Comparative risk studies performed by EPA and its Science Advisory Board has consistently ranked indoor air pollution among the top four environmental risks to the public. Children are especially susceptible to air pollution. For this and the reasons noted above, air quality in schools is of particular concern. Good indoor air quality contributes to a favorable learning environment for students, productivity for teachers and staff, and a sense of comfort, health, and well being for school occupants. If pollutant sources are not controlled IAQ problems can occur, even if the HVAC system is working properly.
Air pollutants consist of numerous particles, fibers, mists, molds, bacteria, and gases.
It may be helpful to think of air pollutant sources as fitting into one of the categories in the table shown below. In addition to the number of potential pollutants, indoor air pollutant levels can vary within the school building, or even a single classroom. Pollutants can also vary with time, such as only once each week when floor stripping is done, or continuously such as when fungi is growing in the HVAC system. The effects of IAQ problems on occupants are often vague symptoms rather than clearly defined illnesses. Because people are different, one individual may react to a particular IAQ problem while surrounding occupants have no noticeable ill effects.