Hyytiälä (2007)

Riipinen, I., Kulmala, M., Arnold, F., Dal Maso, M., Birmili, W., ...

This study investigates the connections between atmospheric sulphuric acid and new particle formation during QUEST III and BACCI/QUEST IV campaigns. The campaigns have been conducted in Heidelberg...

Boundary layer concentrations and landscape scale emissions of volatile organic compounds in early spring (2007)

Haapanala, S., Rinne, J., Hakola, H., Hellén, H., Laakso, L., Lihavainen, H., ...

Boundary layer concentrations of several volatile organic compounds (VOC) were measured during two campaigns in springs of 2003 and 2006. The measurements were conducted over boreal landscapes near...

Airborne measurements of nucleation mode particles I: coastal nucleation and growth rates (2007)

O'Dowd, C. D., Yoon, Y. J., Junkerman, W., Aalto, P., Kulmala, M., Lihavainen, H., ...

A light aircraft was equipped with a bank of Condensation Particle Counters (CPCs) (50% cut from 3?5.4?9.6 nm) and a nano-Scanning Mobility Particle Sizer (nSMPS) and deployed along the west coast of...

Detecting charging state of ultra-fine particles: instrumental development and ambient measurements (2007)

Laakso, L., Gagné, S., Petäjä, T., Hirsikko, A., Aalto, P. P., Kulmala, M., ...

The importance of ion-induced nucleation in the lower atmosphere has been discussed for a long time. In this article we describe a new instrumental setup ? Ion-DMPS ? which can be used to detect...

Relation of air mass history to nucleation events in Po Valley, Italy, using back trajectories analysis (2007)

Sogacheva, L., Hamed, A., Facchini, M. C., Kulmala, M., Laaksonen, A.

In this paper, we study the transport of air masses to San Pietro Capofiume (SPC) in Po Valley, Italy, by means of back trajectories analysis. Our main aim is to investigate whether air masses...

Non-volatile residuals of newly formed atmospheric particles in the boreal forest (2007)

Ehn, M., Petäjä, T., Birmili, W., Junninen, H., Aalto, P., Kulmala, M.

The volatility of sub-micrometer atmospheric aerosol particles was studied in a rural background environment in Finland using a combination of a heating tube and a scanning mobility particle sizer....

Nucleation and growth of new particles in Po Valley, Italy (2007)

Hamed, A., Joutsensaari, J., Mikkonen, S., Sogacheva, L., Dal Maso, M., Kulmala, M., ...

Aerosol number distribution measurements are reported at San Pietro Capofiume (SPC) station (44°39' N, 11°37' E) for the time period 2002?2005. The station is located in Po Valley, the largest...

Technical Note: The heterogeneous Zeldovich factor (2007)

Vehkamäki, H., Määttänen, A., Lauri, A., Napari, I., Kulmala, M.

In this technical note we present the exact form of the Zeldovich factor for heterogeneous nucleation on spherical pre-existing particles. We study the error caused by planar pre-existing surface...

Hygroscopic properties of ultrafine aerosol particles in the boreal forest: diurnal variation, solubility and the influence of sulfuric acid (2007)

Ehn, M., Petäjä, T., Aufmhoff, H., Aalto, P., Hämeri, K., Arnold, F., ...

The hygroscopic growth of aerosol particles present in a boreal forest was measured at a relative humidity of 88%. Simultaneously the gas phase concentration of sulfuric acid, a very hygroscopic...

Identification and classification of the formation of intermediate ions measured in boreal forest (2007)

Hirsikko, A., Bergman, T., Laakso, L., Dal Maso, M., Riipinen, I., Hõrrak, U., ...

We have measured the size distributions of air ions (0.42?7.5 nm in diameter) with the Balanced Scanning Mobility Analyzer in boreal forest, in Southern Finland since spring 2003. The size range...

Evaluation and modeling of the size fractionated aerosol particle number concentration measurements nearby a major road in Helsinki – Part II: Aerosol measurements within the SAPPHIRE project (2007)

Hussein, T., Kukkonen, J., Korhonen, H., Pohjola, M., Pirjola, L., Wraith, Darren, ...

This study presents an evaluation and modeling exercise of the size fractionated aerosol particle number concentrations measured nearby a major road in Helsinki during 23 August–19 September 2003...

Sub-micron atmospheric aerosols in the surroundings of Marseille and Athens: physical characterization and new particle formation (2007)

Petäjä, T., Dal Maso, M., Junninen, H., Koponen, I. K., Hussein, T., ...

The properties of atmospheric aerosol particles in Marseille and Athens were investigated. The studies were performed in Marseille, France, during July 2002 and in Athens, Greece, during June 2003....

Sub-micron atmospheric aerosols in the surroundings of Marseille and Athens: physical characterization and new particle formation (2007)

Petäjä, T., Dal Maso, M., Junninen, H., Koponen, I. K., Hussein, T., ...

The properties of atmospheric aerosol particles in Marseille and Athens were investigated. The studies were performed in Marseille, France, during July 2002 and in Athens, Greece, during June 2003....

Evaluation and modeling of the size fractionated aerosol particle number concentration measurements nearby a major road in Helsinki – Part II: Aerosol measurements within the SAPPHIRE project (2007)

Hussein, T., Kukkonen, J., Korhonen, H., Pohjola, M., Pirjola, L., Wraith, Darren, ...

This study presents an evaluation and modeling exercise of the size fractionated aerosol particle number concentrations measured nearby a major road in Helsinki during 23 August–19 September 2003...

Evaluation and modeling of the size fractionated aerosol particle number concentration measurements nearby a major road in Helsinki – Part II: Aerosol measurements within the SAPPHIRE project (2007)

Hussein, T., Kukkonen, J., Korhonen, H., Pohjola, M., Pirjola, L., Wraith, Darren, ...

This study presents an evaluation and modeling exercise of the size fractionated aerosol particle number concentrations measured nearby a major road in Helsinki during 23 August–19 September 2003...

Evaluation and modeling of the size fractionated aerosol particle number concentration measurements nearby a major road in Helsinki – Part II: Aerosol measurements within the SAPPHIRE project (2007)

Hussein, T., Kukkonen, J., Korhonen, H., Pohjola, M., Pirjola, L., Wraith, Darren, ...

This study presents an evaluation and modeling exercise of the size fractionated aerosol particle number concentrations measured nearby a major road in Helsinki during 23 August–19 September 2003...

Evaluation and modeling of the size fractionated aerosol particle number concentration measurements nearby a major road in Helsinki - Part II: Aerosol measurements within the SAPPHIRE project (2007)

Hussein, T., Kukkonen, J., Korhonen, H., Pohjola, M., Pirjola, L., Wraith, Darren, ...

This study presents an evaluation and modeling exercise of the size fractionated aerosol particle number concentrations measured nearby a major road in Helsinki during 23 August-19 September 2003 and...

Ambient sesquiterpene concentration and its link to air ion measurements (2007)

B. Bonn, A. Hirsikko, H. Hakola, T. Kurtén, L. Laakso, M. Boy, ...

Ambient air ion size distributions have been measured continuously at the Finnish boreal forest site in Hyytiälä since spring 2003. In general, these measurements show a maximum of air ions below...

Hydrocarbon fluxes above a Scots pine forest canopy: measurements and modeling (2007)

J. Rinne, R. Taipale, T. Markkanen, T. M. Ruuskanen, H. Hellén, M. K. Kajos, ...

We measured the fluxes of several hydrocarbon species above a Scots pine (<I>Pinus sylvestris</I>) stand using disjunct eddy covariance technique with proton transfer reaction –...

Concentrations and fluxes of aerosol particles during the LAPBIAT measurement campaign at Värriö field station (2007)

T. M. Ruuskanen, M. Kaasik, P. P. Aalto, U. Hõrrak, M. Vana, M. Mårtensson, ...

The LAPBIAT measurement campaign took place in the Värriö SMEAR I measurement station located in Eastern Lapland in the spring of 2003 between 26 April and 11 May. In this paper we describe the...

Evaluation and modeling of the size fractionated aerosol particle number concentration measurements nearby a major road in Helsinki ─ Part II: Aerosol measurements within the SAPPHIRE project (2007)

T. Hussein, J. Kukkonen, H. Korhonen, M. Pohjola, L. Pirjola, D. Wraith, ...

This study presents an evaluation and modeling exercise of the size fractionated aerosol particle number concentrations measured nearby a major road in Helsinki during 23 August–19 September...

Contribution of mixing in the ABL to new particle formation based on observations (2007)

J. Lauros, E. D. Nilsson, M. Dal Maso, M. Kulmala

The connection between new particle formation and micro- and mesoscale meteorology was studied based on measurements at SMEAR II station in Southern Finland. We analyzed turbulent conditions...

Using a moving measurement platform for determining the chemical composition of atmospheric aerosols between Moscow and Vladivostok (2007)

S. Kuokka, K. Teinilä, K. Saarnio, M. Aurela, M. Sillanpää, R. Hillamo, ...

The TROICA-9 expedition (Trans-Siberian Observations Into the Chemistry of the Atmosphere) was carried out at the Trans-Siberian railway between Moscow and Vladivostok in October 2005. Measurements...

Concentrations and fluxes of aerosol particles during the LAPBIAT measurement campaign in Värriö field station (2007)

T. M. Ruuskanen, M. Kaasik, P. P. Aalto, U. Hõrrak, M. Vana, M. Mårtensson, ...

The LAPBIAT measurement campaign took place in the SMEAR I measurement station located in Eastern Lapland in the spring of 2003 between 26 April and 11 May. In this paper we describe the measurement...

A chemistry-transport model simulation of middle atmospheric ozone from 1980 to 2019 using coupled chemistry GCM winds and temperatures (2007)

J. Damski, L. Thölix, L. Backman, J. Kaurola, P. Taalas, J. Austin, ...

A Global 40-year simulation from 1980 to 2019 was performed with the FinROSE chemistry-transport model based on the use of coupled chemistry GCM-data. The main focus of our analysis is on...

Hydrocarbon fluxes above a Scots pine forest canopy: Measurements and modeling (2007)

J. Rinne, R. Taipale, T. Markkanen, T. M. Ruuskanen, H. Hellén, M. K. Kajos, ...

We measured the fluxes of several hydrocarbon species above a Scots pine (<it>Pinus sylvestris</it>) stand using disjunct eddy covariance technique with proton transfer reaction –...

Estimating the NH3:H2SO4ratio of nucleating clusters in atmospheric conditions using quantum chemical methods (2007)

T. Kurtén, L. Torpo, M. R. Sundberg, H. Vehkamäki, M. Kulmala

We study the ammonia addition reactions of H2SO4·NH3 molecular clusters containing up to four ammonia and two sulfuric acid molecules using the ab initio method RI-MP2 (Resolution of Identity...

Understanding the formation of biogenic secondary organic aerosol from α-pinene in smog chamber studies: role of organic peroxy radicals (2007)

B. Bonn, H. Korhonen, T. Petäjä, M. Boy, M. Kulmala

This study focusses on the description of the nucleation process observed during the ozone reaction of the biogenic monoterpene α-pinene in smog chambers. Therefore, a detailed aerosol dynamics...

Evaluation and modeling of the size fractionated aerosol number concentration measurements near a major road in Helsinki (2007)

T. Hussein, J. Kukkonen, H. Korhonen, M. Pohjola, L. Pirjola, D. Wraith, ...

This study presents an evaluation and modeling of the size fractionated aerosol number concentrations that were measured near a major road of Itäväylä in Helsinki, during 23 August – 19...

Chemical composition of atmospheric aerosols between Moscow and Vladivostok (2007)

S. Kuokka, K. Teinilä, K. Saarnio, M. Aurela, M. Sillanpää, R. Hillamo, ...

The TROICA-9 expedition (Trans-Siberian Observations Into the Chemistry of the Atmosphere) was carried out at the Trans-Siberian railway between Moscow and Vladivostok in October 2005. Measurements...

Contribution of mixing in the ABL to new particle formation based on some observations (2007)

J. Lauros, E. D. Nilsson, M. Dal Maso, M. Kulmala

The connection between new particle formation and micro- and mesoscale meteorology was studied based on measurements at SMEAR II station in Southern Finland. We analyzed turbulent conditions...

The role of VOC oxidation products in continental new particle formation (2007)

A. Laaksonen, M. Kulmala, C. D. O'Dowd, J. Joutsensaari, P. Vaattovaara, S. Mikkonen, ...

Aerosol physical and chemical properties and trace gas concentrations were measured during the QUEST field campaign in March–April, 2003, in Hyytiälä, Finland. Our aim was to understand the...

