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| Titel |
Characterization of ambient volatile organic compounds and their sources in Beijing, before, during, and after Asia-Pacific Economic Cooperation China 2014 |
| VerfasserIn |
J. Li, S. D. Xie, L. M. Zeng, L. Y. Li, Y. Q. Li, R. R. Wu |
| 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 ; 15, no. 14 ; Nr. 15, no. 14 (2015-07-20), S.7945-7959 |
| Datensatznummer |
250119911
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| Publikation (Nr.) |
 copernicus.org/acp-15-7945-2015.pdf |
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| Zusammenfassung |
| Ambient volatile organic compounds (VOCs) were measured using an online
system, gas chromatography–mass spectrometry/flame ionization detector
(GC-MS/FID), in Beijing, China, before, during, and after Asia-Pacific
Economic Cooperation (APEC) China 2014, when stringent air quality control
measures were implemented. Positive matrix factorization (PMF) was applied
to identify the major VOC contributing sources and their temporal
variations. The secondary organic aerosols potential (SOAP) approach was
used to estimate variations of precursor source contributions to SOA
formation. The average VOC mixing ratios during the three periods were
86.17, 48.28, and 72.97 ppbv, respectively. The mixing ratios of total VOC
during the control period were reduced by 44 %, and the mixing ratios of
acetonitrile, halocarbons, oxygenated VOCs (OVOCs), aromatics, acetylene,
alkanes, and alkenes decreased by approximately 65, 62, 54,
53, 37, 36, and 23 %, respectively. The mixing ratios of all
measured VOC species decreased during control, and the most affected species
were chlorinated VOCs (chloroethane, 1,1-dichloroethylene, chlorobenzene).
PMF analysis indicated eight major sources of ambient VOCs, and emissions
from target control sources were clearly reduced during the control period.
Compared with the values before control, contributions of vehicular exhaust
were most reduced, followed by industrial manufacturing and solvent
utilization. Reductions of these three sources were responsible for 50,
26, and 16 % of the reductions in ambient VOCs. Contributions of
evaporated or liquid gasoline and industrial chemical feedstock were
slightly reduced, and contributions of secondary and long-lived species were
relatively stable. Due to central heating, emissions from fuel combustion
kept on increasing during the whole campaign; because of weak control of
liquid petroleum gas (LPG), the highest emissions of LPG occurred in the
control period. Vehicle-related sources were the most important precursor
sources likely responsible for the reduction in SOA formation during this
campaign. |
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