Not only are cardiovascular diseases the leading cause of death for men in the United States, but they’re also the biggest killer in the world, leading to about 17.9 million deaths each year, according to the World Health Organization (WHO). A number of unhealthy things people do put them at risk for heart disease — smoking, poor diet, and staying sedentary are high on that list. But there’s another factor that can do major damage to your heart, one that most people don’t know about: breathing in polluted air.
Since 2015, the WHO has included air pollution as a risk factor for heart diseases. Breathing in, for example, particulate matter — extremely small particles of solid, hazardous elements in the air, also known as PM2.5 or PM10 depending on its size — increases the risk of cardiovascular deaths by 69%.
Luckily, there are several easy ways you can protect yourself from air pollution — and protect your heart in the process.
The Air Pollution Effect
The biggest myth about air pollution’s effect on health is that it mainly hurts the lungs, says Sanjay Rajagopalan, M.D., director of the Cardiovascular Research Institute at Case Western Reserve University’s School of Medicine.
“Nearly 60% of all the deaths because of air pollution are not because of lung problems, as it's commonly misperceived, but because of strokes and heart attacks,” Rajagopalan says. As many as 5 to 7 million patients succumb to the health effects of air pollution a year, and some studies put that number as high as 9 million — with some experts even saying these estimates are too low, Rajagopalan adds.
Globally, air pollution may be responsible for about a quarter of all cardiovascular disease deaths, says Michael Brauer, Ph.D., a professor of public health at the University of British Columbia. Of 18.5 million deaths from cardiovascular disease globally in 2019, 19% of those, or 3.5 million deaths, can be attributed to air pollution, according to the Institute for Health Metrics and Evaluation.
The percentage of cardiovascular disease deaths in 2019 that can be attributed to air pollution.
There’s a great disparity between how polluted the air is in high-income countries versus low-income countries. Even within countries, more privileged socioeconomic areas often have less exposure to air pollution. Yet even the tiniest bit of air pollution can hurt the heart. The risks only go up from there. When air pollution levels are high, the risk for heart attacks increases by 2% to 5%. The risk is much higher, almost 10- to 20-fold, if you’re chronically exposed to air pollution, Rajagopalan says.
Research has shown that the lifetime risk of cardiovascular events — such as arrhythmias, ischemic heart disease, heart failure, and cardiac arrest — increases by about 8% to 18% for every 10 microg/m3 of PM2.5 in the air, which is only a small increase in air pollution. Other research has revealed a 4.5% increase in coronary artery disease risk with every 10-microg/m3 increase in PM2.5.
The repercussions of air pollution can be seen even down to the hour, Brauer says. He points to one of his studies, which shows that when people are exposed to increased PM2.5 in the air during wildfire season, they report more heart issues within just an hour of exposure.
How Air Pollution Hurts the Heart
Damage to the lungs from air pollution can result in damage to the heart, such as by increasing the risks of arrhythmias. “Receptors in the lungs are part of our nervous system that control heart rhythm,” Brauer says. So when particulate matter gets inside the lungs, it can speed up the heart so much that it can fail to pump enough blood to the body. In the worst cases, this can be fatal.
Air pollution also slows metabolism, which can lead to premature aging of the blood vessels and heart. This can accelerate the buildup of plaque in the blood vessels, which may obstruct the passage of blood from the heart to the body, resulting in a heart attack.
Additionally, air pollution causes inflammation, and the continued presence of inflammatory elements in the bloodstream also leads to vascular aging. “Your body [when constantly exposed to air pollution] is sort of always at this heightened state of inflammation that can lead to impacts on all kinds of organ systems,” Brauer says.
A very tiny percentage of the small particles in air pollution actually seep into the bloodstream. Although this is often portrayed as one of the main risks of air pollution, Brauer notes, only about 2% of the ultrafine particulate matter that makes its way into the body actually passes into the bloodstream, where it can directly harm blood vessels.
Lastly, air pollution fosters other chronic noncommunicable diseases such as diabetes and high blood pressure. These diseases can, in turn, increase the risk of heart disease.
But the risks aren’t the same for everyone. “Air pollution exposure can be more harmful for certain people with underlying morbidities or existing health issues,” says Rebecca Saari, Ph.D., a professor of civil and environmental engineering at the University of Waterloo in Ontario, Canada. In fact, a study by the American Heart Association shows that the short-term effects of air pollution primarily affect people with pre-existing disease and, specifically, pre-existing cardiac disease.
Older people are also at high risk of the effects air pollution can have on the heart, says Albert Presto, Ph.D., a professor of mechanical engineering at Carnegie Mellon University’s College of Engineering. “Even though air pollution is and has been decreasing, the risk profile may not keep pace because of an aging population,” he says.
How to Protect Your Heart From Air Pollution
Tiny changes to your daily life can mitigate the effects of air pollution on your heart.
When you think about air pollution, you probably think big cities, avenues full of cars, and a lot of engine exhaust. You’re not wrong, but a lot of air pollution exposure actually occurs inside the home, mainly from cooking with oil, gas, coal, or wood, or from old furniture that is deteriorating and releasing bits and pieces of material.
To reduce air pollution in the home — and particularly super tiny PM2.5 — a HEPA filter is your best bet, Presto says. HEPA filter air cleaners lower indoor PM2.5 by 29%, according to this 2018 study. HEPA filters are especially effective at filtering out black carbon pollution — the sooty black particles released from burning fossil fuel — according to a study by the Department of Health of Cincinnati. However, HEPA filters can be expensive; the filter alone can cost up to $90, and air purifiers with HEPA filters can go for thousands.
A furnace filter — the kind in your furnace used to protect its blower fan from any dust or pollutants getting sucked in — that is MERV13 or better is another good option for keeping the air inside your house clean, Presto says. MERV is a rating system used for air filters. MERV13 and 14 filters capture more than 80% of particles that are between 1 and 3 microns in diameter.
“If I go to my local big box store to buy furnace filters, I usually have a choice of anywhere between MERV6 and MERV14,” Presto says. “Higher MERV numbers indicate filters that capture particles more efficiently because these filters have a combination of more surface area and smaller pore sizes.”
A low-cost alternative to a HEPA filter is the Corsi-Rosenthal Box, which is a box fan attached to a MERV13 filter.
Don’t forget to replace air filters regularly. Studies have shown HEPA filters, for example, decline in effectiveness by more than 50% after five months of use. “The better the filter, the faster it will get clogged, so it needs to get replaced more often than a filter that lets a lot of particles through,” Presto says.
When out and about, N95 masks can protect you from air pollution. Wearing an N95 mask significantly reduces a person's exposure to wildfire smoke pollution, according to a study published last year. The researchers estimated that wearing an N95 mask properly and for two-thirds of the day could reduce the increased risk of hospitalization that wildfire PM2.5 brings, from 66% with no mask to 21% with a mask.
You can also use local data about air pollution to plan out your day and avoid as much exposure as possible. Air quality apps like BreezoMeter make it possible to access real-time information about the air quality around you, updated hourly and complemented with air pollution forecasts. This can inform your decision on, say, when to go running during the day or when to open your windows.
“That's a very easy way, from day to day, to reduce your exposure to harmful air quality,” says Yvonne Boose, Ph.D., an atmospheric science specialist at BreezoMeter. You might even want to check that air quality forecast and history data when it comes to selecting which side of town you’d like to move to, she says.
But although individual actions can help protect you and your family, the root problem is much more systemic. “It's really easy to tell somebody to stop smoking,” Brauer says. “It's hard to tell somebody to stop getting polluted air.”