| Due to their adverse health effects and important role in atmospheric environment, PM10and PM2.5pollution have drawn great attention from the government authorities and researchers worldwidely. In China, the frequently occurred haze pollution has arouse the wide concern of social communities. Although the Beijing-Tianjin-Hebei region is most heavily polluted, many other districts, including Wuhan, are also suffered from the haze pollution. On the other hand, unlike Beijing, Shanghai, Guangzhou, research on PM10and PM2.5pollution is relatively lacking in Wuhan, China. Moreover, the emission of vehicle exhausts, one of the main sources of the fine particulate matter, presents great differences in its contribution to the atmospheric particulates in different time and different places. Therefore, more researches in this aspect are needed in Wuhan. In this study, continuously monitoring was conducted for8periods at a curbside site, in order to gain more knowledge about PM10and PM2.5pollution in the road micro-environment. It is hoped that these data would be valuable for the haze pollution control in Wuhan.During August2012to December2013, PM10and PM2.5monitoring was carried out for8periods at the side of Nanhu Road, where daily traffic flow is rather considerable. Each monitoring period lasted for15days. Comparisons were made with the corresponding daily average mass concentration of PM10and PM2.5from Wuhan Environmental Protection Bureau and the background monitoring site located on campus of Huazhong Agricultural University. The spatial-temporal characteristics of PM10and PM2.5concentration, and the relationship between the traffic flow and the PM10and PM2.5mass concentration were explored, taking the meteorological factors into account. In addition, selected element contents in PM samples collected by filters were determined using ICP-AES and EDXRF. Subsequently, possible PM sources of this monitoring site were estimated preliminarily by the method of PC A and correlation analysis.Results showed that, from August2012to December2013, the daily average concentrations of PM10were204.1μg/m3,136.1μg/m3,190.5μg/m3and268.0μg/m3in spring, summer, autumn and winter, respectively. And the corresponding daily average concentrations of PM2.5were132.3μg/m3,73.9μg/m3,110.9μg/m3and171.7μg/m3. The exceeding rates of PM10and PM2.5were relatively low in summer. As for the other three seasons, the exceeding rates were all over50%. In terms of seasonal variations, the PM10and PM2.5pollution in winter is the most serious, and air qualtiy in summer is the best. Considering the hourly variation of PM10and PM2.5, higher PM concentrations were observed at7:00-9:00and21:00-23:00, PM level between11:00-16:00were relatively low and no significant fluctuations were observed. The concentration of PMio and PM2.5were both negatively correlated with temperature; on the other hand, the humidity has no significant influence on PM10concentration, but was positively correlated with PM2.5concentration. The mean PM2.5/PM10ratio were61%,55%,59%and62%in spring, summer, autumn and winter, respectively, suggesting that PM2.5accounted for a large proportion of PM10. Comparing the PM level of2012and2013, it was found that the PM pollution in2013was generally similar to that in2012, though there was a worsening tendency for the winter period in2013. In addition, results showed that in summer, during which the pollution was relatively less serious, the PM concentrations at the curbside site were higher, reflecting the contribution of vehicle exhaust. But in winter, in which the pollution was much serious, the PM concentrations of the urban district were obviously higher than those of the roadside, revealing the notable contribution of the urban area. As expected, the PM concentrations at the curbside were much higher than the ones of the campus, which also suggested that the curbside air was unfavorably affected by the vehicle exhaust. As for the heavy metal content, the Fe content was the highest, followed by Zn, Pb, Mn, and Cu. The enrichment factors of Cd, Cu, Pb and Zn were high in PM10and PM2.5, and the daily variation of these four heavy metals were obvious, suggesting the important contribution of anthropogenic source. In addition, from the EDXRF analysis, elements of Al、Si, Ti, Fe, Ca, S and K were abundant. Further, PCA and correlation analysis among the elements suggested that the main pollution sources were possibly soil and building dust, urban road dust, coal combustion, and vehicle exhaust. |
PDF Full Text Request