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| Titel |
Size-resolved aerosol water-soluble ionic compositions in the summer of Beijing: implication of regional secondary formation |
| VerfasserIn |
S. Guo, M. Hu, Z. B. Wang, J. Slanina, Y. L. Zhao |
| 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 ; 10, no. 3 ; Nr. 10, no. 3 (2010-02-01), S.947-959 |
| Datensatznummer |
250008023
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| Publikation (Nr.) |
 copernicus.org/acp-10-947-2010.pdf |
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| Zusammenfassung |
| To characterize aerosol pollution in Beijing, size-resolved aerosols were
collected by MOUDIs during CAREBEIJING-2006 field campaign at Peking
University (urban site) and Yufa (upwind rural site). Fine particle
concentrations (PM1.8 by MOUDI) were 99.8±77.4 μg/m3 and
78.2±58.4 μg/m3, with PM1.8/PM10 ratios
of 0.64±0.08 and 0.76±0.08 at PKU and Yufa, respectively, and secondary
compounds accounted for more than 50% in fine particles. PMF model
analysis was used to resolve the particle modes. Three modes were resolved
at Yufa, representing condensation, droplet and coarse mode. However, one
more droplet mode with bigger size was resolved, which was considered
probably from regional transport. Condensation mode accounted for
10%–60% of the total mass at both sites, indicating that the
gas-to-particle condensation process was important in summer. The formation
of sulfate was mainly attributed to in-cloud or aerosol droplet process (PKU
80%, Yufa 70%) and gas condensation process (PKU 14%, Yufa 22%).
According to the thermodynamic instability of NH4NO3, size
distributions of nitrate were classified as three categories by RH. The
existence of Ca(NO3)2 in droplet mode indicated the reaction of
HNO3 with crustal particles was also important in fine particles. A
rough estimation was given that 69% of the PM10 and 87% of the
PM1.8 in Beijing urban were regional contributions. Sulfate, ammonium
and oxalate were formed regionally, with the regional contributions of
90%, 87% and 95% to PM1.8. Nitrate formation was local
dominant. In summary regional secondary formation led to aerosol pollution
in the summer of Beijing. |
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