南京市大气气溶胶中多环芳烃的污染趋势

Pollution Trend of Polycyclic Aromatic Hydrocarbons(PAHs) in Nanjing Atmospheric Aerosol

对南京市2001年、2002年、2004年以及2005年夏季和冬季所采集到34个PM10和64个PM2.5样品中16种优控多环芳烃(PAHs)进行了分析,结果表明,南京市大气气溶胶PAHs污染有加重的趋势,且冬季大气中PAHs的污染比夏季严重.通过一些特征标志PAHs的比值,初步判定PAHs主要来自于化石燃料的污染,没有新的污染源加入.FLA/Py比值判定表明南京的大气污染形式由煤烟型和油型燃烧相结合的污染方式转为油型为主的污染形式的趋势.

The sixteen precedence-controlled polycyclic aromatic hydrocarbons （PAHs） of EPA in PM2.5 and PM10 in Nanjing atmosphere in the years of 2001, 2002, 2004 and 2005 were determined. The research results showed that PAHs pollution in Nanjing air became more serious than before, and the air pollution in winter was worse than that in summer. Through some diagnostic index of PAHs ratios to judge the PAHs pollution source, the ratio Ph/（Ph＋An）〉 0. 7 accounts for PAHs originated from lubricating oil of fossil fuel using. In Nanjing the ratios ranged between 0. 68-0. 96 in PM2.5 and PM10 in two seasons. Except that the average value which was 0. 68 in PM2.5 in winter of 2004, the other ratio values were all bigger than 0. 7. The results showed that PAHs in Nanjing atmosphere mainly came from fossil fuel pollution, and there were no new pollution source during measure time. FLA/Py ratio can be used as a distinguishing index of fossil fuel burning style. The ratio values close to 1.40 and 1.0 represent coal-burning and oil-burning styles respectively. In 2001 and 2002, FLA/Py value ranged from 1.30- 1.52 and 1. 30- 1. 96 respectively, which were all near 1. 40, so the pollution style was coal-burning. However, the ratio value was between 0. 80~1.18, more adjacent to 1.0 in 2004 and 2005, which represented oilburning. Linked to the measured ratio during the observation period, it can be seen that the pollution style in Nanjing air has changed from coal-burning and oil-burning to oil-burning mainly in recent years. This complexion may be explained in the following reasons： air-conditioner usage in downtown changed; traditional heating style changed; vehicle exhaust became bigger as the cars increased.