| Spatial distribution of PM2.5 in southern suburbs of Xi'an and influence of meteorological factor were studied base on the monitoring values of daily average of Xi'an University of Architecture and Technology during November 2007 to October 2008 and heating period from 2008 to 2009 in this study,furthermore,three heavy metals Pb,Ni and Cd of PM2.5 were analyzed,and investigated its source,influence on human health and countermeasure of pollution prevention.It is approximately similar of distributed tendency of monthly mean concentration of PM2.5 and PM10,a large proportion of PM2.5 were engaged in PM10 and it was steady, the average value was 72%,average values of each season of PM2.5 and PM10 approximately were:winter＞autumn＞spring＞summer;the daily concentration distribution of PM2.5 in heating period demonstrated definite discipline,there approximately were two fastigium,during 12 to 15 pm and 21 to 24 pm;average concentration of PM2.5 in time of unheating period and heating period in southern suburbs of Xi'an were 63.43μg/m3 and 108.95μg/m3,it was 4.23 and 7.26 times to stateside PM2.5 air quality standards;The grain diameter of PM2.5 focused on range 0.375μm-2.423μm.There was a consanguineous relationship between mass concentration of PM2.5 and various kinds of meteorologic condition:the relationship between PM2.5 and total amount of cloud and humidity level was a positive correlation,the relationships between PM2.5 and atmospheric pressure,air temperature,hours of sunshine,quantity of radiation,wind speed and visibility were negative correlation.Among these factors, quantity of radiation and relative humidity level consumingly influence on mass concentration of PM2.5,mass concentration of PM2.5 influence on visibility and make it lower.A large discrepancy of various kinds of heavy metal concentration presented in time of sampling,the average concentration of Pb was 0.266μg/m3,the concentration of Ni was 0.013μg/m3,and Cd was 0.006μg/m3,the average concentration of Pb was obviously higher than the average concentration of Ni and Cd;we analyzed the source of heavy metal with the method of enrichment factor,the result manifested Pb and Cd were mainly sourced in contribution from people,Ni was mainly rooted in natural source;and investigated the influence of heavy metal on people health and proposed the interrelated countermeasure of pollution prevention. |
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