The air purifier industry has grown substantially in the last decade or so, especially in cities like Hong Kong and Tokyo where pollution is a major problem. Although the value of the product seems self-explanatory, the actual service that it provides is somewhat murky; despite what salesmen have claimed, air purifier manufacturers have paid for very few studies to back up the benefits of their products, medical or otherwise. It’s worth stating that air purifiers aren’t considered medical devices by the FDA, so they’re not regulated. After having done a little research on the topic, I can tell you what we do and don’t know:
This is because more air purifiers are really just dust filters, and they’re each going to limit dust to varying degrees. Lower-tier “purifiers” may help to filter out some of the larger chunks of dust and allergens in your home, while other higher-priced filters may justify their price by featuring HEPA, “electrostatic”, or “carbon” filters that can filter out smaller floating allergens like animal dander. The truth is, electrostatic filters can actually only remove large particulate, while purifiers that use HEPA filters aren’t necessarily good because HEPA filters themselves have a wide range of effectiveness. All in all, these filters can be somewhat helpful in terms of keeping a household cleaner and limiting allergens to some extent, but as products they generally aren’t worth the listed price.
If you want a filter because you’re interested in eliminating mold and fungus spores, harmful airborne bacteria and viruses, or toxic gasses and chemicals that can cause lung cancer, the most trusted products on the market are also the most expensive. That said, there are good air purifiers that have been shown to help people. For example, a recent study showed that asthmatic children that lived in households with strong air purifiers showed reduced symptoms and visited the doctor fewer times. However, the benefit from using an air purifier for people with more serious breathing conditions may not be proportionally reflected among people with standard allergies.
- Even with the best filters, doctors disagree about the effects.
“They fall into the second-line category under the heading, ‘Can’t hurt, may be helpful,'” Dr. Elizabeth Matsui explained to the New York times regarding air filters. Dr. Matsui is a professor at Johns Hopkins who is also the chairwoman of the air pollution and indoor allergen committee for the American Academy of Allergy, Asthma and Immunology. “First-line steps” in the battle against allergies included keeping windows closed, wearing glasses outdoors and changing clothes and showering upon returning home. At the end of the day, the allergens that inspire most people to buy air purifiers don’t even stay in the air very long, and once they settle on surfaces there’s little an air purifier can do to eliminate them. All in all, it’s a murky industry that may be too ambiguous to be worth your investment.