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Percentage change in several chemical variables in China in response to reduced emissions of primary pollutants in February 2020 during the COVID‐19 pandemic. Panels from the top to the bottom: NOx, ozone, and PAN. Left column: reduction in all emission; center panel: reduction in NOx emissions only; right panel: reduction in VOC and CO emissions only. Results for other chemical species are provided in the supplementary information (Figure S9).
