Do Air Purifiers Really Work? We Asked Doctors

We asked pediatricians and immunologists if investing in an air purifier to help your family survive allergy season is smart or a waste of money. Here are the tips they gave so that you can be sure you're spending wisely.

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Sure, warmer weather brings out the best in nature. Everything is green, in bloom, and bright. But for kids with seasonal allergies (and their parents of course) it can be a time of misery. Itchy eyes, sneezing, and coughing can zap the fun right out of playing outside in that fresh air.

"In the spring season, pollens and mold can trigger symptoms of nasal congestion, runny nose, sneezing, eye watering, and itching," says Amiinah Kung, M.D., allergy and immunology at Northwestern Medicine Central DuPage Hospital. The most common types of allergens come summer? Tree pollens and grass pollen tend to be most problematic, according to Meng Chen, M.D., pediatrician at Stanford Children's Health.

The symptoms of seasonal allergies occur when your child's immune system identifies environmental triggers as harmful invaders, and they can present themselves even before your toddler heads to preschool. "Developing seasonal allergies requires multiple seasons of exposure, and that is why infants are not susceptible to seasonal allergies, but may develop symptoms as they age," says Natasha Burgert, M.D., a board-certified pediatrician. "The distinct pattern of seasonal symptoms can be seen as early as the age of 2."

While there are lots of ways to treat and prevent these seasonal allergies in kids of all ages, one that has been a hotly debated is using an air purifier. So we asked our experts to get you the answers you want to know before adding this pricey investment to your cart.

What Is an Air Purifier and How Does It Work?

Air purifiers have a quite literal name for how they work. "Air purifiers use fans or ions to attract small particles in the air and then capture them on a filter, which removes them from circulation," says David Stukus, M.D., pediatric allergist and immunologist at Nationwide Children's Hospital.

It is important to understand their limited ability to impact circulated air throughout the home. Other than the immediate space or room where they are located, they are not going to impact small particles distributed on other levels or rooms.

Can Air Purifiers Really Help Spring Allergies?

There is mixed opinion if air purifiers are really a reliable solution to help prevent seasonal allergies. On one hand, they do work to clear the air of the stuff that's making your child miserable. "Allergens in the air in your home can trigger allergy symptoms, and air filtration can help decrease the amount of airborne allergens in your home and can help with allergy and asthma symptoms," says Dr. Chen.

However, they may provide very limited capabilities by performing best in small spaces and can be expensive and difficult to maintain.

"Air purifiers are very low on the list of recommended approaches to allergen avoidance inside the home," says Dr. Stukus. "They don't work well for outdoor pollen allergens and have very limited use for indoor allergens, which often settle on carpeting and furniture and do not remain airborne for long. There is also routine maintenance involved with changing filters."

A 2011 study did find that HEPA purifiers did have clinical benefits, but particularly in single room settings. However, research in general is very limited on their effectiveness. "There is not enough significant evidence to recommend air purifiers for allergy control in children," says Dr. Burgert.

Choosing the Best Air Purifier

If you're looking to try out an air purifier as an allergy treatment and prevention method, look for one that has a HEPA filter, is suited for your room size, and is used and cleaned properly according to the model. When it comes to choosing an effective air purifier, there are a few things to look out for.

"We recommend air purifiers with a HEPA filter; HEPA stands for high-efficiency particulate air," says Dr. Meng. "Stand-alone air purifiers are designed for a single room, so you should use it with the door closed and check that your air filter can accommodate the size of the room. And since air purifiers can be expensive, if you only have one air purifier, we recommend putting it in the bedroom since you spend a consolidated amount of time there while sleeping."

Besides a portable air purifier, there are also ways you can install air purifiers into your home's ventilation system. "If you have a central ventilation and/or heating/cooling system, you can also buy an air filter for this system," says Dr. Meng. "Look for the MERV (minimum efficiency reporting value) rating of the filter. Ideally, the MERV rating should be at least 11, and higher values are better. And make sure you clean or replace these filters regularly." According to the American College of Allergy, Asthma & Immunology, filters should be replaced every three months.

The Bottom Line

Air purifiers can help seasonal allergies, but they may not be the most effective method. "Air purifiers only filter the air in a very confined space inside the home, which limits their benefit," says Dr. Stukus. "Other than the immediate space or room where they are located, they are not going to impact small particles distributed on other levels or rooms."

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