Wang Cheng-Hui, Chen Jun-Hui, Han Li, Xu Chen-Xi, Wang Bo, Li Ying-Jie, Liu Zheng, Qian Jun
Sichuan Academy of Environmental Sciences, Chengdu 610041, China.
Huan Jing Ke Xue. 2020 Sep 8;41(9):3951-3960. doi: 10.13227/j.hjkx.202002153.
To investigate the seasonal variations in the concentrations of atmospheric volatile organic compounds (VOCs) in the urban area of Chengdu, VOC species were monitored from December 2018 to November 2019, and the concentrations, chemical composition, chemical reactivity, and sources of VOCs were analyzed. Average volume fraction of VOCs in spring, summer, autumn, and winter are 32.29×10, 36.25×10, 40.92×10, and 49.48×10, respectively. The concentrations in winter are significantly higher than the winter concentrations measured in other areas. There is no significant difference between VOC concentrations in spring and summer, but component concentrations vary from season to season. In winter, alkanes account for the largest proportion of total VOCs owing to vehicle emissions. The proportion of oxygen (nitrogen)-containing volatile organic compounds in summer and autumn is much higher than that in spring and winter. Volatile emissions from primary sources and secondary conversions have a great contribution. The average concentration of key components of VOCs in different seasons did not change significantly. C-C alkanes, ethylene, acetylene, and dichloromethane concentrations may be significantly affected by vehicle exhaust, oil and gas volatilization, solvent use, and LPG fuel use. ·OH consumption rate and OFP calculations show that key active species are mainly /-xylene, ethylene, propylene, 1-hexene, toluene, isopentane, and -butane. Therefore, these species should be given priority in emissions control measures. Since the temperature in spring and summer is higher than in autumn and winter, and the UV rays are more intense, PMF analysis reveals the natural sources and the secondary emission sources as the major sources. The oil and gas volatilization source contributes to 9% of VOC concentrations in summer. The major VOC sources in autumn and winter are vehicle exhaust and combustion sources. Emissions from the combustion sources contribute to 25% and emissions from the catering sources in autumn and winter contribute to 9% of total VOC levels.
为研究成都市城区大气挥发性有机化合物（VOCs）浓度的季节变化，于2018年12月至2019年11月对VOCs物种进行了监测，并分析了VOCs的浓度、化学组成、化学反应活性和来源。春、夏、秋、冬四季VOCs的平均体积分数分别为32.29×10、36.25×10、40.92×10和49.48×10。冬季的浓度显著高于其他地区冬季所测浓度。春季和夏季的VOC浓度无显著差异，但各组分浓度随季节变化。冬季，由于机动车排放，烷烃在总VOCs中占比最大。夏季和秋季含氧（氮）挥发性有机化合物的比例远高于春季和冬季。一次源挥发性排放和二次转化贡献很大。不同季节VOCs关键组分的平均浓度变化不显著。碳 - 碳烷烃、乙烯、乙炔和二氯甲烷的浓度可能受机动车尾气、油气挥发、溶剂使用和液化石油气燃料使用的显著影响。·OH消耗率和OFP计算表明，关键活性物种主要为间/对二甲苯、乙烯、丙烯、1 - 己烯、甲苯、异戊烷和正丁烷。因此，在排放控制措施中应优先考虑这些物种。由于春夏季温度高于秋冬，且紫外线更强，则PMF分析表明天然源和二次排放源为主要来源。油气挥发源在夏季对VOC浓度的贡献率为9%。秋冬季节VOC的主要来源是机动车尾气和燃烧源。燃烧源排放占总VOC水平的25%，秋冬餐饮源排放占9%。
