3 myths about clean indoor air

If microscopic air-borne particles of pollen, dust or pet dander make you sneeze or wheeze, filtering the air you breathe seems like a logical solution. Yet installing air filters and cleaning air ducts isn't as efficient as many people think. Here are some common held beliefs that you may need to rethink.

Advertisements proclaim air filters are "essential" for people with allergies to pollen, dust mites, mold spores and pet dander. It seems to make sense that removing these misery-producing bits from the air would bring relief, but here's the odd truth: there's scant proof that they ease most allergy and asthma symptoms. When Canadian doctors reviewed 10 air filter studies, they concluded filtered air didn't improve lung function, and showed only small improvements for symptoms like coughing, sneezing, watery eyes and runny noses. If you're a dog or cat lover with pet-dander allergies and you can't bear to part with your pet, an air filter may help. One study of 30 allergic pet owners found that two-thirds of those who installed HEPA filters in their bedrooms and living rooms needed less allergy medication.

These purport to work by attracting and trapping particles with positive or negative electrical charges. The high-voltage wire used to ionize air particles converts oxygen into ozone, a highly reactive molecule. Even in tiny amounts, ozone damages lung tissue and can cause throat irritation, coughing, chest pain and shortness of breath — something you don't need, especially if you have allergies or asthma.

Many duct-cleaning companies would have you believe you need a high-priced clean out of all air ducts because they are breeding grounds for the mold spores and dust that aggravate allergies and asthma.  That is not the truth. Duct cleaning has never been proven to prevent health problems. One study even found that, contrary to what duct cleaners claim, most of the ducts tested were virtually free of dust mites.  The project could actually stir up dust rather than cleaning the air unless the vacuum equipment used to clean ducts is vented to the outdoors or uses a HEPA filter.

Having allergies can be a struggle, but it's important to know what steps will help you and which could end up doing more damage.