The effects of rapid urbanization on the levels in tropospheric nitrogen dioxide and ozone over East China

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• 作者：Jianping Huang ; Chenhong Zhou ; Xuhui Lee ; Yunxuan Bao ; Xiaoyan Zhao ; Jimmy Fung ; Andreas Richter ; Xiong Liu ; Yiqi Zheng
• 关键词：Nitrogen dioxide ; Ozone ; Satellite retrieval ; Seasonal change ; Troposphere ; Urbanization
• 刊名：Atmospheric Environment
• 出版年：2013
• 出版时间：October, 2013
• 年：2013
• 卷：77
• 期：Complete
• 页码：558-567
• 全文大小：6558 K

文摘

Over the past few decades, China has experienced a rapid increase in urbanization. The urban built-up areas (population) in Beijing, Shanghai, and Guangzhou increased by 197 % (87 % ), 148 % (65 % ), and 273 % (25 % ), respectively, from 1996 to 2011. We use satellite retrieval data to quantify the effects of rapid urbanization on the yearly and seasonal changes in tropospheric nitrogen dioxide (NO₂) over East China. The results show that rapid urbanization has a profound effect on tropospheric columns of NO₂. During 1996-2011, the tropospheric columns of NO₂ over the surrounding areas of Guangzhou, Shanghai, and Beijing increased by 82 % , 292 % , and 307 % , respectively. The tropospheric columns of NO₂ reach their maximum in winter and minimum in spring. The anthropogenic emissions related to urbanization are a dominant factor in the long-term changes in the yearly and seasonal mean tropospheric columns of NO₂, whereas meteorological conditions such as the prevailing winds and precipitation account for the unique spatial patterns. Around the time of the 2008 Beijing Olympic Games, the tropospheric columns of NO₂ over Beijing urban area significantly reduced by 48 % in July, 35 % in August, and 49 % in September, relative to the same monthly averages over 2005-2007. However, this trend was reversed after the Games, and the increased rate was even larger than before. Our results show that the tropospheric NO₂ above the three regions increased at rates 1.3-8 times faster than the rates in a recent inventory estimate of NO_x emissions for 2000-2010. We also discuss the influence of urbanization on tropospheric ozone and find that the Ozone Monitoring Instrument (OMI) retrieval tropospheric column shows that ozone levels are relatively insensitive to urbanization and changes in tropospheric NO₂.