Air purifiers can be great for trapping fine particles like dust, pollen, and smoke that swirl about in your home's air, as Consumer Reports discovered in its tests of portable and whole-house air purifiers. But some gasses readily pass through even the best air purifiers, including two that can harm you:
Radon. This radioactive gas, colorless and odorless, seeps up through the foundations of 1 in 15 U.S. homes, and after smoking it's the top cause of lung cancer. Overexposure is symptom-free, and once you're exposed, there's no treatment. Smokers in the household are particularly at risk.
Short-term (2- to 7-day) kits for radon detection, such as the top-scoring RTCA 4 Pass Charcoal Canister, $23, are available. But because the radon level can vary from day to day, we generally recommend kits that work for 90 days or more; of these, the Accustar Alpha Track Test Kit AT 100, $25, topped our tests of radon test kits. The Environmental Protection Agency advises you call in a pro for potential mitigation (about $1,200 for an average house) if you get a level between 2 and 4 pico Curies per liter (pCi/L). Mitigation should bring the pCi/L down below the 2 mark.
Carbon monoxide. Also colorless and odorless, this silent killer can strike without warning if it leaks from a faulty furnace, gas clothes dryer, or other fuel-fired appliance such as a generator. Install a CO alarm on every level of your house, including the basement—and skip the temptation to buy combination smoke/CO alarms, which are often good at detecting one risk but not both. Replace CO alarms every five years. Check our Ratings for CO alarms, which include such recommended models as the First Alert OneLInk CO511B, $85, an interconnected alarm that makes all alarms in the house go off when one is triggered; and the standalone First Alert CO615, $30.
Before shopping for any of the above, be sure to see our buying guides for air purifiers, radon test kits, and CO alarms.
—Ed Perratore (@EdPerratore on Twitter)