Analyse On Pollution Characters And Source Apportionment Of PM_2.5 In Traffic Roads Of Foshan City

Particulate matter is one of the primary pollutants that affect China’s air quality.In recent years, with the rapid growth of urban vehicle ownership,the particulatematter that especially transportation activities emissions has become one of theimportant sources of the urban air pollution,especially for articulate matter pollutionin traffic micro environment. In the light of the characteristics of motor vehicleexhaust emission,fine particulate matter PM_2.5has been taken as research emphasisof particulate matter pollution in traffic environment because of traffic activities.PM10and PM_2.5samples were taken at Jihua main-road、Tongji secondary mainroad and Huyanxi branch road in the main district of Foshan in winter、spring、summer and autumn of2012-2013year and analyzed for heavy metalelements,water-solubility ions in PM_2.5samples by ICP-MS and IC, respectively.Pollution characteristics of Heavy metal elements and water-solubility ions in PM_2.5were investigated in this work. And also it discussed source apportionment of PM_2.5by factor analysis （FA）.During sampling,The daily average concentration of PM_2.5was146.8μg/m3inthe traffic environment of Foshan city,64.5μg/m3for Wan liang （background）. Thepollution of PM_2.5in the traffic environment of Foshan city was obviously moreserious than the city during the same period. The seasonal change of PM_2.5concentrations was spring>winter>autumn>summer, as the same with the changetrend of atmospheric diffusion dilution ability. In all traffic environment samplingpoints, PM_2.5concentration’s changes were in the order: JiHua>tongji>huayuan, andhad a significant positive correlation with traffic through the analysis.The average ofPM_2.5/PM10was66.0%in traffic environment during the period of sampling.On the analysis of12kinds of heavy metal elements in PM_2.5,the total amountof heavy metal elements in PM_2.5occupied,on average,6.1%in PM_2.5. The contentsof Mg、Al、Fe、Ca were higher, followed by Zn and Pb in three sampling points.These heavy metals in each traffic environment followed byJiHua>Tongji>Huayuanxi road, which was mainly related to the difference of road traffic dust pollution.Seasonal change for concentration of heavy metal elements isin accordance with the change trend of PM_2.5mass concentration. The analysis ofenrichment factor showed that the pollution of Cd、Zn、Pb、As is the most seriousfromman-made source.On the analysis of9water-soluble ion in PM_2.5, the average total concentrationof water-soluble is29.3μg/m3, accounted for22.0%of PM_2.5in the trafficenvironment of Foshan city during sampling. The total mass concentration ofwater-soluble ion in PM_2.5of different traffic sample points showed that Tongji>Huayuanxi>JiHua road in spring and summer, Tongji>Huayuanxi>JiHua road inautumn and winter.During sampling, SO42-、 NO3-and NH4+is the mainwater-soluble ions of traffic environment.And among different trafficenvironment,there is no statistically significant for the difference of water-solubleion concentration, change has also no obvious regularity. In addition, seasonaldistribution also vary. During sampling, among three traffic environment samplingpoint,NH4+and SO42-in PM_2.5has the highest correlation,followed by NH4+andNO3-.And the influence of second transformation to SO42-is greater than NO3-. Theinfluence of the motor vehicle emission source for atmospheric water solublecomponents was close to fixed emission source. The influence of sea salt to watersoluble components are small. In addition, Fine particulate matter in winter is partialto acid, to alkaline in summer, and more neutral in the spring and autumn season.The principal component analysis was used for studying, which showed theresult that the source of heavy metal elements and water-soluble ions in PM_2.5fromthe traffic environment of Foshan city are motor vehicle emissions、secondaryaerosols、coal、soil dust and biomass burning.Motor vehicle emissions was the main.