Differences in fine particle chemical composition on clear and cloudy days.
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ABSTRACT:
SUBMITTER: Christiansen AE
PROVIDER: S-EPMC8353954 | biostudies-literature |
REPOSITORIES: biostudies-literature
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Project description:RationaleThere are unexplained geographical and seasonal differences in the short-term effects of fine particulate matter (PM(2.5)) on human health. The hypothesis has been advanced to include the possibility that such differences might be due to variations in the PM(2.5) chemical composition, but evidence supporting this hypothesis is lacking.ObjectivesTo examine whether variation in the relative risks (RR) of hospitalization associated with ambient exposure to PM(2.5) total mass reflects differences in PM(2.5) chemical composition.MethodsWe linked two national datasets by county and by season: (1) long-term average concentrations of PM(2.5) chemical components for 2000-2005 and (2) RRs of cardiovascular and respiratory hospitalizations for persons 65 years or older associated with a 10-microg/m(3) increase in PM(2.5) total mass on the same day for 106 U.S. counties for 1999 through 2005.Measurements and main resultsWe found a positive and statistically significant association between county-specific estimates of the short-term effects of PM(2.5) on cardiovascular and respiratory hospitalizations and county-specific levels of vanadium, elemental carbon, or nickel PM(2.5) content.ConclusionsCommunities with higher PM(2.5) content of nickel, vanadium, and elemental carbon and/or their related sources were found to have higher risk of hospitalizations associated with short-term exposure to PM(2.5).
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Project description:Particle chemical composition affects aerosol optical and physical properties in ways important for the fate, transport, and impact of atmospheric particulate matter. For example, hygroscopic constituents take up water to increase the physical size of a particle, which can alter the extinction properties and atmospheric lifetime. At the collocated AERosol RObotic NETwork (AERONET) and Interagency Monitoring of PROtected Visual Environments (IMPROVE) network monitoring stations in rural Bondville, Illinois, we employ a novel cloudiness determination method to compare measured aerosol physicochemical properties on predominantly cloudy and clear sky days from 2010 to 2019. On cloudy days, aerosol optical depth (AOD) is significantly higher than on clear sky days in all seasons. Measured Ångström exponents are significantly smaller on cloudy days, indicating physically larger average particle size for the sampled populations in all seasons except winter. Mass concentrations of fine particulate matter that include estimates of aerosol liquid water (ALW) are higher on cloudy days in all seasons but winter. More ALW on cloudy days is consistent with larger particle sizes inferred from Ångström exponent measurements. Aerosol chemical composition that affects hygroscopicity plays a determining impact on cloudy versus clear sky differences in AOD, Ångström exponents, and ALW. This work highlights the need for simultaneous collocated, high-time-resolution measurements of both aerosol chemical and physical properties, in particular at cloudy times when quantitative understanding of tropospheric composition is most uncertain.
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Project description:Epidemiologic and health impact studies are inhibited by the paucity of global, long-term measurements of the chemical composition of fine particulate matter. We inferred PM2.5 chemical composition at 0.1° × 0.1° spatial resolution for 2004-2008 by combining aerosol optical depth retrieved from the MODIS and MISR satellite instruments, with coincident profile and composition information from the GEOS-Chem global chemical transport model. Evaluation of the satellite-model PM2.5 composition data set with North American in situ measurements indicated significant spatial agreement for secondary inorganic aerosol, particulate organic mass, black carbon, mineral dust, and sea salt. We found that global population-weighted PM2.5 concentrations were dominated by particulate organic mass (11.9 ± 7.3 ?g/m(3)), secondary inorganic aerosol (11.1 ± 5.0 ?g/m(3)), and mineral dust (11.1 ± 7.9 ?g/m(3)). Secondary inorganic PM2.5 concentrations exceeded 30 ?g/m(3) over East China. Sensitivity simulations suggested that population-weighted ambient PM2.5 from biofuel burning (11 ?g/m(3)) could be almost as large as from fossil fuel combustion sources (17 ?g/m(3)). These estimates offer information about global population exposure to the chemical components and sources of PM2.5.
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Project description:BACKGROUND:Most epidemiological studies address health effects of atmospheric particulate matter (PM) using mass-based measurements as exposure surrogates. However, this approach ignores many critical physiochemical properties of individual atmospheric particles. These properties control the deposition of particles in the human lung and likely their toxicity; in addition, they likely have larger spatial variability than PM mass. OBJECTIVES:This study was designed to quantify the spatial variability in number, size, source, and chemical mixing state of individual particles in a populous urban area. We quantified the population exposure to these detailed particle properties and compared them to mass-based exposures. METHODS:We performed mobile sampling using an advanced single-particle mass spectrometer to measure the spatial variability of number concentration of source-resolved 50-1,000?nm particles and particle mixing state in Pittsburgh, Pennsylvania. We built land-use regression (LUR) models to estimate their spatial patterns and coupled them with demographic data to estimate population exposure. RESULTS:Particle number concentration had a much larger spatial variability than mass concentration within the city. Freshly emitted particles from traffic and cooking drive the variability in particle number, but mass concentrations are dominated by aged background particles composed of secondary materials. In addition, people exposed to elevated number concentrations of atmospheric particles are also exposed to more externally mixed particles. CONCLUSIONS:Our advanced measurement technique provides a new exposure picture that resolves the large intra-city spatial heterogeneity in traffic and cooking particle number concentrations in the populous urban area. Our results provide a complementary and more detailed perspective compared with bulk measurements of composition. In addition, given the influence of particle mixing state on properties such as particle deposition in the lung, the large spatial gradients of chemical mixing state may significantly influence the health effects of fine PM. https://doi.org/10.1289/EHP5311.
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Project description:While numerous studies have demonstrated the adverse effects of fine particulate matter (PM) on human health, little attention has been paid to its impact on offspring health. The multigenerational toxic effects on Caenorhabditis elegans (C. elegans) were investigated by acute exposure. PM2.5 and PM1 samples were collected and analysed for their chemical composition (inorganic ions, metals, OM, PAHs) in different seasons from April 2019 to January 2020 in Lin’an, China. A higher proportion of organic carbon components (34.3%, 35.9%) and PAHs (0.0144%, 0.0200%) occupied the PM2.5 and PM1 samples in winter, respectively. PM1 in summer was enriched with some metal elements (2.7%). Exposure to fine PM caused developmental slowing and increased germ cell apoptosis, as well as inducing intestinal autofluorescence and reactive oxygen species (ROS) production. PM1 caused stronger toxic effects than PM2.5. The correlation between PM component and F0 generation toxicity index was analysed. Body length, germ cell apoptosis and intestinal autofluorescence were all highly correlated with Cu, As, Pb, OC and PAHs, most strongly with PAHs. The highest correlation coefficients between ROS and each component are SO42− (R = 0.743), Cd (R = 0.816) and OC (R = 0.716). The results imply that OC, PAHs and some transition metals play an important role in the toxicity of fine PM to C. elegans, where the organic fraction may be the key toxicogenic component. The multigenerational studies show that PM toxicity can be passed from parent to offspring, and gradually returns to control levels in the F3–F4 generation with germ cell apoptosis being restored in the F4 generation. Therefore, the adverse effects of PM on reproductive damage are more profound.
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| PRJEB40002 | ENA