Characterization of positive air ions in boreal forest air at the Hyytiälä SMEAR station (2007)

U. Hõrrak, P. P. Aalto, J. Salm, K. Komsaare, H. Tammet, J. M. Mäkelä, ...

The behavior of the concentration of positive small (or cluster) air ions and naturally charged nanometer aerosol particles (aerosol ions) has been studied on the basis of measurements carried out in...

Formation and characteristics of ions and charged aerosol particles in a native Australian Eucalypt forest (2007)

T. Suni, M. Kulmala, A. Hirsikko, T. Bergman, L. Laakso, P. P. Aalto, ...

Biogenic aerosol formation is likely to contribute significantly to the global aerosol load. In recent years, new-particle formation (NPF) has been observed in various ecosystems around the world but...

Black carbon concentration trends in Helsinki during 1996–2005 (2007)

L. Järvi, H. Junninen, A. Karppinen, R. Hillamo, A. Virkkula, T. Mäkelä, ...

The black carbon (BC) concentration trends were studied during ten years in Helsinki, Finland. Measurements were made in three campaigns between 1996 and 2005 at an urban area locating two kilometres...

New particle formation in the front range of the Colorado Rocky Mountains (2007)

M. Boy, T. Karl, A. Turnipseed, R. L. Mauldin, E. Kosciuch, J. Greenberg, ...

New particle formation is of interest because of its influence on the properties of aerosol population, and due to the possible contribution of newly formed particles to cloud condensation nuclei....

SALSA – a Sectional Aerosol module for Large Scale Applications (2007)

H. Kokkola, H. Korhonen, R. Makkonen, A. Asmi, S. Järvenoja, ...

The sectional aerosol module SALSA is introduced. The model has been designed to be implemented in large scale climate models, which require both accuracy and computational efficiency. We have used...

Atmospheric aerosol and ion characteristics during EUCAP (Eucalypt Forest Aerosols and Precursors) (2007)

Suni, Tanja, Ristovski, Zoran, Morawska, Lidia, Guenther, Alex, Turnipseed, Andrew, Sogacheva, Larisa, ...

We measured the characteristics and dynamics of atmospheric ions, aerosol particles, and their precursors in an intensive field campaign in a Eucalypt forest in Tumbarumba, South-East Australia, in...

Evaluation and modeling of the size fractionated aerosol particle number concentration measurements nearby a major road in Helsinki – Part II: Aerosol measurements within the SAPPHIRE project (2007)

Hussein, T., Kukkonen, J., Korhonen, H., Pohjola, M., Pirjola, L., Wraith, Darren, ...

This study presents an evaluation and modeling exercise of the size fractionated aerosol particle number concentrations measured nearby a major road in Helsinki during 23 August–19 September 2003...

Atmospheric aerosol and ion characteristics during EUCAP (Eucalypt Forest Aerosols and Precursors) (2007)

Suni, Tanja, Ristovski, Zoran, Morawska, Lidia, Guenther, Alex, Turnipseed, Andrew, Sogacheva, Larisa, ...

We measured the characteristics and dynamics of atmospheric ions, aerosol particles, and their precursors in an intensive field campaign in a Eucalypt forest in Tumbarumba, South-East Australia, in...

Evaluation and modeling of the size fractionated aerosol particle number concentration measurements nearby a major road in Helsinki – Part II: Aerosol measurements within the SAPPHIRE project (2007)

Hussein, T., Kukkonen, J., Korhonen, H., Pohjola, M., Pirjola, L., Wraith, Darren, ...

This study presents an evaluation and modeling exercise of the size fractionated aerosol particle number concentrations measured nearby a major road in Helsinki during 23 August–19 September 2003...

Atmospheric sulfuric acid and aerosol formation: implications from atmospheric measurements for nucleation and early growth mechanisms. (2006)

Sihto, L.H., Kulmala, M., Kerminen, V.M., Dal Maso, M., Petäjä, T., Riipinen, I., ...

We have investigated the formation and early growth of atmospheric secondary aerosol particles building on atmospheric measurements. The measurements were part of the QUEST 2 campaign which took...

Chemical composition of boundary layer aerosol over the Atlantic Ocean and at an Antarctic site (2006)

Virkkula, A., Teinilä, K., Hillamo, R., Saarikoski, S., Aurela, M., ...

Aerosol chemical composition was measured over the Atlantic Ocean in November?December 1999 and at the Finnish Antarctic research station Aboa in January 2000. The concentrations of all anthropogenic...

Ambient sesquiterpene concentration and its link to air ion measurements (2006)

Bonn, B., Hirsikko, A., Hakola, H., Kurtén, T., Laakso, L., Boy, M., ...

Ambient air ion size distributions have been measured continuously at the Finnish boreal forest site in Hyytiälä since spring 2003. In general, these measurements show a maximum of air ions below...

Relation of air mass history to nucleation events in Po Valley, Italy, using back trajectories analysis (2006)

Sogacheva, L., Hamed, A., Facchini, M. C., Kulmala, M., Laaksonen, A.

In this paper, we study the transport of air mass to San Pietro Capofiume (SPC) in Po Valley, Italy, by means of back trajectory analysis. Our main aim is to investigate whether air masses originate...

Connections between atmospheric sulphuric acid and new particle formation during QUEST III?IV campaigns in Heidelberg and Hyytiälä (2006)

Riipinen, I., Kulmala, M., Arnold, F., Dal Maso, M., Birmili, W., ...

This study investigates the connections between atmospheric sulphuric acid and new particle formation during QUEST III and BACCI/QUEST IV campaigns. The campaigns have been conducted in Heidelberg...

Boundary layer concentrations and landscape scale emissions of volatile organic compounds in early spring (2006)

Haapanala, S., Rinne, J., Hakola, H., Hellén, H., Laakso, L., Lihavainen, H., ...

Boundary layer concenrations of several volatile organic compounds (VOC) were measured during two campaigns in springs of 2003 and 2006. Measurements were conducted over boreal forests near SMEAR II...

Aerosol formation over the Boreal forest in Hyytiälä, Finland: monthly frequency and annual cycles ? the roles of air mass characteristics and synoptic scale meteorology (2006)

Nilsson, E. D., Kulmala, M.

New atmospheric particles with diameters of 3?10 nm and their subsequent growth to cloud condensation nucleus have been observed at various places in the European boundary layer. These events have...

Non-volatile residuals of newly formed atmospheric particles in the boreal forest (2006)

Ehn, M., Petäjä, T., Birmili, W., Junninen, H., Aalto, P., Kulmala, M.

The volatility of sub-micrometer atmospheric aerosol particles was studied in a rural background environment in Finland using a combination of a heating tube and a scanning mobility particle sizer....

Hygroscopic properties of ultrafine aerosol particles in the boreal forest: diurnal variation, solubility and the influence of sulfuric acid (2006)

Ehn, M., Petäjä, T., Aufmhoff, H., Aalto, P., Hämeri, K., Arnold, F., ...

Freshly formed atmospheric aerosol particles are neither large enough to efficiently scatter incoming solar radiation nor able to act as cloud condensation nuclei. As the particles grow larger, their...

Nucleation and growth of new particles in Po Valley, Italy (2006)

Hamed, A., Joutsensaari, J., Mikkonen, S., Sogacheva, L., Dal Maso, M., Kulmala, M., ...

Aerosol number distribution measurements are reported at San Pietro Capofiume (SPC) station (44°39' N, 11°37' E) for the time period 2002?2005. The station is located in Po Valley, the largest...

Waterfalls as sources of small charged aerosol particles (2006)

Laakso, L., Hirsikko, A., Grönholm, T., Kulmala, M., Luts, A.

In this study, we measured (to our knowledge, for the first time) the mobility distributions of cluster and intermediate ions with an ion spectrometer near a waterfall. We observed that the...

Identification and classification of the formation of intermediate ions measured in boreal forest (2006)

Hirsikko, A., Bergman, T., Laakso, L., Dal Maso, M., Riipinen, I., Hõrrak, U., ...

We have measured the size distributions of air ions (0.42?7.5 nm in diameter) with the Balanced Scanning Mobility Analyzer in boreal forest, in Southern Finland since spring 2003. The size range...

Technical note: The heterogeneous Zeldovich factor (2006)

Lauri, A., Napari, I., Kulmala, M.

In this technical note we present the exact form of the Zeldovich factor for heterogeneous nucleation on spherical pre-existing particles. We study the error caused by planar pre-existing surface...

Airborne measurements of nucleation mode particles I: coastal nucleation and growth rates (2006)

O'Dowd, C. D., Yoon, Y. J., Junkerman, W., Aalto, P., Kulmala, M., Lihavainen, H., ...

A light aircraft was equipped with a bank of Condensation Particle Counters (CPCs) (50% cut from 3?5.4?9.6 nm) and a nano-Scanning Mobility Particle Sizer (nSMPS) and deployed along the west coast of...

The contribution of boundary layer nucleation events to total particle concentrations on regional and global scales (2006)

Spracklen, D. V., Carslaw, K. S., Kulmala, M., Mann, G. W.

The contribution of boundary layer nucleation events to total particle concentrations on the global scale has been studied by including a new particle formation mechanism in a global aerosol...

Changes in background aerosol composition in Finland during polluted and clean periods studied by TEM/EDX individual particle analysis (2006)

Niemi, J. V., Saarikoski, S., Tervahattu, H., Mäkelä, T., Hillamo, R., Vehkamäki, H., ...

Aerosol samples were collected at a rural background site in southern Finland in May 2004. The elemental composition, morphology and mixing state of individual aerosol particles in three size...

Detecting charging state of ultra-fine particles: instrumental development and ambient measurements (2006)

Laakso, L., Gagné, S., Petäjä, T., Hirsikko, A., Aalto, P. P., Kulmala, M., ...

The importance of ion-induced nucleation in the lower atmosphere has been discussed for a long time. In this article we describe a new instrumental setup ? Ion-DMPS ? which can be used to detect...

Impact of H2SO4/H2O coating and ice crystal size on radiative properties of sub-visible cirrus (2006)

Räisänen, P., Bogdan, A., Sassen, K., Kulmala, M., Molina, M. J.

Recent laboratory experiments showed that at conditions resembling those near the tropopause region, small quasi-spherical ice particles can be coated by a liquid H2SO4/H2O over-layer formed after...

Atmospheric sulphuric acid and aerosol formation: implications from atmospheric measurements for nucleation and early growth mechanisms (2006)

Kulmala, M., Dal Maso, M., Petäjä, T., Riipinen, I., ...

We have investigated the formation and early growth of atmospheric secondary aerosol particles building on atmospheric measurements. The measurements were part of the QUEST 2 campaign which took...

MALTE ? Model to predict new aerosol formation in the lower troposphere (2006)

Boy, M., Hellmuth, O., Korhonen, H., Nilsson, E. D., Revelle, D., Turnipseed, A., ...

The manuscript presents a detailed description of the meteorological and chemical code of Malte ? a model to predict new aerosol formation in the lower troposphere. The aerosol dynamics are achieved...

Factors of air ion balance in a coniferous forest according to measurements in Hyytiälä, Finland (2006)

Tammet, H., Hõrrak, U., Laakso, L., Kulmala, M.

A new theoretical model includes dry deposition of ions onto the forest canopy and takes into account different parameters of positive and negative ions. Explicit algebraic solution of the air ion...

Foliage surface ozone deposition: a role for surface moisture? (2006)

Altimir, N., Kolari, P., Vesala, T., Bäck, J., Suni, T., ...

This paper addresses the potential role of surface wetness in ozone deposition to plant foliage. We studied Scots pine foliage in field conditions at the SMEARII field measurement station in Finland....

Foliage surface ozone deposition: a role for surface moisture? (2006)

Altimir, N., Kolari, P., Vesala, T., Bäck, J., Suni, T., ...

This paper addresses the potential role of surface wetness in ozone deposition to plant foliage. We studied Scots pine foliage in field conditions at the SMEARII field measurement station in Finland....

Seasonal variation of mono- and sesquiterpene emission rates of Scots pine (2006)

Hakola, H., Tarvainen, V., Bäck, J., Ranta, H., Bonn, B., Rinne, J., ...

The seasonal variation of mono-and sesquiterpene emission rates of Scots pine was measured from April to October in 2004. The emission rates were measured daily in the afternoons with the exception...

The contribution of boundary layer nucleation events to total particle concentrations on regional and global scales (2006)

Spracklen, D. V., Carslaw, K. S., Kulmala, M., Mann, G. W.

The contribution of boundary layer (BL) nucleation events to total particle concentrations on the global scale has been studied by including a new particle formation mechanism in a global aerosol...

Changes in background aerosol composition in Finland during polluted and clean periods studied by TEM/EDX individual particle analysis (2006)

Niemi, J. V., Saarikoski, S., Tervahattu, H., Mäkelä, T., Hillamo, R., Vehkamäki, H., ...

