Fig. 1. Structure of ozone lidar

Fig. 2. Ozone concentrations monitored by DIAL (495 m) and Guangzhou tower (498 m)

Fig. 3. Correlation analysis of ozone concentrations monitored by DIAL (495 m) and Guangzhou tower (498 m)

Fig. 4. Daily variation of ozone concentration monitored by lidar for different seasons. (a) Spring; (b) summer; (c) autumn; (d) winter

Fig. 5. Ozone profile of local pollution (top and bottom horizontal lines represent maximum and minimum values, top and bottom of box represent 75th and 25th percentiles, and red solid and black square represent median and average)

Fig. 6. Ozone vertical distribution on May 14-18, 2018

Fig. 7. Daily variations of ozone concentration and near- ground nitrogen dioxide concentration at different heights

Fig. 8. Clustering analysis results of backward trajectory angular distance of each season in Guangzhou. (a) Spring; (b) summer; (c) autumn; (d) winter

Fig. 9. Extinction coefficient and ozone profile at different ozone transmission heights. (a)(b) 0.3-0.7 km; (c)(d) 0.8-1 km; (e)(f)1.1 km or more (top and bottom horizontal lines represent maximum and minimum values, top and bottom of box represent the 75th and 25th percentiles, and red and black squares represent the median and average)

Fig. 10. Extinction coefficient and ozone correlation at different ozone transmission heights. (a) 0.3-0.7 km; (b) 0.8-1.0 km

Fig. 11. Ozone vertical distributions of Guangzhou on November 29, 2017. (a) Extinction coefficient; (b) ozone concentration

Fig. 12. Backward track of Guangzhou on November 29, 2017

Fig. 13. Ozone concentration of different heights at different times on November 29, 2017