Indoor air contaminants come in a variety of forms and originate from multiple sources. Interactions between building materials and furnishings, activities and equipment inside the building, internal temperature and relative humidity, filtration and ventilation system operations, climate and building occupants all contribute to the indoor air quality (IAQ) in commercial, industrial, residential and medical buildings. Poor IAQ can cause a number of health issues such as, allergies, dryness and irritation to the eyes, nose, throat, and skin. It can also cause headaches, shortness of breath, hypersensitivity, sinus congestion, coughing, sneezing, nausea, and dizziness. Sick employees are less productive, more likely to be absent from work and can amount to a considerable cost to the employer.
Depending on the type of building, the main causes of poor indoor air quality are different. For residential homes, carbon monoxide, pet dander, dust mites and mold spores are some common contributors. In recreational centers with arenas and swimming pools, there is the possibility of ammonia, carbon monoxide, chlorine and ozone leaks and/or carbon dioxide build-up. For public places like shopping malls, grocery stores, airports, hospitals and parking garages the main concerns are carbon monoxide and nitrogen dioxide gases from gas and diesel engine exhaust in vehicle parking areas or potentially being drawn indoors from improperly operating ventilation equipment or delivery vehicles left running while parked close to large building air intakes.