北京市大气PM_(10)中有机污染物的分布特征

大气有机污染物直接影响着人类的健康及其赖以生存的环境。通过采集北京市2005年春、夏、秋、冬4季不同功能区的大气PM10样品,经索氏抽提分离得到饱和烃、芳香烃、非烃、沥青质4个组分,对不同功能区不同季节大气有机物污染水平及其分布特征进行探讨。结果表明:大气PM10中有机物年均质量浓度达41.39μg/m3,为清洁对照点十三陵的1.4倍;一年中,冬季污染最严重,PM10中有机污染物的质量浓度达67.04μg/m3,为春季的1.2倍、秋季的2.1倍、夏季的4.5倍;有机组分含量呈现非烃>沥青质>芳烃>饱和烃的变化趋势,说明燃煤污染在北京市大气有机污染中仍然起主导作用;各功能区的有机污染程度不同,表现出工业区(商业区)>居民区(交通区)>清洁区的特点,但不同季节的变化不完全一致;不同功能区有机组分的比例体现出不同污染源的相对影响。

Distribution Characteristics of Extractable Organic Matter in Atmospheric PM10 in Beijing

PM10 is one of the most important forms of air pollution,and its harmful organic compounds can be absorbed into the human body to result in different diseases,and to impact the human living environment.In the PM10 samples collected in different function zones of Beijing during four seasons of 2005,the extractable organic matter(EOM) was obtained by ultrasonic extraction and separated into saturated hydrocarbon,aromatics,non-hydrocarbons and asphaltenes,the content and distribution of EOM show that the annual average concentration of organic compounds in PM10 was 41.39 μg/m3,being 1.4 times higher than that in cleanliness district Ming Tombs site.The organic pollution level in winter was the most serious,the mass concentration of organic compound in PM10 was 67.04 μg/m3,which was 1.2,2.1 and 4.5 times higher than that in spring,autumn and summer,respectively.The concentration order of organic compositions is non-hydrocarbons,asphaltenes,aromatics and saturated hydrocarbon,indicating that organic pollution of Beijing city mainly results from coal-burning.The concentration of EOM was various in different function zones,presenting industrial or commercial zones>living or traffic zones>cleanliness zone,but during four seasons the variety of EOM was different.The contribution of pollution sources to different percentages of EOM depended on different function zones.