Department of Health and Human Services

Schools

Why is indoor air quality important in schools?

According to a 1995 U.S. Government Accounting Office report, an estimated 50 percent of the nation's schools have problems linked to poor indoor air quality (IAQ). With nearly 55 million people, or 20 percent of the U.S. population, spending their days inside elementary and secondary schools, IAQ problems in schools are a significant public health concern. All types of schools-whether new or old, big or small, elementary or high school-can experience IAQ problems. Poor IAQ in schools can be associated with many issues, including but not limited to moisture and mold growth, combustion pollutants such carbon monoxide, volatile organic chemicals/compounds, and radon.

For details and guidance on IAQ issues in schools, see the U.S. Environmental Protection Agency's (EPA) Healthy School Environments and Indoor Air Quality Tools for Schools. For information regarding the impact of indoor air quality on student performance, refer to US EPA: Indoor Air Quality and Student Performance.

Sources of Indoor Air Pollutants

Over the past few decades, concern about indoor air pollutants has increased. Contributing to poor indoor air quality are construction of more tightly sealed buildings, reduced ventilation rates to save energy, the use of synthetic building materials and furnishings, and increased use of chemical products such as pesticides, housekeeping supplies, and personal care products. The four basic factors affecting IAQ are indoor air pollutant sources; heating, ventilation, and air-conditioning (HVAC) systems; pollutant pathways; and occupants.

Typical sources of indoor air pollutants and conditions that can have an impact on IAQ in schools:

• Moisture and biological/microbial agents
• Heating, Ventilating & Air Conditioning (HVAC) Systems
• Temperature and Humidity Control
• Humidity and Microbial Growth
• Combustion Products
• Volatile Organic Compounds
• Radon
• Pesticides
• Environmental Tobacco Smoke
• Asbestos
• Lead-Based Paint
• Information on Indoor Air Quality Program for Schools
• Some Notes on Asthma

Moisture and Biological/Microbial Agents:Moisture problems in buildings can result in the growth or amplification of biological/microbial organisms such as mold, mildew, dust mites, and bacteria. Exposure to these organisms can increase risk of allergic illness, trigger asthma, foster respiratory infections, or cause other health effects. Typical sources of moisture include structural leaks, plumbing leaks, flooding, and HVAC-related humidity control problems.

For detailed information on moisture and biological/microbial growth:
NC DHHS: School Mold Letter (PDF)*
NC DHHS: Mold and Human Health
US EPA: Biological Contaminants
US EPA: Mold/Moisture/Mildew
US EPA: Managing Asthma in School Environments
Minnesota Department of Health: Investigating Mold in Public Schools

Heating, Ventilation & Air Conditioning (HVAC) Systems: HVAC systems should be designed to meet the needs of a specific building based on its design, use, and occupant activities. The HVAC system should filter the air, heat or cool as necessary, and control relative humidity during the cooling season. Some systems also introduce outdoor air during this process to dilute building contaminants. After all these actions take place, the tempered air is then circulated throughout the structure. A poorly maintained HVAC system can allow water to build up in the unit, creating conditions where the system itself can become a reservoir for biological contaminants. Inadequate systems can fail to remove moisture from the air, creating conditions in which mold and mildew can grow. For these reasons, it is very important that HVAC systems be inspected on a regular basis to ensure that the systems are clean and functioning properly.

For more information:
US EPA: Fact Sheet: Ventilation and Air Quality in Offices

Temperature and Humidity Control: Temperature and humidity are two of the most important indicators of a building's IAQ. They are also extremely important to the occupant's perception of IAQ. Achieving thermal comfort (acceptable temperature and humidity conditions) for all occupants is a difficult, if not impossible, task. The American Society of Heating, Refrigeration, and Air-Conditioning Engineers (ASHRAE) has published recommended standards for thermal comfort parameters. Maintaining a building within the following ranges of temperature and relative humidity will satisfy the thermal comfort requirements of most occupants.

Humidity and Microbial Growth: In addition to thermal comfort, the control of relative humidity is important to limit the growth of microorganisms such as mold and dust mites. To control microorganisms, it is best to keep relative humidity below 60% (to control mold) and 50% (to control dust mites) at all times, including unoccupied hours. High relative humidity can foster proliferation of mold and dust mites.

Combustion Products: Carbon monoxide, nitrogen oxides, particulates, and other pollutants can create serious IAQ problems in buildings. A few examples of combustion pollutant sources are unvented fossil-fuel (oil, kerosene) heaters, unvented gas stoves and ovens, and back-drafting and malfunctioning furnaces and water heaters. From an acute hazard standpoint, carbon monoxide is a deadly gas that kills over 200 people year in the United States. Other pollutants such as nitrogen oxides can cause breathing problems, particularly in sensitive individuals, and can trigger asthma attacks. To ensure that combustion pollutants do not create IAQ problems, the following steps should be taken:

1. Vent all potential sources outside the building.
2. Conduct regular maintenance and inspection of all systems.

For details on combustion products/pollutants:
US EPA: Respirable Particles/Combustion Products
US EPA: Carbon Monoxide (CO)

Volatile Organic Compounds: Volatile organic compounds (VOC) are emitted from paints, solvents, building materials, air fresheners, dry-cleaned clothing, aerosol sprays, adhesives, fabrics, and many more sources. In fact, indoor air may contain several hundred different VOCs. Some of these VOCs can cause eye, nose and throat irritation; headaches; loss of coordination; nausea; and damage to the liver, kidneys, and central nervous system. Some of these chemicals can cause cancer in animals; some are suspected or known to cause cancer in humans. One of the more common VOCs found indoors is formaldehyde. Formaldehyde is an important chemical used widely by industry to manufacture building materials and numerous household products.

