粗粒子气溶胶远距离输送造成华南严重空气污染的分析

Air pollution episode in southern China due to the long range transport of coarse particle aerosol

2009年4月末,发生了一次罕见的粗粒子气溶胶远距离输送造成华南地区出现严重的空气污染事件,其特征主要是气溶胶质量浓度超标,而能见度没有明显恶化,对这次空气污染事件进行分析的结果表明.在过程中,粗细粒子质量比(PM2.5/PM10)有明显的3次下降,最低达到0.3,即PM2.5仅占PM10的30%,这与珠江三角洲地区通常以细粒子为主的污染特征有很大不同,反映了外来粗粒子的侵入特征.长江流域浮尘天气的沙尘粒子变性后,长距离输送污染物叠加本地污染物,造成这次严重空气污染事件.

At the end of April 2009,a serious air pollution episode caused by long range transport of coarse particle aerosol occurred in Southern China.This episode was characterized by the excessive aerosol mass concentration without obvious visibility degradation.This paper investigates the underlying reasons for this typical air pollution episode in southern china.We found that there were three times of significant decrease of PM2.5-to-PM10 ratio,with the lowest value of 0.3.This was very different from the typical air pollution characteristics in the Pearl River Delta（PRD） region where the ambient aerosols are generally dominated by fine particles.This clearly reflected the intrusion of coarse particles from outside PRD.We concluded that the floating dust particles,which may age at the Yangtze River Delta and then transport to the PRD,together with the local pollutants,were responsible for this severe air pollution episode.