Aerosol Vertical Distribution and Typical Air Pollution Episodes over Northeastern China during 2016 Analyzed by Ground-based Lidar

摘要

The industrial city of Shenyang in northeastern China has undergone a period of rapid development; long-term aerosol vertical properties could be relevant to more clearly understanding local emissions and their regional transportation. Aerosol optical depth (AOD), planetary boundary layer (PBL) height, and the vertical profiles of extinction coefficient, were measured and analyzed with ground-based Lidar during 2016 in Shenyang. Ground-level particulate matter mass concentrations, meteorological parameters, backward trajectories, and Moderate Resolution Imaging Spectroradiometer products were used to study the pollutant sources in four cases using the potential source contribution function and concentration-weighted trajectory methods. The results indicate that the AOD was 0.10 ± 0.10 to 0.23 ± 0.34 from January to May, and approximately 0.49 ± 0.39 in July. The PBL height was highest in March (1318.7 ± 696.5 m) and lowest in winter (877.1 ± 508.1 m to 950.7 ± 762.3 m). The mass concentrations of PM_(10), PM_(2.5), and PM_(1.0) were highest in January at 148.2 ± 77.8 μg m~(–3), 106.0 ± 58.8 μg m~(–3), and 33.8 ± 20.5 μg m~(–3); and lowest in June at 56.2 ± 27.8 μg m~(–3), 33.7 ± 18.3 μg m~(–3), and 9.3 ± 6.0 μg m~(–3), respectively. The concentrations of SO_(2) and CO were higher in winter and lower in summer, whereas O_(3) concentrations were higher in summer and lower in winter. The monthly extinction coefficient was affected by dust events in spring and new particle generation in summer, as well as by biomass-burning and coal-burning emissions in autumn and winter. Four pollution sources—from northwestern, eastern, northern, and northeastern China—were selected to analyze the different paths and sources of pollutants affecting Shenyang. The results of this paper will be helpful in the study of continuous year-round aerosol vertical properties and the regional pollution features of northeast China.