What Methods Can Be Used To Control Indoor Airborne Pollution?

The three most common approaches to reducing indoor airborne pollution are:

Source Control
The first approach -- source control -- involves minimizing the use of products and materials that cause indoor pollution, employing good hygiene practices to minimize biological contaminants (including the control of humidity and moisture, and occasional cleaning and disinfection of wet or moist surfaces), and using good housekeeping practices to control particles.

Ventilation
The second approach -- outdoor ventilation -- is also effective and commonly employed. Ventilation methods include installing an exhaust fan close to the source of contaminants, increasing outdoor airflows in mechanical ventilation units, and opening windows, especially when pollutant sources are in use.

Purifiers
The third approach -- airborne contaminant purification -- is the best method used to supplement source control and ventilation. Air filters, electronic airborne particle cleaners and ionizers are often used to remove airborne particles, and gas adsorbing material is sometimes used to remove gaseous contaminants when source control and ventilation are inadequate.

Recommendation
The public is advised to use proven methods of controlling indoor airborne pollution. These methods include eliminating or controlling pollutant sources, increasing outdoor air ventilation, and using proven methods of cleaning airborne contaminants .

Conclusions
Overall, the American Lung Association recommends that proven source control strategies be employed as a primary means of reducing exposure to pollutants. However, physical studies which do not measure health effects do show that certain airborne contaminant cleaners are effective in removing certain indoor airborne pollutants. Thus, as an adjunct to effective source control and adequate ventilation, highly efficient airborne contaminant cleaners can be useful in further reducing levels of certain indoor airborne pollutants. More research on the health benefits of air purifiers is needed to provide complete evidence that would better address the circumstances of intended use. Manufacturers, clinicians, government agencies, and private industries can all assist with providing and interpreting this research in order to better inform the public.

Based on the limited available data, we conclude that if allergen sources are present in a residence, airborne contaminant cleaning alone has not been proven effective at reducing airborne allergen-containing particles to levels at which no adverse effects are anticipated. Cats, for example, generally shed allergen at a much greater rate than purification systems can effect removal. Dust mites excrete allergens in fecal particles in sequestered environments (i.e., within the carpet or the bedding). For individuals sensitive to dust mite allergen, the use of impermeable mattress coverings appears to be as effective as the use of a laminar flow airborne contaminant cleaning unit above the bed. Source control should always be the first choice for allergen control in residences.