广州市灰霾期间大气颗粒物中有机碳和元素碳的粒径分布

THE SIZE DISTRIBUTION OF ORGANIC CARBON AND ELEMENTAL CARBON DURING HAZE PERIOD IN GUANGZHOU

使用冲击式采样器(MOUDI)采集广州市灰霾形成过程的大气颗粒物.分析了有机碳(OC)和元素碳(EC).结果表明,灰霾期间大气主要消光部分积聚态颗粒物及其中的OC和EC,在PM10(可吸入颗粒物)中所占的比例及其绝对浓度要远高于正常天气.正常天气OC和EC呈双模态分布,严重灰霾天气EC的粒径分布呈单一模态分布,OC的粒径分布呈双模态分布,峰值都向大粒径方向偏移.结果显示,大气颗粒物、OC和EC在积聚态的大幅度增长是形成灰霾天气的重要原因.

Airborne particles had been collected during a haze episode （21-Dec 2005 to 26-Dec 2005 ） . Organic carbon （OC） and elemental carbon （EC） were characterized by Sunset carbon analyzer. In this study, the proportion of accumulation mode particles, OC and EC in haze days were higher than those in normal days. OC was bimodal distribution during both normal and heavy haze period; however, EC was bimodal during normal period and monomodal during heavy haze period. Accumulation modal of both OC and EC tended to shift toward larger size during heavy haze days. The result shows the greatly increase of airborne particle, OC and EC in accumulation mode is the important cause of haze formation.