Modes in the size distributions of atmospheric inorganic aerosol

John, Walter; Wall, Stephen; Ondo, J.L.; Winklmayr, Wolfgang

doi:10.1016/0960-1686(90)90327-j

Cited by 266 publications

(126 citation statements)

References 10 publications

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“…One mode was observed around 0.20 mm (condensation mode) and the second and larger mode was at around 0.70 mm (droplet mode) (John et al, 1990;Eldering et al, 1994). Size distributions measured at Fresno, CA, for two different seasons (winter and spring) with an SMPS system showed a bi-modal distribution (Lawless et al, 2001).…”

Section: Size-resolved Mass Distributionsmentioning

confidence: 96%

“…The two modes are overlapping and the condensation mode appears as a ''shoulder'' in the raw measurements. Several authors (Hering and Friedlander, 1982;Wall et al, 1988;John et al, 1990;McMurry and Wilson, 1983) have reported the existence of these two modes in the size distribution of the inorganic aerosol from ambient samples. The sulfate condensation mode is associated with the gas phase oxidation of SO 2 and the droplet mode is the product of heterogeneous reactions mainly in clouds and the accumulation of material from the lower mode.…”

Section: Summermentioning

confidence: 99%

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Mass size distributions and size resolved chemical composition of fine particulate matter at the Pittsburgh supersite

Cabada

Rees

Takahama

et al. 2004

Atmospheric Environment

165

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Size-resolved aerosol mass and chemical composition were measured during the Pittsburgh Air Quality Study. Daily samples were collected for 12 months from July 2001 to June 2002. Micro-orifice uniform deposit impactors (MOUDIs) were used to collect aerosol samples of fine particulate matter smaller than 10 mm. Measurements of PM 0.056 , PM 0.10 , PM 0.18 , PM 0.32 , PM 0.56 , PM 1.0 , PM 1.8 and PM 2.5 with the MOUDI are available for the full study period. Seasonal variations in the concentrations are observed for all size cuts. Higher concentrations are observed during the summer and lower during the winter.Comparison between the PM 2.5 measurements by the MOUDI and other integrated PM samplers reveals good agreement. Good correlation is observed for PM 10 between the MOUDI and an integrated sampler but the MOUDI underestimates PM 10 by 20%. Bouncing of particles from higher stages of the MOUDI (>PM 2.5 ) is not a major problem because of the low concentrations of coarse particles in the area. The main cause of coarse particle losses appears to be losses to the wall of the MOUDI.Samples were collected on aluminum foils for analysis of carbonaceous material and on Teflon filters for analysis of particle mass and inorganic anions and cations. Daily samples were analyzed during the summer (July 2001) and the winter intensives (January 2002). During the summer around 50% of the organic material is lost from the aluminum foils as compared to a filter-based sampler. These losses are due to volatilization and bounce-off from the MOUDI stages. High nitrate losses from the MOUDI are also observed during the summer (above 70%). Good agreement between the gravimetrically determined mass and the sum of the masses of the individual compounds is obtained, if the lost mass from organics and the aerosol water content are included for the summer. For the winter no significant losses of material are detected and there exists reasonable agreement between the gravimetrical mass and the sum of the concentrations of the individual compounds.Ultrafine particles (below 100 nm) account on average, for o 5% of the PM 2.5 mass, and show different composition for the summer and the winter. During the summer the ultrafine mass is 50% carbonaceous material (organic material and elemental carbon) and 50% inorganic (mainly sulfate and ammonium); during the winter these percentages are 70% and 30%, respectively.

