Before you buy an air purifier, try some simple, common-sense steps to reduce indoor air pollution. Begin by vacuuming often, banning smoking indoors, minimizing use of candles and wood fires, and using exhaust fans in kitchen, bath, and laundry areas. Test your home for radon gas, which can cause lung cancer (test kits cost about $15). Don't store chemicals, solvents, glues, or pesticides in your house. Minimize the risk of deadly carbon monoxide gas by properly maintaining heating equipment, wood stoves, fireplaces, chimneys, and vents--and by installing carbon-monoxide alarms on all levels of your home. And don't idle your car, run fuel-burning power equipment, or light a barbecue grill in your garage, basement, or in confined spaces near your home.
Air-purifier models with an electrostatic precipitator remove pollutant particles by charging them as they pass through and collecting them on an oppositely charged metal plate or filter. In the process, they produce some ozone as a byproduct. You'll also find dedicated ozone generators, which produce relatively large amounts of this gas by design. While ozone in the upper atmosphere protects us from the sun's ultraviolet rays, ground-level ozone is an irritant that can worsen asthma and compromise your ability to fight respiratory infections. We believe that air purifiers that emit even small amounts of ozone are a poor choice if someone in your household has pulmonary problems or allergy symptoms. We also suggest that you avoid dedicated ozone generators entirely, given their high ozone emissions.
Check an air purifier's efficiency rating
If you still want one, use this air-purifier guide to choose. The Association of Home Appliance Manufacturers certifies most room models as part of a voluntary program that includes appropriate room size and maximum clean-air delivery rate (CADR), a measure of cleaning speed. We judge a CADR above 350 to be excellent and below 100 to be poor. Choose a model designed for an area larger than yours for better cleaning at a lower, quieter speed. Many whole-house filters list a minimum efficiency reporting value (MERV), developed by the American Society of Heating, Refrigerating, and Air-Conditioning Engineers. The top performers in our tests typically had a MERV higher than 10.
Learn more ways to improve the air quality at your home.
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