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| Titel |
Formation of hydroxyl radical from San Joaquin Valley particles extracted in a cell-free surrogate lung fluid |
| VerfasserIn |
H. Shen, C. Anastasio |
| 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 ; 11, no. 18 ; Nr. 11, no. 18 (2011-09-20), S.9671-9682 |
| Datensatznummer |
250010087
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| Publikation (Nr.) |
 copernicus.org/acp-11-9671-2011.pdf |
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| Zusammenfassung |
| Previous studies have suggested that the adverse health effects from ambient
particulate matter (PM) are linked to the formation of reactive oxygen
species (ROS) by PM in cardiopulmonary tissues. While hydroxyl radical (•OH)
is the most reactive of the ROS species, there are few quantitative studies
of •OH generation from PM. Here we report on •OH formation from PM collected
at an urban (Fresno) and rural (Westside) site in the San Joaquin Valley
(SJV) of California. We quantified •OH in PM extracts using a cell-free,
phosphate-buffered saline (PBS) solution with or without 50 μM
ascorbate (Asc). The results show that generally the urban Fresno PM
generates much more •OH than the rural Westside PM. The presence of Asc at a
physiologically relevant concentration in the extraction solution greatly
enhances •OH formation from all the samples. Fine PM (PM2.5) generally
makes more •OH than the corresponding coarse PM (PMcf, i.e. with diameters of 2.5 to
10 μm) normalized by air volume collected, while the coarse PM typically
generates more •OH normalized by PM mass. •OH production by SJV PM is reduced
on average by (97 ± 6) % when the transition metal chelator
desferoxamine (DSF) is added to the extraction solution, indicating a
dominant role of transition metals. By measuring calibration curves of •OH
generation from copper and iron, and quantifying copper and iron
concentrations in our particle extracts, we find that PBS-soluble copper is
primarily responsible for •OH production by the SJV PM, while iron often
makes a significant contribution. Extrapolating our results to expected
burdens of PM-derived •OH in human lung lining fluid suggests that typical
daily PM exposures in the San Joaquin Valley are unlikely to result in a
high amount of pulmonary •OH, although high PM events could produce much
higher levels of •OH, which might lead to cytotoxicity. |
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