北京奥林匹克运动会期间大气超细颗粒物的水平和粒径分布

Status and distribution of atmospheric ultrafine particles during Olympics Games in Beijing

目的:了解北京市奥林匹克运动会期间超细颗粒物的浓度、粒径分布特点,并探寻对超细颗粒物浓度可能产生影响的因素。方法:采用TSI公司生产的超细颗粒物监测仪每天监测24h20～500nm粒径颗粒物数量浓度,对监测数据进行整理,并进行描述性分析。结果:奥林匹克运动会期间20～100nm粒径范围超细颗粒物数量浓度的平均值为5920.43个/cm3,30～50nm粒径范围颗粒物占数量浓度比例最大,为23.49%,每天24h内超细颗粒物数量浓度有中午及晚上两个高峰。结论:奥林匹克运动会期间北京市超细颗粒物的数量浓度比以往有较大程度的降低,粒径为20～30nm、>30～50nm的超细颗粒物浓度可能与光照强度有关,超细颗粒物数量浓度与温度、湿度及光照时间具有相关性。

Objective：To understand the characteristics of size and concentration of the ultrafine particles（UFPs）during the 2008 Olympics in Beijing,as well as the influencing factors for number concentration of UFPs.Methods：Ultrafine particle monitor model 3031,manufactured by USA TSI Co.,was used to monitor the daily number concentration of 20-500 nm particles,and descriptive analysis was conducted based on the data collected.Results：During the Olympics,the mean value of number concentration for 20-100 nm particulate matter is 5 920.43 particles/cm3.Particles ranging 30-50 nm account for the largest portion（23.49%）among particles of all sizes.There are two peak values on the curve of 24 hours＇ number concentration for 20-100 nm particles,respectively,at noon and evening.Conclusion：This paper indicates that the number concentration of ultrafine particles registered considerable reduction in the 2008＇s Olympics compared to the pre-Olympics years.And observation of the curves indicated that the number concentrations of the UFPs with bigger size are related to traffic volume,whereas for smaller size UFPs,illumination may be a more important influencing factor.Also there are significant correlations between number concentration and temperature as well as relative humidity.