Indoor pollution solution: Do air purifiers actually work?

February 18, 2020

Given the fact that indoor air can harbor up to five times higher concentrations of certain pollutants than outdoor air—odors, smoke, dust, pet dander—you might be tempted to acquire an air purifier. But in reality, not all air purifiers necessarily live up to the marketing hype, according to a report by the Good Housekeeping Institute.

Most air purifiers comprise a filter, or multiple filters; as well as a fan that sucks in and circulates air. As air moves through the filter, pollutants and particles are captured and the clean air is pushed back out into the living space.

Some use ionizers to help attract particles like static: Negative ions bond to dust and allergens and make them settle out of the air. Good Housekeeping warns, if you’re interested in buying an air cleaner that uses ionizers, make sure it does not produce ozone, a gas made up of three oxygen atoms that is often claimed to help break down pollutants. Ozone could be a lung irritant and further aggravate asthma conditions.

The majority of filters are designed to capture particles like dust and pollen, but don’t catch gases like VOCs (volatile organic compounds) or radon from the air that may accumulate from adhesives, paints, or cleaning products. Allergens that are embedded into furniture or flooring also are not captured by them.

 That would require an adsorbent, like activated carbon. In fact, the Environmental Protection Agency warns that the functionality of air purifiers is limited in terms of filtering out gases, and that you must frequently replace filters for optimal functionality, usually about every three or so months.

If you are concerned about mold, Good Housekeeping recommends buying a dehumidifier or humidifier to help maintain the appropriate moisture levels in your home and stave off mold growth issues. Air purifiers do not prevent mold growth, so it is necessary to eliminate the source of moisture that is allowing it to grow.

However, if you are an allergy or asthma sufferer, an air purifier with a HEPA filter may be helpful for you as it will be good at removing fine airborne particles. HEPA is an acronym for High Efficiency Particulate Air. HEPA filters capture variously sized particles within a multi-layered netting usually made out of very fine fiberglass threads (much thinner than the size of a human hair strand!) with varying sized gaps.

So, after all of this, if you still are interested in purchasing an air filter, the Good Housekeeping Institute advocates that you consider the following:

  • CADR (clean-air delivery rating): This measures the cleaning speed of the purifier for removal of smoke, dust, and pollen. Look for a CADR of at least 300; above 350 is really great.
  • Size guidelines:  Choose a model that is designed for an area larger than the one you are outfitting it for if you want to operate it at a lower, quieter setting.
  • AHAM (Association of Home Appliance Manufacturers) Verified mark: AHAM’s standards are design to ensure the safety, efficiency and performance of many home care appliances, including air purifiers. While voluntary, most reputable air purifiers have undergone this certification program, which often provides a CADR rating and size guidelines.
  • True HEPA: True HEPA filters are effective at removing ultra fine particles (think: dust, dander, pollen, mold,and other common allergens in the home). The industry standard for such is that the unit must be able to remove at least 99.97% of particulates measuring 0.3 micron diameter in a lab setting,

Finally, the best advice is to address the source of indoor air pollution and ventilate your home. If you can, keep your windows open to prevent locking irritants into rooms (when air purifiers aren’t running!). Create a stronger cross draft by opening windows on opposite sides of the room if possible.

 Research contact: @goodhousekeepi1

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