What are the risks of combined exposure to poor air quality and extreme heat?
The combination of extreme heat and poor air quality can be particularly harmful. Approximately 489,000 heat-related deaths occur globally each year, according to the World Health Organization, while the combined effects of ambient air pollution and household air pollution are associated with 6.7 million annual premature deaths globally. One 2022 study published in the American Journal of Respiratory and Critical Care Medicine found that mortality risk on days with combined exposure increases by an estimated 21%.
Fine particle pollution from wildfire smoke can cause shortness of breath, coughing, dizziness, or fatigue and can aggravate heart and lung diseases and other chronic health issues, while extreme heat can exacerbate illnesses like cardiovascular disease, diabetes, and asthma.
“We know that many of the impacts of air pollution are through the ways in which it strains our cardiovascular and respiratory systems, and we know that heat also strains our cardiovascular system and our respiratory system,” says Allan Just, Nazareth-Ferguson Family University associate professor of public health at Brown University. “When it’s hot out, your heart needs to work harder to push blood out to the periphery to try to cool you down, and when it’s polluted, the small particles can get from your lungs into your bloodstream, and they cause inflammation, and they can damage your heart tissue.”