Study On Atmospheric Environmental Risk In Xigu Chemical Industry Area Of Lanzhou

As a gathering place of the chemical materials,chemical industry area involving a large number of dangerous substances and risk sources,diffusion of atmospheric pollutant occurs after sudden leakage,and it may cause personal injury and property damage,furthermore,emergency evacuations effect the normal order of production and life,it has a serious potential threat to the atmospheric environment.Aimed at the current status quo on the reserch of atmospheric environmental risk in our country,this study used a semi-quantitative method to make the partition and the classification for atmospheric environmental risk.Firstly this paper contrasted the leakage model and diffusion model of dangerous chemicals,respectively summarized its applicability and advantages and disadvantages,fixed leakage model in accordance with the material physical and chemical properties,chose Gaussian model by the gas separation and application status to simulate the diffusion of dangerous chemicals.Secondly this study introduced the internationally main short-term acute exposure to air concentration limits,determined a selection that the limits should be based on Acute Expossure Guideline Levels(AEGLs)of US Environmental Protection Agency(EPA)primarily,in the absence of AEGLs used Emergency Response Planning Guidelines(ERPGs)and Temporary Emergency Expossure Limits(TEELs),added median lethal concentration(LC50)and Immediately Dangerous to Life or Health(IDLH)to compare the diversity between two kinds of standards.Finally,this study introduced the Emission Weighted Proximity Model to estimate the risk and to make partition and classification.Xigu district is one of the important petrochemical bases in our country,which lives tens of thousands of residents in this area at the same time,it's a typical risk hazard from historical development.Based on the study case of Xigu Chemical Idustry Area in Lanzhou,we used the investigation and statistics of the environmental risk source,selected 4 typical substances with reference articles and actual situations,determined the intensity of major hazard installations by leakage model,confirmed the appropriate meteorological dispersion conditions in atmospheric dispersion model,combined with healthy evaluation standards,used the RiskSystem to simulate the distance of AEGLs effect for major hazard installations,which farthest distance reaches 1781.6m from the Ammonia storage tank.In the end,we estimated the regional atmospheric environmental risk and made the partition and the classification,the most affected areas of risk concentrated in the plant-site,but there are also some influenced settlements within the confines of threat to health or death,according to the research findings,the settlements which affected by ammonia are Shigang,Shuidongmen,Jiajiabao and Moujiabao,affected by carbon monoxide are Shigang,Jiajiabao and Moujiabao,affected by hydrogen sulfide is Daijiahewan,affected by chloromethane of the planned project is Lijiazhuang,we ranked the settlements by the level of risk from high to low orders are Jiajiabao,Moujiabao,Shigang,Lijiazhuang,Shuidongmen and Daijiahewan.The method in this paper takes advantage of the analysis of atmospheric environmental risk to make the partition and the classification of the regional risk,provides bases for risk prevention and regional transformation.