For additional details on VOCs, including sources, health effects, and control methods, see:
Formaldehyde in Mobile Classrooms (N.C. DHHS) (PDF)*
US EPA: Organic Gases (VOCs)
US EPA: Formaldehyde
US CPSC: Update on Formaldehyde
California Air Resources Board: Reducing Formaldehyde in Schools

Radon: Radon is a naturally occurring, gaseous radioactive element having the chemical symbol Rn. Radon is harmlessly dispersed in outdoor air, but when trapped in buildings, it can be harmful, especially at elevated levels. This radioactive gas can seep into buildings from soil and rocks beneath and around the foundation of the structure. There are no immediate symptoms from radon exposure. However, long-term radon exposure has been linked to between 7,000 and 30,000 lung cancer deaths each year. Lung cancers usually occur years (5-25) after exposure. Smokers are at higher risk of developing radon-induced lung cancer. In North Carolina, the radon program is administered by the Radiation Protection Branch of the Department of Environment and Natural Resources.

For detailed information on testing, health effects, and control methods, see:
NC DENR: Radon In North Carolina Schools
US EPA: Radon
US EPA: Radon in Schools

Pesticides: Pesticides used in and around schools can cause IAQ problems. One of US EPA's top initiatives over the last several years is to assure that children are protected from potential pesticide exposure, particularly in homes and schools. To minimize potential pesticide exposure in schools, the use of integrated pest management (IPM) is encouraged. IPM is an effective and environmentally sensitive approach to pest management that relies on a combination of common-sense practices.

See the following for details on pesticides and IPM programs:
US EPA: Integrated Pest Management in Schools
National Pesticide Information Center
National IPM Network (North Carolina): North Carolina Pest Management Information
NC Department of Agriculture & Consumer Services: Structural Pest Control Division
NC Department of Agriculture & Consumer Services: Pesticide Section
University of Florida: School IPM

Environmental Tobacco Smoke (ETS): Second-hand smoke, or environmental tobacco smoke (ETS), is a mixture of the smoke given off by the burning end of a cigarette, pip, or cigar, and the smoke that is exhaled from the lungs of the smoker. ETS can cause significant IAQ problems in buildings. ETS contains more than 4,000 chemical compounds, approximately 40 of which are carcinogens or suspected carcinogens. Secondhand smoke has been classified by the U.S. Environmental Protection Agency (EPA) as a known cause of lung cancer in humans (Group A carcinogen). Children who breathe ETS are more likely to suffer from ear infections, pneumonia, bronchitis and other lung diseases. ETS can increase the risk of asthma attacks in persons with asthma. For all these reasons, smoking should not be allowed in schools.

Additional information on smoking and ETS can be found at the following web sites:
NC DHHS: Tobacco Prevention and Control Branch
US EPA: Secondhand Smoke/ETS

Asbestos: Some building products used in schools may contain asbestos. If you have concerns about asbestos in your school refer to the NC DHHS web site, "Asbestos in North Carolina," for more information.

Lead-Based Paint: Lead-based paint may have been used in your school. Dust and particles from lead-based paint can cause adverse health effects, particularly in children. If you have concerns about lead-based paint, please refer to the NC DHHS web site, "Lead Poisoning in North Carolina."

Indoor Air Quality Program for Schools

The U.S. Environmental Protection Agency has developed "IAQ Tools for Schools," (TFS) a guidance program on how to develop an overall IAQ program for schools and school systems. The program includes a TFS Action Kit, training programs, and training/educational videos. For more information on the TFS program, see the EPA web site, Indoor Air Quality (IAQ) Tools for Schools.

Some Notes on Asthma:
A recent study of seventh- and eighth-graders in North Carolina found that 27% have asthma-like symptoms. According to the survey, students with asthma were reportedly more likely to smoke than their asymptomatic peers. Almost half of the children with asthma, and a third with wheezing, reported sleep disturbances. These children also limited their activities - such as sports, chorus, and other social interactions with friends - because of their breathing problems. They were 37 times more likely to miss school than their peers without asthma symptoms.

Based on Medicaid reimbursement rates, health experts estimate that costs for emergency room and hospital care for these 7th and 8th graders may be as much as $15.4 million over a one-year period. This sum does not include physician visits, prescription costs, or higher reimbursement rates of private insurers. Nor does it include days lost at work when a parent has to stay home with a sick child. When added with the costs associated with children in other age groups, North Carolina and its families are spending an estimated $100 million annually for asthma-related consequences and services for children.

For more information on asthma:
US EPA: Managing Asthma in School Environments
US EPA: Asthma and the Indoor Environment
American Lung Association of North Carolina

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