Aerosol Mass Size Distributions Research Articles

On the correlation of atmospheric aerosol components of mass size distributions in the larger region of a central European city

Mass size distributions of atmospheric aerosols have been sampled in the region of Vienna, a typical city in central Europe, at an urban and a rural site. The aerosol was collected simultaneously by cascade impactors. Two experiments which had a duration of 4 weeks each, were performed in August 1999 and in January/February 2000. Daily sampling periods were from 8:00 to 20:00, and from 20:00 to 8:00. An evaluation of the mass size distributions is represented in this paper. Emphasis is on the relationships of different aerosol components in a local and a regional context. The main results are as follows. The main components of the atmospheric aerosol are a fine aerosol, the accumulation aerosol, and a coarse aerosol. Specific coarse modes with modal diameters of 4.7mm average and geometric standard deviations of about 3 occur at the urban and at the rural site, some times surprisingly strong. The fine and the coarse modes are very likely related to motor-car traffic. Usually the PM2.5 and PM10 aerosols are regionally strongly correlated. Occasionally, this correlation is effectively disturbed by local and/or regional emissions. Time series of correlation coefficients reveal an episodic character of the atmospheric aerosol. Periods of strong inter-site correlations of PM2.5 and PM10 indicate the dominance and the co-variation of the accumulation aerosols or the dominance and the co-variation of the coarse modes. r 2004 Elsevier Ltd. All rights reserved.

IMAGES‐SCAPE2: A modeling study of size‐ and chemically resolved aerosol thermodynamics in a global chemical transport model

Chemically and size‐resolved aerosol mass size distributions are simulated online using the Intermediate Model of Global Evolution of Species (IMAGES). Aerosol‐phase thermodynamics is coupled to this chemical transport model using the Simulating Composition of Atmospheric Particles at Equilibrium (SCAPE2) module. Emphasis is placed on the equilibrium concentrations of aerosol ammonium, nitrate, sulfate, and water content subject to the interaction with ions from sea salt and dust. Transport for both aerosol and gas‐phase species is solved using a semi‐Lagrangian scheme driven by monthly mean climatological variables provided by European Centre for Medium‐Range Weather Forecasts (ECMWF) analysis. This study presents estimates of annual average dry mass size distributions at selected stations in North America and Europe. Simulations are performed to observe the major differences between the coupled IMAGES‐SCAPE2 model and IMAGES alone for key aerosol species. Nitrate concentrations predicted with IMAGES‐SCAPE2 compare better with observations than those calculated with IMAGES alone. Model results show that aerosol size distributions are generally bimodal. This study finds that over polluted continental regions, the presence of sea‐salt and dust aerosol potentially increases the formation of sulfate by 20–80%. Nitrate formation is enhanced by 14–60%, whereas ammonium formation is decreased by 20–60%. Nitrate plays an important role to determine the size distributions in many European stations. The presence of water changes the general shape of the size distribution, placing maximum values on larger size ranges.

Mass Concentration and Size-Resolved Chemical Composition of Atmospheric Aerosols Sampled at the Pescadores Islands during Asian Dust Storm Periods in the Years of 2001 and 2002

