上海市大气沉降物中多环芳烃赋存特征及其来源

Concentration characteristics and potential sources of polycyclic aromatic hydrocarbons in atmospheric deposition in Shanghai

以上海市大气沉降为研究对象,采集了上海市8月、9月、10月3个月的大气沉降物,分析了上海市大气沉降物中16种PAHs的质量浓度、空间分布特征和组成结构,计算了上海市8个采样点∑15PAHs大气沉降物通量.同时,采用正定矩阵因子分解（PMF）模型对大气沉降中的PAHs进行源解析,模型对PAHs的来源有较为细致的判读,结果表明：大气沉降物中∑16PAHs的浓度范围0.458-21.013μg/L,其中,溶解相中∑16PAHs的浓度范围为0.174-0.625μg/L,颗粒相中∑16PAHs的浓度范围为0.275 20.455μg/L.上海市∑15PAHs大气沉降通量在0.24-14.74μg/（m^2·d）之间,沉降通量均值为2.77μg/（m^2·d）.根据PMF模型解析,机动车尾气排放为大气沉降物中PAHs的主要污染物,源贡献率为40.23%,其次,居民烹调、煤炭燃烧、石油挥发泄露和炼焦排放依次占23.73%、14.75%、14.35%和6.92%.

To study the atmospheric deposition in Shanghai, we have collected deposition samples in August, September and October in 2014. The concentration,spatial distribution and composition of sixteen polycyclic aromatic hydrocarbons（PAHs） were analyzed. Atmospheric deposition fluxes of ∑15PAHs at eight sampling sites were also calculated. The potential sources of PAHs were apportioned by positive matrix factorization model（PMF）, which could produce a quantitative interpretation. Our results indicated that the total concentrations of PAHs ranged from 0.458μg/L to 21.013μg/L in atmospheric deposition. Furthermore, the PAHs concentrations in dissolved phase varied from 0.174μg/L to 0.625μg/L, while in particulate phase from 0.275μg/L to 20.455μg/L. The atmospheric deposition flux of ∑15PAHs in sampling sites ranged from 0.24μg/（m^2·d）to 14.74μg/（m^2·d）and the mean deposition flux of ∑15PAHs was 2.77μg/（m^2·d）. According to the apportionment results using PMF model, the first major sources of PAHs were categorized as mobile vehicle exhausts, such as gasoline car exhausts and diesel car exhausts, which constantly contribute 40.23% to the total PAHs pollution. Another four sources（residential cooking, coal combustion, oil spill and volatilization, coking and coal smelting） identified by PMF model, account for 23.73%, 14.75%, 14.35% and 6.92% respectively.