Few issues cause parents as much concern as the health of their children. But if you worry about what they eat, what they drink or the materials used to make their toys, why doesn’t the pollution in schools to which children are exposed cause the same concern?
As we mentioned in the article ‘Indoor air quality in schools and nurseries: why is proper ventilation important?’, indoor air quality (IAQ) in schools is a fundamental pillar for the health and academic performance of students. An environment laden with pollutants, with excess carbon dioxide (CO₂), or the presence of volatile organic compounds (VOCs) and particulate matter (PM) can cause drowsiness, lack of concentration and even increase the transmission of viruses.
However, the key question is not whether we should ventilate, but when and how to do so in a smart and efficient way. Opening windows indiscriminately can be counterproductive, introducing more pollution from outside or generating unsustainable energy costs.
How to know when to properly ventilate classrooms in colleges and schools? Practical guide
To know how to improve indoor air pollution and implement truly effective ventilation protocols in classrooms, it is important to understand the critical points that put air quality at risk.
Classroom ventilation based on CO₂ thresholds
Carbon dioxide (CO₂) is the benchmark indicator for measuring air quality in occupied indoor spaces. We exhale it when we breathe, so its concentration increases rapidly in a crowded classroom. A high CO₂ level not only indicates poor ventilation, but is also directly correlated with an increased risk of respiratory disease transmission and decreased cognitive performance.
Acting according to measurable thresholds is essential, which is why it is necessary to have CO₂ and indoor air quality meters that determine the concentrations of air pollutants in real time.
- Optimal Level (<800 ppm): considered good indoor air quality. In this range, comfort and concentration are at their highest.
- Warning Level (800 – 1,000 ppm): if the carbon dioxide concentration is at this threshold, it indicates that ventilation is insufficient and should be initiated or reinforced. This is the time to have an automatic alert that tells us it is time to take action on ventilation before the effects of CO₂ become more noticeable.
- High Level (> 1000 ppm): the RITE determines the indoor air quality type IDA 2 for classrooms and educational spaces, establishing 1000 ppm of CO₂ as the maximum acceptable value under normal operating conditions.
The energy challenge: effective and sustainable ventilation in educational centres
In order to have a sustainable and comfortable ventilation protocol, it is important to adapt to climatic conditions and especially to energy consumption in heating and cooling.
Ventilation in winter should aim to renew the air while losing as little heat as possible. To do this, instead of leaving windows ajar for hours, it is more efficient to open them completely for short periods (3-5 minutes) several times a day, allowing for rapid air renewal without significantly cooling surfaces, thus facilitating the recovery of a comfortable temperature.
Whenever possible, it is advisable to prioritise cross ventilation by opening a door and a window on opposite sides to maximise air flow and reduce the time needed for ventilation.
In summer, the challenge is to ventilate effectively without overheating the classroom. Ventilating first thing in the morning, taking advantage of the coolest time of the day, will allow the building’s thermal mass to cool down, and the use of blinds, awnings or curtains on windows exposed to the sun will allow windows to be kept open without direct solar radiation drastically increasing the indoor temperature.
As in winter, cross ventilation will be the most effective strategy for improving thermal comfort and renewing the air efficiently.
As with air pollutants, in order to know whether thermal comfort conditions (temperature and humidity) are within acceptable ranges, it is essential to have real-time measurement of temperature and relative humidity, which allows ventilation periods to be shortened or lengthened in order to maintain air quality and comfort in the classroom.
Why use an indoor air quality monitor to optimise ventilation in classrooms? Main advantages
Ventilation strategies in school classrooms are often inefficient, as they are basically carried out ‘by eye’ based on the criteria of the people present in the classroom.
This subjective approach often means that both students and teachers spend long periods of time breathing polluted, poor-quality air.
This is where the use of a real-time air quality monitoring system such as Nanoenvi IAQ plays a key role, transforming ventilation management into a precise science.
- Total visibility. The meter provides constant and reliable data on key parameters (CO₂, humidity, temperature, VOCs, PM2.5 particles), making the invisible visible and allowing you to understand what is happening in the classroom air at any given moment.
- Energy and cost efficiency. Ventilating indiscriminately or without criteria can cause heating or air conditioning bills to skyrocket. The Nanoenvi IAQ CAI monitor indicates the exact moment when ventilation is necessary and when windows can be closed extremely easily thanks to the LED colour code included in the device, optimising energy consumption without sacrificing air quality.
- Guarantee of a safe environment. Thanks to its programmable alerts, centre staff can be automatically notified when a parameter exceeds the recommended threshold, allowing immediate action to be taken before air quality deteriorates.
- Data-driven decisions. The use of this sensor allows the creation of customised ventilation protocols for each space, adapted to occupancy, use and specific conditions, ensuring that the measures taken are always the most effective.
Sources:
- Asere, L., & Blumberga, A. (2018). Energy efficiency – indoor air quality dilemma in public buildings. Energy Procedia, 147, 445-451. doi:http://doi.org/c3gf
- Oliveira, M., Slezakova, K., Delerue-Matos, C., Pereira, M., & Morais, S. (2019). Children environmental exposure to particulate matter and polycyclic aromatic hydrocarbons and biomonitoring in school environments: A review on indoor and outdoor exposure levels, major sources and health impacts. Environment International, 124, 180-204. doi:http://doi.org/c3p2
- Rivas, I., Querol, X., Wright, J., & Sunyer, J. (2018). How to protect school children from the neurodevelopmental harms of air pollution by interventions in the school environment in the urban context. Environment International, 121, 199-206. doi:http://doi.org/gfncj8
- Laboratorio de Investigación en Fluidodinámica y Tecnologías de la Combustión (LIFTEC) Centro Mixto Univ. Zaragoza / CSIC
- https://www.ucm.es/file/medicion-de-co2-y-ventilacion-ucm
