2007年春节期间北京大气颗粒物中多环芳烃的污染特征

利用大流量颗粒物采样器分昼夜采集了2007年春节前后大气气溶胶中PM10和PM2.5样品,并采用气相色谱-质谱技术对PM2 5样品中的多环芳烃进行了检测.春节期间大气颗粒物中PM10和PM2 5夜间平均质量浓度为232 ug·m-3和132 ug·m-3,分别高于白天的PM10(194ug·m-3)和PM2.5(107ug·m-3);除夕后颗粒物日平均质量浓度为252.3 ug·m-3(PM10)和123.8ug·m-3 (PM2.5),分别高于除夕前的166.7 ug·m-3(PM10)和106.8 ug·m-3(PM2.5);同时夜间PM2.5中多17种多环芳烃(PAHs)的总浓度都高于相应白天的总浓度,且除夕前多环芳烃日均总浓度为95.9 ng·m-3,高于除夕后的58.9 ng·m-3.结果表明,除了受一定的气象条件的影响外,大量燃放烟花爆竹会对大气颗粒物浓度有影响.但对大气中的多环芳烃影响不大,而春节期间工业及交通污染排放的减少削减了排放到大气中的PAHs.根据荧蒽/芘等比值指标判别北京PAHs主要以燃煤为主、交通为次的混合局地源污染.

Pollution Characteristic of PAHs in Atmospheric Particles During the Spring Festival of 2007 in Beijing

Research on PM10, and PM2.5, aerosols had been carried out with sampler of large flow capacity during the Spring Festival of 2007 in Beijing, and the concentration of polycyclic aromatic hydrocarbons (PAHs) in PM2.5, samples were determined via GC-MS. The average concentrations of aerosols are higher in the night (PM10: 232 microg x m(-3); PM2.5: 132 microg x m(-3)) than those in the day time (PM10: 194 microg x m(-3); PM2.5: 107 microg x m(-3)). The average concentrations are higher after the new year's eve (PM10: 252.3 microg x m(-3), PM2.5: 123.8 microg x m(-3)) compared with those before (PM10: 166.7 microg x m(-3), PM2.5: 106.8 microg x m(-3)). And we also find that the concentration of PAHs in PM2.5 aerosols is generally higher in the night (106.4 ng x m(-3)) than that in the day time (44.2 ng x m(-3)), and the total concentration of 17 PAHs before new year's eve (95.9 ng x m(-3)) is higher than that after (58.9 ng x m(-1)). Those results may mean that the aerosols are influenced by burning of fireworks in addition to be subjected to the meteorological condition. At the same time, there is little influence of playing fireworks on the PAHs concentration, and the changes of the concentration of PAHs can be explained by the decrease of industrial and vehicular transportation pollutant during the Festival period. It can be judged by the characteristic ratio such as Fuloranthene/pyrene that the primary resource of PAHs in particles is the combustion of coal, and the combustion of gasoline is in the next place.