合肥市臭氧及其前体物污染特征及源解析

利用合肥市臭氧和VOCs连续观测数据分析了合肥市臭氧及其前体物污染特征,并使用NAQPMS模型研究了合肥市不同季节臭氧来源情况。结果表明:O₃已经成为影响合肥市环境质量的主要污染因子,O₃高值区主要集中在5—6月和9月。合肥市大气VOCs中烷烃含量最丰富,其次是烯烃、芳香烃和炔烃;主要物种为乙烷、丙烷、乙炔、正戊烷、乙烯、环戊烷、异戊烷、正丁烷、异丁烷和甲苯。合肥市O₃生成主要受VOCs控制,其中,烯烃是合肥市O₃生成贡献最大的关键活性组分,乙烯的OFP贡献率居首位。合肥市不同季节O₃来源差异较大,其中,本地排放是主要来源,夏季占比为50%,其余季节占比为30%~45%,O₃存在跨省长距离输送特征,主导风向的变化是造成合肥市臭氧来源季节性变化的重要因素。

Pollution Characteristics and Sources Apportionment of Ozone and Its Precursors in Hefei

The characteristics of ozone pollution and its precursors in Hefei were analyzed by using the continuous observational data of ozone and VOCs in Hefei,and the ozone sources in different seasons in Hefei were studied by using the NAQPMS model.The results showed that ozone had become the main pollution factor affecting the environmental quality of Hefei,and the high value area of ozone was mainly concentrated in May-June and September.Alkanes were the most abundant VOCs in the atmosphere of Hefei,followed by olefins,aromatics and alkynes.The major species were ethane,propane,acetylene,n-pentane,ethylene,cyclopentane,isopentane,n-butane,isobutane and toluene.The generation of ozone was dominated by VOCs in Hefei.Alkenes were the key active component contributing most to the ozone formation in Hefei,while the OFP contribution rate of ethylene was the highest among all species.The source of O₃ varied greatly from season to season.Local emissions were the main source,accounting for 50 percent in summer and 30-45 percent in the rest of the year,which mainly constitute of the transport contribution from adjacent province.The change of dominant wind direction was an important factor in the seasonal variation of ozone sources in Hefei.