Source Apportionment And Health Risk Assessment Of Urban And Rural Atmospheric Particulate Matter In Winter And Spring Of Anyang City

In this study,the mass concentrations and chemical fraction characteristics of atmospheric particulate matter(PM_2.5 and PM₁₀)were studied by sampling in urban and rural areas during the winter heating period and spring non-heating period,respectively,and the pollution sources were analyzed by absolute principal component-multiple linear regression（APCS-MLR）and backward trajectory;finally,a health risk evaluation model was used to calculate the heavy metals in particulate matter at three different routes（inhalation,ingestion and exposure）to different exposed populations for carcinogenic and non-carcinogenic risks,and the results of the study showed that:（1）The spatial and temporal distributions of atmospheric particulate matter in Anyang during the observation period are significantly different,with the mean mass concentrations of PM_2.5 and PM₁₀ being 104.55±63.75μg/m³ and 159.32±90.14μg/m³,respectively.Spatially,rural areas in Anyang are more polluted than urban areas.The pollution characteristics of the two points are consistent on the time scale,and both show a higher pollution level in the heating season than in the non-heating season.The coal-fired heating in the heating season and the windy and sandy weather in the non-heating season are the main causes of the high PM_2.5 load.Due to the increase of potential pollution sources,the pollution is more serious in urban areas during daytime and heavier in rural areas at night.According to the study on the influence of meteorological factors on the concentration of particulate matter,it was found that wind speed and humidity have significant negative and positive correlation with particulate matter,respectively,and wind direction has an effect on particulate matter to some extent,while temperature has no significant effect on the concentration of particulate matter.（2）The average mass concentrations of water-soluble ions(NO₃^-,NH₄⁺,SO₄^2-,Ca²⁺,Cl^-,K⁺,Na⁺,F^-and Mg²⁺)in PM_2.5 and PM₁₀ were 50.45±41.08μg/m³ and 78.86±57.63μg/m³.In terms of time and space,the concentration of water-soluble ions has little overall change.SNA accounted for more than half of water-soluble ions,and the secondary pollution in Anyang was serious in winter.NO₃^-the highest proportion in all ion SO₄^2-concentration significantly decreased compared with previous years,the ratio of NO₃^-/SO₄^2-far more than 1,Anyang is influenced by motor options than fixed source,explain Anyang the main pollution sources along with the economic structure adjustment has been from the traditional coal-burning pollution into primarily mobile source such as automobile exhaust pollution.（3）In terms of the spatial distribution of inorganic element（potassium（K）,magnesium（Mg）,calcium（Ca）,sodium（Na）,zinc（Zn）,iron（Fe）,aluminum（Al）,nickel（Ni）,cobalt（Co）,manganese（Mn）,chromium（Cr）,copper（Cu）,lead（Pb））concentrations,rural areas are higher than urban areas,mainly due to the greater influence of flour mills and power plants around rural sampling sites.Temporally,the concentrations of inorganic elements are higher in the heating season than in the non-heating season.The elemental content of K,Ca,Fe,Zn,Al,and Cr in particulate matter in Anyang is much higher than in other cities,which is closely related to the pollution emission of Anyang Iron and Steel Group.the calculation of EF shows that the enrichment effect of fine particles is stronger,and the toxic heavy metals they contain are a greater threat to people.（4）Due to the increase in local coal combustion and the transport of dust from outside,the main sources of atmospheric aerosols in winter are coal combustion sources and dust sources,which contribute 42%and 25%to urban areas and 11%and 20%to rural areas,respectively.In addition,there are local industrial sources in urban areas（19%）and local biomass burning sources in rural areas（10%）.The main sources of pollution in spring are secondary,industrial and dust sources,which contribute 25%,23%and 9%to urban areas and 31%,29%and 26%to rural areas,respectively.Due to the complexity of urban human activities,the main sources of pollution in urban areas are more than in rural areas,where the contribution of traffic pollution sources,which are more significant,amounted to 20%.（5）In winter the pollutants are influenced by the static weather and the blockage of the Taihang Mountains mainly originate from the Hebei,Shandong and Henan provinces to the east of the Taihang Mountains and north of Anyang.The high value area of WPSCF increased significantly in spring,mainly in the surrounding cities southeast of Anyang city.In addition,the larger range of WPSCF high value area of PM₁₀ indicates that the sources are dispersed and greatly influenced by other provinces,while the WPSCF high value area of PM_2.5 accounts for a relatively small proportion and the sources are concentrated and mainly from local sources.（6）In terms of health risks,inhalation is the safest of the three approaches（skin contact,inhalation and ingestion）,and skin contact and ingestion are the most harmful.Among all inorganic elements,Co and Cr have the greatest carcinogenic and non-carcinogenic risks for children and adults.There was no significant difference in cancer risk between adults and children.