广州番禺大气成分站挥发性有机物的污染特征

Pollution characteristics of volatile organic compounds in Panyu Composition Station

应用GC/FID在线挥发性有机物(VOCs)检测仪,于2011年6月-2012年5月在中国气象局广州番禺大气成分观测站进行了1a的连续监测,获得了具有高时间分辨率的VOCs组成、含量及其时间变化规律.结果表明:VOCs浓度月变化范围是(40.99-65.400)×10-9,月平均浓度48.10×10-9,冬季VOCs浓度高于夏季.VOCs日浓度变化范围是(35.10-59.13)×10-9.VOCs组分随季节变化所占比例不同,烷烃、烯烃和芳香烃全年平均所占比例分别为58%、16%和26%.采样点在7月份没有周末效应,而在12月份表现出显著周末效应.国庆长假期间的大气VOCs浓度比国庆节放假前、后均有大幅度降低,降幅分别达到39.3%和56.7%.采样点的大气VOCs浓度与风速呈负相关性.当风向为NNE、NE和SSW时,风速较大,VOCs的浓度较低;当风向为WNW和ENE时则相反.由于夏季温度高使溶剂挥发性和植物排放增强,所以导致BTEX(苯、乙苯、甲苯和二甲苯)和异戊二烯的浓度在夏季明显高于冬季.

Volatile organic compounds （VOCs） were continuously measured by on-line gas chromatography spectrum instrument coupled with fire ion detector from June 2011 to May 2012 at Guangzhou Panyu atmospheric component Station （GPACS）, China Meteorological Bureau. The variation pattern of VOC concentrations and compositions was obtained with high time resolution. The results showed that monthly variation of VOCs concentration ranged from 40.99×10^9 to 65.40×10^9 and the averaged monthly concentration was 48.10×10^9. The concentrations of VOCs were higher in winter than in summer. The diurnal variation of VOCs concentrations ranged from 35.10×10^9 to 59.13 ×10^9.The annual average proportions of alkanes, alkenes and aromatics were 58%, 16% and 26% respectively, its constitutional characterizations varied from different seasons. It was no weekend effect during July while it was very apparent during December. The concentrations of total VOCs in China National holidays were 39.3% and 56.7% lower respectively than in fore-and-aft China National holidays. The VOC concentrations had an anti-correlation with wind speed. The VOCs concentrations were low when the wind directions were NNE, NE and SSW because of the high wind speed, which was in contrary with the situation when the wind directions were WNW and ENE. BTEX and isoprene were dramatically higher in summer than in winter due to the fact that higher temperature caused higher solvent evaporation and plant emission.