This study investigated the mass concentration and size distribution of atmospheric aerosols collected at the Pescadores Islands during Asian dust storm periods in the years of 2001 and 2002. As part of an island-wide Asian dust sampling network covering Taiwan and its surrounding islands, an atmospheric aerosol sampling site was established at Xiaumen, Pescadores Islands since March 2001. Xiaumen was at the northwest tip of the Pescadores Islands located at the center of Taiwan Strait and approximately 110 kilometers from the West Coast of the Taiwan Main Island. The sampling protocol was conducted to collect sea level atmospheric aerosols for further physical and chemical analysis. This study revealed that five Asian dust storms invaded the Pescadores Islands during the sampling campaign. The mass concentration of atmospheric aerosols, particularly PM(subscript 2.5-1O), were 2-3 times higher than background levels (i.e., non-Asian dust storm periods). Comparison of hourly PM10 concentration between Xiaumen and ambient air quality monitoring stations in Taiwan indicated that Asian dust storms usually invaded from either the northeast or the northwest and could last for approximately 2 - 4 days. Moreover, Asian dusts could be preliminarily validated in situ by observing the change of their apparent colors from dark gray to light brown. Comparison of hourly PM10 concentration measured at the Pescadores Islands and Taiwan Main Island during the Asian dust storm periods showed that the Asian dust storm invaded Taiwan from either the northwest or the northeast. Increasing both concentration and coarse particle mode in the size distribution of atmospheric aerosols validated the invasion of Asian dust storms. Significant increase of SO4(superscript 2-), Cl(superscript -), Na(superscript +), NH4(superscript +), Mg(superscript 2+) and Ca^(superscript 2+) concentration on coarse particle mode was also observed for Asian dusts. This suggested that not just natural soil dusts but also anthropogenic pollutants and oceanic spray could accompany the Asian dust storms and arrive at the Pescadores Islands.

Influence of Long-Range Transport Dust Particles on Local Air Quality: A Case Study on Asian Dust Episodes in Taipei during the Spring of 2002

In the spring of 2002, an intensive field measurement campaign was conducted to investigate the impact of Asian dust transport on local air quality in Taipei, Taiwan. The mass concentration, size distribution and chemical composition of the atmospheric aerosols were measured. Air quality data collected by the Taiwan EPA during this period were also analyzed. It was found that the content of crustal elements in aerosols could drastically increase on the arrival of air masses transported from the desert areas in Northwestern China and Mongolia. Time series analysis of aerosol measurements, air quality data, and meteorological conditions identified six Asian dust transport episodes occurring in the spring of 2002. In order to apportion the ambient aerosol burden between local and long-range sources, nitrogen oxides (NO(subscript x)) was chosen as a local pollution tracer and a simplified algorithm based on the NO(subscript x) and PM10 correlation was proposed. It was estimated that long-range transported aerosols contributed as much as 87% to the PM10 in Taipei on Feb. 11, the most intense dust event in 2002. A weak event that occurred on Mar. 23 contributed 35% to the PM10. Our results indicate that the air quality impact due to Asian transport dust is still important even during weak dust events.

Size distributions of water-soluble organic carbon in ambient aerosols and its size-resolved thermal characteristics

Abstract Aerosol mass size distributions of water-soluble organic carbon (WSOC) were studied at a coastal site in Hong Kong. Eleven sets of 72-h samples were collected using an eight-stage impactor sampler over three seasons in 2000–2001. Regardless of air mass origins being mainly marine or continental, WSOC exhibited bimodal size distributions with a dominant fine mode and a minor coarse mode in the size range of >0.43 μm. The two modes had a mass mean aerodynamic diameter (MMAD) of 0.7±0.1 and 4.0±0.3 μm, respectively. The fine WSOC accounted for the major proportion of the total WSOC, ranging from two-thirds to four-fifths. The WSOC mixtures were resolved into 3–5 peaks under controlled progressive heating and combustion conditions. A positive matrix factorization analysis deconvoluted the WSOC mixtures into three component groups of different thermal behaviors. The three groups of WSOC species were postulated to be low, medium, and high molecular weight (MW) polar compounds on the basis of their thermal evolution features. On average, they accounted for 21%, 39%, and 40% of fine WSOC ( 2.1 μm) was largely made of the low MW polar compound group. The low MW group had a bimodal distribution with a dominant coarse mode, likely associated with sea salt aerosols. The medium and the high MW groups had a single mode distribution in the droplet mode, both with an average MMAD of 0.7±0.1 μm. Their droplet mode presence indicated that they were associated with cloud-processed particles. There is evidence to suggest that the high MW group was likely secondary in origin, formed during cloud processing.

Particle size distribution and respiratory deposition estimates of beryllium aerosols in an extraction and processing plant.

