The challenge of improving visibility in Beijing
-
Published:2010-08-24
Issue:16
Volume:10
Page:7821-7827
-
ISSN:1680-7324
-
Container-title:Atmospheric Chemistry and Physics
-
language:en
-
Short-container-title:Atmos. Chem. Phys.
Author:
Zhang Q. H.,Zhang J. P.,Xue H. W.
Abstract
Abstract. The "Blue Sky Project" was proposed in 1998 to investigate by how much emissions should be reduced to increase blue sky frequency in Beijing, which hosted the Summer Olympics in 2008. This paper focuses on the temporal variation of visibility and its dependence on meteorological conditions and suspended particles at Beijing using the hourly observed visibility data at Beijing Capital International Airport (BCIA) from 1999 to 2007. It has been found that about 47.8% (24.2%) of the hours in Beijing are "bad" ("good") hours with visibility below 10 km (equal or higher than 20 km) between 1999 and 2007. Due to the high Relative Humidity (RH), summer is the season with the lowest mean visibility in a year. Although PM10 index was reported in a decreasing trend (Chan and Yao, 2008), the increase of RH has resulted in a decreasing trend of visibility over BCIA in the summer from 1999 to 2007. To ensure blue sky ("good" visibility) for Olympics 2008, daily mean PM10 index should have been reduced from 81 to 44. This requires that not only vehicle emissions, but also other emissions should be limited. Observations verify that blue-sky-hour rate increased significantly after mean PM10 index was reduced to 53 during Olympics 2008, however, the visibility of 2009 returned to the mean level from 1999 to 2007 during the period 8−24 August. RH (aerosol) contribute 24% (76%) of the improvement of visibility during August 2008.
Publisher
Copernicus GmbH
Subject
Atmospheric Science
Reference28 articles.
1. Bäumer, D., Vogel, B., Versick, S., Rinke, R., Möhler, O., and Schnaiter, M.: Relationship of visibility, aerosol optical thickness and aerosol size distribution in an ageing air mass over South-West Germany, Atmos. Environ., 42, 989–998, 2008. 2. Chan, C. K., and Yao, X.: Air pollution in mega cities in China, Atmos. Environ., 42, 1–42, 2008. 3. Chan, C. Y., Xu, X. D., Li, Y. S., Wong, K. H., Ding, G. A., Chan, L. Y., and Cheng, X. H.: Characteristics of vertical profiles and sources of PM2.5, PM10 and carbonaceous species in Beijing, Atmos. Environ., 39, 5113–5124, 2005. 4. Chang, D., Song, Y., and Liu, B.: Visibility trends in six megacities in China 1973-2007, Atmos. Res., 94, 161–167, 2009. 5. Che, H., Zhang, X., Li, Y., Zhou, Z., and Chen, Z.: Relationship between horizontal extinction coefficient and PM10 concentration in Xi'an, china, during 1980–2002, China Particuology, 4, 327–329, 2006.
Cited by
131 articles.
订阅此论文施引文献
订阅此论文施引文献,注册后可以免费订阅5篇论文的施引文献,订阅后可以查看论文全部施引文献
|
|