珠三角产业重镇大气VOCs污染特征及来源解析

Characteristics and source apportionment of volatile organic compounds in an industrial town of Pearl River Delta

2019年在珠三角典型产业重镇佛山市狮山镇在线监测大气挥发性有机化合物(VOCs),并开展大气VOCs污染特征、臭氧生成潜势(OFP)及来源贡献分析.观测期间共测得56种VOCs物种,总挥发性有机物(TVOCs)体积浓度为(39.64±30.46)×10^(-9),主要组成为烷烃(56.5%)和芳香烃(30.1%).大气VOCs在冬季和春季浓度较高.VOCs各组分呈“U”型日变化特征,污染时段的日变化幅度明显大于非污染时段.相对增量反应活性(RIR)结果表明研究区域的O_(3)生成处于VOCs控制区.2019年VOCs的OFP为107.40×10^(-9),其中芳香烃对总OFP贡献最大(54.6%).OFP浓度最高的10种VOCs占总OFP的80.3%,占TVOCs体积浓度的59.9%,高反应活性的VOCs物种在研究区域具有较高的大气浓度,应重点控制.正交矩阵因子分析模型(PMF)来源解析结果表明,溶剂使用源(42.4%)和机动车排放源(25.8%)是研究区域2019年大气VOCs的主要来源,其次为工业过程源(14.6%)、汽油挥发(7.9%)和天然源(1.7%),控制上述源的VOCs排放是缓解该地区臭氧污染的有效策略.

The volatile organic compounds(VOCs)were continuously measured in the typical industrial town Shishan in Foshan in the Pearl River Delta region,and their characteristics of variability,Ozone Formation Potentials(OFP)and source apportionment were analyzed in 2019.A total of 56 VOCs species were detected during sampling time.The concentrations of TVOCs(total VOCs)were(39.64±30.46)×10-9,and the dominated VOC components were alkanes(56.5%)and aromatics(30.1%).The general trend of seasonal variation indicated higher concentrations in spring and winter.The classified VOCs were characterized by"U"diurnal variation.The range of diurnal variation of polluted period was obviously greater than that of unpolluted period.The relative incremental reactivities(RIR)showed that ground-level ozone formation in the study area was generally limited by the concentrations of VOCs.The OFP concentrations of VOCs were 107.40×10^(-9)with the highest contributions from aromatics(54.6%).The summed of the top 10 OFP compounds accounted for 80.3%of the total OFP and 59.9%of the TVOCs.The concentrations of the key active VOCs species were higher,which should be paid more attention.Probabilistic matrix factorization(PMF)model was used to identify the sources of the VOCs.Solvent use(42.4%)and vehicle(25.8%)were the major sources of VOCs emissions in 2019,followed by industrial process(14.6%),fuel evaporation(7.9%)and biogenic emissions(1.7%).The result suggests that controlling the emission sources above would be an effective strategy to alleviate photochemical ozone pollution.