Aerosol samples were collected at a rural background site in southern Finland in May 2004 during pollution episode (PM1~16 µg m?3, backward air mass trajectories from south-east), intermediate...

Impact of H2SO4/H2O coating and ice crystal size on radiative properties of sub-visible cirrus (2006)

Räisänen, P., Bogdan, A., Sassen, K., Kulmala, M., Molina, M. J.

Recent laboratory experiments showed that at conditions resembling those near the tropopause region, small ice particles can be coated by a liquid H2SO4/H2O over-layer formed after the freezing of...

MALTE ? model to predict new aerosol formation in the lower troposphere (2006)

Boy, M., Hellmuth, O., Korhonen, H., Nilsson, E. D., Revelle, D., Turnipseed, A., ...

The manuscript presents a detailed description of the meteorological and chemical code of Malte ? a model to predict new aerosol formation in the lower troposphere. The aerosol dynamics are achieved...

Atmospheric sulphuric acid and aerosol formation: implications from atmospheric measurements for nucleation and early growth mechanisms (2006)

Kulmala, M., Dal Maso, M., Petäjä, T., Riipinen, I., ...

We have investigated the formation and early growth of atmospheric secondary aerosol particles building on atmospheric measurements. The measurements were part of the QUEST 2 campaign which took...

Chemical composition of boundary layer aerosol over the Atlantic Ocean and at an Antarctic site (2006)

Virkkula, A., Teinilä, K., Hillamo, R., Saarikoski, S., Aurela, M., ...

Aerosol chemical composition was measured over the Atlantic Ocean in November?December 1999 and at the Finnish Antarctic research station Aboa in January 2000. The concentrations of all anthropogenic...

Factors of air ion balance in a coniferous forest according to measurements in Hyytiälä, Finland (2006)

Tammet, H., Hõrrak, U., Laakso, L., Kulmala, M.

A new mathematical model describing air ion balance was developed and tested. It has improved approximations and includes dry deposition of ions onto the forest canopy. The model leads to an explicit...

New particle formation in air mass transported between two measurement sites in Northern Finland (2006)

Komppula, M., Korhonen, H., Lihavainen, H., Kulmala, M., ...

This study covers four years of aerosol number size distribution data from Pallas and Värriö sites 250 km apart from each other in Northern Finland and compares new particle formation events...

Critical assessment of the current state of scientific knowledge, terminology, and research needs concerning the role of organic aerosols in the atmosphere, climate, and global change (2006)

Fuzzi, S., Andreae, M. O., Huebert, B. J., Kulmala, M., Bond, T. C., Boy, M., ...

In spite of impressive advances in recent years, our present understanding of organic aerosol (OA) composition, physical and chemical properties, sources and transformation characteristics is still...

Measurements of optical properties of atmospheric aerosols in Northern Finland (2006)

Aaltonen, V., Lihavainen, H., Komppula, M., Hatakka, J., Eneroth, K., ...

Three years of continuous measurements of aerosol optical properties and simultaneous aerosol number size distribution measurements at Pallas GAW station, a remote subarctic site in the northern...

Cluster activation theory as an explanation of the linear dependence between formation rate of 3nm particles and sulphuric acid concentration (2006)

Kulmala, M., Lehtinen, K. E. J., Laaksonen, A.

According to atmospheric observations new particle formation seems to be a function of sulphuric acid concentration to the power from one to two. The nucleation theorem then predicts that the...

Size and composition measurements of background aerosol and new particle growth in a Finnish forest during QUEST 2 using an Aerodyne Aerosol Mass Spectrometer (2006)

Allan, J. D., Alfarra, M. R., Bower, K. N., Coe, H., Jayne, J. T., Worsnop, D. R., ...

The study of the growth of nucleation-mode particles is important, as this prevents their loss through diffusion and allows them to reach sizes where they may become effective cloud condensation...

Chemical composition of boundary layer aerosol over the Atlantic Ocean and at an Antarctic site (2006)

Virkkula, A., Teinilä, K., Hillamo, R., Saarikoski, S., Aurela, M., ...

Aerosol chemical composition was measured over the Atlantic Ocean in November?December 1999 and at the Finnish Antarctic research station Aboa in January 2000. The concentrations of all anthropogenic...

Ambient sesquiterpene concentration and its link to air ion measurements (2006)

Bonn, B., Hirsikko, A., Hakola, H., Kurtén, T., Laakso, L., Boy, M., ...

Ambient air ion size distributions have been measured continuously at the Finnish boreal forest site in Hyytiälä since spring 2003. In general, these measurements show a maximum of air ions below...

Relation of air mass history to nucleation events in Po Valley, Italy, using back trajectories analysis (2006)

Sogacheva, L., Hamed, A., Facchini, M. C., Kulmala, M., Laaksonen, A.

In this paper, we study the transport of air mass to San Pietro Capofiume (SPC) in Po Valley, Italy, by means of back trajectory analysis. Our main aim is to investigate whether air masses originate...

Connections between atmospheric sulphuric acid and new particle formation during QUEST III?IV campaigns in Heidelberg and Hyytiälä (2006)

Riipinen, I., Kulmala, M., Arnold, F., Dal Maso, M., Birmili, W., ...

This study investigates the connections between atmospheric sulphuric acid and new particle formation during QUEST III and BACCI/QUEST IV campaigns. The campaigns have been conducted in Heidelberg...

Boundary layer concentrations and landscape scale emissions of volatile organic compounds in early spring (2006)

Haapanala, S., Rinne, J., Hakola, H., Hellén, H., Laakso, L., Lihavainen, H., ...

Boundary layer concenrations of several volatile organic compounds (VOC) were measured during two campaigns in springs of 2003 and 2006. Measurements were conducted over boreal forests near SMEAR II...

Aerosol formation over the Boreal forest in Hyytiälä, Finland: monthly frequency and annual cycles ? the roles of air mass characteristics and synoptic scale meteorology (2006)

Nilsson, E. D., Kulmala, M.

New atmospheric particles with diameters of 3?10 nm and their subsequent growth to cloud condensation nucleus have been observed at various places in the European boundary layer. These events have...

Non-volatile residuals of newly formed atmospheric particles in the boreal forest (2006)

Ehn, M., Petäjä, T., Birmili, W., Junninen, H., Aalto, P., Kulmala, M.

The volatility of sub-micrometer atmospheric aerosol particles was studied in a rural background environment in Finland using a combination of a heating tube and a scanning mobility particle sizer....

Hygroscopic properties of ultrafine aerosol particles in the boreal forest: diurnal variation, solubility and the influence of sulfuric acid (2006)

Ehn, M., Petäjä, T., Aufmhoff, H., Aalto, P., Hämeri, K., Arnold, F., ...

Freshly formed atmospheric aerosol particles are neither large enough to efficiently scatter incoming solar radiation nor able to act as cloud condensation nuclei. As the particles grow larger, their...

Nucleation and growth of new particles in Po Valley, Italy (2006)

Hamed, A., Joutsensaari, J., Mikkonen, S., Sogacheva, L., Dal Maso, M., Kulmala, M., ...

Aerosol number distribution measurements are reported at San Pietro Capofiume (SPC) station (44°39' N, 11°37' E) for the time period 2002?2005. The station is located in Po Valley, the largest...

Waterfalls as sources of small charged aerosol particles (2006)

Laakso, L., Hirsikko, A., Grönholm, T., Kulmala, M., Luts, A.

In this study, we measured (to our knowledge, for the first time) the mobility distributions of cluster and intermediate ions with an ion spectrometer near a waterfall. We observed that the...

Identification and classification of the formation of intermediate ions measured in boreal forest (2006)

Hirsikko, A., Bergman, T., Laakso, L., Dal Maso, M., Riipinen, I., Hõrrak, U., ...

We have measured the size distributions of air ions (0.42?7.5 nm in diameter) with the Balanced Scanning Mobility Analyzer in boreal forest, in Southern Finland since spring 2003. The size range...

Technical note: The heterogeneous Zeldovich factor (2006)

Lauri, A., Napari, I., Kulmala, M.

In this technical note we present the exact form of the Zeldovich factor for heterogeneous nucleation on spherical pre-existing particles. We study the error caused by planar pre-existing surface...

Airborne measurements of nucleation mode particles I: coastal nucleation and growth rates (2006)

O'Dowd, C. D., Yoon, Y. J., Junkerman, W., Aalto, P., Kulmala, M., Lihavainen, H., ...

A light aircraft was equipped with a bank of Condensation Particle Counters (CPCs) (50% cut from 3?5.4?9.6 nm) and a nano-Scanning Mobility Particle Sizer (nSMPS) and deployed along the west coast of...

The contribution of boundary layer nucleation events to total particle concentrations on regional and global scales (2006)

Spracklen, D. V., Carslaw, K. S., Kulmala, M., Mann, G. W.

The contribution of boundary layer nucleation events to total particle concentrations on the global scale has been studied by including a new particle formation mechanism in a global aerosol...

Changes in background aerosol composition in Finland during polluted and clean periods studied by TEM/EDX individual particle analysis (2006)

Niemi, J. V., Saarikoski, S., Tervahattu, H., Mäkelä, T., Hillamo, R., Vehkamäki, H., ...

Aerosol samples were collected at a rural background site in southern Finland in May 2004. The elemental composition, morphology and mixing state of individual aerosol particles in three size...

Detecting charging state of ultra-fine particles: instrumental development and ambient measurements (2006)

Laakso, L., Gagné, S., Petäjä, T., Hirsikko, A., Aalto, P. P., Kulmala, M., ...

The importance of ion-induced nucleation in the lower atmosphere has been discussed for a long time. In this article we describe a new instrumental setup ? Ion-DMPS ? which can be used to detect...

Impact of H2SO4/H2O coating and ice crystal size on radiative properties of sub-visible cirrus (2006)

Räisänen, P., Bogdan, A., Sassen, K., Kulmala, M., Molina, M. J.

Recent laboratory experiments showed that at conditions resembling those near the tropopause region, small quasi-spherical ice particles can be coated by a liquid H2SO4/H2O over-layer formed after...

Atmospheric sulphuric acid and aerosol formation: implications from atmospheric measurements for nucleation and early growth mechanisms (2006)

Kulmala, M., Dal Maso, M., Petäjä, T., Riipinen, I., ...

We have investigated the formation and early growth of atmospheric secondary aerosol particles building on atmospheric measurements. The measurements were part of the QUEST 2 campaign which took...

MALTE ? Model to predict new aerosol formation in the lower troposphere (2006)

Boy, M., Hellmuth, O., Korhonen, H., Nilsson, E. D., Revelle, D., Turnipseed, A., ...

The manuscript presents a detailed description of the meteorological and chemical code of Malte ? a model to predict new aerosol formation in the lower troposphere. The aerosol dynamics are achieved...

Factors of air ion balance in a coniferous forest according to measurements in Hyytiälä, Finland (2006)

Tammet, H., Hõrrak, U., Laakso, L., Kulmala, M.

A new theoretical model includes dry deposition of ions onto the forest canopy and takes into account different parameters of positive and negative ions. Explicit algebraic solution of the air ion...

Foliage surface ozone deposition: a role for surface moisture? (2006)

Altimir, N., Kolari, P., Vesala, T., Bäck, J., Suni, T., ...

This paper addresses the potential role of surface wetness in ozone deposition to plant foliage. We studied Scots pine foliage in field conditions at the SMEARII field measurement station in Finland....

Foliage surface ozone deposition: a role for surface moisture? (2006)

Altimir, N., Kolari, P., Vesala, T., Bäck, J., Suni, T., ...

This paper addresses the potential role of surface wetness in ozone deposition to plant foliage. We studied Scots pine foliage in field conditions at the SMEARII field measurement station in Finland....

Seasonal variation of mono- and sesquiterpene emission rates of Scots pine (2006)

Hakola, H., Tarvainen, V., Bäck, J., Ranta, H., Bonn, B., Rinne, J., ...

The seasonal variation of mono-and sesquiterpene emission rates of Scots pine was measured from April to October in 2004. The emission rates were measured daily in the afternoons with the exception...

The contribution of boundary layer nucleation events to total particle concentrations on regional and global scales (2006)

Spracklen, D. V., Carslaw, K. S., Kulmala, M., Mann, G. W.

The contribution of boundary layer (BL) nucleation events to total particle concentrations on the global scale has been studied by including a new particle formation mechanism in a global aerosol...

Changes in background aerosol composition in Finland during polluted and clean periods studied by TEM/EDX individual particle analysis (2006)

Niemi, J. V., Saarikoski, S., Tervahattu, H., Mäkelä, T., Hillamo, R., Vehkamäki, H., ...

Aerosol samples were collected at a rural background site in southern Finland in May 2004 during pollution episode (PM1~16 µg m?3, backward air mass trajectories from south-east), intermediate...