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Section: Size-resolved Mass Distributionsmentioning

confidence: 96%

Section: Summermentioning

confidence: 99%

Mass size distributions and size resolved chemical composition of fine particulate matter at the Pittsburgh supersite

Cabada

Rees

Takahama

et al. 2004

Atmospheric Environment

165

View full text Add to dashboard Cite

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“…This calculation was done for both scenarios a and d because, for the particle size ranges considered here, the filter efficiency curve is more sensitive to changes in particle diameter than the deposition-rate curve. 26 To evaluate the sensitivity of the model to uncertainty in size distribution measurement, we varied the MMD of both sulfate and nitrate between 0.5 and 0.7 mm in our calculations of F. Previous studies have reported an MMD of 0.7 mm for nitrate and sulfate size distributions when measurements are resolved to account for sampler collection efficiencies (e.g., 38,39 ). We also considered the impact of uncertainty in EC size distributions.…”

Section: Sensitivity Analysesmentioning

confidence: 99%

Variability in the fraction of ambient fine particulate matter found indoors and observed heterogeneity in health effect estimates

Hodas

Meng

Lunden

et al. 2012

J Expo Sci Environ Epidemiol

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Exposure to ambient (outdoor-generated) fine particulate matter (PM 2.5 ) occurs predominantly indoors. The variable efficiency with which ambient PM 2.5 penetrates and persists indoors is a source of exposure error in air pollution epidemiology and could contribute to observed temporal and spatial heterogeneity in health effect estimates. We used a mass balance approach to model F for several scenarios across which heterogeneity in effect estimates has been observed: with geographic location of residence, residential roadway proximity, socioeconomic status, and central air-conditioning use. We found F is higher in close proximity to primary combustion sources (e.g. proximity to traffic) and for lower income homes. F is lower when PM 2.5 is enriched in nitrate and with central air-conditioning use. As a result, exposure error resulting from variability in F will be greatest when these factors have high temporal and/or spatial variability. The circumstances for which F is lower in our calculations correspond to circumstances for which lower effect estimates have been observed in epidemiological studies and higher F values correspond to higher effect estimates. Our results suggest that variability in exposure misclassification resulting from variability in F is a possible contributor to heterogeneity in PM-mediated health effect estimates.

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“…(11) using the measured values of temperature and relative humidity as well as the current values of the indoor gas concentrations. An initial particle size of 0.5 µm was assumed for the ammonium nitrate particles, based on measurements of the nitrate size distribution for southern California (Wall 1988, John 1990). Correspondingly, a penetration coefficient of 0.8 and a deposition rate coefficient of 0.12 h -1 were used based upon experiments performed in the research house (Thatcher 2002).…”

Section: P Dep Kˆmentioning

confidence: 99%

The transformation of outdoor ammonium nitrate aerosols in the indoor environment

Lunden

Revzan

Fischer

et al. 2003

Atmospheric Environment

136

117

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Recent studies associate particulate air pollution with adverse health effects; however, the exposure to indoor particles of outdoor origin is not well characterized, particularly for individual chemical species. We conducted a field study in an unoccupied, single-story residence in Clovis, California to provide data and analyses to address issues important for assessing exposure. We used real-time particle monitors both outdoors and indoors to quantify PM-2.5 nitrate, sulfate, and carbon. The results show that measured indoor ammonium nitrate concentrations were significantly lower than would be expected based solely on penetration and deposition losses. The additional reduction can be attributed to the transformation indoors of ammonium nitrate into ammonia and nitric acid gases, which are subsequently lost by deposition and sorption to indoor surfaces. A mass balance model that accounts for the kinetics of ammonium nitrate evaporation was able to reproduce measured indoor ammonium nitrate and nitric acid concentrations, resulting in a fitted value of the deposition velocity for nitric acid of 0.56 cm s -1 . The results indicate that indoor exposure to outdoor ammonium nitrate in Central Valley of California are small, and suggest that exposure assessments based on total particle mass measured outdoors may obscure the actual causal relationships for indoor exposure to particles of outdoor origin.

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Modes in the size distributions of atmospheric inorganic aerosol

Cited by 266 publications

References 10 publications

Mass size distributions and size resolved chemical composition of fine particulate matter at the Pittsburgh supersite

Mass size distributions and size resolved chemical composition of fine particulate matter at the Pittsburgh supersite

Variability in the fraction of ambient fine particulate matter found indoors and observed heterogeneity in health effect estimates

The transformation of outdoor ammonium nitrate aerosols in the indoor environment

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