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| Titel |
Reactive oxygen species associated with water-soluble PM2.5 in the southeastern United States: spatiotemporal trends and source apportionment |
| VerfasserIn |
V. Verma, T. Fang, H. Guo, L. King, J. T. Bates, R. E. Peltier, E. Edgerton, A. G. Russell, R. J. Weber |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
1680-7316
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| Digitales Dokument |
URL |
| Erschienen |
In: Atmospheric Chemistry and Physics ; 14, no. 23 ; Nr. 14, no. 23 (2014-12-08), S.12915-12930 |
| Datensatznummer |
250119216
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| Publikation (Nr.) |
 copernicus.org/acp-14-12915-2014.pdf |
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| Zusammenfassung |
| We assess the potential of the water-soluble fraction of atmospheric fine
aerosols in the southeastern United States to generate reactive oxygen
species (ROS) and identify major ROS-associated emission sources.
ROS-generation potential of particles was quantified by the dithiothreitol
(DTT) assay and involved analysis of fine particulate matter (PM) extracted
from high-volume quartz filters (23 h integrated samples) collected at
various sites in different environmental settings in the southeast,
including three urban-Atlanta sites, in addition to a rural site. Paired
sampling was conducted with one fixed site in Atlanta (Jefferson Street),
representative of the urban environment, with the others rotating among
different sites, for ~250 days between June 2012 and
September 2013 (N=483). A simple linear regression between the DTT
activity and aerosol chemical components revealed strong associations
between PM ROS-generation potential and secondary organic aerosol (WSOC – water-soluble organic carbon) in
summer, and biomass burning markers in winter. Redox-active metals were also
somewhat correlated with the DTT activity, but mostly at urban and roadside
sites. Positive matrix factorization (PMF) was applied to apportion the
relative contribution of various sources to the ROS-generation potential of
water-soluble PM2.5 in urban Atlanta. PMF showed that vehicular
emissions contribute uniformly throughout the year (12–25%), while
secondary oxidation processes dominated the DTT activity in summer (46%)
and biomass burning in winter (47%). Road dust was significant only
during drier periods (~12% in summer and fall). Source
apportionment by chemical mass balance (CMB) was reasonably consistent with
PMF, but with higher contribution from vehicular emissions (32%). Given
the spatially large data set of PM sampled over an extended period, the
study reconciles the results from previous work that showed only region- or
season-specific aerosol components or sources contributing to PM ROS
activity, possibly due to smaller sample sizes. The ubiquitous nature of the
major sources of PM-associated ROS suggests widespread population exposures
to aerosol components that have the ability to catalyze the production of
oxidants in vivo. |
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