Fig. 1. Structure of the differential absorption lidar

Fig. 2. Surface weather changes during the observation period. (a) Visibility and mass concentration of the particulate matter; (b) precipitation and air pressure; (c) relative humidity and temperature; (d) wind direction and speed

Fig. 3. Changes in the mass concentration of pollutants during the observation period. (a) Particulate matter; (b) O₃ and NO₂; (c) CO and SO₂

Fig. 4. Temperature sounding profile during the observation period. (a) 16th; (b) 17th; (c) 18th; (d) 19th ; (e) 20th; (f) 21st

Fig. 5. Height field of the 850 hPa potential. (a) 15th; (b) 16th; (c) 17th; (d) 18th; (e) 19th; (f) 20th

Fig. 6. Wind field with a height of 10 m. (a) 15th; (b) 16th; (c) 17th; (d) 18th; (e) 19th; (f) 20th

Fig. 7. Time and space distribution of pollutants measured by differential absorption lidar. (a) Particle extinction coefficient; (b) O₃ mass concentration

Fig. 8. Aerosol extinction coefficient at different moments

Fig. 9. O₃ mass concentration at different moments

Fig. 10. Dackward trajectory of the air mass from 2018-12-15T19:00—2018-12-17T19:00

Fig. 11. NAAPS simulated aerosol. (a) 2018-12-15T08:00； (b) 2018-12-16T08:00； （c） 2018-12-16T20:00； （d） 2018-12-17T02:00