Fig. 4: Cumulative risk assessment of 14-days combined exposure.

We stratified by the 25th percentile of daily average temperature, The 0–0 (comfortable temperature–low pollution) is set as the reference, with the remaining groups defined as 0–1 (comfortable temperature–high pollution), 1–0 (low temperature–low pollution), 1–1 (low temperature–high pollution), 2–0 (high temperature–low pollution), and 2–1 (high temperature–high pollution).