某城市交通区大气多环芳烃污染的时空分布特征

Distribution Characteristics of Airborne PAHs with the Changes of Space and Time in a Traffic Area of a City

[目的]了解城市交通区不同地区和不同时间内颗粒物中多环芳烃的分布特征。[方法]对某城市某交通区不同地点颗粒物和多环芳烃的含量分别进行了监测,同时在1个地点进行了连续24h监测。[结果]不同地段颗粒物中多环芳烃的含量不同,总体趋势是:高架下大气中颗粒物多环芳烃的污染比高架上严重;城区比郊区污染严重;隧道内比隧道外污染严重。同时,同一地点颗粒物及其中多环芳烃连续24h的监测结果表明,在24h内,大气中颗粒物及其中的多环芳烃含量有规律的波动,在清晨、下午出现两个高峰。研究还发现在颗粒物和其中多环芳烃之间存在明显的相关性,相关系数为0.231,并得到了回归模型;对不同粒径的成分分析结果表明,PM2.5占PM10的30%～50%,是主要的多环芳烃携带颗粒物。[结论]交通因素以及周围环境因素是导致大气中颗粒物多环芳烃污染浓度改变的主要因素之一;PM2.5是主要的多环芳烃的携带者。

[ Objective ] To understand the distribution characteristic, the concentrations of particle-bound PAHs in a traffic area of a city with the changes of location and time. [ Methods ] The concentrations of particulate matter and particlebound PAHs were monitored in different locations, and also monitored for 24h at a same location. [ Results ] The concentrations of particle-bound PAHs were different at different location. The trend was that the pollution of particle-bound PAHs under the viaduct was more serious than on the viaduct, more serious in the city center than in suburb, more serious in the tunnel than out of the tunnel. The concentrations of particulate matter and particle-bound PAHs had a regular fluctuation at a location in 24 hours, and two peak values appeared in the morning and afternoon. The correlation coefficient between particulate matters and particle-bound PAHs was 0.231, and the regression model was also established. By the analysis of components of different diameter particulate matters, it was found that the quantity of PM2.5 accounted 30-50 percent of the quantity of PM10, and PM2.5 seemed the main particulate matters onto which PAHs absorbed. [ Conclusion ] The factors of traffic and environment are two of many reasons that lead to the concentration of particle-bound PAHs change. PM2.5 is the main PAHs carrier.