If you live near a highway, or on a busy city street, something lurking in your home that you can't see, smell or hear could be raising your blood pressure. Tiny particles of air pollution from car exhaust, brake dust and tire wear that seep indoors can wreak havoc on your heart.

But here's the good news: a simple and affordable fix may be sitting on a store shelf right now. Using a HEPA (high-efficiency particulate air) filter in your home can significantly lower systolic blood pressure, the top number in a blood pressure reading, especially if your readings are a bit high to begin with, a new study finds.

The improvement in systolic pressure is notable. The results correspond to a 6 percent reduction in risk for serious cardiac events.

A team of researchers led by Douglas Brugge, Professor and Chair of the Department of Public Health Sciences at University of Connecticut Health, set out to see whether using HEPA filters to clear household air could make a measurable difference in heart health.

Turns out, they can.

The study involved 154 adults who lived close to high-traffic roads, hotspots for microscopic air pollutants. These particles, known as PM2.5, are small enough to penetrate deep into the lungs, and even enter our bloodstream. How small? Around 30 times smaller than the width of a strand of human hair.

Numerous studies have shown a link between PM2.5 exposure and cardiovascular disease. Breathing in pollution from traffic puts a strain on our cardiovascular system, raising heart rate and tightening blood vessels. Over time, it can also damage arteries, which increases the risk of high blood pressure.

Study participants were randomly assigned to use either real HEPA filters or sham filters (units with no filter inside) in their homes for a month. After a period with no filtration, they switched to the opposite setup. Participants' blood pressure was measured before and after each phase.

The result? People with elevated systolic blood pressure — above 120mm Hg — saw a 2.8 mm Hg drop in just one month when using real HEPA filters. That may sound small, but it's a meaningful reduction in terms of reducing the risk of heart attack and stroke.

“Elevated blood pressure is one of the leading causes of illness and death, so even small changes in blood pressure are impactful,” Brugge explained in a media release.

The case for clean indoor air is strong, yet almost 120 million adults in the U.S. have high blood pressure and nearly one in four Americans live near high-traffic roadways. This makes the findings especially relevant — even for those who might not think they're at risk.

HEPA filters work by trapping fine particles that float in the air, including those from vehicle emissions, cooking, smoking and, recently, smoke from wildfires. Air purifiers with HEPA filters are readily available in stores and online, making them an accessible heart-health tool for most people.

Air purifiers with HEPA filters are readily available in stores and online, making them an accessible heart-health tool for most people.

The improvement in systolic pressure from air purifier use is notable, even though the study found no change in diastolic blood pressure (the bottom number in a blood pressure reading). The results correspond to a 6 percent reduction in risk for serious cardiac events.

The findings are compelling and actionable, though the study had limitations. Most participants were white and higher-income, and people taking blood pressure medication were excluded.

The takeaway? In a world where much feels out of our control, doing what you can to keep the air inside your home clean may be one of the simplest, smartest things you can do to reduce your exposure to pollution, protect your lungs and keep your blood pressure in check may be one of the simplest, smartest things you can do.

You can also work on lowering your blood pressure by following the guidance of the American Heart Association:

  • Eating a well-balanced diet with plenty of fresh fruits and vegetables and avoiding processed foods
  • Limiting alcohol
  • Engaging in regular physical activities
  • Managing stress
  • Reaching and maintaining a healthy weight
  • Quitting smoking – or not starting.
  • Working with your healthcare professional and properly taking any medication

Lowering blood pressure by just a few points is no small accomplishment. It could mean your future holds one less pill and fewer visits to the ER.

The study is published in JACC, Journals of the American College of Cardiology .