宜昌城区冬季大气污染的气象成因对比分析研究

2016年冬季,宜昌城区空气质量比上年冬季明显改善,通过采用对比分析、相关分析及后向轨迹分析等方法,诊断可能的原因.结果表明,宜昌城区冬季空气污染主要是由于细颗粒物导致,2016年冬季PM2.5、PM10、SO2浓度较2015年冬季明显降低,主要原因包括含硫燃料燃烧明显减少、外源性污染物的输入明显减少、降水清除以及减排措施有力等.后向轨迹分析结果显示,两年冬季污染最严重时段的污染物路径来源不同,2015年冬季最严重的污染过程主要是由于上游北方远距离的外源性污染的快速输入、在本地下沉导致,2016年冬季最严重的污染过程则是由于来自偏南路径近距离的气团叠加本地污染源,在垂直方向累积造成.

Contrastive Analysis for Causes of Winter Air Pollution in Urban Yichang

In winter of 2016, the air quality in urban Yichang shows significant improvement comparing with winter of last year, this paper diagnoses possible reasons by means of contrastive analysis, correlation analysis and back trajectory analysis etc.It turns out that the winter air pollution in urban Yichang mostly resulted from fine particles, the PM2.5, PM10 and SO2 concentration in winter of 2016 has decreased significantly than winter of 2015 by reasons of obvious decreasing of sulfurous fuel combustion, obvious decreasing of exogenous pollutants input, precipitation scavenging and effective emission reduction measures etc.The back trajectory analysis results show that the pollutants in the most polluted period of the two years have different sources and pathways, the most polluted process in winter of 2015 is contributed by rapid input of remote exogenous pollutants of upstream north and local downwash, while the most polluted process in winter of 2016 is because the near air mass from southerly pathway overlaps with local pollution sources and accumulates in vertical direction.