Have Asthma? What to Look for in an Air Filter

Medically Reviewed By William C. Lloyd III, MD, FACS
Close-up of woman's finger turning on air purifier power button

Americans spend 90% of their time indoors, according to the Environmental Protection Agency (EPA). So, if you or a loved one has asthma, you have to pay attention to indoor air quality. Common asthma triggers, including pollen, dust and mold, are present in every home, and high levels of these indoor air pollutants can lead to unnecessary difficulty breathing.

Air filters and air purifiers reduce indoor air pollution and may help people with allergies and asthma—if you get the right filter or purifier. Learn more about the best air filters for asthma and allergies, including HEPA air filters and asthma air purifiers.

Whole House Air Filters for Asthma

If your home has a central heating, ventilation and air conditioning (HVAC) system, the right filter can dramatically improve indoor air quality. Instead of getting the cheapest air filter for your furnace or HVAC system, look for a disposable filter with a minimum efficiency reporting value (MERV) of 11-13. The higher the MERV rating, the better. These filters capture pollen, pet allergens and mold, so you won’t breathe them in. At least one research study has found a reduction in asthma symptoms in households that use disposable high-efficiency MERV 12 HVAC filters.

HEPA filters may reduce indoor air pollution, but they’re not your best choice. HEPA stands for high efficiency particulate air filter, and these filters are designed to trap pollutant particles the first time they pass through the system. Sounds great, right? The problem is that these filters are more resistant to air flow than MERV filters, so they cause your HVAC equipment to work harder, which may cause your system to wear out prematurely.

It is crucially important to change your filter on a regular basis. Most disposable filters should be replaced at least every three months—or sooner, if they fill up quickly. Unfortunately, many people forget to change their furnace filter on a regular basis, and a dirty filter cannot effectively filter pollutants out of the air. Set a reminder on your phone or mark ‘change filter’ on your calendar so you won’t forget.

Air Purifiers for Allergies and Asthma

If you don’t have a central heating or HVAC system, your best bet is an indoor air cleaner or portable air purifier.

DO NOT choose an ‘ozone’ air purifier. These air purifiers produce ozone, a known asthma trigger. Using an ozone air purifier could actually cause an increase in asthma symptoms.

Instead, choose an air purifier that includes a HEPA filter. The Asthma and Allergy Foundation of America has established an asthma & allergy friendly® Certification Program to identify products that meet strict certification standards, including reduction (versus redistribution) of potential allergens and irritants. You can find air cleaners and purifiers that have earned this certification at www.asthmaandallergyfriendly.com.

Most air purifiers and cleaners can only clean the air of one room. You may need more than one to adequately filter the air in your room. If you cannot afford more than one air cleaner, place it in the bedroom. Because humans spend so much time asleep—and because bed bugs and dust mites, two common asthma triggers, tend to accumulate in bedrooms—clean air in the bedroom is crucial for those with asthma.

Note: You will have to change the filters inside portable air cleaners and purifiers as well. Follow the manufacturer’s directions.

The right whole house air filter or HEPA air purifier can improve indoor air quality and may improve the well-being of asthma sufferers.

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  7. Asthma and Allergy Educational Materials and Tools for Patients and Caregivers. Asthma and Allergy Foundation of America. https://www.aafa.org/programs-for-patients-and-caregivers/
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  9. Which is Better for Your HVAC System: HEPA or MERV Filters? General Heating and Air Conditioning. https://genhvac.com/better-hvac-system-hepa-merv-filters/
Medical Reviewer: William C. Lloyd III, MD, FACS
Last Review Date: 2021 Jun 3
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