The mass size distribution of beryllium aerosols generated in the various operational areas of a typical extraction and processing plant was studied using an eight-stage impactor sampler. The total concentration of beryllium in the plant was found to be well below the threshold limit value. The mean value of mass median aerodynamic diameter of beryllium particles observed for various operations ranged from 5.0-9.5 microm. The alveolar deposition for various operational areas was estimated to be 3-5% for nasal breathing and 9-13% for oral breathing based on the International Commission on Radiological Protection (ICRP) human respiratory tract model. Deposition during oral breathing was higher than during nasal breathing by approximately a factor of two to three. This study on exposure characterization was useful for reducing the respirable fraction of beryllium aerosol by optimizing the capture velocity and improving the quality of other control measures.

Particle Size Distribution and Respiratory Deposition Estimates of Beryllium Aerosols in an Extraction and Processing Plant

The mass size distribution of beryllium aerosols generated in the various operational areas of a typical extraction and processing plant was studied using an eight-stage impactor sampler. The total concentration of beryllium in the plant was found to be well below the threshold limit value. The mean value of mass median aerodynamic diameter of beryllium particles observed for various operations ranged from 5.0–9.5 µm. The alveolar deposition for various operational areas was estimated to be 3–5% for nasal breathing and 9–13% for oral breathing based on the International Commission on Radiological Protection (ICRP) human respiratory tract model. Deposition during oral breathing was higher than during nasal breathing by approximately a factor of two to three. This study on exposure characterization was useful for reducing the respirable fraction of beryllium aerosol by optimizing the capture velocity and improving the quality of other control measures.

A case study of aerosol (4.6 nm< Dp

The Air Quality Management community is increasingly turning its attention to urban ‘hot-spots’ where localised high concentrations of pollutants can arise. One such location is the urban street canyon where dispersion is poorly understood or described by regulatory models because of the complexity of the airflow, turbulence and local influences. Similarly, simple metrics such as PM 10 fail to describe the range of sizes, composition, sources and behaviours encompassed by the term ‘particle’. A 2-week experimental case study to measure size-segregated aerosol in the size range 4.6 nm–10 μm at a fine time scale (10 min resolution) was undertaken in a typical street canyon in Manchester. The wind direction incident to the canyon, and hence the vortex flow within the canyon, was found to have a large influence on the number concentrations, with values typically 2–10 times greater in perpendicular flow than the estimated inner-urban background. Concentrations were also inversely related to wind speed and directly related to traffic flow. Coarse mode mass concentrations were generally found to follow urban background PM 10 concentrations except with a 0–5 μg m −3 enhancement related to traffic-induced re-suspension within the canyon. A small pollution episode consisting of coarse material re-suspended by high winds was extended in time within the canyon.

Studies on aerosol optical properties over urban and semi-urban environments of Hyderabad and Anantapur

Aerosols in the troposphere exert an important influence on global climate and the environment through scattering, transmission and absorption of radiation as well as acting as nuclei for cloud formation. Atmospheric aerosol particles influence the earth's radiation balance directly by scattering of infrared energy and indirectly by modifying the properties of clouds through microphysical processes. The present study addresses visibility, radiative forcing, size distribution and attenuation of aerosols over the period from January to May, 2001 for urban and semi-urban regions of Hyderabad and Anantapur. High aerosol loading has been observed over urban environment compared to semi-urban environment. Aerosol optical depth values increased from January to April and then decreased during May over both urban and semi-urban regions. Over urban region, visibility decreased from January to April and increased during May. Similar trend has been observed over semi-urban region with relatively higher values of visibility. Radiative forcing estimated using aerosol optical depth values increased from January to April and then decreased during the month of May over urban and semi-urban areas. High visibility and low radiative forcing has been noticed over semi-urban area due to less aerosol loading. Wavelength exponent and turbidity coefficient registered high values over urban environment compared to semi-urban environment. Attenuation coefficient showed high values over urban region compared to semi-urban region. It reveals that semi-urban environment receives high solar flux than urban environment. Using 10 channel quartz crystal microbalance, measurements of total mass concentration and mass size distribution of near surface aerosols has been made over semi-urban environment and compared with size distribution derived from inversion methods based on aerosol optical depth variation with wavelength. The sensitivity of constrained linear inversions for inferring columnar aerosol size distributions has been discussed in detail in the paper.

