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The incense continued to burn for another 20 minutes or so, and the purifiers ran for 50 minutes total. After 15 minutes he turned each purifier on, set to high. He let the incense burn (five sticks per test sandalwood scent, if you’re wondering) for 15 minutes at the start of each test, getting a baseline reading of the room before the smoke had time to spread, and then measuring as the smoke and particle levels rose. He burned the incense near one corner of the room and put the AeroTrak particle counter between the purifier and the incense, roughly 12 feet from each. Tim placed the machines at the midpoint of the room, approximately 3 feet from the wall and away from any obstacles. (See our blog post about purifiers and wildfire smoke for more.) The tests ran for 65 minutes, with the machines on high. Tim used slow-burning incense to simulate an ongoing wildfire smoke condition.
#Clear the air doc series
(The HEPA 0.3-micron standard falls within the scale that the tobacco-smoke test measures.) Models in the Blue Pure 411 series use the same filtration method as the 211+ and 311 Auto.
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The CADR tests measure purifier effectiveness on three different pollutants-tobacco smoke, dust, and pollen-that correspond to particles of 0.09 to 1.0 micron, 0.5 to 3.0 microns, and 5.0 to 11.0 microns, respectively, so in a sense they represent a tougher standard. CADR numbers in effect give the cubic feet per minute of perfectly pure air that a purifier can produce on its maximum setting. Neither Blueair model is true-HEPA rated, but both are certified by AHAM to have clean air delivery rates (CADR) of 350 and 250, respectively, and they performed exceptionally well in our testing, where we measure each purifier’s effectiveness at capturing HEPA-standard 0.3-micron particles. We also discuss the much-hyped IKEA Förnuftig.Īmong our picks, we have two exceptions to this general rule: the Blue Pure 211+, our pick for large spaces, and the Blue Pure 311 Auto, an also-great pick for standard-size rooms.
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In a new section, we cover a few other purifiers that fit specific needs, including a purifier for handling VOCs, a super-energy-efficient small-space purifier, and a truly smart air purifier. And it doesn’t keep pace with the Mighty or the Blue Pure 211+ in larger rooms. But it’s not terribly energy efficient: Running it 24/7 on medium consumes about $300 of electricity over five years, and seven new filters in that period cost $180, making this model slightly more expensive than the Coway Mighty over the long term. At around $100 to purchase, it’s also the cheapest up front of all our picks. It’s attractive and compact, measuring just 14½ inches tall and 8½ inches in diameter, and its display-shutoff feature means it won’t interrupt sleep with bright lights. On medium, it reduced them by more than 92%. It was impressive in our tests, reducing particulates by more than 97% on its high setting in 30 minutes in a 135-square-foot New York City office. If you need to clean the air in a space of around 200 square feet, the Levoit Core 300 is a solid and inexpensive purifier.
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