Tuesday, November 3, 2009

Indoor air quality

Via Stef '06 at the DEP:

In Our Back Yard; Cleaning Up Indoor Air
Will an air purifier help me?
Many people these days are worried about the quality of air in their homes or offices.  Many of these people try to make their air better with air purifiers or air cleaners.  Unfortunately, this may not help.  Here’s why.
Many air purifiers or air cleaners are really ozone generators.  These usually claim they “make your air smell as fresh as after a spring rain.”  Some advertise they “clean your air with ions,” or that “charged plates pull the particles from your air.”  The idea of these devices is that they either cause the pollutants in the air to become oxidized (and theoretically less harmful); or they make the contaminants become electrically charged so they will stick to ‘charged plates,’ filters, or anything else that can have a static electrical charge- like a TV screen, walls, carpet, or hair.
As the name says, ozone generators make ozone, which everyone knows is harmful when made by pollution outdoors.  The ozone from air cleaners/purifiers is the same ozone, but is made by an electrical charge instead of a chemical reaction.  It takes a lot of ozone to “clean” the pollutants out of indoor air, but it does not take too much ozone to hurt people.  This means that an air cleaner/purifier that ‘cleans’ the air is making enough ozone to be harmful, and one that doesn’t harm people doesn’t really ‘clean’ the air.  A side effect of using ozone to clean the air is that the by-products made when ozone reacts with things in air are often more dangerous than the original pollutant.
So what should you do?  The best thing to do is reduce or remove the source of your air quality problem.  For many people, it means cleaning your house differently or with different products.  For example, use better vacuum cleaner bags, which don’t let as much dirt and dust escape when vacuuming.  This means buying the packages of 3 bags for $10, instead of the packages of 10 bags for $3.  Damp mop the floor instead of sweeping, to keep dust down.  Use cleaning products that advertise low fumes, or no fragrance, because the fumes and smells can bother people.  Mold problem?  Find and fix the water problem that let the mold grow, then remove the mold or mold-contaminated materials.  Stop mold from starting by drying up water leaks, spills, etc. in less than 48 hours.  Not sure what the problem is?  Play detective.  The source of many problems is not too hard to find.  It is usually easier to stop the problem than it is to deal with it once it happens.
If you feel you really need an air cleaner, consider one that only filters air.  And make sure you change the filters!  For more information on air purifiers, or how to find what your air quality problem might be, go to this federal Environmental Protection Agency website at http://www.epa.gov/iaq/, or the Maine Indoor Air Quality Council at www.miaqc.org .
This column was originally submitted in 2003 by Bob Stilwell, the Radon Section Leader at Maine CDC.  In Our Back Yard is a weekly column of the Maine Department of Environmental Protection.

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