Visibility observed at different altitudes is favorable to understand the causes of air pol-lution.We conducted 4-years of observations of visibility at 2.8 and 60 m and particulate matter (PM) concentrations from 2015 to 2018 in Shenyang,a provincial city in Northeast China.The results indicated that visibility increased with the increasing height in winter(especially at night),and decreased with height in summer (especially at the daytime).PM concentration exhibited opposite vertical variation to visibility,reflecting that visibility de-grades with the increase of aerosol concentration in the air.The radiosonde meteorological data showed that weak turbulence in the planetary boundary layer (PBL) in winter favored aerosols' accumulation near the surface.Whereas in summer,unstable atmospheric con-ditions,upper-level moister environment,and regional transport of air pollutants resulted in the deterioration of upper-level visibility.Inter-annual variation in the two-level visibility indicated that the upper-level visibility improved more significantly than low-level visibil-ity,much likely due to the reduction in emission of elevated point sources in Shenyang.Our study suggested that strengthening the control of surface non-point emissions is a promis-ing control strategy to improve Shenyang air quality.

Xiaolan Li;Guiqian Tang;Liguang Li;Weijun Quan;Yangfeng Wang;Ziqi Zhao;Ningwei Liu;Ye Hong;Yanjun Ma

Institute of Atmospheric Environment,China Meteorological Administration,No.388 Changbai South Road,Shenyang,Liaoning 110166,China;State Key Laboratory of Atmospheric Boundary Layer Physics and Atmospheric Chemistry,Institute of Atmospheric Physics,Chinese Academy of Sciences,Beijing 100029,China;Environmental Meteorology Forecast Center of Beijing-Tianjin-Hebei,Beijing 100089,China

环境科学学报（英文版）

[1]Xiaolan Li;Guiqian Tang;Liguang Li;Weijun Quan;Yangfeng Wang;Ziqi Zhao;Ningwei Liu;Ye Hong;Yanjun Ma-.Multilevel air quality evolution in Shenyang:Impact of elevated point emission reduction)[J].环境科学学报（英文版）,2022(03):300-310

Visibility,moister,visibil

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