Exposure to Air Pollution Could Trigger Heart Attack Within an Hour, Study Finds

Even low levels of exposure to air pollutants could trigger a heart attack within an hour, according to a recent study in China.

The study, published in the journal Circulation, evaluated more than 1 million cases of acute coronary syndrome (ACS) over the course of five years. Researchers measured the impact of four common pollutants: fine particulate matter (PM2.5 and PM10), nitrogen dioxide, sulfur dioxide, and carbon monoxide. The results suggested that short-term exposure to any level of these pollutants was associated with the onset of ACS.

Previous research has linked long-term exposure to air pollution to heart disease. Oxidants in the air can prematurely age blood vessels, cause calcium buildup in the coronary artery, and increase the chances of heart attacks or stroke, according to the Environmental Protection Agency (EPA).

“The adverse cardiovascular effects of air pollution have been well documented. But we were still surprised at the very prompt effects,” Haidong Kan, PhD, a professor in the School of Public Health at Fudan University in Shanghai and senior author of the study, said in a press release.

Since the study found no minimum safe threshold of pollution, the findings could be meaningful for countries with lower levels of air pollution, he said.

Nicole Weinberg, MD, a cardiologist at Providence Saint John’s Health Center in Santa Monica, CA, who is not affiliated with the study, told Verywell that calcium deposits or oxidants can build up in the heart arteries, even though they may not block the blood flow right away. This new study showed how pollution can cause “immediate destruction,” in addition to gradual buildup, she said.

For some people, environmental factors like extreme stress or partaking in rigorous exercise can cause a change of flow in the arteries and trigger these pollutants to do damage, she added.

“When you have these environmental toxins in the air in higher-than-normal fashion, they trigger this type of plaque rupture,” Weinberg said.

The body may react to attack different pollutants and in turn block an artery, inducing a heart attack she added.

Health complications like high cholesterol can increase a person’s risk of a heart attack, she said. Working in environments with poor air quality, like factory settings, industrial cities, or ports, can increase someone’s exposure to air pollution, which could trigger a heart attack as well, she added.

According to the Circulation study, older adults and people living cold environments were also at higher risk of having ACS from exposure to air pollutants.

What Does This Study Mean for the U.S. Population?

The new study analyzed data from a large number of patients, so it could have meaningful implications about how air pollution harms heart health in China and around the globe. But without country-specific research, experts say it is unclear how closely the results can apply to people in the United States.

Average U.S. residents probably don’t need to panic about their risk of an immediate heart attack, Weinberg said. However, people may benefit from practicing precautionary measures when traveling to areas with poor air quality.

According to IQAir, which tracks air quality, the average concentration of PM2.5 in the U.S. in 2021 was more than double the World Health Organization air quality guideline. Still, this number is considered “good” in comparison to most other countries ranked.

Scott Ratzan, MD, MPA, MA, distinguished lecturer at CUNY Graduate School of Public Health and Policy, told Verywell that the concentrations of air pollutants make a difference.

“We all have doses of many of these pollutants and exposures,” he said. “But that doesn’t mean that we all are going to have the ill effects from them.”

However, the harmful impact of climate change is “without a doubt is the quintessential issue of our time,” he said, and it is something that individuals and industries should act on.

What Can You Do to Protect Yourself from Air Pollution?

Weinberg said she recommends looking up air quality in your area with an iPhone app like IQ air, which maps out air quality metrics.

If you live in areas with higher levels of pollution, you can wear a mask outdoors, she said. Masks have been used throughout the pandemic to reduce the risk of COVID-19 transmission, but they can also block some air pollutants from entering a person’s mouth and airways. In China, for example, masking is common way to protect against air pollution, Weinberg said.

People with high cholesterol should also try to be mindful of their diet and work to maintain a healthy eating and exercise routine, she added.

Although this new study hasn’t been replicated in the U.S., it might alert authorities to reassess the health risk of air pollution.

“Maybe this is a good springboard for these agencies to say, ‘OK, so now we’ve got some data that shows that even lower levels are significant, so let’s do another sweep of research,’” Weinberg said. “Where does that come from? And should we be making some modifications accordingly?”