Fig. 3: The environmental impacts of ambient temperature and ambient fine PM on chronic respiratory disease mortality rates for the four age groups in rural and urban counties are shown in the US, 2009–2019.
From: Heat and air pollution shape divergent mortality patterns across rural and urban United States

a 0–1, b 1–14, c 15–64, and d 65+. PM2.5 category levels of 5, 15, and 20 μg/m3 were used to represent low, medium, and high air pollution groups, respectively.