Skip to main content
. 2022 Feb 14;210:112899. doi: 10.1016/j.envres.2022.112899

Fig. 1.

Fig. 1

Data source: Before and during the city lockdown (CLD) 31 national + provincial control stations (a) 2020.1.20–2020.1.27 weekly average PM2.5 concentration; (b) 2020.1.28–2020.2.3 weekly average PM2.5 concentration.