Researchers in the United States (U.S.) said exposure to ozone, the main ingredient in smog—even at levels below the U.S. federal safety standards—could increase the risk of going into cardiac arrest.
These findings were recently presented at the American Heart Association (AHA)’s virtual Resuscitation Science Symposium. The study is considered preliminary until published in a peer-reviewed journal.
Smog is a complex mix of volatile hydrocarbons, ozone, oxides of nitrogen and sulfur and particulates. These pollutants enter the gut through contaminated foods and drinks and indirectly by swallowing mucus expelled from the lung.
At the individual level, although people cannot prevent the smog, they can diminish their exposure to it. The researchers analysed records of air pollution concentrations in the neighborhoods of more than 187,000 people, who had cardiac arrests outside the hospital in 28 states between 2013 and 2018.
They compared two types of pollution, ozone and fine particulate matter, from two weeks before a person’s cardiac arrest to levels on the day their heart suddenly stopped beating and found that as ozone levels rose, so did sudden cardiac arrests. In this study, researchers found a higher risk of cardiac arrest at levels as low as 36.9 parts per billion—about half the EPA’s standard.