Overview

In collaboration with National Environment Agency (NEA), scientists at Duke-NUS Medical School in Singapore suggest small particles in air pollution may cause sudden cardiac arrests in some people who are simply going about their daily activities. This makes the need to cut air pollution levels throughout the world even more urgent.

The science and other stuff to know

Previous studies have shown air pollution’s tiny particles may trigger nonfatal heart attacks, as reported by Medical News Today. To confirm whether there’s a close relationship between out-of-hospital cardiac arrests (OHCA) and the levels of small air pollution particles known as PM2.5, researchers at Duke-NUS Medical School examined data between 2009 and 2018.

The team found that 492 out of 18,000 cases of OHCA were linked to high concentrations of PM2.5 particles in the air. The findings of this study have been published in the journal The Lancet Public Health.

“We have produced clear evidence of a short-term association of PM2.5 with out-of-hospital cardiac arrest… [This] is a catastrophic event that often results in sudden death,” study lead Investigator Joel Aik said in a press release.

Aik, from Duke–NUS Medical School at the National University of Singapore, is also an environmental epidemiologist with the NEA.

Despite the clear evidence, Aik and his team, however, cautioned that their findings are based on an observational study. That means we can only speculate on the correlation between pollution levels and cardiac arrest cases.

So what?

The study team suggests that a decrease in PM2.5 could lead to a decrease in cardiac arrest cases. According to the researchers’ hypothesis, a drop of 1 microgram per cubic meter of PM2.5 correlated to an 8 percent reduction in cardiac arrest events. Also, a drop of 3 micrograms per cubic meter saw a 30 percent reduction in OHCA cases.

Researchers also determined a clear reduction in risk from three to five days following exposure to PM2.5 particles. This indicates the effects of these tiny air pollutant particles are short-term. The team concluded that cleaning up city air could save lives and reduce strain on hospitals.

“These results make it clear that efforts to reduce the levels of air pollution particles in the 2.5 micrograms or lower range, and steps to protect against exposure to these particles, could play a part in reducing sudden cardiac arrests, while also reducing the burden on health services,” Aik said.

What’s next?

Researchers behind the new study want to see more done to control air quality in major cities worldwide where air pollution is often an everyday issue.

“New policy interventions, such as phasing out internal combustion engine vehicles, can help to reduce the dangers,” said Marcus Ong, a clinician-scientist from the Duke–NUS Medical School.

Ong added that “individuals can also take simple but significant steps” to protect themselves from OHCA triggered by air pollution. For instance, “wearing high-efficiency air filtration masks during periods when the PM2.5 levels are elevated and not smoking.”