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| Titel |
Impact of emission controls on air quality in Beijing during APEC 2014: lidar ceilometer observations |
| VerfasserIn |
G. Tang, X. Zhu, B. Hu, J. Xin, L. Wang, C. Münkel, G. Mao, Y. Wang |
| 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. 21 ; Nr. 15, no. 21 (2015-11-13), S.12667-12680 |
| Datensatznummer |
250120162
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| Publikation (Nr.) |
 copernicus.org/acp-15-12667-2015.pdf |
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| Zusammenfassung |
| The implementation of emission reductions during the 2014 Asia-Pacific
Economic Cooperation (APEC) summit provides a valuable opportunity to
study air pollution in Beijing. From 15 October to 30 November 2014,
the height of the atmospheric mixing layer and the vertical attenuated
backscattering coefficient profiles were observed online using a~lidar
ceilometer. Compared with fine particulate matter (PM2.5)
and aerosol optical depth (AOD) data, the attenuated backscattering
coefficients measured by the lidar
ceilometer were strongly correlated with the PM2.5 concentration
and AOD (correlation coefficients of 0.89 and 0.86, respectively). This
result demonstrated the reliability of the vertical distribution of
particles measured by the lidar ceilometer.
By classifying different degrees of air pollution based on visibility, we found that during
the transition period of air pollution, which was affected by transport of
southerly flows in the mixing layer, the attenuated backscattering coefficient
from 0 to 1500 m was enhanced by approximately
1.4 Mm−1 sr−1 (140 %). During the polluted period,
the attenuated backscattering coefficient from 0 to 300 m
suddenly increased, and the coefficient near the surface peaked
(approximately 14 Mm−1 sr−1); however,
the attenuated backscattering coefficient from 300 to 900 m
decreased gradually, and the average value from 0 to 1500 m
decreased by 0.5 Mm−1sr−1 (20 %). The
height of the mixing layer gradually decreased, and the ratio of CO / SO2
gradually increased, which indicate that the polluted period was
dominated by local contribution. Due to the emission reductions during APEC (DAPEC),
the concentration of PM2.5 decreased by 59.2 and 58.9 %
and visibility improved by 70.2 and 56.0 % compared to before (BAPEC)
and after APEC (AAPEC), respectively. The contribution of regional
transport in DAPEC decreased by approximately 36 and 25 %, and the local contribution decreased by approximately 48 and 54 % compared to BAPEC and AAPEC,
respectively. The most effective method of controlling air pollution
in the Beijing area is to reduce regional emissions during the transition
period and reduce local emissions during the polluted period. |
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