What are the trends in indoor air quality and their effects on human health?
- Importance of Indoor Air Quality
- Pollutants and Sources
- Other Factors Affecting Indoor Air Quality
- Effects on Human Health
- ROE Indicators
Importance of Indoor Air Quality
“Indoor air quality” refers to the quality of the air in a home, school, office, or other building environment. The potential impact of indoor air quality on human health nationally can be noteworthy for several reasons:
- Americans, on average, spend approximately 90 percent of their time indoors,1 where the concentrations of some pollutants are often 2 to 5 times higher than typical outdoor concentrations.2
- People who are often most susceptible to the adverse effects of pollution (e.g., the very young, older adults, people with cardiovascular or respiratory disease) tend to spend even more time indoors.3
- Indoor concentrations of some pollutants have increased in recent decades due to such factors as energy-efficient building construction (when it lacks sufficient mechanical ventilation to ensure adequate air exchange) and increased use of synthetic building materials, furnishings, personal care products, pesticides, and household cleaners.
Pollutants and Sources
Typical pollutants of concern include:
- Combustion byproducts such as carbon monoxide, particulate matter, and environmental tobacco smoke.
- Substances of natural origin such as radon, pet dander, and mold.
- Biological agents such as molds.
- Pesticides, lead, and asbestos.
- Ozone (from some air cleaners).
- Various volatile organic compounds from a variety of products and materials.
Other Factors Affecting Indoor Air Quality
In addition, several other factors affect indoor air quality, including the air exchange rate, outdoor climate, weather conditions, and occupant behavior. The air exchange rate with the outdoors is an important factor in determining indoor air pollutant concentrations. The air exchange rate is affected by the design, construction, and operating parameters of buildings and is ultimately a function of infiltration (air that flows into structures through openings, joints, and cracks in walls, floors, and ceilings and around windows and doors), natural ventilation (air that flows through opened windows and doors), and mechanical ventilation (air that is forced indoors or vented outdoors by ventilation devices, such as fans or air handling systems).
Outdoor climate and weather conditions combined with occupant behavior can also affect indoor air quality. Weather conditions influence whether building occupants keep windows open or closed and whether they operate air conditioners, humidifiers, or heaters, all of which can affect indoor air quality. Certain climatic conditions can increase the potential for indoor moisture and mold growth if not controlled by adequate ventilation or air conditioning.
Effects on Human Health
Health effects associated with indoor air pollutants include:
- Irritation of the eyes, nose, and throat.
- Headaches, dizziness, and fatigue.
- Respiratory diseases, heart disease, and cancer.