Laboratory simulations and parameterization of the primary marine aerosol production

Martensson, EM; Nilsson, ED; de Leeuw, G; Cohen, LH; Hansson, HC
2003 | J. Geophys. Res.-Atmos. | 108 (D9)
air-sea exchange , births , breaking , bubble bursting , bubbles , dependence , film drop production , jet drops , marine aerosol , primary aerosol , sea salt , seawater surfaces , whitecap , wind-speed

[1] A major source of the primary marine aerosol is the bursting of air bubbles produced by breaking waves. Several source parameterizations are available from the literature, usually limited to particles with a dry diameter D-p > 1 mum. The objective of this work is to extend the current knowledge to submicrometer particles. Bubbles were generated in synthetic seawater using a sintered glass filter, with a size spectra that are only partly the same spectra as measured in the field. Bubble spectra, and size distributions of the resulting aerosol (0.020 - 20.0 mum D-p) of the resulting aerosol, were measured for different salinity, water temperature (T-w), and bubble flux. The spectra show a minimum at similar to1 mum D-p, which separates two modes, one at similar to0.1 mum, with the largest number of particles, and one at 2.5 mum D-p. The modes show different behavior with the variation of salinity and water temperature. When the water temperature increases, the number concentration N-p decreases for D-p < 0.07 μm, whereas for D-p > 0.35 mum, N-p increases. The salinity effect suggests different droplet formation processes for droplets smaller and larger than 0.2 mum D-p. The number of particles produced per size increment, time unit, and whitecap surface (Phi) is described as a linear function of T-w and a polynomial function of D-p. Combining Phi with the whitecap coverage fraction W ( in percent), an expression results for the primary marine aerosol source flux dF(0)/dlogD(p) = W Phi (m(-2) s(-1)). The results are compared with other commonly used formulations as well as with recent field observations. Implications for aerosol-induced effects on climate are discussed.

One year of particle size distribution and aerosol chemical composition measurements at the Zeppelin Station, Svalbard, March 2000-March 2001

Ström, J.; Umegård, J.; Tørseth, K.; Tunved, P.; Hansson, H.-C.; Holmén, K.; Wismann, V.; Herber, A.; König-Langlo, G.
2003 | Phys. Chem. Earth | 28 (1181-1190)

Model simulation of ultrafine particles inside a road tunnel

Gidhagen, L; Johansson, C.; Ström, J; Kristensson, A; Swietlicki, E; Pirjola, L; Hansson, HC
2003 | Atmos. Environ. | 37 (15) (2023-2036)
aerosol model , cfd model , emission factors , field experiment , size distributions , urban , vehicle , vehicle emissions

A monodispersive aerosol dynamic model, coupled to a 3D hydrodynamical grid model, has been used to study the dynamics of ultrafine particles inside a road tunnel in Stockholm, Sweden. The model results were compared to measured data of particle number concentrations, traffic intensity and tunnel ventilation rate. Coagulation and depositional losses to the tunnel walls were shown to be important processes during traffic peak hours, together contributing to losses of 77% of the particles smaller than 10nm and 41% of the particles of size 10-29nm. Particle growth due to water uptake or the presence of a micron-sized, resuspended particle fraction did not have any significant effect on the number of particles lost due to coagulation. Model simulation of particle number concentration response to temporal variations in traffic flow showed that constant emission factors could be used to reproduce the concentration variations of the particles larger than 29nm, while vehicle-speed-dependent factors are suggested to reproduce the variation of the smallest fractions. The emission factors for particle number concentrations estimated from the model simulation are in general higher and show a larger contribution from light-duty vehicles than what has been reported from a tunnel in California. The model study shows that combined measurements and model simulations in road tunnels can be used to improve the determinations of vehicle emission factors for ultrafine particles under realistic driving conditions. (C) 2003 Elsevier Science Ltd. All rights reserved.

Spatial and temporal distribution of the atmospheric aerosols in the lowermost troposphere over the Amazonian tropical rain forest: Do the primary biogenic aerosol emissions control the CCN population?

Krejci, R.; Ström, J.; de Reus, M.; Williams, J.; Andreae, M. O.; Hansson, H.-C.