Premonsoon aerosol mass loadings and size distributions over the Arabian Sea and the tropical Indian Ocean

From the cruise expeditions conducted onboard the Oceanographic Research Vessel Sagar Kanya during 1996–2000 over the Arabian Sea (AS) and the tropical Indian Ocean (TIO), aerosol mass concentrations and size distributions are measured in situ in the radius range of 0.025–12.5 μm and are analyzed. The monthly and yearly mean variabilities and trends in aerosol characteristics during the NE winter monsoon (December–April) over these oceanic regions are studied. The effect of relative humidity (RH) on the measured mass concentrations is calculated and the scaling factors are applied to bring the mass concentrations to 50% RH. The 5‐year mean mass variations show that the aerosol mass concentrations over Coastal India (CI) in the coarse, accumulation, and nucleation modes are higher than those measured over the AS and the TIO. The coarse mode is found to contribute about 20% over CI, the AS, and the TIO. Over all the three regions, the accumulation mode contribution is more or less similar and lies in the range of 42–48%. The nucleation mode aerosols are found to contribute about 32% over CI, 39% over the AS, and 30% over the TIO. The monthly mean accumulation and nucleation mass concentrations over CI and the AS are found to increase from winter to summer as has been seen over land. The winter variability trends show that the aerosol mass concentrations on an average increase by about 22% yr−1, 15% yr−1, and 42% yr−1 over CI, the AS, and the TIO. Examination of the relation between aerosol mass concentrations and wind speeds reveals that the wind index over the AS and the Indian Ocean is higher than most of the other oceanic regions of the world and the background aerosol mass concentration is quite high, which indicates a strong influence from the continent. Lognormal fits made to the aerosol size distribution indicate that the CI, the AS, and the Indian Ocean region measurements could be fitted with three modes. The size distributions are found to peak at ∼0.03, 0.1, and 1.5 μm. The widths of the size distributions show little variations, indicating that while the influx and production of aerosols influenced mainly by meteorological conditions have changed, the physical processes responsible for the shape of the distribution have remained the same over the 5‐year period. The number densities obtained over Indian Ocean region are found to be the highest ever measured when compared with other oceanic regions. The size distributions in the nucleation mode have more than an order of magnitude higher number densities when compared with maritime models. The total aerosol number density (N) and the effective radius (reff) of the aerosol size distributions track the variations of mass concentration and number density distributions. “Effective” refractive indices are suggested for the three regions based on a comparison of the measured and estimated extinction coefficients from the aerosol mass data. Over the AS, two distinct groups of comparisons between measured and estimated extinction coefficients indicate that the sources of aerosols are different. Seven‐day back trajectory analyses show that for one group of values the air masses traveled a long way from Saudi Arabia and Iran/Iraq before reaching the location of measurement, while for the other the air mass originates from Pakistan and passes the Indian Coast of Gujarat through the Thar desert and Rann of Kutch. The measured and calculated single scattering albedo (ω) values are found to compare well within one standard deviation for all the three regions and are in the range of 0.83–0.88, 0.87–0.93, and 0.88–0.99 for CI, AS, and Indian Ocean, respectively. The good agreement between the measured and the calculated ω values indicates that suggested refractive indices for the different oceanic regions are valid.

Composition, size distribution and lung deposition distribution of aerosols collected in the atmosphere of a speleotherapeutic cave situated below Budapest, Hungary

Elemental composition and mass size distribution of cave aerosols were determined by PIXE on seven-stage cascade impactor samples collected in two different sites of the Szemlőhegy-cave, a speleotherapeutic cave situated below Budapest, Hungary. In addition, individual particle analysis was also performed on about 450 aerosol particles. Significant differences were found between the two sampling sites and also in comparison with the external air in both the size distribution and in the composition of the aerosol. On the basis of the obtained data a stochastic lung deposition model was used to calculate total and regional deposition efficiencies of the different types of particles along the human respiratory system. One can conclude that the extrathoracic deposition is quite significant and its role increasing with increasing respiratory minute volume. The regional thoracic deposition is not very sensitive to the size distribution and it has a maximum around the 15–20th airway generations.