Impact of H2SO4/H2O coating and ice crystal size on radiative properties of sub-visible cirrus (2006)

Räisänen, P., Bogdan, A., Sassen, K., Kulmala, M., Molina, M. J.

Recent laboratory experiments showed that at conditions resembling those near the tropopause region, small ice particles can be coated by a liquid H2SO4/H2O over-layer formed after the freezing of...

MALTE ? model to predict new aerosol formation in the lower troposphere (2006)

Boy, M., Hellmuth, O., Korhonen, H., Nilsson, E. D., Revelle, D., Turnipseed, A., ...

The manuscript presents a detailed description of the meteorological and chemical code of Malte ? a model to predict new aerosol formation in the lower troposphere. The aerosol dynamics are achieved...

Atmospheric sulphuric acid and aerosol formation: implications from atmospheric measurements for nucleation and early growth mechanisms (2006)

Kulmala, M., Dal Maso, M., Petäjä, T., Riipinen, I., ...

We have investigated the formation and early growth of atmospheric secondary aerosol particles building on atmospheric measurements. The measurements were part of the QUEST 2 campaign which took...

Chemical composition of boundary layer aerosol over the Atlantic Ocean and at an Antarctic site (2006)

Virkkula, A., Teinilä, K., Hillamo, R., Saarikoski, S., Aurela, M., ...

Aerosol chemical composition was measured over the Atlantic Ocean in November?December 1999 and at the Finnish Antarctic research station Aboa in January 2000. The concentrations of all anthropogenic...

Factors of air ion balance in a coniferous forest according to measurements in Hyytiälä, Finland (2006)

Tammet, H., Hõrrak, U., Laakso, L., Kulmala, M.

A new mathematical model describing air ion balance was developed and tested. It has improved approximations and includes dry deposition of ions onto the forest canopy. The model leads to an explicit...

New particle formation in air mass transported between two measurement sites in Northern Finland (2006)

Komppula, M., Korhonen, H., Lihavainen, H., Kulmala, M., ...

This study covers four years of aerosol number size distribution data from Pallas and Värriö sites 250 km apart from each other in Northern Finland and compares new particle formation events...

Critical assessment of the current state of scientific knowledge, terminology, and research needs concerning the role of organic aerosols in the atmosphere, climate, and global change (2006)

Fuzzi, S., Andreae, M. O., Huebert, B. J., Kulmala, M., Bond, T. C., Boy, M., ...

In spite of impressive advances in recent years, our present understanding of organic aerosol (OA) composition, physical and chemical properties, sources and transformation characteristics is still...

Measurements of optical properties of atmospheric aerosols in Northern Finland (2006)

Aaltonen, V., Lihavainen, H., Komppula, M., Hatakka, J., Eneroth, K., ...

Three years of continuous measurements of aerosol optical properties and simultaneous aerosol number size distribution measurements at Pallas GAW station, a remote subarctic site in the northern...

Cluster activation theory as an explanation of the linear dependence between formation rate of 3nm particles and sulphuric acid concentration (2006)

Kulmala, M., Lehtinen, K. E. J., Laaksonen, A.

According to atmospheric observations new particle formation seems to be a function of sulphuric acid concentration to the power from one to two. The nucleation theorem then predicts that the...

Size and composition measurements of background aerosol and new particle growth in a Finnish forest during QUEST 2 using an Aerodyne Aerosol Mass Spectrometer (2006)

Allan, J. D., Alfarra, M. R., Bower, K. N., Coe, H., Jayne, J. T., Worsnop, D. R., ...

The study of the growth of nucleation-mode particles is important, as this prevents their loss through diffusion and allows them to reach sizes where they may become effective cloud condensation...

Sub-micron atmospheric aerosols in the surroundings of Marseille and Athens: physical characterization and new particle formation (2006)

Petäjä, T., Dal Maso, M., Junninen, H., Koponen, I. K., Hussein, T., ...

The properties of atmospheric aerosol particles in Marseille and Athens were investigated. The studies were performed in Marseille, France during July 2002 and in Athens Greece during June 2003. The...

Sub-micron atmospheric aerosols in the surroundings of Marseille and Athens: physical characterization and new particle formation (2006)

Petäjä, T., Dal Maso, M., Junninen, H., Koponen, I. K., Hussein, T., ...

The properties of atmospheric aerosol particles in Marseille and Athens were investigated. The studies were performed in Marseille, France during July 2002 and in Athens Greece during June 2003. The...

Foliage surface ozone deposition: a role for surface moisture? (2006)

N. Altimir, P. Kolari, T. Vesala, J. Bäck, T. Suni, ...

This paper addresses the potential role of surface wetness in ozone deposition to plant foliage. We studied Scots pine foliage in field conditions at the SMEARII field measurement station in Finland....

Chemical composition of boundary layer aerosol over the Atlantic Ocean and at an Antarctic site (2006)

A. Virkkula, K. Teinilä, R. Hillamo, S. Saarikoski, M. Aurela, ...

Aerosol chemical composition was measured over the Atlantic Ocean in November–December 1999 and at the Finnish Antarctic research station Aboa in January 2000. The concentrations of all...

MALTE – Model to predict new aerosol formation in the lower troposphere (2006)

M. Boy, O. Hellmuth, H. Korhonen, E. D. Nilsson, D. ReVelle, A. Turnipseed, ...

The manuscript presents a detailed description of the meteorological and chemical code of Malte – a model to predict new aerosol formation in the lower troposphere. The aerosol dynamics are...

Atmospheric sulphuric acid and aerosol formation: implications from atmospheric measurements for nucleation and early growth mechanisms (2006)

M. Kulmala, M. Dal Maso, T. Petäjä, I. Riipinen, ...

We have investigated the formation and early growth of atmospheric secondary aerosol particles building on atmospheric measurements. The measurements were part of the QUEST 2 campaign which took...

Impact of H<sub>2</sub>SO<sub>4</sub>/H<sub>2</sub>O coating and ice crystal size on radiative properties of sub-visible cirrus (2006)

P. Räisänen, A. Bogdan, K. Sassen, M. Kulmala, M. J. Molina

Recent laboratory experiments showed that at conditions resembling those near the tropopause region, small quasi-spherical ice particles can be coated by a liquid...

Relation of air mass history to nucleation events in Po Valley, Italy, using back trajectories analysis (2006)

L. Sogacheva, A. Hamed, M. C. Facchini, M. Kulmala, A. Laaksonen

In this paper, we study the transport of air mass to San Pietro Capofiume (SPC) in Po Valley, Italy, by means of back trajectory analysis. Our main aim is to investigate whether air masses originate...

Ambient sesquiterpene concentration and its link to air ion measurements (2006)

B. Bonn, A. Hirsikko, H. Hakola, T. Kurtén, L. Laakso, M. Boy, ...

Ambient air ion size distributions have been measured continuously at the Finnish boreal forest site in Hyytiälä since spring 2003. In general, these measurements show a maximum of air ions below...

MALTE – Model to predict new aerosol formation in the lower troposphere (2006)

M. Boy, O. Hellmuth, H. Korhonen, E. D. Nilsson, D. ReVelle, A. Turnipseed, ...

The manuscript presents a detailed description of the meteorological and chemical code of Malte – a model to predict new aerosol formation in the lower troposphere. The aerosol dynamics are...

Impact of H2SO4/H2O coating and ice crystal size on radiative properties of sub-visible cirrus (2006)

P. Räisänen, A. Bogdan, K. Sassen, M. Kulmala, M. J. Molina

Recent laboratory experiments showed that at conditions resembling those near the tropopause region, small quasi-spherical ice particles can be coated by a liquid H2SO4/H2O over-layer formed after...

The contribution of sulphuric acid to atmospheric particle formation and growth: a comparison between boundary layers in Northern and Central Europe (2005)

Fiedler, V., Dal Maso, M., Boy, M., Aufmhoff, H., Hoffmann, J., Schuck, T., ...

Atmospheric gaseous sulphuric acid was measured and its influence on particle formation and growth was investigated building on aerosol data. The measurements were part of the EU-project QUEST and...

New particle formation in air mass transported between two measurement sites in Northern Finland (2005)

Komppula, M., Korhonen, H., Lihavainen, H., Kulmala, M., ...

This study covers four years of aerosol number size distribution data from Pallas and Värriö sites 250 km apart from each other in Northern Finland and compares new particle formation events...

Critical assessment of the current state of scientific knowledge, terminology, and research needs concerning the role of organic aerosols in the atmosphere, climate, and global change (2005)

Fuzzi, S., Andreae, M. O., Huebert, B. J., Kulmala, M., Bond, T. C., Boy, M., ...

In spite of impressive advances in recent years, our present understanding of organic aerosol (OA) composition, physical and chemical properties, sources and transformation characteristics is still...

Measurements of optical properties of atmospheric aerosols in Northern Finland (2005)

Aaltonen, V., Lihavainen, H., Komppula, M., Hatakka, J., Eneroth, K., ...

Three years of continuous measurements of aerosol optical properties and simultaneous aerosol number size distribution measurements at Pallas GAW station, a remote subarctic site in the northern...

Why formation rate of 3 nm particles depends linearly on sulphuric acid concentration? (2005)

Kulmala, M., Lehtinen, K. E. J., Laaksonen, A.

According to atmospheric observations new particle formation seems to be a function of sulphuric acid concentration to the power from one to two. The nucleation theorem then predicts that the...

Size and composition measurements of background aerosol and new particle growth in a Finnish forest during QUEST 2 using an Aerodyne Aerosol Mass Spectrometer (2005)

Allan, J. D., Alfarra, M. R., Bower, K. N., Coe, H., Jayne, J. T., Worsnop, D. R., ...

The study of the growth of nucleation-mode particles is important, as this prevents their loss through diffusion and allows them to reach sizes where they may become effective cloud condensation...

A look at aerosol formation using data mining techniques (2005)

Hyvönen, S., Junninen, H., Laakso, L., Dal Maso, M., Grönholm, T., Bonn, B., ...

Atmospheric aerosol particle formation is frequently observed throughout the atmosphere, but despite various attempts of explanation, the processes behind it remain unclear. In this study data mining...

CCN activation and cloud processing in simplified sectional aerosol models with low size resolution (2005)

Korhonen, H., Lehtinen, K. E. J., Kulmala, M.

We investigate the influence of low size resolution, typical to sectional aerosol models in large scale applications, on cloud droplet activation and cloud processing of aerosol particles. A...

Observation of 2-methyltetrols and related photo-oxidation products of isoprene in boreal forest aerosols from Hyytiälä, Finland (2005)

Kourtchev, I., Ruuskanen, T., Maenhaut, W., Kulmala, M., Claeys, M.

Oxidation products of isoprene including 2-methyltetrols (2-methylthreitol and 2-methylerythritol), 2-methylglyceric acid and triol derivatives of isoprene (2-methyl-1,3,4-trihydroxy-1-butene (cis...

Characterization of air ions in boreal forest air during BIOFOR III campaign (2005)

Hõrrak, U., Aalto, P. P., Salm, J., Mäkelä, J. M., Laakso, L., Laakso, L., ...

The behavior of the concentration of positive small (or cluster) air ions and naturally charged nanometer aerosol particles (aerosol ions) has been studied on the basis of measurements carried out in...

Characterization of aerosol particle episodes in Finland caused by wildfires in Eastern Europe (2005)

Niemi, J. V., Tervahattu, H., Vehkamäki, H., Martikainen, J., Laakso, L., Kulmala, M., ...

We studied the sources, compositions and size distributions of aerosol particles during long-range transport (LRT) PM2.5 episodes occurred on 12?15 August, 26?28 August and 5?6 September 2002 in...

The contribution of sulphuric acid to atmospheric particle formation and growth: a comparison between boundary layers in Northern and Central Europe (2005)

Fiedler, V., Dal Maso, M., Boy, M., Aufmhoff, H., Hoffmann, J., Schuck, T., ...

Atmospheric gaseous sulphuric acid was measured and its influence on particle formation and growth was investigated building on aerosol data. The measurements were part of the EU-project QUEST and...

Seasonal variation of mono- and sesquiterpene emission rates of Scots pine (2005)

Hakola, H., Tarvainen, V., Bäck, J., Ranta, H., Bonn, B., Rinne, J., ...

The seasonal variation of mono-and sesquiterpene emission rates of Scots pine was measured from April to October in 2004. The emission rates were measured daily in the afternoons with the exception...

A look at aerosol formation using data mining techniques (2005)

Hyvönen, S., Junninen, H., Laakso, L., Dal Maso, M., Grönholm, T., Bonn, B., ...

Atmospheric aerosol particle formation is frequently observed throughout the atmosphere, but despite various attempts of explanation, the processes behind it remain unclear. In this study data mining...

