基于PMF模型的上海市降水中PAHs来源辨析

Identification of Potential Sources of PAHs from Wet Precipitation in Shanghai

运用正定矩阵因子分解模型(PMF)分析上海市全年大气降水中16种EPA优先控制的多环芳烃(PAHs)的来源和输入途径,并测算出各主要来源贡献率。结果表明,上海市中心城区大气降水中PAHs贡献值占前三位的3个因子分别为煤燃烧(20.2%)、汽油燃烧(15.4%)和柴油燃烧(12.5%);城市西郊为焚烧炉(18.9%)、柴油燃烧(18.4%)和煤燃烧(13.8%);城市东郊为热电厂(29.7%)、煤燃烧(23.6%)和柴油燃烧(16.2%)。根据全市总量分析,上海市大气降水中PAHs贡献值占前四位的4个因子分别为煤燃烧(16.4%)、汽油燃烧(14.7%)、热电厂(13.8%)和柴油燃烧(13.7%)。该四种来源的污染物贡献量占全市大气降水中PAHs总量的58.6%。结合上海市实际情况推断,影响上海市大气降水中PAHs含量的主要因素是巨大的城市交通压力以及因人口激增、电力供应短缺所造成的本地东郊区域热电厂满负荷运转下的高强度排放污染。

The potential sources, transport pathway and pollution contribution were identified with the positive matrix factorization（PMF） for 16 EPA priority PAHs in wet precipitation collected one year from Shanghai region. The results showed that the first three PAHs pollution sources in the precipitation of the city center were incomplete combustion of coal（20.2%）, gasoline（15.4%） and diesel（12.5%）. In the western suburb of the city, the sources were incinerators（18.9%）, incomplete combustion of diesel（18.4%） and coal（13.8%）. In the eastern suburbs of the city,the sources were thermal power plant（29.7%）, incomplete combustion of coal（23.6%）and diesel（16.2%）. The top four sources contributing 58.6% of total PAHs pollution in wet precipitation of Shanghai were incomplete combustion of coal（16.4%）, incomplete combustion of gasoline（14.7%）, thermal power plant（13.8%） and the incomplete combustion of diesel（13.7%）. Considering the inference of the actual situation of Shanghai, the main factors affecting the PAHs content in wet precipitation of Shanghai were the huge traffic pressure and the high intensive discharge pollution from the thermal power plants in the eastern suburb of the city which is induced by the electric power supplied to the soared population of the city.