What comes to mind when you hear the words "air pollution?" Chances are you conjure up visions of industrial smoke stacks and herds of automobiles on exhaust-choked highways. While those associations no doubt ring true, the vision that air quality experts say should really come to mind is of our own living rooms.

That's because the air inside our homes is likely to be more polluted than the air outdoors. In fact, according to the EPA, levels of airborne contaminants in the average residence are typically two to five times higher than they are just outside its walls. It's a situation that comes as a surprise to most people, and it's created by two fundamental factors: the fumes, gases, particles, and other contaminants that are released by the products and devices of modern life, and today's energy-efficient construction techniques, which keep heated and cooled air from escaping but also keep air pollution trapped inside.

Hundreds of different indoor air pollutants have been identified by researchers. The silver lining to that unhealthy cloud is that there is a much shorter list of things we can do to keep contaminants out of our homes. Here's how your family can enjoy a breath of fresh indoor air:

• It may sound counterintuitive, but your air will be cleaner if you don't use air fresheners and room deodorizers, which typically fill your home with chemicals that simply cover up bad odors.
• Don't use synthetic chemical cleaning products, which leave airborne micro-droplets behind as they're used. Make your own cleaners or opt for those that use non-toxic and naturally-derived ingredients.
• When you clean, use a damp cloth that attracts and removes dust to avoid stirring contaminants back into the air.
• Carpets and rugs tend to collect indoor pollutants. Vacuum these furnishings at least once a week, preferably with a filtering vacuum cleaner, and give them an occasional shampoo.
• Use chlorine-free dishwasher detergent. Studies have shown that hot dishwasher water can turn the chlorine commonly found in dishwasher detergents into a gas that's released during the cleaning cycle.
• When you have an item cleaned by a conventional dry cleaner, dissipate lingering chemicals by removing it from the bag and airing it out in the garage or other exterior space before you bring it inside.
• Buy furniture and furnishings made from solid wood and not plywood or pressed particleboard, which use glues that emit formaldehyde and other chemical fumes as they age.
• Have your furnace, non-electric water heater, and/or wood stove inspected to make sure they're venting waste gases properly. Gas-burning ranges and stoves should also have some kind of working ventilation.
• Dust mites, a key cause of allergies and asthma, thrive in warm, moist environments. Keeping your home's humidity level below 60% will keep their numbers low.
• Ban pesticides, smoking, mothballs, and perfumes and colognes from your home. These are some of the biggest sources of indoor air pollution in the typical home.
• Store any chemical products your home contains away from living spaces; in the garage or a shed.
• Test your home for radon using a long-range test kit that checks air over the course of several seasons.
• Get some houseplants, which act as natural air filters. Hard-working choices include Boston fern, areca palm, lady palm, bamboo palm, rubber plant, English ivy, ficus, and peace lily.
• Last but not least, open your windows once in awhile and let fresh air in and rinse polluted air out. This is the single most effective strategy you can adopt. And it's the least expensive, too!

photo: Michael Gallacher