Source: GeoHealth
Research has linked higher levels of air pollution to the risk of acute myocardial infarctions, or heart attacks. How these risks differ by demographic, type of air pollution, and type of heart attack is less clear, however, with early studies yielding varied results. These links are crucial to uncover, because as climate change worsens, air pollution is likely to rise alongside other health stressors such as heat.
Zhang et al. pulled heart attack data from 2,322 patients aged 18–55 across the United States from the Variation in Recovery: Role of Gender on Outcomes of Young AMI Patients (VIRGO) study. Nearly 70% of the patients were females, a population that has been underrepresented in previous research. The researchers studied heart attack occurrence alongside concurrent levels of ozone and PM2.5 (airborne particles with a diameter of 2.5 micrometers or smaller) near the patients’ homes.
Notably, the researchers separately analyzed different types of heart attacks. Type 1 heart attacks are caused by plaque buildup and blood clot formation, whereas Type 2 heart attacks result from conditions such as low blood pressure, which reduces oxygen supply without clot formation. A STEMI (ST-segment elevation myocardial infarction) occurs when a completely blocked artery stops blood flow and causes a specific electrocardiogram (ECG) pattern. A non-STEMI happens when an artery is partially blocked, reducing blood flow without producing the same clear ECG changes seen in a STEMI.
The authors found that higher ozone levels were positively correlated with increased heart attacks 4–5 days later, though they found no association with PM2.5 levels. Ozone levels correlated more strongly with Type 2 heart attacks and non-STEMI heart attacks, they say, and they found no association at all between ozone levels and STEMI heart attacks. In addition, non-Hispanic Black patients saw a stronger correlation between higher ozone levels and heart attacks than did non-Hispanic whites. The association between ozone and heart attacks remained significant even with ozone at levels below the guideline recommended by the World Health Organization.
The authors say their findings contrast with those of some previous research. For example, their results point to a link between air pollution and non-STEMI heart attacks, and they did not find a link between PM2.5 and heart attacks. The authors’ analysis also revealed a small, albeit statistically nonsignificant, strengthening of the ozone–heart attack correlation in warmer months versus colder months, which they say could forecast an increase in heart attacks under climate change. (GeoHealth, https://doi.org/10.1029/2024GH001234, 2025)
—Nathaniel Scharping (@nathanielscharp), Science Writer
