摘要：In order to explore the characteristics and sources of PM2s and water-soluble ion pollution in Hengyang City, PM2.s samples were collected in Jan-uary, April, July, and September 2019. Mass concen- tration of PM2s be measured by gravimetry and 9 water-soluble ionic components, such as NHat. K. Nat, Mg2+, Ca?t and F. CI, SO,2, NO:, by ion chro- matography, and then carried out concentration char-acteristics, pH, secondary conversion, source analy-sis and other research work. The results showed that the average seasonal mass concentration of PM2s in Hengyang during the sampling period was 94.25 ug/m3 in winter, 64.76 ug/m3 in spring, 38.30 ug/m3 in autumn and 26.30 ug/m3 in summer, and the total water-soluble ions accounted for 56.17%, 39.16%, 44.42% and 47.14% of the total mass concentration of PM2s, respectively. The ratio of anion and cation equivalents shows that PM2s is acidic in autumn andwinter in Hengyang, and alkaline in spring and sum- mer. The annual average values of SOR were 0.467 and NOR were 0.202, what's more, the secondary conversion of gaseous precursors was obvious in winter, spring and autumn, because their AE/CE was much larger than 0.1. In addition to NH NO; and (NHa)2SO4, there is also a small amount ofNHaCl in spring and summer. However, on the basis of NHANO3 and (NHa)2SO4 in autumn and winter, there are still very small amounts of nitrates, such asNaNO3 and KNO3. Source analysis found that water- soluble ions in atmospheric PM2s mainly originated from the secondary conversion of industrial emis-sions, coal burning, biomass combustion, and sec- ondary transformation of gaseous precursors emitted from coal combustion and motor vehicles.