ILEAPS Open Science Conference

aerosol , aircraft measurements , ccn , convection , lba-claire , tropics , troposphere

Laboratory Simulations and Parameterization of the Primary Marine Aerosol Production.

Mårtensson, E.M.; Nilsson, E.D.; de Leeuw, G.; Cohen, L.H.; Hansson, H.-C.
2003 | J. Geophys. Res. | 108

Hygroscopic properties of mixed ammonium sulfate and carboxylic acids particles

Hameri, K; Charlson, R; Hansson, HC
2002 | AIChE J | 48 (6) (1309-1316)
aerosol-particles , atmospheric particles , behavior , deliquescence , dependence , droplets , growth , los-angeles , organic compounds , relative-humidity

The hygroscopic growth of internally mixed ammonium sulfate and carboxylic acid particles was measured as a function of relative humidity by using a tandem differential mobility analyzer (TDMA). In TDAM experiments the organic compounds with different solubilities act in several ways, ranging from the behavior of totally insoluble substance to that of soluble compounds. The hygroscopic properties for mixtures containing either adipic acid or phthalic acid together with ammonium sulfate indicate that the organic fraction of the particles behaves as an inert mass and does not contribute to water uptake. The mixtures involving malonic acid or succinic acid increased the water uptake of the ammonium sulfate part only. The results indicate that the solubility of the organic fraction in individual aerosol particles clearly influences the aerosol-water interaction.

Submicrometer aerosol particle size distribution and hygroscopic growth measured in the Amazon rain forest during the wet season

Zhou, JC; Swietlicki, E; Hansson, HC; Artaxo, P
2002 | J. Geophys. Res.-Atmos. | 107 (D20)
amazon rain-forest , apportionment , basin , behavior , brazil , characterization experiment ace-1 , claire , dmps , hygroscopicity , marine boundary layer , pacific , range , size distribution , smoke , tdma , transport

The number-size distribution and hygroscopic growth of submicrometer aerosol particles were measured in central Amazonia during the first Cooperative LBA Airborne Regional Experiment (CLAIRE) wet season experiment in March-April 1998. This was the first time ever that these types of measurements were performed in the Amazon rain forest. A Differential Mobility Particle Sizer (DMPS) was used to measure aerosol number-size distribution with diameters in the range 3-850 nm. The observed total number concentrations were frequently between 300 and 600 cm(-3) with a mean value around 450 cm(-3). Two aerosol particle modes (Aitken and accumulation mode) were always present. The average particle concentrations for those two modes were 239 and 177 cm(-3), with geometric diameters of 68 and 151 nm, respectively. An ultrafine mode had a number concentration and a mean diameter of 92 cm(-3) and 24 nm, respectively, and only occurred at 18% of the time, causing the size distribution to be trimodal instead of bimodal. The hygroscopic growth of aerosol particles was measured in situ with a Hygroscopic Tandem Differential Mobility Analyzer (H-TDMA) at six dry particle diameters between 35 and 265 nm. In contrast to the bimodal hygroscopic behavior found in polluted continental environments, the hygroscopic properties of aerosol particles in the Amazon rain forest is essentially unimodal with average diameter growth factors of 1.16-1.32 from dry to 90% relative humidity (RH). Aerosol soluble volume fractions were, in general, between 0.14 and 0.27, estimated by assuming that only ammonium hydrogen sulphate interacted with water vapour.

Hygroscopic properties of mixed ammoniumm sulfate and carboxylic acid particles.

Hämeri, K.; Charlson, R.; Hansson, H.-C.
2002 | AIChE J | 48 (1309-1316)

Gas-aerosol relationships of H2SO4, MSA, and OH: Observations in the coastal marine boundary layer at Mace Head, Ireland

Berresheim, H; Elste, T; Tremmel, HG; Allen, AG; Hansson, HC; Rosman, K; Dal Maso, M; Makela, JM; Kulmala, M; O'Dowd, CD
2002 | J. Geophys. Res.-Atmos. | 107 (D19)
accommodation coefficient , atmospheric sulfur , coastal marine boundary layer , condensation nuclei , field observations , gas-to-particle conversion , hydroxl radical , mass-spectrometer , methane sulfonic acid , methanesulfonic-acid , particle formation , sulfuric acid , ternary nucleation

