What is house dust?

Rather than a single substance, so-called house dust is a varied mixture of potentially allergenic materials. It may contain fibers from different types of fabrics; cotton lint, feathers, and other stuffing materials; dander from cats, dogs, and other animals; bacteria; mold and fungus spores (especially in damp areas); food particles; bits of plants and insects; and other allergens peculiar to an individual home.

House dust also contains microscopic mites. They live in bedding, upholstered furniture, and carpets, and they thrive in summer and die in winter. In a warm, humid house, however, they continue to thrive even in the coldest months. The particles seen floating in a shaft of sunlight include dead dust mites and their waste-products. These waste-products, which are proteins, actually provoke the allergic reaction.

Air Cleaning:

What methods can be used to control indoor air pollution?

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

Source Control: Eliminate or control the sources of pollution; although it is difficult to force pets outdoors, stop smokers and eliminate all odors.

Ventilation: Dilute and exhaust pollutants through outdoor air ventilation; in the winter however, venting to the outdoors may increase heating and energy costs.

Air Cleaning: Remove pollutants through proven air cleaning methods and products.

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.

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

The third approach -- air cleaning -- the best method is used to supplement source control and ventilation. Air filters, electronic particle air 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 air pollution including dust mites. These methods include eliminating or controlling pollutant sources, increasing outdoor air ventilation, and using proven methods of air cleaning.