by David Story, P.E., LEED AP
The United States Environmental Protection Agency (EPA) reports that approximately 50 percent of schools have poor indoor air quality (IAQ), mostly due to the age and poor condition of school buildings. The EPA promotes adopting IAQ best practices to create a healthy learning environment. Studies have shown adequate ventilation with filtration and thermal comfort improves test scores, reduces absenteeism, and enhances student and staff productivity.
Good indoor air quality (IAQ) management controls airborne pollutants, incorporates filtered outdoor air into the building, and maintains acceptable temperature and humidity levels. It contributes to a favorable environment conducive to student learning. Without it, bad indoor air quality can reduce student and staff performance and have a negative impact on attendance.
Health problems from poor IAQ include:
- Irritation of the eye, nose, throat, and/or skin
- Allergic reactions
- Shortness of breath
- Sinus congestion
What causes IAQ to be bad?
Reducing or blocking the flow of fresh air into the building reduces the quality of IAQ. A major source of indoor air pollution is chemical emissions from furnishings, building materials, and cleaning supplies. These pollutants, commonly referred to as volatile organic compounds (VOCs), can trigger asthma, allergies, and headaches. Maintaining the ventilation rate is important to ensure the systems work correctly to incorporate fresh air instead of recirculating poor quality air.
Commons causes of poor IAQ include:
- System installed incorrectly
- Air dampers closed to conserve energy and not reopened
- Lack of proper maintenance caused an imbalance and prevented the system from operating properly
- School cleanings when the system is turned off increased the amount of VOCs
IAQ Best Practices
- Displacement ventilation systems improve air quality and reduce energy consumed by only ventilating the occupied zone. A displacement diffuser incorporates fresh outdoor air with overhead air to create neutral air close to the desired room temperature, taking less energy to heat or cool. The process benefits from stratification – hot at the ceiling, cool at the floor – and gently ventilates at floor level as opposed to a traditional system which requires great amounts of air to be heated or cooled and dispersed via overhead air distribution.
- Occupancy sensors control ventilation and energy usage. Sensors utilize ultrasonic and infrared waves to detect empty rooms and pause the air ventilation system. Demand control ventilation is especially helpful in a school setting during events such as school-wide assemblies. With the students in the gym or auditorium, the systems automatically conserve energy by not ventilating the vacant classrooms.
- Carbon dioxide sensors maintain indoor air quality by monitoring appropriate levels. Ventilation is automatically adjusted to keep air quality optimized. This is especially important near areas where waiting buses release toxic fumes.
- Radiant flooring enhances thermal comfort by providing even heat distributed across the room. Plastic tubing placed within the concrete of the floor requires less heat. It heats the surface to 80 degrees which radiates into the air, as opposed to conventional systems which heat thin tubing around the bottom perimeter of the wall to 180 degrees and then blow hot air into the room.
Investing in a quality IAQ management system is an investment not only in your building, but in your students and staff. It makes the health and comfort of building occupants a priority.