Most people are aware that outdoor air pollution can pose health risks, but many do not know that indoor air pollution can also have significant health effects. Environmental Protection Agency (EPA) studies of human exposure to air pollutants indicate that indoor levels of pollutants may be 2-5 times, and occasionally more than 100 times, higher than outdoor levels. These levels of indoor air pollutants may be of particular concern because most people spend about 90 percent of their time indoors. Perhaps the most sensitive of school building inhabitants are asthmatic children. Based on a 1997 National Health Interview Survey (CDC, 2001), it was estimated that 25.7 million people had been diagnosed with asthma by a health professional in their lifetime. That estimate increased to 26.3 million in 1998. The highest prevalence was seen in children 5-17 years of age, with 130.1 per 1,000 in 1997 and 135.0 per 1,000 in 1998 (CDC, 2001). Asthma accounts for an estimated 10.1 million lost school days annually (CDC, 2001).

Asthma Triggers Include
Allergic Reactions:	pollens, feathers, molds, animals, some Foods, house dust, latex
Infections:	Influenza, Pneumonia
Second Hand Smoke Cockroaches Emotional Stress & Excitement Vigorous Exercise Cold Air
Occupational Dust & Vapors:	plastics, grains, metals, wood, sulfur dioxide, auto exhaust, grains, ozone
Sleep (Nocturnal Asthma)
Household Products:	paint, cleaners, sprays, drugs, aspirin
Heart Medications
www.lungusa.org/asthma/astastrig.html

In recent years, comparative risk studies performed by EPA and its advisory board have consistently ranked indoor air pollution among the top five environmental risks to public health. Children may be especially susceptible to air pollution. The same concentration of pollutants can result in higher body burdens in children than adults because children breathe a greater volume of air relative to their body weight.

Over the past several decades, our exposure to indoor air pollutants has increased due to a variety of factors, including the construction and renovation of more tightly sealed buildings, reduced ventilation rates to save energy, the use of synthetic building materials and furnishings, and the use of personal care products, pesticides, and housekeeping supplies. In addition, our activities and decisions, such as deferring maintenance to "save" money, can lead to problems from sources and ventilation. Indoor air pollutants can originate within the building or be drawn in from outdoors. If pollutant sources are not controlled, indoor air quality (IAQ) problems can arise, even if the heating ventilation and air condition (HVAC) system is properly designed, operated, and maintained. Air contaminants consist of particles, dust, fibers, bioaerosols, and gases or vapors.

Indoor air pollutant concentration levels can vary by time and location within the school building, or even a single classroom. Pollutants can be emitted from point sources, such as science storerooms, or from area sources, such as newly painted surfaces. Also, pollutants can vary with time, such as only when floor stripping is done, or continuously, such as mold growing in the HVAC system.

Heating, ventilation, and air condition system design and operation can impact the temperature, humidity, and contaminant level in the building. The heating, ventilation, and cooling system includes all heating, cooling, and ventilating equipment serving a school: boilers or furnaces, chillers, cooling towers, air handling units, exhaust fans, ductwork, and filters. A properly designed and functioning HVAC system:

• Controls temperature and relative humidity to provide thermal comfort
• Distributes adequate amounts of outdoor air to meet ventilation needs of school occupants
• Isolates and removes odors and other contaminants through pressure control, filtration, and exhaust fans.

Not all HVAC systems are designed to accomplish all of these functions. Some buildings rely only on natural ventilation. Others lack mechanical cooling equipment, and many function with little or no humidity control.

Nurses are often the only health care providers in the school setting. School nurses are aware of the health status of the students and those with particular vulnerabilities. This knowledge and awareness places school nurses in a special position to make a link between health effects experienced by the school population and the environmental conditions within the school. School nurses have a tremendous opportunity to educate students, parents, and staff and provide resources regarding IAQ issues. By tracking and documenting symptoms, and association with particular rooms or areas in the school building, nurses can provide a crucial role in connecting health complaints to the school environment.

Indoor Air Quality problems are most likely to affect those with preexisting health conditions and those who are exposed to tobacco smoke. Student health records should include information about known allergies and other medically documented conditions, such as asthma, as well as any reported sensitivity to chemicals. Privacy considerations may limit the student health information that can be disclosed, but to the extent possible, information about students' potential sensitivity to IAQ problems should be provided to teachers. This is especially true for classes involving potential irritants (e.g., gaseous or particle emissions from art, science, or industrial/vocational education sources).