Is a negative-ion generator a filtering device?
Yes and no. A negative-ion generator uses electric current to produce negative ions (free electrons). The ions attach themselves to particulates in the air causing them cling to oppositely charged walls and furnishings. This can result in slightly cleaner air, but dirtier walls. Some negative-ion generators have a built-in filter that captures the charged particulates. Sometimes these devices are not sold for their filtering ability at all. There are studies showing if there is an overabundance of negative ions in the air, some people can have a feeling of well-being—they just feel better. On the other hand, these devices create a certain amount of ozone that other people find irritating. 87. Didn’t NASA find that house plants could clean the air naturally? Again, yes and no. In the 1980s, NASA performed a fairly simple experiment. They placed a house plant inside a sealed chamber with a certain amount of formaldehyde. Then, after waiting a while, they measured the concentration of the
