北京市大气光化学氧化剂污染研究

The Study on Pollution of Atmospheric Photochemical Oxidants in Beijing

根据在北京市开展的光化学氧化剂系列研究，讨论北京市主要光化学氧化剂Ｏ３ ，Ｈ２ Ｏ２ 和有机过氧化物的污染浓度水平及其污染特征，探讨光化学氧化剂的形成机制及其主要影响因素。结果表明，北京市存在严重的光化学氧化剂污染，中关村大气臭氧（Ｏ３） 最大浓度不仅逐年递增，而且Ｏ３ 最大值的出现时间也提前，说明大气光化学活性逐年增强。光化学烟雾的重要产物过氧化氢（ Ｈ２ Ｏ２） 和甲基过氧化氢（ ＭＨＰ） 的浓度水平较高，最大浓度分别为３－６９ 和３－２６ μｇ／ｍ ３ 。日益严重的大气ＮＯｘ 污染为光化学氧化剂的生成提供了充足的前体物，北京市的大气污染已逐渐转为机动车尾气污染型，控制北京市光化学氧化剂污染的有效途径是降低ＮＯｘ

On the basis of a series of studies on photochemical oxidants in Beijing,this paper presents the pollution levels of photochemical oxidants,such as ozone (O 3),hydrogen peroxide (H 2O 2) and organic peroxides,in Beijing and their characteristics,and explores formation mechanism of the photochemical oxidants and its impact factors.The results showed that the pollution of photochemical oxidants was serious in Beijing.The maximum hourly mean concentration of O 3 increased year by year,the time to have the peak value was also getting earlier than before,which fact indicated that photochemical reactivity was enhanced yearly.The concentration levels of H 2O 2 and methyl hydroperoxide (MHP),which were the important products of photochemical smog,were high,their maximum concentrations were 3.69 and 3.26 μg/m 3 respectively.In recent years,the air pollution in Beijing is being characterized by traffic exhaust pollution.Increasing NO x pollution provides abundant precursors for the formation of photochemical oxidants,and therefore reduction of NO x emission is an effective way to control pollution of photochemical oxidants in Beijing.