What health issues can be caused by poor IAQ?

Health effects from indoor air pollutants fall into two categories:

• Those that are experienced immediately after exposure, and
• Those that do not show up until years later.

Immediate effects, which may show up after a single exposure or repeated exposures, include irritation of the eyes, nose, throat, headaches, dizziness, and fatigue. Immediate effects are usually short-term and treatable. Sometimes, the prescribed treatment is to simply eliminate the person’s exposure to the source of the pollution, if the source can be identified. Symptoms of some diseases, such as asthma, can show up soon after exposure to some indoor air pollutants.

The likelihood of an individual developing immediate reactions to indoor air pollutants depends on several factors, such as age and pre-existing medical conditions. In other cases, whether a person reacts to a pollutant can be determined by individual sensitivity, which varies from person to person. Some people can become sensitized to biological pollutants (i.e., molds, mildews) after repeated exposures, and it appears that some people can become sensitized to chemical pollutants (i.e., carbon monoxide, nitrogen oxide) as well.

Other health effects may show up either years after the exposure has occurred, or only after long or repeated periods of exposure. The consequences of these types of exposures can include respiratory diseases, heart disease, and cancer.

While pollutants commonly found in indoor air can be responsible for many harmful effects, there is considerable uncertainty about what concentrations or periods of exposure are necessary to produce specific adverse health effects. Further research is needed to better understand which health effects can occur after exposure to the low-level pollutant concentrations, as well as higher-level concentrations.