Observation of 2-methyltetrols and related photo-oxidation products of isoprene in boreal forest aerosols from Hyytiälä, Finland (2005)

Kourtchev, I., Ruuskanen, T., Maenhaut, W., Kulmala, M., Claeys, M.

Oxidation products of isoprene including 2-methyltetrols (2-methylthreitol and 2-methylerythritol), 2-methylglyceric acid and triol derivatives of isoprene (2-methyl-1,3,4-trihydroxy-1-butene (cis...

CCN activation and cloud processing in sectional aerosol models with low size resolution (2005)

Korhonen, H., Lehtinen, K. E. J., Kulmala, M.

We investigate the influence of low size resolution, typical to sectional aerosol models in large scale applications, on cloud droplet activation and cloud processing of aerosol particles. A...

Characterization of aerosol particle episodes in Finland caused by wildfires in Eastern Europe (2005)

Niemi, J. V., Tervahattu, H., Vehkamäki, H., Martikainen, J., Laakso, L., Kulmala, M., ...

We studied the sources, compositions and size distributions of aerosol particles during long-range transport (LRT) PM2.5 episodes which occurred on 12?15 August, 26?28 August and 5?6 September 2002...

The contribution of sulphuric acid to atmospheric particle formation and growth: a comparison between boundary layers in Northern and Central Europe (2005)

Fiedler, V., Dal Maso, M., Boy, M., Aufmhoff, H., Hoffmann, J., Schuck, T., ...

Atmospheric gaseous sulphuric acid was measured and its influence on particle formation and growth was investigated building on aerosol data. The measurements were part of the EU-project QUEST and...

Temperature and light dependence of the VOC emissions of Scots pine (2005)

Tarvainen, V., Hakola, H., Hellén, H., Bäck, J., Hari, P., Kulmala, M.

The volatile organic compound (VOC) emission rates of Scots pine (Pinus sylvestris L.) were measured from trees growing in a natural forest environment at two locations in Finland. The observed total...

Sulphuric acid closure and contribution to nucleation mode particle growth (2005)

Boy, M., Kulmala, M., Ruuskanen, T. M., Pihlatie, M., Reissell, A., Aalto, P. P., ...

Sulphuric acid concentrations were measured and calculated based on pseudo steady state model with corresponding measurements of CO, NOx, O3, SO2, methane and non-methane hydrocarbon (NMHC)...

Effects of SO2 oxidation on ambient aerosol growth in water and ethanol vapours (2005)

Petäjä, T., Hämeri, K., Vaattovaara, P., Joutsensaari, J., Junkermann, W., ...

Hygroscopicity (i.e. water vapour affinity) of atmospheric aerosol particles is one of the key factors in defining their impacts on climate. Condensation of sulphuric acid onto less hygroscopic...

Commentary on cloud modelling and the mass accommodation coefficient of water (2005)

Laaksonen, A., Vesala, T., Kulmala, M., Winkler, P. M., Wagner, P. E.

The mass accommodation coefficient of water is a quantity for which different experimental techniques have yielded conflicting values in the range 0.04-1. From the viewpoint of cloud modelling, this...

On the growth of nucleation mode particles: source rates of condensable vapor in polluted and clean environments (2005)

Kulmala, M., Petäjä, T., Mönkkönen, P., Koponen, I. K., Dal Maso, M., Aalto, P. P., ...

The growth properties of nucleation mode particles were investigated. The variation of source rates of condensable vapors in different locations and environmental conditions was analyzed. The...

Measurements of organic gases during aerosol formation events in the boreal forest atmosphere during QUEST (2005)

Sellegri, K., Hanke, M., Umann, B., Arnold, F., Kulmala, M.

Biogenic VOCs are important in the growth and possibly also in the early stages of formation of atmospheric aerosol particles. In this work, we present 10 min-time resolution measurements of organic...

Measurements in a highly polluted Asian mega city: observations of aerosol number size distribution, modal parameters and nucleation events (2005)

Mönkkönen, P., Koponen, I. K., Lehtinen, K. E. J., Hämeri, K., Uma, R., Kulmala, M.

Diurnal variation of number size distribution (particle size 3-800nm) and modal parameters (geometric standard deviation, geometric mean diameter and modal aerosol particle concentration) in a highly...

New particle formation in air mass transported between two measurement sites in Northern Finland (2005)

Komppula, M., Korhonen, H., Lihavainen, H., Kulmala, M., ...

This study covers four years of aerosol number size distribution data from Pallas and Värriö sites 250 km apart from each other in Northern Finland and compares new particle formation events...

Critical assessment of the current state of scientific knowledge, terminology, and research needs concerning the role of organic aerosols in the atmosphere, climate, and global change (2005)

Fuzzi, S., Andreae, M. O., Huebert, B. J., Kulmala, M., Bond, T. C., Boy, M., ...

In spite of impressive advances in recent years, our present understanding of organic aerosol (OA) composition, physical and chemical properties, sources and transformation characteristics is still...

Measurements of optical properties of atmospheric aerosols in Northern Finland (2005)

Aaltonen, V., Lihavainen, H., Komppula, M., Hatakka, J., Eneroth, K., ...

Three years of continuous measurements of aerosol optical properties and simultaneous aerosol number size distribution measurements at Pallas GAW station, a remote subarctic site in the northern...

Why formation rate of 3 nm particles depends linearly on sulphuric acid concentration? (2005)

Kulmala, M., Lehtinen, K. E. J., Laaksonen, A.

According to atmospheric observations new particle formation seems to be a function of sulphuric acid concentration to the power from one to two. The nucleation theorem then predicts that the...

Size and composition measurements of background aerosol and new particle growth in a Finnish forest during QUEST 2 using an Aerodyne Aerosol Mass Spectrometer (2005)

Allan, J. D., Alfarra, M. R., Bower, K. N., Coe, H., Jayne, J. T., Worsnop, D. R., ...

The study of the growth of nucleation-mode particles is important, as this prevents their loss through diffusion and allows them to reach sizes where they may become effective cloud condensation...

A look at aerosol formation using data mining techniques (2005)

Hyvönen, S., Junninen, H., Laakso, L., Dal Maso, M., Grönholm, T., Bonn, B., ...

Atmospheric aerosol particle formation is frequently observed throughout the atmosphere, but despite various attempts of explanation, the processes behind it remain unclear. In this study data mining...

CCN activation and cloud processing in simplified sectional aerosol models with low size resolution (2005)

Korhonen, H., Lehtinen, K. E. J., Kulmala, M.

We investigate the influence of low size resolution, typical to sectional aerosol models in large scale applications, on cloud droplet activation and cloud processing of aerosol particles. A...

Observation of 2-methyltetrols and related photo-oxidation products of isoprene in boreal forest aerosols from Hyytiälä, Finland (2005)

Kourtchev, I., Ruuskanen, T., Maenhaut, W., Kulmala, M., Claeys, M.

Oxidation products of isoprene including 2-methyltetrols (2-methylthreitol and 2-methylerythritol), 2-methylglyceric acid and triol derivatives of isoprene (2-methyl-1,3,4-trihydroxy-1-butene (cis...

Characterization of air ions in boreal forest air during BIOFOR III campaign (2005)

Hõrrak, U., Aalto, P. P., Salm, J., Mäkelä, J. M., Laakso, L., Laakso, L., ...

The behavior of the concentration of positive small (or cluster) air ions and naturally charged nanometer aerosol particles (aerosol ions) has been studied on the basis of measurements carried out in...

Characterization of aerosol particle episodes in Finland caused by wildfires in Eastern Europe (2005)

Niemi, J. V., Tervahattu, H., Vehkamäki, H., Martikainen, J., Laakso, L., Kulmala, M., ...

We studied the sources, compositions and size distributions of aerosol particles during long-range transport (LRT) PM2.5 episodes occurred on 12?15 August, 26?28 August and 5?6 September 2002 in...

The contribution of sulphuric acid to atmospheric particle formation and growth: a comparison between boundary layers in Northern and Central Europe (2005)

Fiedler, V., Dal Maso, M., Boy, M., Aufmhoff, H., Hoffmann, J., Schuck, T., ...

Atmospheric gaseous sulphuric acid was measured and its influence on particle formation and growth was investigated building on aerosol data. The measurements were part of the EU-project QUEST and...

Seasonal variation of mono- and sesquiterpene emission rates of Scots pine (2005)

Hakola, H., Tarvainen, V., Bäck, J., Ranta, H., Bonn, B., Rinne, J., ...

The seasonal variation of mono-and sesquiterpene emission rates of Scots pine was measured from April to October in 2004. The emission rates were measured daily in the afternoons with the exception...

A look at aerosol formation using data mining techniques (2005)

Hyvönen, S., Junninen, H., Laakso, L., Dal Maso, M., Grönholm, T., Bonn, B., ...

Atmospheric aerosol particle formation is frequently observed throughout the atmosphere, but despite various attempts of explanation, the processes behind it remain unclear. In this study data mining...

Observation of 2-methyltetrols and related photo-oxidation products of isoprene in boreal forest aerosols from Hyytiälä, Finland (2005)

Kourtchev, I., Ruuskanen, T., Maenhaut, W., Kulmala, M., Claeys, M.

Oxidation products of isoprene including 2-methyltetrols (2-methylthreitol and 2-methylerythritol), 2-methylglyceric acid and triol derivatives of isoprene (2-methyl-1,3,4-trihydroxy-1-butene (cis...

CCN activation and cloud processing in sectional aerosol models with low size resolution (2005)

Korhonen, H., Lehtinen, K. E. J., Kulmala, M.

We investigate the influence of low size resolution, typical to sectional aerosol models in large scale applications, on cloud droplet activation and cloud processing of aerosol particles. A...

Characterization of aerosol particle episodes in Finland caused by wildfires in Eastern Europe (2005)

Niemi, J. V., Tervahattu, H., Vehkamäki, H., Martikainen, J., Laakso, L., Kulmala, M., ...

We studied the sources, compositions and size distributions of aerosol particles during long-range transport (LRT) PM2.5 episodes which occurred on 12?15 August, 26?28 August and 5?6 September 2002...

The contribution of sulphuric acid to atmospheric particle formation and growth: a comparison between boundary layers in Northern and Central Europe (2005)

Fiedler, V., Dal Maso, M., Boy, M., Aufmhoff, H., Hoffmann, J., Schuck, T., ...

Atmospheric gaseous sulphuric acid was measured and its influence on particle formation and growth was investigated building on aerosol data. The measurements were part of the EU-project QUEST and...

Temperature and light dependence of the VOC emissions of Scots pine (2005)

Tarvainen, V., Hakola, H., Hellén, H., Bäck, J., Hari, P., Kulmala, M.

The volatile organic compound (VOC) emission rates of Scots pine (Pinus sylvestris L.) were measured from trees growing in a natural forest environment at two locations in Finland. The observed total...

Sulphuric acid closure and contribution to nucleation mode particle growth (2005)

Boy, M., Kulmala, M., Ruuskanen, T. M., Pihlatie, M., Reissell, A., Aalto, P. P., ...

Sulphuric acid concentrations were measured and calculated based on pseudo steady state model with corresponding measurements of CO, NOx, O3, SO2, methane and non-methane hydrocarbon (NMHC)...

Effects of SO2 oxidation on ambient aerosol growth in water and ethanol vapours (2005)

Petäjä, T., Hämeri, K., Vaattovaara, P., Joutsensaari, J., Junkermann, W., ...

Hygroscopicity (i.e. water vapour affinity) of atmospheric aerosol particles is one of the key factors in defining their impacts on climate. Condensation of sulphuric acid onto less hygroscopic...

Commentary on cloud modelling and the mass accommodation coefficient of water (2005)

Laaksonen, A., Vesala, T., Kulmala, M., Winkler, P. M., Wagner, P. E.

The mass accommodation coefficient of water is a quantity for which different experimental techniques have yielded conflicting values in the range 0.04-1. From the viewpoint of cloud modelling, this...

On the growth of nucleation mode particles: source rates of condensable vapor in polluted and clean environments (2005)

Kulmala, M., Petäjä, T., Mönkkönen, P., Koponen, I. K., Dal Maso, M., Aalto, P. P., ...

The growth properties of nucleation mode particles were investigated. The variation of source rates of condensable vapors in different locations and environmental conditions was analyzed. The...

Measurements of organic gases during aerosol formation events in the boreal forest atmosphere during QUEST (2005)

Sellegri, K., Hanke, M., Umann, B., Arnold, F., Kulmala, M.

Biogenic VOCs are important in the growth and possibly also in the early stages of formation of atmospheric aerosol particles. In this work, we present 10 min-time resolution measurements of organic...

Measurements in a highly polluted Asian mega city: observations of aerosol number size distribution, modal parameters and nucleation events (2005)

Mönkkönen, P., Koponen, I. K., Lehtinen, K. E. J., Hämeri, K., Uma, R., Kulmala, M.

