Indoor Biological Pollutants

Biological pollutants are or were living organisms that promote poor indoor air quality. Biological pollutants can travel through the air, are often invisible, and may be a major cause of days lost from work or school, and of doctor and hospital visits. Some common indoor biological pollutants are:

Some of these substances are in every home. It is impossible to get rid of them all, and even a spotless home may permit the growth of biological pollutants. Two conditions are essential to support biological growth: nutrients and moisture. These conditions can be found in many locations, such as bathrooms, damp or flooded basements, wet appliances (such as humidifiers or air conditioners), and even some carpets and furniture (1). Surveys show that 30% to 50% of all structures have damp conditions which may encourage the growth and buildup of biological pollutants. This percentage is likely to be higher in warm, moist climates (1)

Allergic reactions may be the most common health problem associated with indoor air quality and biological pollutants. Allergies are often connected with such indoor pollutants as animal dander (mostly from cats and dogs), dust mites (microscopic animals living in household dust), and pollen. Allergic reactions can range from mildly uncomfortable to life-threatening, as in a severe asthma attack (1). Some common signs and symptoms are:

The following are some very informative external links that pertain to Indoor Biological Pollutants:

These are some informative external links that pertain to allergies:

EXTOXNET FAQS IndoorAir Pollution Home


1. The Consumer Product Safety Commission (CPSC) and the American Lung Association, Biological Pollutants in Your Home, March 1997. URL:

This Page prepared by B.T. Johnson, November 1997 UCD EXTOXNET FAQ Team.