南京北郊大气VOCs变化特征及来源解析

利用2011-03-01~2012-02-29南京北郊大气VOCs观测资料,对大气VOCs浓度变化特征和特征物比值差异展开研究,并应用PCA/APCS受体模型对不同季节VOCs来源进行了解析.结果表明,南京大气总VOCs体积混合比为43.52×10-9,其中烷烃占45.1%、烯烃占25.3%、炔烃占7.3%和芳香烃占22.3%.总VOCs体积混合比呈现夏季高,冬季低的季节变化.VOCs组分中烷烃在冬季最高,烯烃夏季最高,芳香烃春季最高,炔烃冬季最高.特征物比值(VOCs/乙炔)和T/B比值反映出观测点受周边工业区影响较大.VOCs源解析表明,主要来源来自工厂生产、机动车排放、燃料燃烧、生产活动挥发、溶剂使用和自然源.虽然有季节变化,但与工业生产活动相关的来源占大气VOCs 45%~63%,其次为机动车来源占34%~50%.

Characteristics and Source Apportionment of Volatile Organic Compounds (VOCs) in the Northern Suburb of Nanjing

Based on the data of volatile organic compounds (VOCs) collected continuously from 1^st Mar, 2011 to 29^th Feb, 2012 in the northern suburb of Nanjing, characteristics of their variability, differences of ratios of tracers and source apportionment by principal component analysis/absolute principal component scores (PCA/APCS) were analyzed. The results showed that the total VOCs mixing ratios were 43.52×10^-9, which accounted for 45.1% of alkanes, alkenes for 25.3%, alkyne for 7.3%, and aromatics for 22.3%. There was an obviously seasonal variation of VOCs, with the maximum in summer and the minimum in winter. There was an obvious seasonal variation of VOCs component, with highest alkanes in winter, highest alkenes in summer, highest aromatic in spring, and highest alkyne in winter. By using the specific pollutant ratios (hydrocarbons/acetylene and toluene/benzene) method, it indicated that the observation site was greatly affected by the surrounding industrial areas. Source analysis of VOCs by PCA/APCS mode showed that the sources consisted of industrial production sources, automobile emission sources, combustion sources, industrial production volatilization sources, solvent use sources and biogenic emission sources. In addition, there were seasonal variations. Overall, the sources related to industrial production activities represented 45%-63% of VOCs, and they were followed by automobile emission sources, which represented 34%-50%.