Aerosol radiative, physical, and chemical properties in Beijing during June 1999

Beijing experiences air pollution such that the sky overhead is gray much of the time even on cloudless days. In order to understand the cause of this problem, the aerosol light scattering coefficient σsp and absorption coefficient σap were measured under dry conditions (instrumental relative humidity &lt;40%) during a 1‐week intensive field sampling period in June 1999 in Beijing, China. Additional measurements included the aerosol mass size distribution, chemical composition of the aerosol mass having particle diameters less than 2.5 μm (PM2.5) as well as the chemical composition of the total suspended particulate matter. The mean (and standard deviation) for hourly averages of σsp, σap, and the single‐scattering albedo ω were 488 Mm−1 (370 Mm−1), 83 Mm−1 (40 Mm−1), and 0.81 (0.08), respectively, which is significantly higher than values reported in urban regions of the United States. The relatively high values of σsp were accompanied by a daily mean value for the PM2.5 mass concentration of 136 μg m−3 (48 μg m−3), which is significantly higher than the proposed U.S. 24‐hour average mean National Ambient Air Quality Standard of 65 μg m−3. The visual range during the field study, based on measurements of σsp and σap, was typically less than 6 km. For several days that did not have rain or fog, there was a clear diurnal trend in σsp, σap, and ω, with peak values in the early morning and minima that occur in the evenings. The peaks correspond to minima in ambient temperature and maxima in relative humidity. Mass size distribution measurements indicate that although ∼80% of the aerosol mass was located in the coarse particle mode (Dp &gt; 1.0 μm), the submicron aerosol was responsible for ∼80% of the light scattering at 530 nm. The largest contribution to the PM2.5 aerosol mass was due to organic compounds, which accounted for ∼30% of the mass. The contributions of sulfate, ammonium, and nitrate to the PM2.5 mass concentration were ∼15%, 5%, and 8%, respectively. Mineral aerosol contributed ∼16% to the PM2.5 aerosol mass. These data show that combustion‐related particles rather than wind‐blown dust dominated the light extinction budget during June 1999.

Aerosol mass-size distributions at a tropical coastal environment: response to mesoscale and synoptic processes

Regular measurements of total mass concentration and mass-size distribution of near-surface aerosols, made using a ten-channel Quartz Crystal Microbalance (qcm) Impactor for the period October 1998–December 1999 at the tropical coastal station Trivandrum (8.5°N, 77°E), are used to study the response of aerosol characteristics to regional mesoscale and synoptic processes. Results reveal that aerosol mass concentrations are generally higher under land breeze conditions. The sea breeze generally has a cleansing effect, depleting the aerosol loading. The continental air (LB regime) is richer in accumulation mode (submicron) aerosols than the marine air. On a synoptic scale, aerosol mass concentration in the submicron mode decreased from an average high value of ∼86 μg m −3 during the dry months (January–March) to ∼11 μg m −3 during the monsoon season (June–September). On the contrary mass concentration in the supermicron mode increased from a low value of ∼15 μg m −3 during the dry months to reach a comparatively high value of ∼35 μg m −3 during April, May. Correspondingly, the effective radius ( R eff) increased from a low value of 0.15–0.17 μm to ∼0.3 μm indicating a seasonal change in the size distribution. The mass-size distribution shows mainly three modes, a fine mode (∼0.1 μm); a large mode (∼0.5 μm) and a coarse mode (∼3 μm). The fine mode dominates in winter. In summer the large mode becomes more conspicuous and the coarse mode builds up. The fine mode is highly reduced in monsoon and the large and coarse modes continue to remain high (replenished) so that their relative dominance increases. The size distribution tends to revert to the winter pattern in the post-monsoon season. Accumulation (submicron) aerosols account for ∼98% of the total surface area and ∼70% of the total volume of aerosols during winter. During monsoon, even though they still account for ∼90% of the area, their contribution to the volume is reduced to ∼50%; the coarse aerosols account for the rest.

