夏季典型背景及城市地区VOCs对比研究

A Comparative Study of Summer VOCs Between Typical Background and Urban Stations

选取武夷山、庞泉沟和长岛3个具有代表性的空气背景站点及其周边城市站点,分析研究夏季环境空气中挥发性有机污染物(VOCs)的特征。结果表明,庞泉沟、武夷山、长岛背景站点的总挥发性有机物(TVOCs)平均浓度分别为(24.71±7.89)×10^(-9)、(7.94±5.82)×10^(-9)、(11.98±5.34)×10^(-9),分别比对应的城市站点低42%、43%、11%。背景站点TVOCs中的烷烃占比为67%~72%,明显高于城市站点;背景站点与城市站点TVOCs中的烯烃和芳香烃占比无显著差异;但背景站点炔烃占比(2%~3%)明显低于城市地区(10%~24%)。背景站点异戊二烯浓度在09:00—15:00出现峰值,且TVOCs浓度变化趋势与异戊二烯浓度变化趋势关联性较强,说明背景站点受自然源影响较大。臭氧生成潜势(OFP)分析结果表明,烯烃及芳香烃对背景地区与城市地区臭氧生成有较大影响,城市地区总OFP远大于背景地区,乙烯、甲苯等对城市地区OFP的贡献较大,异戊二烯对背景地区OFP的贡献较大。

In this paper,three representative atmospheric background sites in Wuyishan,Pangquangou and Changdao and their surrounding urban sites were selected to analyze the characteristics of volatile organic compounds(VOCs)in summer ambient air by manual and automatic monitoring methods.The results showed that the average concentrations oftotal volatile organic compounds(TVOCs)in Pangquangou,Wuyishan and Changdao were(24.71±7.89)×10^(-9),(7.94±5.82)×10^(-9),(11.98±5.34)×10^(-9),respectively,which were 42%,43%and 11%lower than those in urban sites.The proportion of alkanes in the background sites was 67%-72%,which was significantly higher than that in the urban sites.The proportion of alkanes and aromatics in the background sites were not significantly different from that in the urban sites,but the proportion of alkynes in the background sites was 2%-3%,which was significantly lower than that in the urban areas.The isoprene of the background site which was highly influenced by the natural sources had a peak from 09:00 to 15:00 during the day,and the change trend of the TVOCs concentration in the background site was strongly correlated with the change trend of the isoprene concentration,it showed that the background site was greatly influenced by natural resources.The ozone formation potential(OFP)results showed that the background and urban stations of olefins and aromatic hydrocarbons had a greater impact on the formation of ozone.The total OFP in urban area was much larger than that in background area,the contribution of ethylene and toluene to the total OFP in urban area was larger than that in background area,the contribution of isoprene to the total OFP in background area is larger than that in urban area.