By-products of combustion (such as CO, CO ₂ , NO _x )

Unvented kerosene and gas heaters, gas appliances, wood- and gas-burning fireplaces, leaking chimneys and furnaces, tobacco smoke, automobile exhaust in attached garages

Eye, nose, and throat irritation, impaired lung function and respiratory function in children, bronchitis, lung cancer, flu-like symptoms.

Environmental tobacco smoke

Cigarettes, cigars, pipes

Eye, nose, and throat irritation, headaches, pneumonia. Increased risk of respiratory and ear infections in children. Lung cancer and increased risk of heart disease.

Formaldehyde

Pressed wood products (hardwood, plywood wall paneling, particleboard, fiberboard) used in buildings and furniture, urea-formaldehyde foam insulation, permanent press textiles, glue, ETS, vehicle exhaust, stoves, fireplaces

Eye, nose, and throat irritation, coughing, fatigue, rashes, and allergic reactions. Causes cancer in animals. Death at very high concentration.

Other volatile organic compounds

Paints, solvents, wood preservatives, aerosol sprays, cleaners and disinfectants, moth repellents, air fresheners, hobby supplies, and dry cleaned clothes

Eye, nose, and throat irritation, headaches, loss of coordination; nausea, damage to kidney and central nervous system. Some cause cancer in animals. Some may cause cancer in humans.

Radon

Local geology, soil, water

Lung cancer, possibility of stomach cancer

Pesticides

Garden and lawn chemicals, poisons for pest control

Eye, nose, and throat irritation, damage to central nervous system and kidney, cancer