Biological contaminants are living organisms or their derivatives such as bacteria, viruses, fungi, molds, mildews and house dust. They are often found in indoor environments where they can be easily transported in air. Some biological contaminants trigger allergic reactions and asthma. Infectious illnesses, such as influenza, measles, and chicken pox are transmitted through the air. Molds and mildews release disease-causing toxins. Risks from exposure to these contaminants can be reduced through proper ventilation and hygiene in the home. The EPA offers guidance on improving indoor air quality through its publications, outreach activities, hotlines and other resources.

Recommended EPA Web pages

• An Introduction to Indoor Air Quality: BIological Pollutants
  Biological contaminants include bacteria, molds, mildew, viruses, animal dander and cat saliva, house dust mites, cockroaches, and pollen.
• Mold Resources
  This page discusses how mold is produced and the associated risks to human health and property.
• EPA Microbiology Home Page
  Access to microbiology-related information that has been developed or managed by the Agency.

Air Pollutants
Aerosols, Asbestos, Carbon Monoxide, Chlorofluorocarbons (CFCs), Criteria Air Pollutants, Ground Level Ozone, Hazardous Air Pollutants (HAPs), Hydrochlorofluorocarbons (HCFCs), Lead, Mercury, Methane, Nitrogen Oxides (NOx), Particulate Matter (PM), Propellants, Radon, Refrigerants, Sulfur Oxides (SOx), Volatile Organic Compounds (VOCs)

Biological Contaminants

Carcinogens

Chemicals
Benzene, Chlorofluorocarbons (CFCs), Chromated Copper Arsenate (CCA), Dichloroethylene (DCE), Dioxins, Endocrine Disruptors, Ether, Ethylbenzene, Furans, Halons, Hazardous Air Pollutants (HAPs), Heavy Metals, Hydrochlorofluorocarbons (HCFCs), Inorganic Cyanides, Ketones, Methane, Methyl Bromide, Methyl Chloride, Methyl-T-Butyl-Ether (MTBE), Nitrogen Oxides (NOx), Organic Cyanides, Particulate Matter (PM), Perchloroethylene (PCE), Phthalates, Polychlorinated Biphenyls (PCBs), Radionuclides, Styrene, Sulfur Hexafluoride (SF6), Sulfur Oxides (SOx), Toluene, Trichloroethylene (TCE), Volatile Organic Compounds (VOCs)

Microorganisms
Coliform, Cryptosporidium, Viruses

Ozone

Radiation
Ionizing Radiation, Radiation Detection, Radiation Exposure, Radiation Protection, Radionuclides, Radon

Soil Contaminants
Acetone, Arsenic, Barium, Benzene, Cadmium, Chloroform, Cyanide, Lead, Mercury, Polychlorinated Biphenyls (PCBs), Tetrachloroethylene, Toluene, Trichloroethylene (TCE)

Toxic Substances
Persistent Bioaccumulative Toxic Pollutants (PBTs), Persistent Organic Pollutants (POPs), Toxicological Profiles

Water Pollutants
Arsenic, Contaminated Sediment, Disinfection Byproducts, Dredged Material, Lead, Microbial Pathogens