苏州市大气VOCs特征及来源解析

基于苏州市2020年7—10月VOCs离线采样数据, 探讨苏州市VOCs的时空分布特征、来源及其臭氧生成潜势(OFP), 并与国内其他研究进行对比。结果表明, 苏州市夏季VOCs平均浓度为47.1 nL/L, OFP平均贡献为334.7 μg/m³, 芳香烃和含氧挥发性有机物(OVOCs)是VOCs 的重要组分, 对臭氧生成贡献较大, 其浓度和组分与上海市趋势相似。PMF结果表明, VOCs的6个主要浓度来源排序为液化石油气挥发源(20.7%)>有机溶剂使用源(19.5%)>工业源(17.5%)>机动车尾气排放源>其他源>燃烧源, 苏州市液化石油气挥发源高于长三角地区普遍水平。长三角地区芳香烃浓度较高, 与较高的工业和溶剂使用源贡献相关。总体来说, 芳香烃和OVOCs对苏州市大气环境影响较大, 贡献较大的是表面涂层源、加油站、道路移动源、石化与化工源, 应重点管控。

Characteristics and Source Apportionment of VOCs in Suzhou,China

VOCs concentrations based on offline sampling in Suzhou from July to October 2020 were monitored, and temporal and spatial distribution characteristics, ozone formation potential (OFP) and sources of VOCs were conducted and compared with other studies in China. The results showed that the average concentration of VOCs in Suzhou in the summer is 47.1 nL/L, the average OFP is 334.7 μg/m³, and the aromatic hydrocarbons and oxygenated organics (OVOCs) are important components of VOCs in Suzhou and contribute a lot to ozone generation. The trends of VOCs concentration and composition in Suzhou are similar with those in Shanghai. Positive matrix factorization (PMF) model results showed that six major sources of VOCs in Suzhou are liquefied petroleum gas volatilization sources (20.7%), solvent usage sources (19.5%) and industrial sources (17.5%), followed by other sources, vehicle exhaust emission sources and combustion sources, in which the contribution of liquefied petroleum gas volatilization sources is higher than the general level in Yangtze River Delta. The higher concentration of aromatic hydrocarbons in the Yangtze River Delta is related to the higher contribution of industrial and solvent uses. In general, aromatic hydrocarbons and OVOCs have a greater impact on the atmospheric environment of Suzhou. The main sources are surface coating, gas stations, traffic emission, petrochemical sources and electric heating sources, which should be mainly controlled.