The best air purifiers, according to doctors and experts

Spring means pollen ... and pollen means it's allergy season.

While most people are aware of pollutants floating around outside, it may come as a surprise to learn that people with allergies may be even more vulnerable indoors.

“The Environmental Protection Agency has reported that indoor air — where we spend more than three-quarters of our days — is often even more polluted versus outdoor air,” said Dr. Clifford Bassett, founder and medical director of Allergy and Asthma Care of New York and author of The New Allergy Solution.

For clean air, eliminate sources of pollution, like cigarette smoke, air fresheners, wood burning fireplaces and harsh cleaning chemicals, noted Dr. Denitza Blagev, a pulmonologist at Intermountain Medical Center in Salt Lake City, Utah.

People with allergies should decrease exposure to triggers (use allergy-proof bedding for dust mites, wear wraparound sunglasses to block outside pollen) and work with a doctor on a medication strategy, said Bassett.

An indoor air filter or purifier can also be effective in removing harmful pollutants, said Blagev.

Stand-alone units that are designed to filter a designated area should be placed in rooms where you spend most of your time, like the bedroom, Blagev added. But, remember to change the filter regularly based on the manufacturer’s suggestion.

With so many options out there, it can be tough to find a the best air filter that's both effective and safe. But, since April is the best time to buy an air purifier, here are a few suggests from doctors that pass the test:

Honeywell True HEPA Allergen Remover, $108, Walmart

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HEPA stands for high-efficiency particle air. A HEPA filter is designed to remove 99.97 percent of airborne particles (measuring .3 micrometers or greater) in diameter passing through it.

“Room air cleaners with a HEPA filter are the best choice,” said Dr. James L. Sublett, chief medical officer at Family Allergy and Asthma in Louisville, Kentucky. One brand he likes is Honeywell. Also, consider the size of the room for the best efficiency. This specific model helps clean rooms up to 155 square feet.

AeraMax 100 Air Purifier, $84 (usually $99), Amazon

The Allergy and Asthma Foundation of America certifies household products as "asthma and allergy friendly,” so it’s a great resource to help narrow down the best air purifiers, said Bassett. The AeraMax 100 has been certified by the foundation. It's a portable air cleaner that removes 99.97 percent of airborne particles. It best fits rooms that are up to 200 square feet.

Rabbit Air MinusA2 Ultra Quiet HEPA Air Purifier, $550, Amazon

This is a splurge, but Rabbit Air purifiers come with some serious perks. This one can purify a room up to 700 square feet. Bassett said he likes this brand because it makes customizable filters that address odors, toxins or pet allergens. It can also be mounted on a wall. And, it looks attractive.

Dyson Pure Cool Link Air Purifier, $349 (usually $500), Amazon

This is another option that’s been certified “asthma and allergy friendly” by the AAFA. It features a HEPA and carbon filter that traps particles as small as 0.3 microns. “The most harmful particulates are the smallest, or less than 2.5 microns in size,” said Blagev.

AirFree Lotus, $400, Bed Bath & Beyond

Some air purifiers intentionally produce ozone (it's usually noted in the advertisements). But, these can be dangerous for your health. “Ozone is a colorless, odorless gas that contributes to an increased risk of asthma and other respiratory symptoms,” said Blagev. Look for air purifiers that don’t generate ozone. This model in particular is certified by the California Air Resources Board, since it meets the limit on ozone emissions.

Peace Lily Plant, $3, Amazon

“I am a fan of attempting to get an indoor clean air boost with various NASA-studied plants that have been found to potentially scrub and purify indoor air of common pollutants,” said Bassett. Peace Lily and English Ivy are two good options. It may surprise you that Amazon sells live plants. But, they do.

AllergyZone Furnace Filter, $17, Amazon

This isn’t a traditional air purifier or cleaner, either, but it plays a critical role in keeping the air in your home free of allergens. “I recommend using a HEPA air cleaner in combination with a high efficiency furnace filter on the HVAC system, like those from AllergyZone,” said Sublett. With this combination, pollutants don't stand a chance.

Now that you know what to look for in an air filter, check out some of Amazon's best-sellers, too! Some of them were even mentioned in our TODAY segment on the best time to buy household appliances ... no wonder so many are on sale.

Germ Guardian 3-in-1 Air Purifier With True HEPA Filtration, $84 (usually $150), Amazon

Levoit LV-H132 Air Purifier with True Hepa Filter, $75 (usually $90), Amazon

Hamilton Beach TrueAir Ultra Quiet HEPA Air Purifier, $40, Amazon

GermGuardian AC4100 3-in-1 air purifier with HEPA filter, $54 (usually $90), Amazon