移动源排放VOCs特征及臭氧生成潜势研究—以兰州市为例

高浓度近地面臭氧(O_3)污染是国内外许多城市面临的大气污染问题,且近年来O_3浓度呈逐渐升高的趋势.随着城市规模日益扩大,移动源成为VOCs的主要排放源之一,对移动源的O_3生成潜势进行评估,并识别其关键物种和重点污染区域,可为城市O_3控制对策的制定提供科学依据.本文以兰州市移动源为例,结合排放系数、交通流量及相关统计数据,建立兰州市VOCs移动源排放清单,并使用最大增量反应活性(MIR)估算移动源VOCs的臭氧生成潜势(OFP).结果表明,兰州市汽油车是移动源中最主要的OFP贡献源类,占移动源的71.12%;烯烃和芳香烃为移动源总OFP主要的贡献者,主要贡献物种为:乙烯、丙烯、甲醛、3-甲基-1-丁烯、甲苯、正丁烯、乙炔、间二甲苯、1,2,4-三甲基苯、邻二甲苯,这10个物种的OFP占移动源总OFP的67.29%;根据兰州市移动源VOCs排放的OFP贡献空间分布结果,移动源VOCs排放的重点控制区域为城关区和七里河区.

Emission characteristics and ozone formation potential of VOCs from mobile sources:A pilot study in Lanzhou

High-concentration ground-level ozone (O₃) is an air pollution problem that many Chinese and foreign cities are confronted with, and its concentration tends to gradually increase in recent years. With the increasing development of urbanization, mobile sources have become one of the main emission sources of VOCs. Assessing the potential of mobile sources generating O₃ and recognizing key OFP contributors and major polluted areas can provide scientific bases for making O₃ control strategies in cities. Taking the mobile sources in Lanzhou as an example, we built a moving emission source list of VOCs in Lanzhou in combination with emission factors, traffic flow and related statistics, and estimate the ozone formation potential (OFP) of VOCs by maximum incremental reactivity(MIR). Gasoline cars are the main OFP contributor, accounting for 71.12% of mobile sources. Alkenes and Arenes are two main OFP contributors of mobile sources. Ethene, propylene, methanal, 3-methyl-1-butene, methylbenzene, n-butene, ethyne, m-xylene, 1, 2, 4-trimethylbenzene, and o-xylene are the top 10 species in terms of OFP, contributing for 67.29% of mobile sources. According to the OFP spatial distribution result of VOCs emitted by mobile sources in Lanzhou, the key control areas of VOCs emitted by mobile sources were found to be Chengguan District and Qilihe District.