If you’re concerned about indoor air quality, you may have noticed ads for a type of appliance called a portable air purifier. Purchasers hope that these boxes will suck in dirty air and discharge clean air, but few homeowners know how these appliances operate.
In this article, I’ll try to answer a few basic questions about portable air purifiers:
If you Google “air purifiers,” you’ll quickly discover retailers who make outlandish claims. Air purifiers are the radiant barriers of the IAQ world. In other words, air purifiers often work, but the field seems to attract a lot of charlatans.
For example, in an online ad, a company called Dyson claims that its appliance “automatically purifies to remove allergens, pollutants and gases from the air.” Well, if the device removes gases from the air, that must mean that the device simply emits particulates — probably by spraying the room with soot. I think I’ll pass. I’d rather have an air purifier that removes the solids from the air and lets the gases pass right through.
Portable air purifiers are devices that sit on the floor of a room. A portable air purifier is designed to clean the air of a single room, not an entire house. Most air purifiers include a fan; the device pulls air into the appliance, does something to the air, and then discharges it. Most models cost between $100 and $1,000.
Most air purifiers include a particulate filter — a filter that in some cases meets the standard for a HEPA (high efficiency particulate air) filter. Other air purifiers claim to clean the air with an activated charcoal filter or with ultraviolet (UV) light. Still others claim to clean the air by emitting negative ions or ozone.
Let’s clear the air right from the start: