Figure 2

Time series of PM2.5 and the water-ion concentrations from March 1, 2021, to May 31, 2021, in Lanzhou, China (colored bars indicate dust storm days).

Time series of PM2.5 and the water-ion concentrations from March 1, 2021, to May 31, 2021, in Lanzhou, China (colored bars indicate dust storm days).