兰州市大气沉降尘中正构烷烃分布及环境意义

文章主要分析了兰州市冬季采暖期大气沉降尘有机质正构烷烃的组成,其分布型式主要有三种类型:一种是前峰为主的双峰型,以C12～C25,C27,C29,C31为主峰碳,具有较明显的奇偶优势;第二种是双峰型,以C12～C25,C27,C29,C31为主峰碳,奇偶优势不明显;第三种为后峰为主的单峰型,C27,C29,C31为主峰碳8。兰州市的大气总颗粒物TSP中有机质为后峰为主的单峰型,C29,C31为主峰碳,而C24～C27的含量也相对较多,是构成TSP中有机质正构烷烃的主要组分。兰州市冬季产生的大气颗粒物中有机质主要来源于陆生高等植物和人类活动源,如燃煤、油制品的不完全燃烧、汽车尾气的排放等,从正构烷烃图谱中也可以明显反映出兰州市冬季人类活动源有较大的比例,冬季植被状态较差。沉降尘中微生物的作用也可能是增加有机质含量的一种因素。

Distribution of n-alkane and Environmental Significance about the Lanzhou Atmospheric Dust

Organic components of alkane in falling dust of Lanzhou City,Gansu Province was analyzed to estimate the air quality of Lanzhou during winter which is the heating period in northern China and its pollution source. Results showed that there were three distribution types of n-alkane,and the single peak mainly with rear peak has great percentage in TSP of Lanzhou,with dominant peak as C29 and C31 and C24～C27 as main components of alkane in TSP. Organics in air particles were mainly originated from terraneous higher plants and human activities such as coal burning,incomplete burning of oil products and exhaust gas discharged from vehicles. Alkane spectrum illustrated that human activity has significant contribution to TSP and plants in winter are in bad status. Role of microorganism in falling dust may be one of factors in increasing organic mass.