The Pollution Characteristics,source Analysis And Health Risk Assessment Of PM_2.5,PM₁₀ And Their Inorganic Elements In Jiayuguan City

With the acceleration of the process of industrialization in Northwest China,particulate matter pollution has become the primary problem of urban air pollution.Different cities have different sources and laws of various particulate matter in the atmosphere due to their different energy and industrial layouts,climate,geographical conditions and other factors.In order to make the pollution control of atmospheric particulate matter pertinent and precise,it is of practical value and important significance to analyze the source of urban particulate matter.In order to study the four-season PM_2.5,PM₁₀ and its inorganic element pollution characteristics,source analysis,health risks,and regional pollution levels in Jiayuguan City,three representative sampling points were arranged in Jiayuguan City,and they were set up on December 2019.From January to October 2020,we will conduct four-season atmospheric particulate matter PM_2.5,PM₁₀sample collection and inorganic elements（V,Cr,Mn,Co,Ni,Cu,Zn,As,Se,Cd,Ba,Pb,Mg,Al,Ca,Fe）concentration analysis.Using Meteoinfo software and Trajstat plug-in to carry out backward trajectory simulation and particulate matter potential source area analysis.Based on the inorganic element concentration data,PCA principal component analysis and PMF source analysis model were used for source analysis,and then EPA health risk assessment was used,the model carried out the evaluation of carcinogenic risk and non-carcinogenic risk,and finally used the geo-cumulative index method to evaluate the regional heavy metal pollution.The result is as follows:（1）.The PM_2.5 and PM₁₀ pollution in Jiayuguan City is heavier in winter and spring,and lighter in summer and autumn.As for the inorganic elements in the particulate matter,the elements with higher concentrations are mainly four types of crustal elements:Mg,Al,Ca,and Fe,while the concentrations of other elements are relatively low.（2）.According to the backward trajectory simulation and cluster analysis results of Jiayuguan City in the four seasons,Jiayuguan City in the four seasons is more susceptible to air masses from west to northwest.Jiayuguan City has the most serious particulate pollution in spring.The potential source areas of PM_2.5 and PM₁₀ are mostly concentrated at the junction of the Inner Mongolia Autonomous Region and Mongolia in the northeast of the city.The pollution in other seasons is relatively light,and the potential source areas are mostly concentrated in eastern Xinjiang.,Gansu Hexi Corridor area and parts of northern Qinghai Province.（3）.Use the enrichment factor analysis method to evaluate the degree of influence of the inorganic elements in Jiayuguan City PM_2.5 and PM₁₀ by human activities.The elements with enrichment factors greater than 10 are as follows:Winter（Zn,Se,Cd,Pb,Mg）,spring（Se,Cd,Pb）,summer（Se,Cd,Mg）,autumn（Zn,Cd,Pb）,these elements are greatly affected by human activities.（4）.Using the principal component analysis method to analyze the sources of PM_2.5 and PM₁₀ in four seasons in Jiayuguan City,the results show that the major sources of PM_2.5 in winter are dust sources（26.42%）and industrial sources（23.42%）.The main sources that contribute significantly to PM₁₀ in winter are steel dust sources（29.59%）and dust sources（19.57%）.The major sources that contribute significantly to spring PM_2.5 are dust sources（37.32%）and coal sources（18.84%）,and the major sources that contribute significantly to spring PM₁₀ are dust sources（52.67%）and industrial sources（12.98%）.The major sources that contribute significantly to summer PM_2.5 are industrial sources（38.23%）and dust sources（15.28%）,and the major sources that contribute significantly to summer PM₁₀ are industrial sources（42.06%）and construction cement dust（14.44%）.The major sources that contribute significantly to autumn PM_2.5 are industrial sources（36.64%）and traffic sources（14.06%）,and the major sources that contribute significantly to autumn PM₁₀ are dust sources（32.57%）and coal-burning sources（16.69%）.（5）.Using the PMF source analysis model to analyze the sources of PM_2.5 and PM₁₀ in four seasons in Jiayuguan City,the results show that coal-fired sources（44.9%）and fuel oil sources（27.5%）contribute significantly to PM_2.5 in winter.The sources that contribute significantly to PM₁₀ in winter are dust sources（24.8%）and coal sources（46.8%）.The sources that contribute significantly to PM_2.5 in spring are dust sources（62.6%）and construction cement dust（21.9%）,and the sources that contribute significantly to PM₁₀ in spring are dust sources（75.4%）and construction cement dust（18.5%）.The sources that contribute significantly to summer PM_2.5 are industrial sources（30.2%）and steel dust sources（45.6%）,and the sources that contribute significantly to summer PM₁₀ are industrial sources（19.1%）and steel dust sources（58.3%）.The sources that contribute significantly to the fall of PM_2.5 are dust sources（50%）and construction cement dust（30.2%）,and the sources that contribute significantly to the fall of PM₁₀ are industrial sources（21.6%）and dust sources（43.8%）.（6）.Use the EPA health risk assessment model to evaluate the carcinogenic risk of Cr,Ni,As,Co,Cd,and Pb in PM_2.5 and PM₁₀ in the four seasons,and calculate the non-carcinogenic risk of Cu,Mn,Zn,Pb,and V,the results show that the carcinogenic risks of carcinogenic elements in the four seasons are all expressed as"children>adult male>adult female".Except for the Cr element in PM_2.5 in winter and the Cr element in PM₁₀ in the four seasons,which showed a certain carcinogenic risk,the carcinogenic risks of the other elements in the four seasons were all at an acceptable level.The non-carcinogenic risks of the non-carcinogenic elements in the four seasons are all expressed as"adult male>child>adult female".There is a certain non-carcinogenic risk of Mn in PM₁₀ in spring and the non-carcinogenic risk index HI of PM₁₀ in this season is greater than 1,indicating that there is non-carcinogenic risk,the non-carcinogenic risk of particulate matter in the rest of the season is at an acceptable level.（7）.Use the geo-accumulation index method to evaluate the regional heavy metal pollution of inorganic elements in PM_2.5 and PM₁₀ in four seasons.The results show that the three types of elements Se,Cd,and Pb are mostly severe pollution in the assessment of regional heavy metal pollution in the four seasons.The pollution degree of crustal elements is relatively light,and some elements produced in metallurgical industry production also have a certain degree of pollution,And it is relatively serious in winter.