Parents need to be aware of the air quality in their children’s classrooms. Before the 2020s, air quality in schools wasn’t a mainstream topic. But now, after a pandemic, experts are taking a closer look into what students are breathing.1  

It’s worth noting that children spend a considerable amount of their time inside schools.2 There, indoor air quality (IAQ) makes a huge impact on learning and well-being.3 As such, parents should be aware of what their children are breathing.  

Why is school air quality important? 
Classrooms don’t run efficiently when everyone is unhealthy from breathing bad air. Exposure to low-quality and poorly ventilated spaces exposes kids to carbon dioxide (CO₂), volatile organic compounds (VOCs), and particulate matter (PM). Headaches, asthma flare-ups, allergies, and respiratory illnesses coincide with sleepiness, dizziness, nausea, and other issues you wouldn’t want anyone to experience, especially during class.  

Furthermore, children are particularly susceptible to air pollution. Their smaller bodies are still developing, and they breathe larger quantities of air relative to their size than adults do. Then, there are usually a bunch of kids packed into the same classroom. Then, a lot of schools are older buildings with outdated heating, ventilation, and air conditioning (HVAC) systems. If machinery is poorly functioning or in need of repair/filter replacement, air quality will suffer.4  

It’s time to W.A.T.C.H. air quality 
So, IAQ is important. But it can only be helped when students and educators are aware of what air quality is and how to improve conditions when they deteriorate.  

To help people remember the importance of air quality, engineer and editor Joey Fox created the W.A.T.C.H. acronym: W for windows, A for air movement, T for thermostat, C for CO₂ levels, and H for HEPA filter (and Corsi-Rosenthal box).5 This simple tool includes tips that kids can use to breathe better.

It’s true. Opening windows is arguably the simplest method to ventilate a space effectively. This practice is even more effective when nearby doors are also – this way, a crosswind can form. However, there are situations where external factors like extreme weather or pollution make this impractical. If conditions permit, it is advisable to crack the windows whenever possible. A little ventilation goes a long way toward improving IAQ.

Air movement 
It’s very common for classrooms to have some sort of heating, ventilation, and air conditioning (HVAC) system installed. However, it can be difficult for kids to tell if air is flowing through the ducts. For an easy answer, they can tie a string or ribbon around the vents. If the string moves, things are good. If not, it’s possible things are switched off or broken. In this case, it’s a good idea to draw attention to this problem. Ventilation should always be flowing within classrooms.  

While these devices are most frequently used to regulate temperature, they have other useful settings. Here’s the thing: They’re often switched to automatic. This activates fans only when heating or cooling is needed, it won’t activate and ventilate otherwise. Automatic is fine for unoccupied rooms but try turning on a fan whenever inside.  

Carbon dioxide levels 
CO₂ is a naturally occurring gas that is a direct indicator of a room’s air quality. However, whenever many people gather indoors, the CO₂ they produce can build up without ventilation. According to the Centers for Disease Control and Prevention (CDC), the amount of CO₂ in a room above 800 parts per million (ppm) indicates a need for ventilation.6 For reference, fresh outside air usually hovers around 420 ppm. 

While CO₂ is harmless in small doses, high levels can cause drowsiness, fatigue, and poor cognitive performance.7 Furthermore, significant concentrations mean that people are rebreathing air that has already been exhaled. This increases the likelihood of airborne virus transmission.8  

To know if CO₂ is reaching problematic levels, some form of monitoring device is required. We recommend the Aranet4 HOME. This wireless device automatically tracks CO₂, humidity, temperature, and atmospheric pressure in real-time. They’re so user-friendly that many schools have already adopted them.9 

HEPA filters or Corsi-Rosenthal box 
Air filtration devices play a direct role in improving IAQ. They do so by removing airborne particles and pollutants, making nearby environments healthier and more comfortable. Many different high efficiency particulate air (HEPA) filtered systems are available in the market, offering a wide range of options at varying prices. 

On the other hand, Corsi-Rosenthal boxes can be constructed as do-it-yourself (DIY) projects. However, it’s essential to be mindful of their noise, as some Corsi-Rosenthal boxes are disruptively loud. When operating on low settings, they produce less noise. However, running on low means they won’t filter the air as effectively. To make up for this, multiple devices can be used. 

Moving forward 
In conclusion, as parents, it’s essential that we prioritize children’s well-being and the air they’re exposed to in school. By using the W.A.T.C.H. acronym, we can empower kids to be more aware of air quality, understand its impact, and know how to improve conditions. Together, let’s work to create a healthy, safe environment for all our little ones. 


  1. Air Quality Monitoring in Schools and Classrooms. 
  2. Impact of indoor environmental quality on students’ wellbeing and performance in educational building through life cycle costing perspective.…pdf. 
  3. Introduction to Indoor Air Quality. 
  4. School Districts Frequently Identified Multiple Building Systems Needing Updates or Replacement. 
  5. How Can You Clean The Air? W.A.T.C.H. 
  6. Improving Ventilation In Buildings.,outdoor%20air%20into%20the%20space 
  7. Impacts of Indoor Air Quality on Cognitive Function.,2.1-2.4%25%20lower%20throughput 
  8. CO2 concentration as an indicator of indoor ventilation performance to control airborne transmission of SARS-CoV-2. 
  9. 5000 CO2 Monitors to Glasgow Schools. 

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