Chemical compositions and reconstructed light extinction coefficients of particulate matter in a mega-city in the western Yangtze River Delta, China
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- 作者：Guofeng Shen ; Miao Xue ; Siyu Yuan ; Jie Zhang ; Qiuyue Zhao ; Bing Li ; Haisuo Wu ; Aijun Ding
- 关键词：Chemical composition ; Reconstructed light extinction coefficient ; Deciview index ; Backward air trajectory ; Western YRD region
- 刊名：Atmospheric Environment
- 出版年：February, 2014
- 年：2014
- 卷：83
- 期：Complete
- 页码：14-20
- 全文大小：934 K
文摘
Ambient particulate matter was collected in a megacity, Nanjing in western YRD during the spring and summer periods. Chemical compositions of fine PM including organic carbon, elemental carbon, elements and water soluble ions were analyzed. The light extinction coefficients were reconstructed following the IMPROVE formula. Organic matter was the most abundant composition in PM2.5 (20-25% of total mass), followed by the inorganic ions. During the spring time, geological materials contributed 25% of the total PM2.5. Estimated light extinction coefficient ranged from 133 to 560聽Mm鈭? with the deciview haze index value of 26-40聽dv, indicating strong light extinction by PM and subsequently low visibility in the city. Reconstructed ammonium sulfate, ammonium nitrate, organic matter and light absorption carbon in fine PM contributed significantly (37聽卤聽10, 16聽卤聽6, 15聽卤聽4 and 10聽卤聽3%, respectively) to the total light extinction of PM, while soil (5-7%) and sea salt fractions (2-4%) in fine PM and coarse PM (6-11%) had relatively minor influences. The results of backward air trajectory showed that the site was strongly influenced by the air from the eastern (39%) and southeastern (29%) areas during the sampling period. Air plumes from the Southeastern had both high PM mass pollution and large light extinction, while the air mass originating from the Northwestern resulted in high PM mass loading but relatively lower light extinction.