关键词: 非甲烷烃, 稳定碳同位素, 大气, 兰州市

Abstract: Isotopic composition of nonmethane hydrocarbons, sampled by Tenax TA adsorption tube and detected by thermal desorption-gas chromatography-isotope ratio mass chromatography was analyzed in the main functional area, Lanzhou. The results show that the average δ¹³C values of transportation related sources is - 28. 7‰, significantly below the value of coal-combustion exhaust( - 24. 1‰) . In summer the average δ¹³C values of atmospheric NMHCs are close to each other( from - 29. 5‰ to - 27.4‰), while in winter the average δC values in Xigu industrial estate(-25.5‰) is larger than that in Panxuanlu(-28.8‰) and Erdianchang(- 31.2‰). The results of source analysis indicate that the atmospheric NMHCs in Panxuanlu are mainly emitted by transportation related sources both in summer and winter; the atmospheric NMHCs in Xigu industrial estate in winter are mainly influenced by coal-combustion exhaust, while in summer n-alkanes and benzene are mainly from transportation related sources; in winter atmosphere in Erdianchang pentane, hexane and benzene are from transportation related sources; in summer atmosphere in residential area the NMHCs are mainly influenced by transportation related sources and some unknown sources; benzene is mainly emitted by transportation related sources and was detected in every sampling site both in winter and summer. To reduce the pollution of NMHCs, it is important to control transportation related sources.

Key words: non-methane hydrocarbons( NMHCs), stable carbon isotope, atmosphere, Lanzhou