[1] Atmospheric concentrations of gaseous sulfuric acid (H2SO4), methane sulfonic acid (MSA), and hydroxyl radicals (OH) were measured by chemical ionization mass spectrometry (CIMS) during the second New Particle Formation and Fate in the Coastal Environment (PARFORCE) campaign in June 1999 at Mace Head, Ireland. Overall median concentrations in marine background air were 1.5, 1.2, and 0.12 x 10(6) cm(-3), respectively. H2SO4 was also present at night indicating significant contributions from nonphotochemical sources. A strong correlation was found between daytime OH and H2SO4 levels in clean marine air suggesting a fast local production of H2SO4 from sulfur precursor gases. Steady state balance calculations of ambient H2SO4 levels agreed with measured concentrations if either very low H2SO4 sticking coefficients (0.02-0.03) or sources in addition to the SO2 + OH reaction were assumed. Overall, variations in ambient H2SO4 levels showed no correlation with either the tidal cycle or ultrafine particle (UFP) concentrations. However, on particular days an anticorrelation between H2SO4 and UFP levels was occasionally observed providing evidence for the contribution of H2SO4 to new particle formation and/or particle growth. Gaseous MSA concentrations were inversely correlated with dew point temperature reflecting a highly sensitive gas-particle partitioning equilibrium of this compound. The present observations seriously question the general use of MSA as a conservative tracer to infer the relative production yield of H2SO4 from dimethylsulfide (DMS) oxidation. MSA/H2SO4 concentration ratios typically ranged between 0.06 and 1.0 in marine air at ground level. Measured diel OH profiles showed a significant deviation from concurrent variations of the ozone photolysis frequency. They also showed up to 1 order of magnitude lower values compared to OH concentrations calculated with a simple photochemical box model. These differences were most pronounced during particle nucleation events occurring on sunny days around noon and at low tide. The present results suggest that both the oxidation capacity and the particle formation potential in the coastal boundary layer were significantly affected by reactions of unknown compounds prevailing in this type of environment.

Coastal new particle formation: Environmental conditions and aerosol physicochemical characteristics during nucleation bursts

O'Dowd, CD; Hameri, K; Makela, J; Vakeva, M; Aalto, P; de Leeuw, G; Kunz, GJ; Becker, E; Hansson, HC; Allen, AG; Harrison, RM; Berresheim, H; Geever, M; Jennings, SG; Kulmala, M
2002 | J. Geophys. Res.-Atmos. | 107 (D19)
aerosols , atmosphere , cloud condensation nuclei , coastal particles , cycle , growth , iodine , marine boundary layer , nucleation , oxide , sea-salt-sulfate , tides

[1] Nucleation mode aerosol was characterized during coastal nucleation events at Mace Head during intensive New Particle Formation and Fate in the Coastal Environment (PARFORCE) field campaigns in September 1998 and June 1999. Nucleation events were observed almost on a daily basis during the occurrence of low tide and solar irradiation. In September 1998, average nucleation mode particle concentrations were 8600 cm(-3) during clean air events and 2200 cm(-3) during polluted events. By comparison, during June 1999, mean nucleation mode concentrations were 27,000 cm(-3) during clean events and 3350 cm(-3) during polluted conditions. Peak concentrations often reached 500,000-1,000,000 cm(-3) during the most intense events and the duration of the events ranged from 2 to 8 hours with a mean of 4.5 hours. Source rates for detectable particle sizes (d > 3 nm) were estimated to be between 10(4) and 10(6) cm(-3) s(-1) and initial growth rates of new particles were as high as 0.1-0.35 nm s(-1) at the tidal source region. Recently formed 8 nm particles were subjected to hygroscopic growth and were found to have a growth factor of 1.0-1.1 for humidification at 90% relative humidity. The low growth factors implicate a condensable gas with very low solubility leading to detectable particle formation. It is not clear if this condensable gas also leads to homogeneous nucleation; however, measured sulphuric acid and ammonia concentration suggest that ternary nucleation of thermodynamically stable sulphate clusters is still likely to occur. In clear air, significant particle production (>10(5) cm(-3)) was observed with sulphuric acid gas-phase concentration as low as 2 x 10(6) molecules cm(-3) and under polluted conditions as high as 1.2 x 10(8) molecules cm(-3).

