Characteristics of Water-Soluble Ions and Sources of PM2.5 During Autumn and Winter in Yangquan City
Daily samples of atmospheric PM2.5 were collected from October 15,2017 to December 23,2017 in Yangquan city,China.The characteristics and sources of the main water-soluble ions were determined by ion chromatography.The source apportionment of wa-ter-soluble ions in PM2.5 was conducted by using Pearson correlation,Positive Matrix Factorization(PMF)and Potential source contri-bution function(PSCF).The results showed that the total mass concentration of water-soluble ions was 22.41±11.53 μg/m3,ac-counting for 34.1%of PM2.5.The proportion of SO42-、NO3-和NH4+(SNA)in water-soluble ions was 81%in polluted days,which was much higher than that in clean days(62%),while the proportion of Ca2+,Mg2+,Cl-and K+decreased significantly in polluted days,indicating that secondary inorganic pollution was more serious in polluted days.SOR(0.17)and NOR(0.13)in polluted days were significantly higher than that in clean weathers with SOR of 0.11 and NOR of 0.06,and the secondary ion conversion in polluted days was higher.The contributions of major sources to water-soluble ions were secondary transformations(37.4%),combustion sources(38.2%)and dust sources(24.4%),with combustion and dust sources contributing less to water-soluble ions and secondary transfor-mations contributing more under polluted days.The analysis of potential source areas shows that SNA is mainly influenced by short-range transport of polluted air masses from the northeastern and southern regions.
PM2.5water-soluble ionscharacteristicsourceYangquan city