Diurnal variation of number size distribution (particle size 3-800nm) and modal parameters (geometric standard deviation, geometric mean diameter and modal aerosol particle concentration) in a highly...

Seasonal variation of mono- and sesquiterpene emission rates of Scots pine (2005)

H. Hakola, V. Tarvainen, J. Bäck, H. Ranta, B. Bonn, J. Rinne, ...

The seasonal variation of mono-and sesquiterpene emission rates of Scots pine was measured from April to October in 2004. The emission rates were measured daily in the afternoons with the exception...

The contribution of sulphuric acid to atmospheric particle formation and growth: a comparison between boundary layers in Northern and Central Europe (2005)

V. Fiedler, M. Dal Maso, M. Boy, H. Aufmhoff, J. Hoffmann, T. Schuck, ...

Atmospheric gaseous sulphuric acid was measured and its influence on particle formation and growth was investigated building on aerosol data. The measurements were part of the EU-project QUEST and...

Characterization of aerosol particle episodes in Finland caused by wildfires in Eastern Europe (2005)

J. V. Niemi, H. Tervahattu, H. Vehkamäki, J. Martikainen, L. Laakso, M. Kulmala, ...

We studied the sources, compositions and size distributions of aerosol particles during long-range transport (LRT) PM<sub>2.5</sub> episodes occurred on 12–15 August, 26–28...

Characterization of air ions in boreal forest air during BIOFOR III campaign (2005)

U. Hõrrak, P. P. Aalto, J. Salm, J. M. Mäkelä, L. Laakso, L. Laakso, ...

The behavior of the concentration of positive small (or cluster) air ions and naturally charged nanometer aerosol particles (aerosol ions) has been studied on the basis of measurements carried out in...

Observation of 2-methyltetrols and related photo-oxidation products of isoprene in boreal forest aerosols from Hyytiälä, Finland (2005)

I. Kourtchev, T. Ruuskanen, W. Maenhaut, M. Kulmala, M. Claeys

Oxidation products of isoprene including 2-methyltetrols (2-methylthreitol and 2-methylerythritol), 2-methylglyceric acid and triol derivatives of isoprene (2-methyl-1,3,4-trihydroxy-1-butene (cis...

Why formation rate of 3 nm particles depends linearly on sulphuric acid concentration? (2005)

M. Kulmala, A. Laaksonen

According to atmospheric observations new particle formation seems to be a function of sulphuric acid concentration to the power from one to two. The nucleation theorem then predicts that the...

Measurements of optical properties of atmospheric aerosols in Northern Finland (2005)

V. Aaltonen, H. Lihavainen, M. Komppula, J. Hatakka, K. Eneroth, ...

Three years of continuous measurements of aerosol optical properties and simultaneous aerosol number size distribution measurements at Pallas GAW station, a remote subarctic site in the northern...

Critical assessment of the current state of scientific knowledge, terminology, and research needs concerning the role of organic aerosols in the atmosphere, climate, and global change (2005)

S. Fuzzi, M. O. Andreae, B. J. Huebert, M. Kulmala, T. C. Bond, M. Boy, ...

In spite of impressive advances in recent years, our present understanding of organic aerosol (OA) composition, physical and chemical properties, sources and transformation characteristics is still...

New particle formation in air mass transported between two measurement sites in Northern Finland (2005)

M. Komppula, H. Korhonen, H. Lihavainen, M. Kulmala, ...

This study covers four years of aerosol number size distribution data from Pallas and Värriö sites 250 km apart from each other in Northern Finland and compares new particle formation...

Characterization of aerosol particle episodes in Finland caused by wildfires in Eastern Europe (2005)

Niemi, J. V., Tervahattu, H., Vehkamäki, H., Martikainen, J., Laakso, L., Kulmala, M., ...

We studied the sources, compositions and size distributions of aerosol particles during long-range transport (LRT) PM2.5 episodes which occurred on 12–15 August, 26– 28 August and 5–6 September...

Fatty acids on continental sulfate aerosol particles (2005)

Tervahattu, H., Juhanoja, J., Vaida, V., Tuck, A. F., Niemi, J. V., Kupiainen, K., ...

Published 2005 American Geophysical Union. Reproduced by permission of American Geophysical Union.

Continental impact on marine boundary layer coarse particles over the Atlantic Ocean between Europe and Antarctica (2005)

Niemi, J. V., Tervahattu, H., Virkkula, A., Hillamo, D., Teinilä, K., Koponen, I. K., ...

Aerosol samples were collected in the Atlantic marine boundary layer between the English Channel and Antarctica during November–December 1999. The composition of coarse (aerodynamic diameter 1–3...

A pseudo-Lagrangian model study of the size distribution properties over Scandinavia: transport from Aspvreten to Värriö (2004)

Tunved, P., Korhonen, H., Ström, J., Lehtinen, K. E. J., Kulmala, M.

The evolution of the aerosol size distribution during transport between Aspvreten (58.8° N, 17.4° E) and Värriö (67.46° N, 29.35° E) was studied using a pseudo-Lagrangian approach. Aerosol...

Effects of SO2 oxidation on ambient aerosol growth in water and ethanol vapours (2004)

Petäjä, T., Hämeri, K., Vaattovaara, P., Joutsensaari, J., Junkermann, W., ...

Hygroscopicity (i.e. water vapour affinity) of atmospheric aerosol particles is one of the key factors in defining their impacts on climate. Condensation of sulphuric acid onto less hygroscopic...

On cloud modelling and the mass accommodation coefficient of water (2004)

Laaksonen, A., Vesala, T., Kulmala, M., Winkler, P. M., Wagner, P. E.

The mass accommodation coefficient of water is a quantity for which different experimental techniques have yielded conflicting values in the range 0.04?1. From the viewpoint of cloud modelling, this...

On the growth of nucleation mode particles: source rates of condensable vapor in polluted and clean environments (2004)

Kulmala, M., Petäjä, T., Mönkkönen, P., Koponen, I. K., Dal Maso, M., Aalto, P. P., ...

The growth properties of nucleation mode particles were investigated. The variation of source rates of condensable vapors in different locations and environmental conditions was analyzed. The...

Temperature and light dependence of the VOC emissions of Scots pine (2004)

Tarvainen, V., Hakola, H., Hellén, H., Bäck, J., Hari, P., Kulmala, M.

The volatile organic compound (VOC) emission rates of Scots pine (Pinus sylvestris L.) were measured from trees growing in a natural forest environment at two locations in Finland. The emission rate...

Sulphuric acid closure and contribution to nucleation mode particle growth (2004)

Boy, M., Kulmala, M., Ruuskanen, T. M., Pihlatie, M., Reissell, A., Aalto, P. P., ...

Sulphuric acid concentrations were measured and calculated based on pseudo steady state model with corresponding measurements of CO, NOx, O3, SO2, methane and non-methane hydrocarbon (NMHC)...

Measurements in a highly polluted Asian mega city: observations of aerosol number size distribution, modal parameters and nucleation events (2004)

Mönkkönen, P., Koponen, I. K., Lehtinen, K. E. J., Hämeri, K., Uma, R., Kulmala, M.

Diurnal variation of number size distribution (particle size 3?800 nm) and modal parameters (geometric standard deviation, geometric mean diameter and modal aerosol particle concentration) in a...

Measurements of organic gases during aerosol formation events in the boreal forest atmosphere during QUEST (2004)

Sellegri, K., Hanke, M., Umann, B., Arnold, F., Kulmala, M.

Biogenic VOCs are important in the growth and possibly also in the formation of atmospheric aerosol particles. In this work, we present 10 min-time resolution measurements of organic trace gases at...

Ion production rate in a boreal forest based on ion, particle and radiation measurements (2004)

Laakso, L., Petäjä, T., Lehtinen, K. E. J., Kulmala, M., Paatero, J., Hõrrak, U., ...

In this study the ion production rates in a boreal forest are studied based on two different methods: 1) cluster ion and particle concentration measurements, 2) external radiation and radon...

Kinetic nucleation and ions in boreal particle formation events (2004)

Laakso, L., Anttila, T., Lehtinen, K. E. J., Aalto, P. P., Kulmala, M., Hõrrak, U., ...

In order to gain a more comprehensive picture on different mechanisms behind atmospheric particle formation, measurement results from QUEST 2-campaign are analyzed with an aid of an aerosol dynamic...

Atmospheric particle formation events at Värriö measurement station in Finnish Lapland 1998?2002 (2004)

Vehkamäki, H., Dal Maso, M., Hussein, T., Flanagan, R., Hyvärinen, A., Lauros, J., ...

We have identified 147 clear 8 nm diameter particle formation events at the SMEAR I station in Värriö, northern Finland during calendar years 1998?2002. The events have been classified in detail...

Multicomponent aerosol dynamics model UHMA: model development and validation (2004)

Korhonen, H., Lehtinen, K. E. J., Kulmala, M.

A size-segregated aerosol dynamics model UHMA (University of Helsinki Multicomponent Aerosol model) was developed for studies of multicomponent tropospheric aerosol particles. The model includes...

Initial steps of aerosol growth (2004)

Kulmala, M., Laakso, L., Lehtinen, K. E. J., Riipinen, I., Dal Maso, M., Anttila, T., ...

The formation and growth of atmospheric aerosols depend on several steps, namely nucleation, initial steps of growth and subsequent ? mainly condensational ? growth. This work focuses on the initial...

Kinetic nucleation and ions in boreal forest particle formation events (2004)

Laakso, L., Anttila, T., Lehtinen, K. E. J., Aalto, P. P., Kulmala, M., Hõrrak, U., ...

In order to gain a more comprehensive picture on different mechanisms behind atmospheric particle formation, measurement results from QUEST 2-campaign are analyzed with an aid of an aerosol dynamic...

Atmospheric particle formation events at Värriö measurement station in Finnish Lapland 1998-2002 (2004)

Vehkamäki, H., Dal Maso, M., Hussein, T., Flanagan, R., Hyvärinen, A., Lauros, J., ...

During the calendar years 1998-2002, 147 clear 8nm diameter particle formation events have been identified at the SMEAR I station in Värriö, northern Finland. The events have been classified in...

Ion production rate in a boreal forest based on ion, particle and radiation measurements (2004)

Laakso, L., Petäjä, T., Lehtinen, K. E. J., Kulmala, M., Paatero, J., Hõrrak, U., ...

In this study the ion production rates in a boreal forest were studied based on two different methods: 1) cluster ion and particle concentration measurements, 2) external radiation and radon...

Modelling the formation of organic particles in the atmosphere (2004)

Anttila, T., Kulmala, M., Laaksonen, A., O'Dowd, C. D.

Particle formation resulting from activation of inorganic stable clusters by a supersaturated organic vapour was investigated using a numerical model. The applied aerosol dynamic model included a...

Multicomponent aerosol dynamics model UHMA: model development and validation (2004)

Korhonen, H., Lehtinen, K. E. J., Kulmala, M.

A size-segregated aerosol dynamics model UHMA (University of Helsinki Multicomponent Aerosol model) was developed for studies of multicomponent tropospheric aerosol particles. The model includes...

Overview of the field measurement campaign in Hyytiälä, August 2001 in the framework of the EU project OSOA (2004)

Boy, M., Petäjä, T., Dal Maso, M., Rannik, Ü., Rinne, J., Aalto, P., ...

As part of the OSOA (Origin and formation of Secondary Organic Aerosols) project, two intensive field campaigns were conducted in Melpitz, Germany and Hyytiälä, Finland. This paper gives an...

A new feedback mechanism linking forests, aerosols, and climate (2004)

Kulmala, M., Suni, T., Lehtinen, K. E. J., Dal Maso, M., Boy, M., Reissell, A., ...

The possible connections between the carbon balance of ecosystems and aerosol-cloud-climate interactions play a significant role in climate change studies. Carbon dioxide is a greenhouse gas, whereas...

Urban aerosol number size distributions (2004)

Hussein, T., Puustinen, A., Aalto, P. P., Mäkelä, J. M., Hämeri, K., Kulmala, M.

Aerosol number size distributions have been measured since 5 May 1997 in Helsinki, Finland. The presented aerosol data represents size distributions within the particle diameter size range 8-400nm...

A pseudo-Lagrangian model study of the size distribution properties over Scandinavia: transport from Aspvreten to Värriö (2004)

Tunved, P., Korhonen, H., Ström, J., Lehtinen, K. E. J., Kulmala, M.

The evolution of the aerosol size distribution during transport between Aspvreten (58.8° N, 17.4° E) and Värriö (67.46° N, 29.35° E) was studied using a pseudo-Lagrangian approach. Aerosol...

Effects of SO2 oxidation on ambient aerosol growth in water and ethanol vapours (2004)

Petäjä, T., Hämeri, K., Vaattovaara, P., Joutsensaari, J., Junkermann, W., ...

