Fig. 3.

Concentration–response relationships between long-term PM_2.5, NO₂, and O₃ exposures and stroke incidence from (a) single pollutant models and (b) tri-pollutant models, and (c) probability distribution functions (PDF) of long-term PM_2.5, NO₂, and O₃ exposures. (a, b) The concentration-response curves, derived from the single-pollutant or tri-pollutant models, are shown for the concentration ranges between 0.1th to 99.9th percentiles of the pollutants, i.e. with 0.2% poorly constrained extreme values excluded. (c) The PDF shows the distribution of each exposure in the cohort and the shading areas (from the darkest to the lightest) represent pollutant concentration ranges of the IQR (i.e., 25th to 75th percentiles), 95% (2.5th to 97.5th), and 99.8% (0.1th to 99.9th), respectively. IQR, interquartile range. HR, hazard ratio.