Illustration: Kieran Blakey

The Nuance

Do You Really Need an Air Purifier?

What they can and can’t do, and why some air purifiers may come with risks

Published in
5 min readMar 12, 2020


DDuring the back half of the 19th century — a time when tuberculosis was widespread in smog-choked cities across the United States and Europe — fresh air was thought to be a potent elixir for diseases of the mind and body. This was the golden age of the spa town, and the unwell flocked to mountain, desert, or seaside resorts — often at the direction of their doctors — in order to recuperate in the clean, salubrious air.

Fresh air has since gone out of fashion as a primary form of medical treatment. But as vehicle traffic, factories, and seasonal wildfires spread pollutants across large swaths of the country and rates of asthma continue to rise, air purifiers have become a hot retail item. While research on the long-term health benefits of these devices is lacking, experts say they likely do some good — certainly for those who suffer from lung-related health problems and probably for everyone else too.

A 2011 review of the research on air filters and cleaners found that a range of these products — from whole house HVAC filters to portable single-room air purifiers — improved symptoms among people with asthma and allergy-related respiratory disease. “Airborne particulates can trigger allergies or act as irritants, and air cleaners can be effective at filtering these out,” says Dr. James Sublett, author of that review and a clinical professor of pediatric allergy and immunology at the University of Louisville School of Medicine.

SScience shows that airborne pollutants raise a person’s risks for a range of diseases. Exposure to ambient air pollution — composed mostly of large and small particles of hundreds of different chemicals — can interfere with the action of specialized T-cells, which normally help calm down the immune system and reduce inflammation. One 2010 study in the Journal of Allergy and Clinical Immunology found that this T-cell interference was associated with higher levels of asthma among kids. The lead author of that study later said these and other pollution-induced immune system changes could also play a role in the development of allergies, cancer, heart disease, autoimmune disease, and endocrine disorders —…



Markham Heid

I’m a long-time contributor at TIME and other media orgs. I write mostly about health. I grew up in Michigan, but these days I live in southwest Germany.