| Since the promulgation of the"Action Plan for Air Pollution Prevention and Control"in 2013,China's air quality has improved significantly,and the annual average PM2.5concentration in several regions has shown a decreasing trend,but the atmospheric pollution of northern cities in Henan Province is still severe,especially in autumn and winter.The high PM2.5 concentration incidents with particulate matter as the primary pollutant occur frequently.Anyang is an important industrial city in the north of Henan Province,and it is also one of the"2+26"cities on the Beijing-Tianjin-Hebei air pollution transport path.Therefore,it will be practically significant to study the pollution levels and chemical composition characteristics of PM2.5 in Anyang,as well as to determine the contribution of emission sources and analyze the health risks,in order to finally develop an effective pollution control strategies.In this study,PM2.5was sampled at Anyang Environmental Protection Bureau during the typical months of2018 to analyze the PM2.5 concentration and the composition including elemental carbon?EC?,organic carbon?OC?,water-soluble ions and inorganic elements.By using positive definite matrix factorization model?PMF?and health risk assessment model,the sources contribution of PM2.5 and health risks to different groups of people were investigated qualitatively and quantitatively.The main conclusions are drawn as follow:During the study period,the annual average concentration of PM2.5 in Anyang was found to be 85.81±45.43?g/m3,and the average annual concentration of water-soluble ions was found to be 48.21±30.04?g/m3and account for 54.78%of the mass of PM2.5,the atmospheric aerosol was alkaline.The annual average values of nitrogen oxidation rate and sulfur oxidation rate were found to be 0.25 and 0.37,respectively.The annual average concentrations of OC and EC were 15.96±10.92 and 1.42±0.71?g/m3respectively,and the annual average concentration of secondary organic carbon was 8.91?g/m3,accounted for 44.60%of the OC mass concentration.Inorganic elements accounted for 13.5%of the mass concentration of PM2.5,with S,Cl,K,Si,Ca,Fe and Al were the main inorganic elements.Elements such as Ti,Mg,Fe,Na,Sr,and Ca mainly come from natural emission sources while elements such as Cd,Se,Sb,Sn,Pb,Zn,and As mainly come from anthropogenic activities.From PMF model source apportionment results,the annual average PM2.5contribution could be known:secondary inorganic aerosol?42.4%?,coal combustion?25.7%?,motor vehicle?14.1%?,industrial process?7.6%?,soil dust?6.0%?and construction dust?4.2%?.In terms of exposure types,ingestion exposure has a long-term non-carcinogenic health risk to all populations,while inhalation exposure and dermal exposure have no non-carcinogenic health risks to any populations.The combined effect of the three exposure types could cause serious cancer risk for all populations,and mainly comes from ingestion exposure and inhalation exposure.From results of PMF,it could be known the industrial process and motor vehicles could cause a serious cancer risk to all people.Combining PM2.5 pollution sources and health risk assessment results,the priority of emission control of Anyang should be sources with high contributions to secondary inorganic particulates,such as coal combustion and motor vehicles.The industrial process also belongs to source category of serious carcinogenic risk that need to be monitored and controlled. |
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