Then testers measured how quickly each air cleaner removed the particles from the air. Some expensive ones had problems. A $400 Oreck air cleaner didn't do a good job at cleaning the air and also produced low levels of ozone, a respiratory irritant. And another $400 LightAir IonFlow did an even worse job of cleaning the air.
"The IonFlow air cleaner was about as effective at removing dust and smoke as having no air cleaner at all," said Consumer Reports' John Galeotafiore.
In fact, unless you have asthma or allergies, you probably don't need an air cleaner at all. If you do suffer from a respiratory condition, Consumer Reports says there are steps you can take before buying one.
"If you have respiratory problems, put dust mite covers on your mattress and pillows. Remove any wall-to-wall carpeting, and don't let any pets into your bedroom," said Galeotafiore.
If you still have symptoms after taking these measures, Consumer Reports did find some air purifiers that performed very well. The $300 Whirlpool AP51030K was top-rated. It's very quiet and has a filter-replacement indicator, which is a very helpful feature.
If you have a forced-air heating or cooling system in your home, you can replace the system's filter with a whole-house filter. These are supposed to be more effective against dust, smoke and pollen. Consumer Reports evaluated several of these and recommends the 3M Filtrete Elite Allergen 2200, which costs $25.
NOTE: The tests were done on portable air purifiers which cannot filter out nuclear radiation. You would need a whole house purifier specifically designed for that purpose and that type was not tested.