杭州城市大气消光系数和能见度的影响因子研究

为了解杭州市能见度下降与大气污染之间的关系，在2001年5月至2002年5月对不同粒径的颗粒物（PM10、PM2.5）的质量浓度进行了观测，结合晴天天气条件下的大气能见度，推算污染物和水汽分子对大气的消光散射，发现细微颗粒物的散射消光特性对杭州市能见度下降起主要作用，并得到能见度与细微颗粒物浓度比值（PM2．5／PM10）的关系；分析了大气能见度和消光系数与PM2．5／PM10和相对湿度的相关系数。

Study on influence factors of urban aerosol on visibility & extinction coefficient

For understanding the relation between visibility decline and air pollution in Hangzhou,authors observed the ambient particle concentration of PM2.5 and PM10 from May 2001 to May 2002,analyzed the visibility under rain-free weather condition,calculated the extinction causing by aerosol and vapor molecule,found that mainly factor on visibility decline is the extinction of minuteness particles in atmosphere. Base on the statistics the seasonal differences of visibility,extinction coefficient,aerosol concentration,PM2.5/PM10 ratio and relative humidity, finally, the regress models of visibility and extinction coefficient forecast are established.