"This week’s heat wave will be accompanied by light winds, which will allow air pollution levels to build, bringing the worst ozone air pollution thus far this year to much of the Midwest and Northeast United States. Ground-level ozone, which is created from chemical reactions between volatile organic carbon (VOC) compounds and nitrogen oxides, is created more readily at warmer temperatures. Extreme heat helps these chemical reactions occur faster, and we can expect to see many areas with ozone pollution topping out in the “Unhealthy” range during the heat wave. At this level of pollution, people who are sensitive to air pollution can see increased risk of stroke, heart attack and breathing problems, and even healthy people may experience discomfort."

"An air pollution episode as widespread and severe as the one this week is a threat to cause hundreds of premature deaths. According to a 2018 study done by the Health Effects Institute (a U.S. non-profit corporation funded by the EPA and the auto industry), ozone pollution in the U.S. caused approximately 12,000 premature deaths per year between 2010 and 2016. Air pollution deaths are calculated using epidemiological studies, which correlate death rates with air pollution levels. Air pollution has been proven to increase the incidence of death due to stroke, heart attack and lung disease. Since these causes of death are also due to other factors—such as lifestyle and family history—we typically refer to air pollution deaths as premature deaths. A premature air pollution-related death typically occurs about twelve years earlier than it otherwise might have, according to Caiazzo et al., 2013."