Hygroscopicity (i.e. water vapour affinity) of atmospheric aerosol particles is one of the key factors in defining their impacts on climate. Condensation of sulphuric acid onto less hygroscopic...

On cloud modelling and the mass accommodation coefficient of water (2004)

Laaksonen, A., Vesala, T., Kulmala, M., Winkler, P. M., Wagner, P. E.

The mass accommodation coefficient of water is a quantity for which different experimental techniques have yielded conflicting values in the range 0.04?1. From the viewpoint of cloud modelling, this...

On the growth of nucleation mode particles: source rates of condensable vapor in polluted and clean environments (2004)

Kulmala, M., Petäjä, T., Mönkkönen, P., Koponen, I. K., Dal Maso, M., Aalto, P. P., ...

The growth properties of nucleation mode particles were investigated. The variation of source rates of condensable vapors in different locations and environmental conditions was analyzed. The...

Temperature and light dependence of the VOC emissions of Scots pine (2004)

Tarvainen, V., Hakola, H., Hellén, H., Bäck, J., Hari, P., Kulmala, M.

The volatile organic compound (VOC) emission rates of Scots pine (Pinus sylvestris L.) were measured from trees growing in a natural forest environment at two locations in Finland. The emission rate...

Sulphuric acid closure and contribution to nucleation mode particle growth (2004)

Boy, M., Kulmala, M., Ruuskanen, T. M., Pihlatie, M., Reissell, A., Aalto, P. P., ...

Sulphuric acid concentrations were measured and calculated based on pseudo steady state model with corresponding measurements of CO, NOx, O3, SO2, methane and non-methane hydrocarbon (NMHC)...

Measurements in a highly polluted Asian mega city: observations of aerosol number size distribution, modal parameters and nucleation events (2004)

Mönkkönen, P., Koponen, I. K., Lehtinen, K. E. J., Hämeri, K., Uma, R., Kulmala, M.

Diurnal variation of number size distribution (particle size 3?800 nm) and modal parameters (geometric standard deviation, geometric mean diameter and modal aerosol particle concentration) in a...

Measurements of organic gases during aerosol formation events in the boreal forest atmosphere during QUEST (2004)

Sellegri, K., Hanke, M., Umann, B., Arnold, F., Kulmala, M.

Biogenic VOCs are important in the growth and possibly also in the formation of atmospheric aerosol particles. In this work, we present 10 min-time resolution measurements of organic trace gases at...

Ion production rate in a boreal forest based on ion, particle and radiation measurements (2004)

Laakso, L., Petäjä, T., Lehtinen, K. E. J., Kulmala, M., Paatero, J., Hõrrak, U., ...

In this study the ion production rates in a boreal forest are studied based on two different methods: 1) cluster ion and particle concentration measurements, 2) external radiation and radon...

Kinetic nucleation and ions in boreal particle formation events (2004)

Laakso, L., Anttila, T., Lehtinen, K. E. J., Aalto, P. P., Kulmala, M., Hõrrak, U., ...

In order to gain a more comprehensive picture on different mechanisms behind atmospheric particle formation, measurement results from QUEST 2-campaign are analyzed with an aid of an aerosol dynamic...

Atmospheric particle formation events at Värriö measurement station in Finnish Lapland 1998?2002 (2004)

Vehkamäki, H., Dal Maso, M., Hussein, T., Flanagan, R., Hyvärinen, A., Lauros, J., ...

We have identified 147 clear 8 nm diameter particle formation events at the SMEAR I station in Värriö, northern Finland during calendar years 1998?2002. The events have been classified in detail...

Multicomponent aerosol dynamics model UHMA: model development and validation (2004)

Korhonen, H., Lehtinen, K. E. J., Kulmala, M.

A size-segregated aerosol dynamics model UHMA (University of Helsinki Multicomponent Aerosol model) was developed for studies of multicomponent tropospheric aerosol particles. The model includes...

Initial steps of aerosol growth (2004)

Kulmala, M., Laakso, L., Lehtinen, K. E. J., Riipinen, I., Dal Maso, M., Anttila, T., ...

The formation and growth of atmospheric aerosols depend on several steps, namely nucleation, initial steps of growth and subsequent ? mainly condensational ? growth. This work focuses on the initial...

Kinetic nucleation and ions in boreal forest particle formation events (2004)

Laakso, L., Anttila, T., Lehtinen, K. E. J., Aalto, P. P., Kulmala, M., Hõrrak, U., ...

In order to gain a more comprehensive picture on different mechanisms behind atmospheric particle formation, measurement results from QUEST 2-campaign are analyzed with an aid of an aerosol dynamic...

Atmospheric particle formation events at Värriö measurement station in Finnish Lapland 1998-2002 (2004)

Vehkamäki, H., Dal Maso, M., Hussein, T., Flanagan, R., Hyvärinen, A., Lauros, J., ...

During the calendar years 1998-2002, 147 clear 8nm diameter particle formation events have been identified at the SMEAR I station in Värriö, northern Finland. The events have been classified in...

Ion production rate in a boreal forest based on ion, particle and radiation measurements (2004)

Laakso, L., Petäjä, T., Lehtinen, K. E. J., Kulmala, M., Paatero, J., Hõrrak, U., ...

In this study the ion production rates in a boreal forest were studied based on two different methods: 1) cluster ion and particle concentration measurements, 2) external radiation and radon...

Modelling the formation of organic particles in the atmosphere (2004)

Anttila, T., Kulmala, M., Laaksonen, A., O'Dowd, C. D.

Particle formation resulting from activation of inorganic stable clusters by a supersaturated organic vapour was investigated using a numerical model. The applied aerosol dynamic model included a...

Multicomponent aerosol dynamics model UHMA: model development and validation (2004)

Korhonen, H., Lehtinen, K. E. J., Kulmala, M.

A size-segregated aerosol dynamics model UHMA (University of Helsinki Multicomponent Aerosol model) was developed for studies of multicomponent tropospheric aerosol particles. The model includes...

Overview of the field measurement campaign in Hyytiälä, August 2001 in the framework of the EU project OSOA (2004)

Boy, M., Petäjä, T., Dal Maso, M., Rannik, Ü., Rinne, J., Aalto, P., ...

As part of the OSOA (Origin and formation of Secondary Organic Aerosols) project, two intensive field campaigns were conducted in Melpitz, Germany and Hyytiälä, Finland. This paper gives an...

A new feedback mechanism linking forests, aerosols, and climate (2004)

Kulmala, M., Suni, T., Lehtinen, K. E. J., Dal Maso, M., Boy, M., Reissell, A., ...

The possible connections between the carbon balance of ecosystems and aerosol-cloud-climate interactions play a significant role in climate change studies. Carbon dioxide is a greenhouse gas, whereas...

Urban aerosol number size distributions (2004)

Hussein, T., Puustinen, A., Aalto, P. P., Mäkelä, J. M., Hämeri, K., Kulmala, M.

Aerosol number size distributions have been measured since 5 May 1997 in Helsinki, Finland. The presented aerosol data represents size distributions within the particle diameter size range 8-400nm...

Multicomponent aerosol dynamics model UHMA: model development and validation (2004)

H. Korhonen, M. Kulmala

A size-segregated aerosol dynamics model UHMA (University of Helsinki Multicomponent Aerosol model) was developed for studies of multicomponent tropospheric aerosol particles. The model includes...

Atmospheric particle formation events at Värriö measurement station in Finnish Lapland 1998–2002 (2004)

H. Vehkamäki, M. Dal Maso, T. Hussein, R. Flanagan, A. Hyvärinen, J. Lauros, ...

We have identified 147 clear 8 nm diameter particle formation events at the SMEAR I station in Värriö, northern Finland during calendar years 1998–2002. The events have been...

Kinetic nucleation and ions in boreal particle formation events (2004)

L. Laakso, T. Anttila, P. P. Aalto, M. Kulmala, U. Hõrrak, ...

In order to gain a more comprehensive picture on different mechanisms behind atmospheric particle formation, measurement results from QUEST 2-campaign are analyzed with an aid of an aerosol dynamic...

Ion production rate in a boreal forest based on ion, particle and radiation measurements (2004)

L. Laakso, T. Petäjä, M. Kulmala, J. Paatero, U. Hõrrak, ...

In this study the ion production rates in a boreal forest are studied based on two different methods: 1) cluster ion and particle concentration measurements, 2) external radiation and radon...

Measurements of organic gases during aerosol formation events in the boreal forest atmosphere during QUEST (2004)

K. Sellegri, M. Hanke, B. Umann, F. Arnold, M. Kulmala

Biogenic VOCs are important in the growth and possibly also in the formation of atmospheric aerosol particles. In this work, we present 10 min-time resolution measurements of organic trace gases at...

Measurements in a highly polluted Asian mega city: observations of aerosol number size distribution, modal parameters and nucleation events (2004)

P. Mönkkönen, I. K. Koponen, K. Hämeri, R. Uma, M. Kulmala

Diurnal variation of number size distribution (particle size 3–800 nm) and modal parameters (geometric standard deviation, geometric mean diameter and modal aerosol particle concentration) in a...

Sulphuric acid closure and contribution to nucleation mode particle growth (2004)

M. Boy, M. Kulmala, T. M. Ruuskanen, M. Pihlatie, A. Reissell, P. P. Aalto, ...

Sulphuric acid concentrations were measured and calculated based on pseudo steady state model with corresponding measurements of CO, NO<sub>x</sub>, O<sub>3</sub>,...

Temperature and light dependence of the VOC emissions of Scots pine (2004)

V. Tarvainen, H. Hakola, H. Hellén, J. Bäck, P. Hari, M. Kulmala

The volatile organic compound (VOC) emission rates of Scots pine (<I>Pinus sylvestris</I> L.) were measured from trees growing in a natural forest environment at two locations in...

On the growth of nucleation mode particles: source rates of condensable vapor in polluted and clean environments (2004)

M. Kulmala, T. Petäjä, P. Mönkkönen, I. K. Koponen, M. Dal Maso, P. P. Aalto, ...

The growth properties of nucleation mode particles were investigated. The variation of source rates of condensable vapors in different locations and environmental conditions was analyzed. The...

On cloud modelling and the mass accommodation coefficient of water (2004)

A. Laaksonen, T. Vesala, M. Kulmala, P. M. Winkler, P. E. Wagner

The mass accommodation coefficient of water is a quantity for which different experimental techniques have yielded conflicting values in the range 0.04–1. From the viewpoint of cloud modelling,...

Effects of SO2 oxidation on ambient aerosol growth in water and ethanol vapours (2004)

T. Petäjä, K. Hämeri, P. Vaattovaara, J. Joutsensaari, W. Junkermann, ...

Hygroscopicity (i.e. water vapour affinity) of atmospheric aerosol particles is one of the key factors in defining their impacts on climate. Condensation of sulphuric acid onto less hygroscopic...

A pseudo-Lagrangian model study of the size distribution properties over Scandinavia: transport from Aspvreten to Värriö (2004)

P. Tunved, H. Korhonen, J. Ström, M. Kulmala

The evolution of the aerosol size distribution during transport between Aspvreten (58.8° N, 17.4° E) and Värriö (67.46° N, 29.35° E) was studied using a pseudo-Lagrangian...

Characterization and source identification of a fine particle episode in Finland (2004)

Niemi, J. V., Tervahattu, H., Vehkamäki, H., Kulmala, M., Koskentalo, T., Sillanpää, M., ...

A strong long-range transported (LRT) fine particle (PM2.5) episode occurred from March 17–22, 2002 over large areas of Finland. Most of the LRT particle mass was in the submicrometre size...

Modelling the formation of organic particles in the atmosphere (2003)

Anttila, T., Kulmala, M., Laaksonen, A., O'Dowd, C.

A modelling study investigating the formation of organic particles from inorganic, thermodynamically stable clusters was carried out. A recently-developed theory, the so-called nano-Köhler theory,...

A new feedback mechanism linking forests, aerosols, and climate (2003)

Kulmala, M., Suni, T., Lehtinen, K. E. J., Dal Maso, M., Boy, M., Reissell, A., ...

Among significant issues in climate change studies are the possible connections between the carbon balance of ecosystems and aerosol-cloud-climate interactions. Carbon dioxide is a greenhouse gas,...

Urban aerosol number size distributions (2003)

Hussein, T., Puustinen, A., Aalto, P. P., Mäkelä, J. M., Hämeri, K., Kulmala, M.

Aerosol number size distributions were measured continuously in Helsinki, Finland from 5 May 1997 to 28 February 2003. The daily, monthly and annual patterns were investigated. The temporal variation...

Overview of the field measurement campaign in Hyytiälä, August 2001 in the framework of the EU project OSOA (2003)

Boy, M., Petäja, T., Dal Maso, M., Rannik, Ü., Rinne, J., Aalto, P., ...