Measurement of210Pb,210Po, and210Bi in Size-Fractionated Atmospheric Aerosols: An Estimate of Fine-Aerosol Residence Times

Lead-210 and {sup 210}Po were measured in size-fractionated aerosol samples collected at several sites in North America. Total particulate mass concentrations of the samples were 23-98 {mu}g/m{sup 3}, with 23-67% of the mass in size ranges below 2 {mu}m. The aerosol mass size distributions below 9 {mu}m were generally bimodal, with a maximum in the coarse-particle range occurring primarily at 3.1 {mu}m and a maximum in the accumulation range occurring at approximately 0.6 {mu}m. Total {sup 210}Pb concentrations were 0.51-1.7 mBq/m{sup 3}, with 63-97% occurring in the size ranges below 2 {mu}m. The {sup 210}Po/{sup 210}Pb ratios suggested residence times of 33-66 days for the aerosols below 2 {mu}m. The {sup 210}Bi/{sup 210}Pb ratios of selected samples gave similar results to the {sup 210}Po/{sup 210}Pb ratios, leading to residence times of 6-67 days, with the largest differences occurring in the larger size ranges.

Aerosol size distributions of elemental and organic carbon in urban and over-water atmospheres

Aerosol mass size distributions of elemental carbon (EC) and organic carbon (OC) were measured to determine the extent to which carbon speciations within ambient aerosols differ between urban and over-water atmospheres. Samples were collected during twenty-one 12-h periods in urban Chicago and over Lake Michigan during the July 1994 and January 1995 sampling intensives. Total particle bound concentrations (sum of all size fractions) of elemental and organic carbon ranged from 0.15 to 0.96 and from 0.94 to 3.04 g m −3, respectively. On average, organic material (OM=1.4×OC) accounts for 18% of the total aerosol mass collected, but ranges from 10% (over-water, winter) to 39% (urban, summer). With regard to individual size fractions, organic matter ranges from 3% (>12 μm over-water, winter) to 49% (0.15–0.45 μm, urban, summer) of the particulate matter mass in the size class. Geometric mean aerodynamic equivalent diameters (GMDs) range from 0.72 to 2.4 μm for suspended particulate matter ( Σ-PM), from 0.52 to 1.4 μm for EC, and from 0.60 to 1.9 μm for OC. Elemental and organic carbon GMDs are larger in the urban atmosphere than over the water during winter, while this trend is not observed in Σ-PM. Furthermore, geometric standard deviations are larger at the urban location in January for both EC and OC, indicating broader size distributions of both species under winter conditions due to greater quantities of EC and OC in large particles.

INAA and PIXE of atmospheric and combustion aerosols.

Using instrumental neutron activation analyses and photon-induced x-ray emission techniques for analysis of size-fractionated atmospheric and combustion aerosols and other emission samples arising from fluidized-bed combustion of North Bohemian lignites up to 42 elements were determined in all samples types. This allowed the evaluation of element enrichment, time trends, and inter-element correlations and the performance of factor analysis of various fractions of atmospheric aerosols. The data obtained on mass and element size distributions of aerosols and emission samples obtained upon lignite combustion in an experimental scale atmospheric fluidized-bed combustor without and with added hydrated lime and limestone were used to elucidate the mechanism of abatement of toxic trace and matrix elements from flue gas.

Aerosol Size Distributions of Polycyclic Aromatic Hydrocarbons in Urban and Over-Water Atmospheres

Aerosol mass size distributions of 41 polycyclic aromatic hydrocarbons (PAHs) were measured during 20 different 12-h periods in urban Chicago and over Lake Michigan during July 1994 and January 1995. Geometric mean aerodynamic equivalent diameters (GMDs) range from 0.72 to 2.39 μm for particulate matter and from 0.33 to 9.85 μm for individual PAHs. GMDs of the less volatile PAHs are larger in the urban atmosphere than over the water during the summer. Geometric standard deviations of the particle size distributions, however, are larger at the urban location for many PAHs, indicating a broader mass size distributions. GMDs of unsubstituted PAHs (except perylene) are well correlated with their log subcooled liquid vapor pressures ( , Pa), following the form: GMD = mg log + bg . Values for mg and bg range from 0.03 to 0.88 and from 0.83 to 8.80, respectively. Higher molecular weight PAHs are sorbed to the finest sized aerosols, but more volatile PAHs are associated with larger particles. The slope (mg) and ...

