长江三角洲地区大气污染过程分析

针对2015年和2016年12月2个月的4次污染过程，利用中分辨率成像光谱仪（MODIS）Terra卫星的气溶胶光学厚度（AOD），Angstrom波长指数（AE）气溶胶数据，并结合PM_2.5和PM₁₀的浓度以及比值变化分析，发现以PM_2.5为代表的人为因素产生的细颗粒物是造成研究地区污染发生的重要因素.并且利用MODIS火点数据以及美国海军气溶胶分析与预测系统（NAAPS）模拟分析污染物成分，发现2015年12月12~16日和19~27日2次污染都以人为因素产生的细粒子污染物为主，沙尘以及生物质燃烧产生的烟粒对研究地区影响较小.2016年12月6~10日和15~18日2次污染过程产生的原因不同，利用潜在源贡献因子分析法（PSCF）分析发现6~10日污染天气的产生主要是由西北方向含有大量沙尘粒子气流以及南方生物质燃烧产生的大量烟粒共同输送到研究地区，加之研究地区大量人为污染细粒子的产生，导致了此次混合型污染天气发生.15~18日污染过程与2015年2次污染过程相似，主要原因都在于人为因素产生的细颗粒污染物的影响，沙尘以及烟粒对污染过程起到了加剧的作用.

Analysis of air pollution episodes over different cites in the Yangtze River Delta

Using the Moderate resolution Imaging Spectroradiometer (MODIS) Terra satellite data, we retrieved the Aerosol optical depth (AOD) and Angstrom Exponent (AE) to analyse the four air pollution episodes that occurred during December 2015 and 2016. This combined with the pollutant concentrations of PM_2.5 and PM₁₀ and studied their variations along with the ratios observed in Nanjing. The fine model particles represented by PM_2.5 which was caused by anthropogenic activities is a main factor resulting in the pollution over this region. Further, the MODIS fire spots and the Navy Aerosol Analysis and Prediction System (NAAPS) aerosol model were used to observe the aerosol sub-types. The pollutant concentrations increased by two times during 12^th-16^th and 19^th-27^th December, 2015. This was mainly attributed to increased dominance of fine particles produced from anthropogenic activities; whereas, the dust and smoke particles have less effect over the study region. Added to the above, two another different air pollution episodes noticed during 6^th-10^th and 15^th-18^th December, 2016. The Potential Source Contribution Function (PSCF) model was used to analyse the air pollution appeared on 6^th-10^th December, 2016which was mainly caused by the transport of dust particles from the northwest of China, and smoke particles produced from biomass burning originated from the southern part of China and local anthropogenic activities. The air pollution process during 15^th-18^th December, 2016 was almost same as that happened with the 2015's which is mainly caused by frequent anthoprogenic activities. It is revealed that the dust and smoke particles aggravated the effects of air pollution during the pollution episodes over Yangtze River Delta.