安徽省输入型沙尘叠加本地污染过程分析

Analysis of Local Pollution Process of Input Sand and Dust Overlay in Anhui Province

以安徽省2018年11月25日至12月1日一次典型的沙尘过程为案例,研究了输入型沙尘过程对安徽省本地污染的叠加效应。结果表明:安徽省春秋季节受北方锋区和南方锋区天气系统交替影响,输入型沙尘污染颗粒物浓度常呈现出明显的双峰特征。受沙尘影响时段,PM 2.5/PM 10将出现显著的降低。若前期安徽省内及上游地区空气较为清洁,受典型输入型沙尘影响,PM 2.5/PM 10比值可降至0.3以下,若输入型沙尘叠加前期本地污染,沙尘气团前锋达到安徽省时,伴随冷锋底部的冷空气会先推动西北方向污染气团向东南传输,引起PM 2.5缓慢上升,安徽省PM 2.5/PM 10比值降低效应不明显,显著低于北方典型城市,一般为0.35~0.55。

The process of local pollution in Anhui Province caused by a typical input type of sand and dust from November 25 to December 1,2018 is emphatically analyzed.The results show that the spring and autumn seasons of Anhui Province are alternately affected by the northern frontal and southern frontal weather systems,and the concentration of imported dust pollution particles often exhibits obvious bimodal characteristics.During the period affected by sand and dust,PM 2.5/PM 10 will be significantly reduced.If the air in Anhui province and upstream area is cleaner in the early stage,the ratio of PM 2.5/PM 10 can be reduced to less than 0.3 under the influence of typically imported dust.If the imported dust superimposes the local pollution in the early stage,the cold air at the bottom of the cold front will first promote the pollution in the northwest direction when the dust front reaches Anhui Province.The air mass travels southeast,causing the slow rise of PM 2.5.The ratio of PM 2.5/PM 10 at the affected stations in Anhui Province can only be reduced to 0.35~0.55 at most.