National studies have shown that air pollution in our homes can be more of a health concern than air pollution outside. Indoor pollutant levels may, in fact, be many times higher than outdoor levels. There are three main reasons why indoor air quality is becoming more of a health concern:
- Compared to many years ago, we spend more time indoors. In the U.S., it is estimated that people today spend up to 90% of their time indoors.
- There has been a large increase in the use of human-made building materials and furnishings, as well as household cleaning, personal care, and pesticide products that contain chemicals.
- Over the past few decades, homes and other buildings have been made “tighter” to save on energy use and costs.
An indoor air pollutant is a substance in the air that may affect the health of people who live in the home. Pollutants could come from outside the home—such as an idling car engine in an attached garage, backyard trash burning, or radon entering the house from the ground below. An air pollutant could also come from inside the home—such as carbon monoxide from a faulty furnace, volatile organic compounds (VOCs) from a freshly painted room, secondhand smoke, mold growing on damp or wet carpeting, or chemicals from hobbies, household cleaning, or personal care products. Bacteria and viruses, pet dander, and insect parts (dust mites or roaches) are other possible indoor air pollutants.
Breathing air pollutants can lead to allergic and asthmatic reactions, infections and other health problems that involve the lungs, nose and throat. For example, pet cats, caged birds and rodents, and dogs can produce dander and other particles that can trigger allergic reactions or asthma symptoms in some people. Secondhand smoke is also harmful to people, especially children.
Exposure to other indoor air pollutants—such as carbon monoxide—can result in headaches, nausea, vomiting, brain damage, and even death. Breathing air with radon increases a person's risk of getting lung cancer. Exposure to VOCs may affect the lungs, brain, and nervous system.
The possible health effects depend on the amount of the pollutant breathed in, the length of time the person is exposed, family history, and age and general health of the person. Babies and young children may be especially sensitive, in part because their organs and immune systems are not fully developed. Older people may also be more sensitive to certain pollutants.