宁波市环境空气中VOCs污染状况及变化趋势分析

基于近7年来的连续监测数据,对宁波市环境空气中挥发性有机物(VOCs)的污染状况及变化趋势进行了初步分析。研究表明:在宁波市环境空气中检测出94种VOCs,其主要成分是饱和烷烃、芳烃、烯烃、卤代烃、卤代芳烃、含氧有机物等,有37种属有毒有害物质,其中苯系物含量最高;宁波市环境空气中苯系物的污染程度与国内外城市基本处于同一水平,近年来的污染状况变化不大,没有明显恶化;空间分布特征显示一类保护区VOCs的排放以天然源为主,二类各功能区VOCs的排放由天然源和局部人为污染源共同形成,三类区以工业污染源排放为主;时间变化趋势显示VOCs在冬季和春季的平均浓度比其他季节高,VOCs的日变化基本呈现2个主浓度峰值特征,跟城市交通流量变化具有很好相关性。

Pollution Status and Trend Analysis of Volatile Organic Compounds in the Ambient Air of Ningbo City

Based on the recent continuous monitoring data of 7 years, the pollution status and trend of volatile organic compounds (VOCs) in the ambient air of Ningbo city were analyzed. The results indicated that: a total of 94 species of VOCs were detected, and the major components were alkanes, aromatics, alkenes, halogen alkanes, halogen aromatics and oxygenated organic compounds, among which 37 species were toxic/hazardous with benzene, toluene, ethyl-benzene, and xylene (BTEX) exhibiting the highest concentration;the pollution status of BTEX in the ambient air of Ningbo City was at the same level with cities of domestic and abroad, and had not been deteriorated significantly in the recent years;distinct spatial patterns of VOC sources were identified, i.e., natural source for functional zone I, combination of natural and anthropogenic source for functional zone II and industrial source for functional zone III;temporal trend of VOCs revealed that the average concentrations of VOCs in winter and spring were higher than other seasons and the diurnal variations of VOCs exhibited two peaks pattern, which correlated well with the variations of the traffic density.