Do Indoor Air Filters Really Help You Breathe Easier?

Do Indoor Air Filters Really Help You Breathe Easier

As a pulmonologist, many of my patients who have respiratory illnesses or lung diseases are often the first people to recognize when the air quality outdoors is poor, especially if they live in areas where air pollution is a problem. I encourage them to avoid going outdoors on those bad air days.

But what about the air indoors? Dirty air indoors can increase breathing difficulties, too.

Can using an indoor air filter improve the air quality inside your home?

As a pulmonologist at Intermountain Medical Center in the Salt Lake City area, I’m currently conducting a study about whether indoor air filters can improve breathing difficulties for former smokers on bad air days.

Our city is surrounded by mountains and has a high elevation, and these factors can lead to more bad air days, especially in the winter when cold air becomes trapped in the valley and we experience temperature inversions, where it’s warmer at high elevations in the mountains than at lower elevations in the valley. Outdoor air pollution is a major contributor to indoor air pollution.

What type of air filter works best at removing pollution indoors?

A High-Efficiency Particulate Arrestance (HEPA) filter with a MERV (Minimum Efficiency Reporting Value) rating of 13 to 16 is most effective at removing the smallest pollution particles. HEPA filters remove more than 99 percent of particulates. These should not be confused with air purifiers that use UV light or electrostatic charges to kill viruses or bacteria.

HEPA filter MERV ratings range from 1 to 16. A low MERV rating (1 to 4) means the filter only traps large particles such as dust. A high MERV rating (13 to 16) means particles of less than 1 micron are removed, such as the PM2.5 particles in outdoor air pollution that cause poor health outcomes.

However, HEPA filters don’t remove radon or ozone, which can also be harmful to the lungs.

Should you use HEPA air filters in your furnace or a stand-alone air filter?

There are stand-alone HEPA filters that can clean the air in one room in your house. You should put it in the room you spend the most time in, which is usually the bedroom. Kitchens and rooms with wood-burning fireplaces can also be a major source of dirty air. There are also HEPA filters you can put in your furnace to filter the air that flows through your house. You can use both stand-alone and furnace filters for maximum effect. Look for a MERV rating of 13-16.

What types of people can most benefit from using an indoor air filter?

Young children, the elderly, and those with a history of chronic heart or lung disease are at most risk of being affected by high pollution levels and are likely to benefit from indoor air filters. Infants face an increased risk of respiratory hospitalizations during periods of high air pollution.

Many asthma and chronic obstructive pulmonary disease (COPD) patients notice significant improvement in their asthma symptoms in a clean indoor environment, which results from taking steps to remove dust and other allergen exposure by limiting carpet and drapes, dusting regularly, removing animals they’re allergic to, and using indoor air filters.

5 ways to improve the air quality inside your home

  • Don’t use a wood-burning fireplace or burn candles or incense
  • Don’t allow smoking inside the home or nearby
  • The particulate pollution associated with burning or smoking will likely overwhelm any cleaning from an indoor air filter.

  • Don’t spray volatile chemicals or cleaners inside your home
  • Do use an exhaust fan in the kitchen
  • Do use HEPA air filters with a MERV rating of 13-16

What else can you do to help improve outdoor air quality?

It takes the whole community to improve air quality. We’re all contributing to and affected by air pollution, whether we’re young or old or have heart or lung disease or not. A few ways to make a difference are to drive your car less, not let your car idle, and drive a car powered by alternative energy sources such as hybrid electric cars. The solutions to better air quality must be addressed by all of us as a community. If we don’t take action, we’ll continue to see increased health costs and lower quality of life in our communities.

How to participate in Intermountain Medical Center’s study on improving indoor air quality

To qualify for this study, you must be a former smoker, over age 40, and have not previously used a HEPA air filter in your home. You can enroll in the study from now through February 2018, with some participants accepted through April of 2018.

For more information, send an email to or call 801-507-4606.