北京市城区大气羰基化合物的季节变化

Seasonal Variations of Carbonyl Compounds in Urban Atmosphere of Beijing

2006年8月19～22日（夏季）、10月24～30日（秋季）和2007年1月20～23日（冬季）,利用被动式扩散采样器（DSD-DNPH）对北京市城区5个地点C1～C10羰基化合物进行了采样.通过高效液相色谱（high performanceliquid chromatography,HPLC）分析,20种羰基化合物被检测出,在夏季、秋季和冬季其总浓度分别为（89.1±23.6）、（85.2±17.5）和（40.0±9.8）μg/m3.其中,甲醛、乙醛和丙酮是浓度最高的3种羰基化合物,它们的浓度从冬季的（7.1±2.1）、（10.3±3.1）、（9.5±1.8）μg/m3增长到夏季的（15.3±9.2）、（12.9±4.9）、（13.3±3.5）μg/m3和秋季的（13.2±4.0）、（13±4.4）、（15.3±4.0）μg/m3.定性分析表明,羰基化合物的污染来源,冬季主要是机动车污染,而夏季和秋季则是来自光化学反应、机动车和餐馆油烟的综合污染.此外,在风速较大、扩散条件较好的条件下,甲醛、乙醛和丙酮等主要污染物浓度明显降低,表明扩散条件对羰基化合物浓度的影响较明显.

A passive diffusive sampling device （DSD-DNPH） was used to collect C1-C10 carbonyl compounds among five sampling sites in the urban area of Beijing among August 19-22 （summer）, October 24-30 （autumn）, 2006 and January 20-23 （winter）, 2007. Through the analysis of sampled carbonyl compounds by High Performance Liquid Chromatography （HPLC）, 20 carbonyl compounds were measured and total concentrations were （89.1 ± 23.6）, （85.2 ± 17.5） and （40,0 ± 9.8） μg/m3 in summer, autumn and winter, respectively. Among the 20 carbonyl compounds, formaldehyde, acetaldehyde and acetone were the most abundant compounds. The concentrations of them increased to （ 15.3 ± 9.2）, （ 12.9 ± 4.9） and （ 13.3 ± 3.5） μg/m3 in summer, and （ 13.2 ± 4.0）, （ 13 ± 4.4） and （ 15.3 ± 4.0） μ/m3 in autumn from （7.1 ± 2.1 ）, （ 10.3 ± 3.1 ） and （9.5 ± 1.8） μg/m3 in winter. Vehicular emissions become the most significant source of carbonyl compounds in winter, while the photochemical reactions and cooking exhaust also play important roles during summer and autumn. In addition, the dispersion conditions have significant effects on the concentration of carbonyl compounds, for the concentrations of the main carbonyl compounds such as formaldehyde, acetaldehyde and acetone, especially, are much lower under good dispersion conditions than bad ones.