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Did you know that indoor air can be more polluted than outdoor air in a big city? This is especially true for schools. In fact, the American Lung Association notes that a typical school packs in four times as many occupants per square foot than an office building. Because occupied classrooms are especially prone to high concentrations of potentially harmful volatile organic compounds (VOCs), proper ventilation is critical when maintaining healthy classroom air. Figure 1 shows the sources of the most common chemical groups of VOCs. In fact, unhealthy indoor air quality (IAQ) can cause students and teachers to suffer from a variety of building-related illnesses — sometimes called Sick Building Syndrome — characterized by headache, dizziness, nausea, cough, chills, difficulty concentrating, etc. Poor IAQ also has financial implications, as student absences can result in decreased government funding and teacher absences can result in higher expenses. Fortunately, an increase in ventilation of just one-cubic-foot per minute can decrease absentee rates by up to two percent.
Just as poor air quality has many negative effects, good air quality improves students’ ability to learn. A study by the Indoor Air Quality Scientific Findings Resources Bank reported that student performance increased between five and ten percent when the room’s ventilation rate was doubled. A separate report revealed that students in classrooms with more fresh air scored 14 to 15 percent higher on standardized test scores compared to students in classrooms with less ventilation.
Choosing the Right IAQ Monitor
Considering that a typical 700-square-foot classroom can exceed healthy thresholds for VOCs within minutes after students arrive (See Figure 2), it is important to monitor air quality. Traditional IAQ sensors use motion, light or heat to signal fans to activate. However, if an HVAC system responds to changes in environment rather than air quality by signaling fans to run more often than needed, it can increase energy costs. Another type of IAQ monitor measures the amount of carbon dioxide (CO2) in the room and signals the HVAC system to circulate fresh air when levels are exceeded. Unfortunately, CO2 sensors cannot detect odors or VOCs, like those from a lunchbox left in a desk over the weekend or gases emitted from old furnishings. A more effective alternative is IAQ monitors equipped with metal oxide semiconductor (MOS)-based sensors that detect a broad range of VOCs. These intelligent air quality (iAQ) sensors increase air flow by triggering the HVAC system to ventilate only when threshold air quality levels for VOCs are exceeded.
If school-wide IAQ monitoring isn’t in the district budget, facility managers can equip teachers with personal USB monitors, like AppliedSensor’s Indoor Air Monitor (Figure 3). Teachers simply plug the device into the
Action Items for Smart Schools
In addition to IAQ monitors, schools can help maintain healthy classrooms by eliminating the sources of VOCs — including carpet, paint, chalk, adhesives, art supplies, science laboratory equipment and more. The U.S. Environmental Protection Agency (EPA) advises school facility managers and designers to use cost-effective, durable products that protect both IAQ and aesthetic qualities. For example, classroom furnishings should be IAQ-safe products that are non-toxic, odorless, easy to clean/maintain and resistant to moisture damage or mold growth.
The EPA’s Tools for Schools program (available online at www.epa.gov/iaq/schools) includes a wealth of information written specifically for school facility managers, administrators, teachers and parents who want to improve the quality of air in their schools. A small investment of time and resources combined with an efficient indoor air monitor can ensure students and school personnel are breathing clean air in a healthy, productive environment.
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