Source apportionment and health risk assessment of metal elements in PM1 on different weather types during autumn and winter-A case study of Qingdao
Over four consecutive autumn-winter seasons spanning from 2018 to 2022,a comprehensive analysis was conducted involving daily sampling of atmospheric PM1 and the subsequent examination of 20 distinct metal elements.The characteristics and sources of metal elements under different weather conditions were analyzed,and their health risks were assessed.The results revealed that on dust days,metal element content(2022.88±2298.00)ng/m3 and their proportion in PM1(6.63％)were higher compared to other weather conditions.Specifically,the metal element content on haze and polluted fog days was 2.06 and 1.70 times higher than on clean days.Carcinogenic metal elements(Ni,Cd,As,Cr,Co,and Pb)and non-carcinogenic metal elements(Mn,Zn,Cu,V,Al,and Ba)showed higher enrichment factors on haze and polluted fog days.Positive matrix factorization(PMF)analysis identified primary sources of metal elements in PM1,including vehicular emissions,coal/biomass combustion,sea salt,crustal sources,industrial emissions,and maritime sources.Vehicular emissions and coal/biomass combustion notably contributed over 72.1％during foggy and hazy days,while maritime sources increased to 1.9％on clear fog days.Backward air trajectory analysis demonstrated that haze days were mainly affected by the transmission of pollutants from northwest to medium and long distances.Ocean-land circulation mainly affected polluted fog days,while dust days were dominated by long-distance transport of northwest dust masses.The non-carcinogenic risks via respiratory exposure to metallic elements in PM1 were deemed negligible.However,the lifetime carcinogenic risks of As and Cr exceeded the threshold of 10-6but remained below 10-4,with the highest risk probability observed during polluted fog and haze days.Consequently,it's recommended to intensify emission control measures targeting As and Cr sources in industrial processes such as coal combustion,metallurgy,and electroplating,particularly during heavy pollution episodes in autumn and winter.
metal elementssource apportionmenthealth risk assessmentPM1Qingdao
万方数据