An Evaluation of PM10 and PM2.5 Size Selective Inlet Performance Using Ambient Aerosol

Ambient aerosol mass size distributions measured in six Australian cities have been used to evaluate the performance of two PM10 and two PM2.5 size selective inlets (SSI) under Australian conditions. Small systematic differences were found between the calculated SSI responses and those of an ideal sampler. However the differences average <10% for both PM10 and PM2.5 inlets, which is the criterion specified in the US and Australian reference methods for PM10 measurement.

Cloud condensation nuclei (CCN) and aerosol mass size distributions at an European background and an urban site

Cloud condensation nuclei (CCN) and aerosol mass size distributions at an European background and an urban site

The contributions of snow, fog, and dry deposition to the summer flux of anions and cations at Summit, Greenland

Experiments were performed during the period May–July of 1993 at Summit, Greenland. Aerosol mass size distributions as well as daily average concentrations of several anionic and cationic species were measured. Dry deposition velocities for SO42− were estimated using surrogate surfaces (symmetric airfoils) as well as impactor data. Real‐time concentrations of particles greater than 0.5 μm and greater than 0.01 μm were measured. Snow and fog samples from nearly all of the events occurring during the field season were collected. Filter sampler results indicate that SO42− is the dominant aerosol anion species, with Na+, NH4+, and Ca2+ being the dominant cations. Impactor results indicate that MSA and SO42− have similar mass size distributions. Furthermore, MSA and SO42− have mass in both the accumulation and coarse modes. A limited number of samples for NH4+ indicate that it exists in the accumulation mode. Na, K, Mg, and Ca exist primarily in the coarse mode. Dry deposition velocities estimated from impactor samples and a theory for dry deposition to snow range from 0.017 cm/s +/− 0.011 cm/s for NH4+ to 0.110 cm/s +/− 0.021 cm/s for Ca. SO42− dry deposition velocity estimates using airfoils are in the range 0.023 cm/s to 0.062 cm/s, as much as 60% greater than values calculated using the airborne size distribution data. The rough agreement between the airfoil and impactor‐estimated dry deposition velocities suggests that the airfoils may be used to approximate the dry deposition to the snow surface. Laser particle counter (LPC) results show that particles &gt; 0.5 μm in diameter efficiently serve as nuclei to form fog droplets. Condensation nuclei (CN) measurements indicate that particles &lt; 0.5 μm are not as greatly affected by fog. Furthermore, impactor measurements suggest that from 50% to 80% of the aerosol SO42− serves as nuclei for fog droplets. Snow deposition is the dominant mechanism transporting chemicals to the ice sheet. For NO3−, a species that apparently exists primarily in the gas phase as HNO3(g), 93% of the seasonal inventory (mass of a deposited chemical species per unit area during the season) is due to snow deposition, which suggests efficient scavenging of HNO3(g) by snowflakes. The contribution of snow deposition to the seasonal inventories of aerosols ranges from 45% for MSA to 76% for NH4+. The contribution of fog to the seasonal inventories ranges from 13% for Na+ and Ca2+ to 26% and 32% for SO42− and MSA. The dry deposition contribution to the seasonal inventories of the aerosol species is as low as 5% for NH4+ and as high as 23% for MSA. The seasonal inventory estimations do not take into consideration the spatial variability caused by blowing and drifting snow. Overall, results indicate that snow deposition of chemical species is the dominant flux mechanism during the summer at Summit and that all three deposition processes should be considered when estimating atmospheric concentrations based on ice core chemical signals.