中国北方典型城市空气中苯系物的污染特征

为了研究中国北方典型城市大气中苯系物的污染状况和季节变化特征,于2008年4月—2009年1月间,选取沈阳和天津共11个监测点位分别采集大气样品,并利用三级冷阱预浓缩-GC-MS方法进行分析.结果表明,天津的苯系物污染浓度比沈阳高,这是因为天津的机动车保有量远远大于沈阳,机动车尾气排放量大.苯系物的污染程度与不同季节的气候变化密切关联,两城市均表现为春秋两季污染严重,冬夏两季污染较轻.城市不同功能区采样点的比较和苯与甲苯(B/T)的比值以及各苯系物之间的相关性分析表明,两城市苯系物污染浓度均受到局部排放源的明显影响,但在大部分地区交通源仍为主要排放源.

Pollution characteristics of BTEX in typical urban air in northern China

In order to study the contamination status and seasonal variations of BTEX in typical cities in northern China,the atmospheric samples were collected at 11 monitoring sites in Shenyang and Tianjin from April 2008 to January 2009.The samples were analyzed by three cold trap pre-enrichment-gas chromatography-mass spectrometry(GC-MS).Results indicated that the concentrations of BTEX in Tianjin were higher than those of Shenyang,most probably because Tianjin has much more motor vehicles and exhaust emissions.The concentrations of BTEX were closely related with different seasons.BTEX pollution in spring and autumn was more serious than in winter and summer in both cities.The comparison of different functional sampling sites,the ratio of benzene/toluene(B/T) and correlation coefficients between BTEX suggested that concentrations of BTEX in the two cities were impacted by some additional emission sources significantly,but traffic emission was the main source of BTEX in most areas.