高影响天气对苏州市大气污染物特征的影响

Effects of High Impact Weather on the Characteristics of Pollutants in Suzhou City

利用苏州市2010—2012年大气污染物逐时质量浓度数据和气象条件资料,分析4类高影响天气对该市大气污染物扩散的影响。研究表明:暴雨对污染物的清除作用主要与降水时间和强度等因子有关,且降水时间的影响大于降水强度;夏季高温日污染物平均质量浓度高于非高温日,PM10、PM2.5、O3、NO2分别增长了29.5%、19.2%、51.3%和13.5%,且O3质量浓度大于321.6μg/m3的日最高气温均在33℃以上;寒潮过境对污染物有很好的清除效应,可对不同污染物影响程度不同;台风带来的大风和降雨能使污染物浓度迅速降低,其来临前的外围下沉气流可能对污染物浓度升高有影响。

The hourly pollution and meteorological data of Suzhou from 2010 to 2012 were used to analyze the effect of four kinds of high impact weather.The results show that the wet deposition of rainstorm is concerned with the precipitation time,wind speed and precipitation intensity.The precipitation time plays a more important role than precipitation intensity.The O3 concentrations of heat wave day are larger than the other days.The in-crease ratio of PM10 ,PM2.5 ,O3 ,NO2 in heat wave days are 29.5%,19.2%,5 1 .3%and 13.5% respectively.The O3 concentrations which larger than 321 .6 μg /m3 appear in the days with the daily maximum temperature exceed 33 ℃.Cold wave can clear away the pollution effectively,but the efficiency depends on the species of pollutant. Strong wind and rainfall brought by the typhoon can reduce the pollution concentrations rapidly.However,the downward flow at outer region of the typhoon may increase the pollution concentrations before the forthcoming ty-phoon.