Fig. 3

Backward trajectories of air masses and air quality along their pathways for various types of rainfall events: (a) HZ (4.12); (b) HD (3.27); (c) CC (8.20); (d) MN (7.22).Map data source: Tianditu Map Import service via the original plugin (version 2021b (9.85)) (https://www.originlab.com).