A dedicated study of New Particle Formation and Fate in the Coastal Environment (PARFORCE): Overview of objectives and achievements

O'Dowd, CD; Hameri, K; Makela, JM; Pirjola, L; Kulmala, M; Jennings, SG; Berresheim, H; Hansson, HC; de Leeuw, G; Kunz, GJ; Allen, AG; Hewitt, CN; Jackson, A; Viisanen, Y; Hoffmann, T
2002 | J. Geophys. Res.-Atmos. | 107 (D19)
anthropogenic aerosols , boreal forest , cloud condensation nuclei , iodine oxide , ireland , mace-head , marine boundary layer , nucleation , ozone , sea-salt-sulfate

[1] A dedicated study into the formation of new particles, New Particle Formation and Fate in the Coastal Environment (PARFORCE), was conducted over a period from 1998 to 1999 at the Mace Head Atmospheric Research Station on the western coast of Ireland. Continuous measurements of new particle formation were taken over the 2-year period while two intensive field campaigns were also conducted, one in September 1998 and the other in June 1999. New particle events were observed on similar to90% of days and occurred throughout the year and in all air mass types. These events lasted for, typically, a few hours, with some events lasting more than 8 hours, and occurred during daylight hours coinciding with the occurrence of low tide and exposed shorelines. During these events, peak aerosol concentrations often exceeded 10(6) cm(-3) under clean air conditions, while measured formation rates of detectable particle sizes (i.e., d > 3 nm) were of the order of 10(4)-10(5) cm(-3) s(-1). Nucleation rates of new particles were estimated to be, at least, of the order of 10(5)-10(6) cm(-3) s(-1) and occurred for sulphuric acid concentrations above 2 x 10(6) molecules cm(-3); however, no correlation existed between peak sulphuric acid concentrations, low tide occurrence, or nucleation events. Ternary nucleation theory of the H2SO4-H2O-NH3 system predicts that nucleation rates far in excess of 10(6) cm(-3) s(-1) can readily occur for the given sulphuric acid concentrations; however, aerosol growth modeling studies predict that there is insufficient sulphuric acid to grow new particles (of similar to1 nm in size) into detectable sizes of 3 nm. Hygroscopic growth factor analysis of recently formed 8-nm particles illustrate that these particles must comprise some species significantly less soluble than sulphate aerosol. The nucleation-mode hygroscopic data, combined with the lack of detectable VOC emissions from coastal biota, the strong emission of biogenic halocarbon species, and the fingerprinting of iodine in recently formed (7 nm) particles suggest that the most likely species resulting in the growth of new particles to detectable sizes is an iodine oxide as suggested by previous laboratory experiments. It remains an open question whether nucleation is driven by self nucleation of iodine species, a halocarbon derivative, or whether first, stable clusters are formed through ternary nucleation of sulphuric acid, ammonia, and water vapor, followed by condensation growth into detectable sizes by condensation of iodine species. Airborne measurements confirm that nucleation occurs all along the coastline and that the coastal biogenic aerosol plume can extend many hundreds of kilometers away from the source. During the evolution of the coastal plume, particle growth is observed up to radiatively active sizes of 100 nm. Modeling studies of the yield of cloud-condensation nuclei suggest that the cloud condensation nuclei population can increase by similar to100%. Given that the production of new particles from coastal biogenic sources occurs at least all along the western coast of Europe, and possibly many other coastlines, it is suggested that coastal aerosols contribute significantly to the natural background aerosol population.

Biogenic emissions and gaseous precursors to forest aerosols.

Janson, R.; Rosman, K.; Karlsson, A.; Hansson, H.-C.
2001 | Tellus | 53B (423-440)
atmospheric particles , monoterpenes , organic aerosol

Contact information

Visiting addresses:

Geovetenskapens Hus,
Svante Arrhenius väg 8, Stockholm

Arrheniuslaboratoriet, Svante Arrhenius väg 16, Stockholm (Unit for Toxicological Chemistry)

Mailing address:
Department of Environmental Science
Stockholm University
106 91 Stockholm

Press enquiries should be directed to:

Stella Papadopoulou
Science Communicator
Phone +46 (0)8 674 70 11