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The changes in long-term and short-term exposure levels of PM2.5 and O3 pollution in China from 2015 to 2022. BTHs Beijing–Tianjin–Hebei and its surrounding regions; FWP: Fen–Wei Plain; YRD: Yangtze River Delta; CC: Chengdu–Chongqing area; PRD: Pearl River Delta. This figure is adapted from Ref. [27].
