“…Among these six criteria air pollutants, PM 2.5 , PM 10 , NO 2 , SO 2 , and CO showed a significant decreasing trend (P < 0.05; Figure 2), which was consistent with other studies (Bao & Zhang, 2020;He et al, 2020;Huang & Li, 2022;K. Li et al, 2022;Mamtimin et al, 2022;Bagherinia et al, 2023;Gao et al, 2023;Jia et al, Zhang et al, 2023). Compared with the pre-lockdown period, the mass concentrations of PM 2.5 , PM 10 , NO 2 , SO 2 , and CO decreased by 46.7%, 40.3%, 48.6%, 45.6%, and 43.2%, respectively, with absolute values of 53.4 μg m -3 , 77.9 μg m -3 , 30.5 μg m -3 , 17.6 μg m -3 , and 0.9 mg m -3 , respectively (Figure 2).…”