广州市交通干线附近细颗粒污染特征

Analysis of Fine Particulate Near the Transportation Routes in Guangzhou City

利用中山大学大气环境监测平台数据,对广州市交通干线附近的ρ(PM2.5)和ρ(PM1)进行了统计学分析,以研究交通干线附近细颗粒污染特征及变化规律.结果表明:2008—2012年广州市PM2.5超标严重,但ρ(PM2.5)有所下降.受季节性污染源及气象因素影响,广州市夏季ρ(PM2.5)平均值为42μg/m3,明显低于春、秋、冬三季.ρ(PM2.5)在工作日与周末差异明显,周末明显高于工作日,而ρ(PM1)在工作日与周末差异不明显.ρ(PM2.5)与ρ(PM1)日变化趋势基本一致,整体上呈白天低、夜晚高,上午低、下午高的特征.ρ(PM2.5)日变化呈单峰,19:00左右达到最大值(53μg/m3);而ρ(PM1)呈双峰变化,在20:00左右达到高峰值(43μg/m3),上午09:00左右也有一小峰值(37μg/m3).ρ(PM2.5)和ρ(PM1)的相关性较好,R(相关系数)为0.94,PM1是PM2.5的主要构成颗粒,所占比重平均值为0.65.ρ(PM2.5)和ρ(PM1)均与交通流量存在相关性,在白天和夜晚变化趋势相一致,但交通流量白天与ρ(PM2.5)更为密切,夜晚则与ρ(PM1)更为密切.

Based on the data obtained from the monitoring sites at Sun Yat-sen University in Guangzhou City from 2008to 2012, variations of PM2.5 and PM1concentration and composition were analyzed and presented by mean comparative analysis, significant test and correlation analysis. During the observation period, the mean ρ（PM2.5） was 53μgm3, and was more than 35μgm3for the new air quality standard （2012） with the concentration of 51.7%. The inter-annual variation of ρ（PM2.5） showed a decreasing trend. In terms of seasonal features, ρ（PM2.5） and ρ（PM1） were affected by seasonal pollution sources and meteorological factors. The ρ（PM2.5） in summer was 42μgm3and was significantly lower than that for other seasons. Furthermore, there is a significant difference between ρ（PM2.5） at weekends and weekdays. The ρ（PM2.5） at weekends was higher than that at weekdays, while ρ（PM1） showed no significant difference between at weekends and weekdays. The daily changes of ρ（PM2.5） and ρ（PM1） showed a similar trend. During the daytime, both ρ（PM2.5） and ρ（PM1） were low in the morning and gradually increased in the afternoon. ρ（PM2.5） reached the maximum value of 53μgm3at 19：00. However, ρ（PM1） showed a small peak value of 37μgm3at 09：00, and then reached a peak of 43μgm3at 20：00. There was a trend consistency between ρ（PM2.5） and ρ（PM1） with a high correlation coefficient （0.94）. This is mainly because the PM1is the major constituent particle in PM2.5, which accounts for 65%. Both the trends of ρ（PM2.5） and ρ（PM1） are related to the traffic flow whenever on daytime or at night. It revealed that the traffic flow on daytime is more closely related to the ρ（PM2.5） trend, while the traffic flow at night is more closely related to the ρ（PM1） trend.