北京部分地区大气PM_(10)中多环芳烃的季节性变化

Seasonal variation character of polycyclic aromatic hydrocarbons in atmospheric PM_(10) of partial areas in Beijing

采集了北京城乡结合部和郊区2003年4个季节大气PM10样品,用超声萃取-GC/MS技术分析了其多环芳烃的组成.结果表明,17种母核多环芳烃总量在8.46～296.57ng/m3之间,城乡结合部的浓度是郊区的1.02～1.58倍.PAHs总量的季节性变化与采样时环境温度显示出较好的负相关性,即冬季＞秋季＞春季＞夏季.郊区和城乡结合部冬季PAHs总量分别是夏季的22.25倍和34.41倍,显示了燃煤取暖对北京冬季大气PAHs污染的贡献极为显著.运用多种多环芳烃比值综合判断,北京大气PM10中PAHs主要以燃煤和机动车尾气混合来源为主,石油源和木材燃烧源的贡献较小.

Atmospheric PM10 samples in urban border and suburban of Beijing were collected in four seasons of the year 2003. Its polycyclic aromatic hydrocarbons (PAHs) composition was analyzed with ultrasonic extraction-GC/MS technique. The total amount of 17 unsubstituted PAHs was 8.46-296.57 ng/m3, with concentration in urban border 1.02-1.58 times of that in suburban area. Seasonal variation of the PAHs total amount displayed well negative correlation with the surrounding temperature of sampling time, that is winter > autumn > spring > summer. The total PAHs amount in suburbans and urban border in winter was 22.25 and 34.41 times of that in summer respectively, showing that in Beijing the contribution of coal combustion for domestic heating to atmospheric PAHs pollution in winter was very marked. Several ratios of PAHs judged complexly that PAHs in atmospheric PM10 in Beijing came mainly from the mixed source of coal combustion and vehicle exhaust. The contribution of petroleum and wood combustion sources was less.