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. 2021 May 4;291:112676. doi: 10.1016/j.jenvman.2021.112676

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Fig. 3 — Top: diurnal variations in averaged measured concentrations of NO₂ (a) and PM_2.5 (b) for the pre-lockdown, during lockdown and post-lockdown periods at GC. Bottom: changes in concentrations based on GAM analysis of NO₂ (c) and PM_2.5 (d) for the pre-lockdown, during lockdown and post-lockdown periods at GC.