Some common indoor air pollutants include:

· Biologicals: Bacteria, mold, viruses, animal dander, pollen, dust mites. These are more likely to be a problem in buildings with high humidity, or water-damage.

· Carbon Monoxide: From unvented gas heaters; leaking chimneys or furnaces; gas stoves; automobile exhaust. Low levels can cause headaches, flu-like symptoms. High levels can be fatal.

· Respirable Particles: From fireplaces, wood stoves, kerosene heaters, and smoking.

· Organic Gases: From household products including: paints, paint strippers, and other solvents; wood preservatives; aerosol sprays; cleansers and disinfectants; moth repellents and air fresheners; stored fuels and automotive products; hobby supplies; dry-cleaned clothing.

· Formaldehyde: Usually from pressed wood products (hardwood plywood paneling, particle board, fiberboard) and furniture made with pressed wood products; or urea-formaldehyde foam insulation.

· Pesticides: Products used to kill household pests, and lawn and garden products that may drift or be tracked into the house.