Smart City

Smart City Sentinel

It's Time to Take Action to Improve Air Quality in Schools

By Special Guest
Terrence DeFranco, CEO and President of Iota Communications

As a parent and concerned citizen, it is obvious that the health and comfort of students and teachers are important factors that contribute to learning and productivity in the classroom, which in turn affect performance and achievement.

The National Center for Educations Statistics surveyed a sample of school districts six years ago and estimated that the average age of the nation’s main school buildings was 55 years old – putting the average date of construction for our nation’s schools at 1959. Additionally, the EPA reports that nearly one-fourth of the nation’s schools have at least one building in need of repair and maintenance, and almost half experience problems with indoor air quality.

Nearly one in five schools nationwide has at least one schoolroom with a radon level above the EPA action level of 4.0 pCi/L (picoCuries per liter). The EPA estimates that more than 70,000 schoolrooms in use today have high radon levels. Why are high radon levels bad? When students and teachers breathe in radon, radioactive particles from radon gas can get trapped in their lungs. Over time, these radioactive particles increase the risk of lung cancer.

Major indoor air pollutants in schools, as well as many commercial buildings are radon, mold, volatile organic compounds, carbon monoxide and dust particles.

Radon forms as the result of uranium in soil or rock breaking down; it can also be released from building materials, such as granite. Mold grows as a result of high indoor humidity, and is known to be common in schools and office buildings. Volatile organic compounds (VOCs), or organic chemicals emitted as gases from products or processes, can come from things like cleaning agents, disinfectants, air fresheners, dehumidifiers, carpet, flooring material, and even furnishings. Carbon monoxide (CO) arises from generators, poorly maintained boilers or furnaces, automobile exhaust from nearby idling vehicles, and more. Dust particles can be produced by lead-based paint, vacuuming, fireplaces, cigarette smoking, or other activities.

The EPA, ASHRAE (American Society of Heating, Refrigerating, and Air-Conditioning Engineers), and LEED (Leadership in Energy & Environmental Design) are in agreement on indoor air quality parameters.

Measuring the Quality of Indoor Air
The presence of particular pollutants—including carbon monoxide, particulate matter (dust), VOCs, humidity, radon, and more—can be detected using Internet of Things (IoT) sensors. Placed strategically throughout a school, sensors take frequent, real-time samples of the air in every area where they are located.

The foundation of sensor technology, MEMS (microelectromechanical systems), is what makes this kind of measurement possible. They translate the concentration of molecules of various substances in the air along a gradient; IoT devices typically use 0–5 volt or 4–20 milliamp (mA) signal. In the case of 0–5 volt, “0” represents the lowest possible measurement, while “5” represents the highest; the sensor is calibrated to the finest increments of that output, so it can relay actual conditions in a way that can be interpreted by the user. Real-time indoor air quality conditions can be viewed on a dashboard, and threshold alerts can be set at certain measurements to alert you when conditions are outside the acceptable range. You can also look back at your readings over time to see patterns and determine potential causes.

Sensor Placement
Sensors are typically placed throughout a school building in the common areas, usually not directly located near induction units, floor fans, or personal heaters, and out of direct sunlight. A wall mount is best, as floors and ceilings may not be indicative of the actual environment.

When mounting a wall sensor, consider the height at which they should be placed. Most commonly they are mounted at height-level or slightly lower, if people primarily remain seated in that particular area. However, the molecular weight of some substances makes them gravitate toward the floor or ceiling; depending on what pollutant you’re trying to track you’ll need to place the sensor accordingly. For example, as you can see on the chart below, methane is lighter than air and so the highest concentrations inside buildings are usually near the ceiling. Conversely, ozone is heavier than air and remains near the floor.

Ventilation Critical to Safe Indoor Air Quality
Ventilation plays an important role in indoor air quality. According to the EPA, ventilation is a “combination of processes which results in the supply and removal of air from inside a building.” Those processes include bringing in outside air, conditioning it and mixing it with indoor air, distributing that air throughout the building, and moving some portion of indoor air outside. If one or more of these processes are underperforming, the quality of indoor air will be affected.

Many commercial academic buildings use mechanical ventilation—fans and ductwork—that are part of the heating and HVAC systems. Some buildings can also utilize natural ventilation by opening doors or windows. The “ventilation rate” is the amount of outdoor air introduced into a space per a unit of time, and is often expressed in cubic feet per minute (cfm).

Temperature/Humidity Levels
Temperature and humidity are considered important elements of air quality by the EPA, in part because of comfort. But too-high temperature and humidity levels have other consequences as well. Mold can begin to form as a result of high humidity; also, the rate at which chemicals are released from building materials is usually higher at higher building temperatures.

Indoor temperatures are sometimes more challenging to control than they seem due to factors such as heat gains from sunlight, outdoor conditions, and the outdoor air ventilation rate. ASHRAE recommends temperatures ranging from 68.5 to 75 degrees Fahrenheit in the winter, and from 75 to 80.5 degrees in the summer; indoor relative humidity should be maintained at or below 65 percent. The EPA recommends humidity levels of between 30 percent and 60 percent to reduce mold growth.

There is no single prescribed method for improving a school’s indoor air quality. The approach each institution should take may depend on a number of factors, including the individual building(s), the outdoor environment, and the extent of the problem.

Sometimes a temporary indoor air quality problem is created simply by a one-off, out-of-the-ordinary activity taking place inside a room or building, such as an overcrowded meeting area. In those cases, a short-term fix may be all that’s needed, such as opening a window or bringing in a fan. But more complex issues—identified by consistently unacceptable air quality monitoring results—will require a different tack. Depending on the issue the school is experiencing, getting an IoT reading may be appropriate.

Keep in mind that the right approach to addressing the issue isn’t always clear at the outset; therefore, it may be helpful to deploy more sensors to get a better understanding of the problem before investing time and resources in attempting to solve it.

About the author: Terrence DeFranco is CEO and President of Iota Communications, Inc, a wireless network carrier and software service company providing Internet of Things (IoT) solutions that optimize energy efficiency, sustainability and operations for commercial and industrial facilities. He can be reached at [email protected]

Edited by Ken Briodagh

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