The Characteristic Analysis And Control Strategies Of PM_2.5in Changsha Great Hexi Pilot Areas

Sources of the ambient PM2.5(aerodynamic diameter less than or equal to2.5) is complicated, as a new kind of pollutants, PM2.5pollution is serious in most cities in China, and damage to the environment and human health, it has become one of the atmospheric environment pollution problems to be solved.Changsha Great Hexi Pilot Areas is located in the eastern north of hunan province, belongs to Changsha. In2020, according to the target and planning, the Pilot Areas will become a ecological and livable new urban area,its construction area is200square kilometers, the resident population is about1.5million people. So studying PM2.5Pollution characteristics of the Pilot Areas,and putting forward the control countermeasures has the great significance.The paper studies concentration level,the time and space distribution characteristics of the PM2.5in a typical season and different functional areas in the Pilot Areas. Research showed that contribution to the larger, accounted for the proportion of PMt0is73%.Of all the samples collected,75%of the Autumn,79.2%of the Winter exceeded the standard criterion.but the difference was not significant between the Autumn and the Winter. the weather condition has certain effect on concentration level of atmospheric particulates. Relative to the suburb and the county area,Central area of PM2.5concentration were higher, and the main trunk road is higher than the minor trunk road but there was no significant difference. Meanwhile, The areas near by the Large construction site has higher concentration level of the PM2.5and were significantly different from the areas far away construction site,this is main factor causing uneven spatial distribution.Research showed that concentration level of heavy metal had no significant differences at different sampling point, the pollution source is consistent. Enrichment factor of heavy metal were higher than10, such as Cd, Hg, As and Pb, its source mainly related to human activities, but it is not entirely from the non soil source,urban fugitive dust may be the main contribution of PM2.5in the Pilot Areas.This paper evaluates the air quality pilot area and on human h ealth risk, study shows that air quality of the Pilot Areas is in a m oderate pollution, health risk value scope of PM2.5and PM10is in t he range of acceptable risk in US EPA (the U.S. environmental pro tection agency) regulations,as1×10-6～1×10-4.On the basis of the above research, this paper put forward the controlcountermeasures and measures of PM2.5in the Pilot Area.