Characteristics And Source Apportionment Of Oxidation Potential And Health Effects Of PM In Cities With Different Pollution Characteristics

Particulate matter（PM）,as a class 1 carcinogen listed by the InternationalCancer Agency,has a series of adverse effects on human health.However,the control of particulate matter in China is based on the mass concentration,and the understanding of health effects and their mechanisms is not perfect.Therefore,it is necessary to further identify and control the pollution sources that contribute more to the health effects of environmental acceptor particulate matter.Currently,the main health risk assessment methods for particulate matter consider the exposure dose response relationship of a single component rather than the overall impact of the interaction of various components in particulate matter,and oxidation potential is a more comprehensive health index for particulate matter.In order to explore more reasonable evaluation criteria for key pollution sources that cause adverse health effects and further realize precise prevention and control of pollution sources,this paper collected samples of environmental acceptor particles and pollution sources from three pollution characteristics cities,namely industrial cities,typical non-industrial cities that are not affected by sand dust and typical non-industrial cities that are affected by sand dust.The oxidation potential of particulate matter and the mass concentration of each component were measured.The composition,health risk and oxidation potential distribution characteristics of environmental acceptor particles in cities with different pollution characteristics were specified.The contribution of different pollution sources to carcinogenic and non-carcinogenic health risks and oxidation potential of particulate matter was calculated and compared with the contribution of pollution sources to mass concentration respectively.Finally,the pollution sources and control levels that need to be controlled are determined.The main conclusions of this study are as follows:（1）The pollution sources of industrial cities have significant effects on the concentration of metal elements,carbon components and polycyclic aromatic hydrocarbons in ambient particulate matter.The concentration of water-soluble ions in typical non-industrial cities that are not affected by sand and dust are higher than those in industrial cities.However,in typical non-industrial cities affected by dust,the pollution sources have significantly greater effects on metal elements and water-soluble ions than on polycyclic aromatic hydrocarbons and carbonaceous components.The main pollution sources of environmental acceptor particles in industrial cities are metal manufacturing,aluminum manufacturing and motor vehicle exhaust.For Longnan,a typical non-industrial city that is not affected by sand dust,the main pollution sources are motor vehicle exhaust,combustion sources and road dust,while the main pollution sources of the typical non-industrial city that is affected by sand dust are dust and combustion sources.（2）Regardless of the pollution characteristics of the city,the carcinogenic health risk of adult males and females is much greater than that of children.The carcinogenic and non-carcinogenic health risks of industrial cities are much greater than those of typical non-industrial cities that are not affected by sand dust and typical non-industrial cities that are affected by sand dust.The carcinogenic risk of Cr,V,As,Co and Ni are greater than 1.00×10^-6,which has a certain carcinogenic risk,and all the elements have no non-carcinogenic risk.Among all pollution sources,steel slag source,stir-fried dust collection powder,road dust,urban dust,combustion and soil dust contributed higher health risk with lower mass concentration,indicating that their health risk coefficient was higher.（3）The DTTm and DTTv of PM_2.5 in industrial cities are 2.3 times and 3.29 times of that in typical non-industrial cities not affected by sand and dust,and 1.33times and 1.38 times of that in typical non-industrial cities affected by sand and dust,respectively.The order of oxidation potential of particulate matter in different cities is not consistent with the order of carcinogenic health risk.Considering the interaction between the components of particulate matter,a relatively comprehensive oxidation potential should be considered first.（4）Based on different p H,ambient temperature and relative humidity of particulate matter,the correlation between each component of particulate matter and its oxidation potential varies greatly,and the complexity of the relationship between components producing oxidation potential in PM can be seen.Based on the contribution of pollution source to the mass concentration of PM and the oxidation potential of pollution sources,the contribution of pollution sources to environmental acceptor particulate matter oxidation potential was calculated.The results show that in typical industrial cities,the major sources of pollution are slag processing plant,electrolytic aluminum and vehicle exhaust,and the major sources of combustion and road dust.In Longnan,a typical non-industrial city that is not affected by sand dust,vehicle exhaust sources contribute more to the oxidation potential of environmental acceptor particles.In Minqin,a typical non-industrial city that is affected by sand dust,vehicle exhaust sources,combustion sources and dust sources contribute more to the oxidation potential of PM_2.5.（5）By comparing the contribution of pollution sources to mass concentration, carcinogenic health risk coefficient and oxidation potential in cities with different pollution characteristics,it can be seen that combustion sources have significant contributions to mass concentration,carcinogenic health risk coefficient and oxidation potential,while slag separation workshops and vehicle exhaust sources have greater contributions to oxidation potential.From the perspective of adverse health effects on human body,combustion source,slag separation plant source and vehicle exhaust source should be primarily controlled.For steel slag source and road dust source that contribute more to carcinogenic health risk,they are classified as the second type of control source,and the third type is the rest of pollution source.（6）In order to realized precise control of particulate pollution sources based on human health and provide scientific basis for environmental benchmark research on particulate chemical composition,oxidation potential and source apportionment,Based on the mass concentration of particulate matter,Fe,Ace,Flu,Nap,Ni,EC,Ace,Ba A,B[ghi]P,Pyr,Chr,Bb F,Inp,Any,Bk F,Al,K and Cl^-should be considered for inclusion in the assessment.Fe,Ace,Flu,Nap,Ni,EC,Ace,Ba A,B[ghi]P,Pyr,Chr,Bb F,Inp and K should be included in terms of carcinogenic health risks of environmental particulate matter.From the perspective of oxidation potential of environmental particles,Cu,Pb,OC,NH₄⁺,K⁺,F^-,NO₃^-,SO₄^2-,Ba A,B[ghi]P,Pyr,Chr,Bb F and Inp should be added.