Do air purifiers work? Here's what they do, and an analysis of risks versus benefits

During the peak of the COVID-19 pandemic, medical professionals offered many suggestions to keep people safe from the airborne virus including masks, isolation and frequent sanitation. One of the suggestions was also air cleaners or air purifiers. The United States Environmental Protection Agency even offered guidance on incorporating the machine into homes.

Air purifiers range between $100 to $600 on Amazon, but are they worth your money? Do air purifiers really work? Dr. Ana Zamora-Martinez, medical director of the interstitial lung disease clinic at the Mayo Clinic, explains air purifiers' purpose, benefits and concerns.

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Do air purifiers work?

Yes, air purifiers are effective in improving the air quality in your home if used correctly. Zamora-Martinez especially recommends finding an air purifier that supports a HEPA (high-efficiency particulate air) filter. The EPA reports that this type of filter has the potential to remove at least 99.97% of dust, pollen, mold bacteria and any tiny airborne particles. Zamora-Martinez cautions that homeowners remember to change the filter every three months.

“I've seen those patients without changing the filter, having more problems than not,” Zamora-Martinez said. “If you want to spend your money, you don't need to buy a Dyson as long as there's a HEPA filter.”

However, the benefits of an air purifier only go so far. Medical professionals suggest prioritizing maintaining a clean home and frequently sanitizing frequently used surfaces. Air purifiers should just be an accessory to your cleaning routine, not a priority.

People with asthma, the flu, COVID-19 or other pulmonary diseases may benefit from adding an air purifier to their home appliances, however, there is no specialized research to support the idea, Zamora-Martinez said.

“It’s (Air purifiers) an adjuvant you can try after you have done everything and are still having symptoms,” Zamora-Martinez said. 

If symptoms of pulmonary diseases do not improve of get worse, you must immediately contact your primary care doctor or a pulmonologist. Persistent or worsening symptoms and discomfort in breathing may be a greater issue that cannot be self-diagnosed and needs to be handled by a medical professional.

What does an air purifier do?

The most common air purifier sold for homes is a filtering air cleaner. According to the University of Massachusetts Amherst, the machines pass air through a filter that isolates polluting particles or gases and returns clean air to the room.  

Some air purifiers include a humidifying feature that releases an ultra-fine mist into the air. Despite the novelty of this feature, it does not benefit like a HEPA filter does. In fact, Zamora-Martinez warns that this may cause more harm than good. 

“They (Air filters with humidifiers) can cause hypersensitivity pneumonitis if they get mold inside or if they don't change the filter, they can be more dangerous and unhealthy,” Zamora-Martinez said. “If you change the filter, you will be fine.”

Zamora-Martinez strongly suggests buying an air purifier with no humidifier and prioritizing changing the filter every three months.

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Do air purifiers help with smoke?

Yes, air purifiers can help with smoke that may contaminate indoor air during wildfires. Portable air purifiers with a HEPA filter are the best for this situation because you can bring the machine with you, wherever you go and stay for longer periods of time, Zamora-Martinez said.

Do air purifiers help with dust?

Yes, air purifiers with a HEPA filter trap polluting particles, including dust, from the air. While it is not a method of getting rid of dust completely, it helps remove the particles in the air you may inhale. Zamora-Martinez also recommends an air purifier in dry climates with sandy environments.   

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Do air purifiers help with allergies?

HEPA air purifiers have the capability to filter out pollen, dust, and other airborne pollutants in a home. This is not the final cure to all allergies but it may help with the physical allergens commonly found in the air.

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