• carbon dioxide;
  • climate change;
  • ozone

[1] Greenhouse gases and particle soot have been linked to enhanced sea-level, snowmelt, disease, heat stress, severe weather, and ocean acidification, but the effect of carbon dioxide (CO2) on air pollution mortality has not been examined or quantified. Here, it is shown that increased water vapor and temperatures from higher CO2 separately increase ozone more with higher ozone; thus, global warming may exacerbate ozone the most in already-polluted areas. A high-resolution global-regional model then found that CO2 may increase U.S. annual air pollution deaths by about 1000 (350–1800) and cancers by 20–30 per 1 K rise in CO2-induced temperature. About 40% of the additional deaths may be due to ozone and the rest, to particles, which increase due to CO2-enhanced stability, humidity, and biogenic particle mass. An extrapolation by population could render 21,600 (7400–39,000) excess CO2-caused annual pollution deaths worldwide, more than those from CO2-enhanced storminess.