2020-2021年苏州市PM_(2.5)中可溶性组分特征及时空变化研究

Study on the Characteristics of Soluble Components and Time-space Changes of PM2.5 in Suzhou from 2020 to 2021

2020—2021年在苏州城区选取2个点位(交通干线、居民区)采集PM_(2.5)样品,测定9种可溶性离子组分浓度。结果表明:观测期内PM_(2.5)日均浓度均值为35μg/m^(3)。9种可溶性离子组分总浓度均值为21.5μg/m^(3);9种可溶性离子组分中浓度最高的3种离子为硝酸根、硫酸根、铵盐总浓度为18.6μg/m^(3),对颗粒物浓度的贡献率较高。可溶性离子组分呈现出冬春季浓度高、夏季浓度最低的季节分布特征。采样期内交通干线及居民区2个点位浓度差异不大。交通干线点位受流动源影响较大。与2015年观测结果相比,硫酸根、硝酸根和铵离子的浓度均下降50%左右,表明苏州市近年来污染物排放管控措施卓有成效。

From 2020 to 2021,PM_(2.5) samples were collected from two sites(traffic trunk lines,residential areas)in Suzhou urban area to determine the concentrations of nine soluble ion components.The average daily concentration of PM_(2.5) in the observation period was 35μg/m^(3).The average total concentration of nine soluble ion components was 21.5μg/m^(3);the three ions with the highest concentration were nitrate,sulfate and ammonium,with a total concentra⁃tion of 18.6μg/m^(3),which had a high contribution to the concentration of particulate matter.The concentrations of sol⁃uble ions in winter and spring were higher than those in summer.During the sampling period,there was no signifi⁃cant difference in the concentrations between the two sites.The location of traffic trunk line is greatly affected by the flow source.Compared with the observation results of Suzhou in 2015,the concentrations of sulfate,nitrate and am⁃monium ions in this study have decreased by about 50%,indicating that the pollutant emission control measures in Suzhou have been effective these year.