On March 22, 2023, Zhicheng set up  6 passive air samplers in Shuntian Town and Chuantang Town (3 samplers*2 sampling sites). During the dry season, a total of 51 passive samplers were set up in the Dongjiang River basin, mainly distributed in Xinfeng County (4 sampling sites), Lianping County (5 sampling sites) and Dongyuan County (8 sampling site).

The spatial distribution of passive air samplers in the dry season