As one part of the OSOA (Origin and formation of Secondary Organic Aerosols) project, two intensive field campaigns were conducted in Melpitz, Germany and Hyytiälä, Finland. This paper gives an...

One year boundary layer aerosol size distribution data from five Nordic background stations (2003)

Tunved, P., Kulmala, M., Aalto, P., Viisanen, Y., Karlsson, H., ...

Size distribution measurements performed at five different stations have been investigated during a one-year period between 01 June 2000 and 31 May 2001 with focus on diurnal, seasonal and...

One year boundary layer aerosol size distribution data from five nordic background stations (2003)

Tunved, P., Kulmala, M., Aalto, P., Viisanen, Y., Karlsson, H., ...

Size distribution measurements performed at five different stations have been investigated during a one-year period between 01 June 2000 and 31 May 2001 with focus on diurnal, seasonal and...

A model for particle formation and growth in the atmosphere with molecular resolution in size (2003)

Lehtinen, K. E. J., Kulmala, M.

The formation and growth of atmospheric aerosol particles is considered using an exact discrete method with molecular resolution in size space. The method is immune to numerical diffusion problems...

Modelling the formation of organic particles in the atmosphere (2003)

Anttila, T., Kulmala, M., Laaksonen, A., O'Dowd, C.

A modelling study investigating the formation of organic particles from inorganic, thermodynamically stable clusters was carried out. A recently-developed theory, the so-called nano-Köhler theory,...

A new feedback mechanism linking forests, aerosols, and climate (2003)

Kulmala, M., Suni, T., Lehtinen, K. E. J., Dal Maso, M., Boy, M., Reissell, A., ...

Among significant issues in climate change studies are the possible connections between the carbon balance of ecosystems and aerosol-cloud-climate interactions. Carbon dioxide is a greenhouse gas,...

Urban aerosol number size distributions (2003)

Hussein, T., Puustinen, A., Aalto, P. P., Mäkelä, J. M., Hämeri, K., Kulmala, M.

Aerosol number size distributions were measured continuously in Helsinki, Finland from 5 May 1997 to 28 February 2003. The daily, monthly and annual patterns were investigated. The temporal variation...

Overview of the field measurement campaign in Hyytiälä, August 2001 in the framework of the EU project OSOA (2003)

Boy, M., Petäja, T., Dal Maso, M., Rannik, Ü., Rinne, J., Aalto, P., ...

As one part of the OSOA (Origin and formation of Secondary Organic Aerosols) project, two intensive field campaigns were conducted in Melpitz, Germany and Hyytiälä, Finland. This paper gives an...

One year boundary layer aerosol size distribution data from five Nordic background stations (2003)

Tunved, P., Kulmala, M., Aalto, P., Viisanen, Y., Karlsson, H., ...

Size distribution measurements performed at five different stations have been investigated during a one-year period between 01 June 2000 and 31 May 2001 with focus on diurnal, seasonal and...

One year boundary layer aerosol size distribution data from five nordic background stations (2003)

Tunved, P., Kulmala, M., Aalto, P., Viisanen, Y., Karlsson, H., ...

Size distribution measurements performed at five different stations have been investigated during a one-year period between 01 June 2000 and 31 May 2001 with focus on diurnal, seasonal and...

A model for particle formation and growth in the atmosphere with molecular resolution in size (2003)

Lehtinen, K. E. J., Kulmala, M.

The formation and growth of atmospheric aerosol particles is considered using an exact discrete method with molecular resolution in size space. The method is immune to numerical diffusion problems...

The study of finely divided aqueous systems as a clue to understanding the formation mechanisms of polar stratospheric clouds:  1.  HNO3/H2O and H2SO4/H2O systems. (2003)

Bogdan, A., Kulmala, M., MacKenzie, A. Robert, Laaksonen, A., Molina, M. J., Avramenko, A.

The study of nanometer-scale aqueous systems (finely divided aqueous systems (FDAS)) can be achieved using the absorption of vapors on fumed silica (SiO2) powder. Being a product of flame synthesis...

One year boundary layer aerosol size distribution data from five Nordic background stations (2003)

P. Tunved, M. Kulmala, P. Aalto, Y. Viisanen, H. Karlsson, ...

Size distribution measurements performed at five different stations have been investigated during a one-year period between 01 June 2000 and 31 May 2001 with focus on diurnal, seasonal and...

Overview of the field measurement campaign in Hyytiälä, August 2001 in the framework of the EU project OSOA (2003)

M. Boy, T. Petäja, M. Dal Maso, Ü. Rannik, J. Rinne, P. Aalto, ...

As one part of the OSOA (Origin and formation of Secondary Organic Aerosols) project, two intensive field campaigns were conducted in Melpitz, Germany and Hyytiälä, Finland. This paper gives an...

Urban aerosol number size distributions (2003)

T. Hussein, A. Puustinen, P. P. Aalto, J. M. Mäkelä, K. Hämeri, M. Kulmala

Aerosol number size distributions were measured continuously in Helsinki, Finland from 5 May 1997 to 28 February 2003. The daily, monthly and annual patterns were investigated. The temporal variation...

Effects of Fine and Ultrafine Particles on Cardiorespiratory Symptoms in Elderly Subjects with Coronary Heart Disease: The ULTRA Study (2003)

De Hartog, J. J., Hoek, G., Peters, A., Timonen, K. L., Ibald-Mulli, A., Brunekreef, B., ...

The ULTRA Study, a study investigating the association between fine and ultrafine particulate air pollution and cardiorespiratory health, was conducted during the winter of 1998–1999 in Amsterdam,...

An improved parameterization for sulfuric acid-water nucleation rates for tropospheric and stratospheric conditions (2002)

Vehkamaki, H., Kulmala, M., Napari, I., Lehtinen, K. E. J., Timmreck, C., Noppel, M., ...

In this paper we present parameterized equations for calculation of sulfuric acid-water critical nucleus compositions, critical cluster radii and homogeneous nucleation rates for tropospheric and...

A model for particle formation and growth in the atmosphere with molecular resolution in size (2002)

Lehtinen, K. E. J., Kulmala, M.

The formation and growth of atmospheric aerosol particles is considered using an exact discrete method with molecular resolution in size space. The method is immune to numerical diffusion problems...

Influence of spectral solar irradiance on the formation of new particles in the continental boundary layer (2002)

Boy, M., Kulmala, M.

The relationship between nucleation events and spectral solar irradiance was analysed using two years of data collected at the Station for Measuring Forest Ecosystem-Atmosphere Relations (SMEAR II)...

The part of the solar spectrum with the highest influence on the formation of SOA in the continental boundary layer (2002)

Boy, M., Kulmala, M.

The relationship between nucleation events and spectral solar irradiance was analysed using two years of data collected at the Station for Measuring Forest Ecosystem-Atmosphere Relations (SMEAR II)...

Field measurements of hygroscopic properties and state of mixing of nucleation mode particles (2002)

Väkevä, M., Kulmala, M., Stratmann, F., Hämeri, K.

An Ultrafine Tandem Differential Mobility Analyser (UF-TDMA) has been used in several field campaigns over the last few years. The investigations were focused on the origin and properties of...

Nucleation events in the continental boundary layer: Influence of physical and meteorological parameters (2002)

Boy, M., Kulmala, M.

The relationship between nucleation events and numerous physical and meteorological parameters was analysed using data collected at the Station for Measuring Forest Ecosystem-Atmosphere Relations...

A model for particle formation and growth in the atmosphere with molecular resolution in size (2002)

Lehtinen, K. E. J., Kulmala, M.

The formation and growth of atmospheric aerosol particles is considered using an exact discrete method with molecular resolution in size space. The method is immune to numerical diffusion problems...

Influence of spectral solar irradiance on the formation of new particles in the continental boundary layer (2002)

Boy, M., Kulmala, M.

The relationship between nucleation events and spectral solar irradiance was analysed using two years of data collected at the Station for Measuring Forest Ecosystem-Atmosphere Relations (SMEAR II)...

The part of the solar spectrum with the highest influence on the formation of SOA in the continental boundary layer (2002)

Boy, M., Kulmala, M.

The relationship between nucleation events and spectral solar irradiance was analysed using two years of data collected at the Station for Measuring Forest Ecosystem-Atmosphere Relations (SMEAR II)...

Field measurements of hygroscopic properties and state of mixing of nucleation mode particles (2002)

Väkevä, M., Kulmala, M., Stratmann, F., Hämeri, K.

An Ultrafine Tandem Differential Mobility Analyser (UF-TDMA) has been used in several field campaigns over the last few years. The investigations were focused on the origin and properties of...

Nucleation events in the continental boundary layer: Influence of physical and meteorological parameters (2002)

Boy, M., Kulmala, M.

The relationship between nucleation events and numerous physical and meteorological parameters was analysed using data collected at the Station for Measuring Forest Ecosystem-Atmosphere Relations...

Influence of spectral solar irradiance on the formation of new particles in the continental boundary layer (2002)

M. Boy, M. Kulmala

The relationship between nucleation events and spectral solar irradiance was analysed using two years of data collected at the Station for Measuring Forest Ecosystem-Atmosphere Relations (SMEAR II)...

A model for particle formation and growth in the atmosphere with molecular resolution in size (2002)

M. Kulmala

The formation and growth of atmospheric aerosol particles is considered using an exact discrete method with molecular resolution in size space. The method is immune to numerical diffusion problems...

Overview of the international project on biogenic aerosol formation in the boreal forest (BIOFOR) (2001)

Kulmala, M., Hameri, K., Aalto, P.P., Makela, J.M., Pirjola, L., Nilsson, E.D., ...

Aerosol formation and subsequent particle growth in ambient air have been frequently observed at a boreal forest site (SMEAR II station) in Southern Finland. The EU funded project BIOFOR (Biogenic...

Field measurements of hygroscopic properties and state of mixing of nucleation mode particles (2001)

Väkevä, M., Kulmala, M., Stratmann, F., Hämeri, K.

An Ultrafine Tandem Differential Mobility Analyser (UF-TDMA) has been used in several field campaigns over the last few years. The investigations were focused on the origin and properties of...

Nucleation events in the continental boundary layer: Influence of physical and meteorological parameters (2001)

Boy, M., Kulmala, M.

The relationship between nucleation events and numerous physical and meteorological parameters was analysed using data collected at the Station for Measuring Forest Ecosystem-Atmosphere Relations...

Field measurements of hygroscopic properties and state of mixing of nucleation mode particles (2001)

Väkevä, M., Kulmala, M., Stratmann, F., Hämeri, K.

An Ultrafine Tandem Differential Mobility Analyser (UF-TDMA) has been used in several field campaigns over the last few years. The investigations were focused on the origin and properties of...

Nucleation events in the continental boundary layer: Influence of physical and meteorological parameters (2001)

Boy, M., Kulmala, M.

The relationship between nucleation events and numerous physical and meteorological parameters was analysed using data collected at the Station for Measuring Forest Ecosystem-Atmosphere Relations...

Nucleation events in the continental boundary layer: Influence of physical and meteorological parameters (2001)

M. Boy, M. Kulmala

The relationship between nucleation events and numerous physical and meteorological parameters was analysed using data collected at the Station for Measuring Forest Ecosystem-Atmosphere Relations...

Field measurements of hygroscopic properties and state of mixing of nucleation mode particles (2001)

M. Väkevä, M. Kulmala, F. Stratmann, K. Hämeri

An Ultrafine Tandem Differential Mobility Analyser (UF-TDMA) has been used in several field campaigns over the last few years. The investigations were focused on the origin and properties of...

Ternary nucleation of H2SO4, NH3 and H2O (2000)

Kulmala, M., Korhonen, P., Laaksonen, A., Viisanen, Y., McGraw, R., Seinfeld, J. H.

A classical theory of the ternary homogeneous nucleation of sulfuric acid—ammonia—water is presented. For NH3 mixing ratios exceeding 1 ppt, the presence of ammonia enhances the binary (sulfuric...

ACE-2 HILLCLOUD. An overview of the ACE-2 ground-based cloud experiment. (2000)

Bower, B. K. N., Choularton, T. W., Gallagher, M. W., Beswick, K. M., Flynn, M. J., Allen, A. G., ...

The ACE‐2 HILLCLOUD experiment was carried out on the island of Tenerife in June–July 1997 to investigate the interaction of the boundary layer aerosol with a hill cap cloud forming over a ridge...

Atmospheric Chemistry and Physics Discussions (1143)

J. Damski, L. Thölix, L. Backman, J. Kaurola, P. Taalas, J. Austin, ...

A chemistry-transport model simulation of middle atmospheric ozone from 1980 to 2019 using coupled chemistry GCM winds and temperatures