广州市交通干线附近细颗粒污染特征

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(PM_2.5)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PM_2.5超标严重,但ρ(PM_2.5)有所下降. 受季节性污染源及气象因素影响,广州市夏季ρ(PM_2.5)平均值为42μg/m3,明显低于春、秋、冬三季. ρ(PM_2.5)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(PM_2.5)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(PM_2.5)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(PM_2.5)和ρ(PM₁)的相关性较好,R(相关系数)为0.94,PM₁是PM_2.5的主要构成颗粒,所占比重平均值为0.65. ρ(PM_2.5)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(PM_2.5)更为密切,夜晚则与ρ(PM₁)更为密切. 

Analysis of Fine Particulate Near the Transportation Routes in Guangzhou City

Based on the data obtained from the monitoring sites at Sun Yat-sen University in Guangzhou City from 2008to 2012, variations of PM_2.5 and PM_{1concentration} and composition were analyzed and presented by mean comparative analysis, significant test and correlation analysis. During the observation period, the mean ρ(PM_2.5) 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(PM_2.5) showed a decreasing trend. In terms of seasonal features, ρ(PM_2.5) and ρ(PM₁) were affected by seasonal pollution sources and meteorological factors. The ρ(PM_2.5) in summer was 42μg/m3and was significantly lower than that for other seasons. Furthermore, there is a significant difference between ρ(PM_2.5) at weekends and weekdays. The ρ(PM_2.5) 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(PM_2.5) and ρ(PM₁) showed a similar trend. During the daytime, both ρ(PM_2.5) and ρ(PM₁) were low in the morning and gradually increased in the afternoon. ρ(PM_2.5) 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(PM_2.5) and ρ(PM₁) with a high correlation coefficient (0.94). This is mainly because the PM_1is the major constituent particle in PM_2.5, which accounts for 65%. Both the trends of ρ(PM_2.5) 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(PM_2.5) trend, while the traffic flow at night is more closely related to the ρ(PM₁) trend.