Elevated mixing ratios and sources of methyl chloride: Results from a survey in the Yangtze River Delta region of China

详细信息    查看全文

• 作者：Ping Song^a ; ^c ; Chuen-Yu Chan^a ; ^{chzy@mail.sysu.edu.cn} ; Fuhai Geng^b ; Qiong Yu^b ; Yifei Guo^d ; Lingwei Yu^a
• 关键词：Methyl chloride ; Mixing ratio ; Source ; The Yangtze River Delta
• 刊名：Atmospheric Research
• 出版年：2012
• 出版时间：2012
• 年：2012
• 卷：104-105
• 期：Complete
• 页码：172-181
• 全文大小：899 K

文摘

Measurements of air samples collected at four urban sites in Shanghai, Taizhou, Liyang and Lin'an and a rural site in Chongming Island of the Yangtze River Delta (YRD) region of China revealed noticeably elevated mixing ratios of methyl chloride (CH₃Cl). Median CH₃Cl mixing ratios reached 0.9-3.9 ppbv at the five sampling locations, significantly higher than most of those reported for other regions in the world. Especially at Liyang site and Taizhou site, CH₃Cl exhibited quite high levels with mixing ratios ranging from 0.9 up to 25.9 ppbv (n = 28) and 0.7 up to 17.3 ppbv (n = 29), respectively.

With good correlation with methylene chloride (CH₂Cl₂) and ethylene dichloride (EDC), abundant CH₃Cl in urban Shanghai, was mainly associated with industrial activities, although biomass burnings exist widely in rural areas of east China. The high concentrations and large variation of CH₃Cl and EDC simultaneously appeared at Liyang site. Spikes of CH₃Cl and EDC concentrations as well as toluene/benzene (T/B) ratios frequently present in easterly airflows indicated an important contribution from emissions of chemical plants clustering in the east of Liyang. Different emission sources may contribute to ambient CH₃Cl at Taizhou site, which was suggested by the two kinds of linear regressions of CH₃Cl to some other compounds detected. The substantially elevated CH₃Cl levels suggest significant influence of intensive industrial activities on the YRD atmosphere.