成都春季大气臭氧污染过程VOCs特征分析

Analysis on the Characteristics of Volatile Organic Compounds in the Process of Atmospheric Ozone Pollution in Spring in Chengdu

2020年4月28日~5月6日成都出现了一次近5年来春末夏初时段污染时间最长,污染程度最重的臭氧污染过程.为了解该污染过程中VOCs对成都臭氧的贡献,通过采用数理统计、臭氧生成潜势(OFP)等方法,对成都市城区VOCs进行分析.结果表明,成都市城区污染前与污染后VOCs体积分数均低于污染中VOCs体积分数.VOCs日变化呈双峰性,分别出现在早高峰时段及凌晨.污染前、污染中、污染后臭氧生成潜势(OFP)浓度值分别为110.5、199.0、93.3μg/m^(3).间/对二甲苯、乙烯、甲苯和邻二甲苯为绝对优势物种.通过分析整个污染过程VOCs特征,为成都春季臭氧污染防治提供技术支撑.

From April 28 to May 6,2020,an ozone pollution process occured in Chengdu,which had the longest pollution duration and the highest pollution degree in late spring and early summer in recent five years.In order to understand the contribution of VOCs to Chengdu’s ozone in the pollution process,the VOCs in Chengdu urban area were analyzed by using mathematical statistics,ozone formation potential(OFP)and other methods.The results showed that the volume fraction of VOCs before and after pollution in Chengdu is lower than the volume fraction of VOCs during pollution.The daily variation of VOCs is bimodal,appeared in the morning peak hours and the early morning respectively.The concentrations of ozone formation potential(OFP)before,during and after pollution is 110.5,199.0,and 93.3μg/m^(3),respectively.Meta/para-xylene,ethylene,toluene and o-xylene are the absolutely dominant species.By analyzing the characteristics of VOCs of the whole pollution process,it provides technical support for the prevention and control of ozone pollution in Chengdu in spring.