In rooms that are well insulated (good insulation is airtight) or where many people are staying (such as in classrooms), ventilation is very important. Sufficient fresh air must be supplied to ensure a healthy indoor climate and to avoid condensation. Poor air quality is often a cause of concentration problems, headaches, stinging eyes and the spread of germs.
Too much ventilation, however, causes unnecessary heat loss and wastes energy.
The CO2 concentration can be used as an indicator of indoor air quality. Outside air always contains around 400 ppm CO2.
Classrooms often do not have a ventilation system. Opening windows and doors is then the only way to ensure good air quality in classrooms. Various strategies are possible: brief and forceful ventilation, continuous air flow (ventilation) or a combination of both.
By regularly airing with the heating switched off, the polluted indoor air is replaced by fresh (but cold) outdoor air and the walls, floors and furniture do not have time to cool down. Another way is to leave some windows and the door ajar and ventilate continuously. This way is more convenient, but often causes more energy loss.
With this action sheet, we investigate how to achieve a healthy indoor climate in an energy-efficient way. The pupils set up their own research. They formulate a research question, think of an experiment, carry it out and formulate a conclusion.
In order to respond to current events, they can choose the angle of the spread of virus particles in a closed environment. This way, the link with other subjects can be made. Which mechanisms cause the spread of the SARS-Cov-2 virus in the context of ventilation? Besides diffusion through droplets, the diffusion through aerosols is also important.
In the action sheet 'The energy box and formulating research questions', you will find tips on how to formulate research questions.
Inspiration for research assignments:
What is ventilation? What is airing?
- What is the best air quality you can achieve in the classroom?
- What factors influence air quality?
- What factors influence the refreshment of indoor air?
- What factors make ventilation difficult?
- Does the size and occupation of the classroom play a role? Or the location of the classroom on the street side? Are the weather conditions important?
Research your classroom
- How does the CO2 concentration in the classroom evolve?
- How corona proof is our classroom?
- Research what influence ventilating and airing has on the air quality in the classroom.
- Ask how the air quality in the classroom is perceived.
- Think of methods to estimate the cooling of the classroom.
What is energy-efficient ventilation?
You can estimate the energy loss qualitatively by following the temperature development with a data logger during the ventilation experiments. You can also use an IR thermometer to follow the cooling of the surface of walls, floors or other objects in the classroom.
- Make an inventory of which heat transport mechanisms are responsible for the cooling and heating of a classroom.
- Compare ventilation and heat transport during summer and winter.
- Think of a way to estimate energy consumption for ventilation and/or airing.
- Which measuring devices from the energy box do you need? A CO2 logger? A temperature logger? An IR thermometer?
- Think of some ways to meet the ventilation standard ( < 900ppm CO2) and test them out. Use one of these three strategies:
- Airing: short and powerful
- Ventilating: continuously with small flow rate (door open/closed)
- Investigate a combination of strategies.
Be creative and think of innovative solutions such as a fan in front of the window.
- Use the outdoor environment for teaching to get a breath of fresh air.
- Set up experiments to evaluate the methods. Apply the most efficient method for a longer period of time.
- Find out if what you learned about the classroom can be extended to the whole or part of the school building.
- What similarities are there?
- What differences are there?
- Convince the entire school to apply your ventilation strategy throughout the school.
- Teachers (of course) set a good example and ensure that there is sufficient ventilation.
- The pupils apply what they learn in the investigation, communicate it to other classes and follow up on the agreements. They can keep track of meter readings if necessary.
- Involve teachers of other subjects. Some examples:
- Language subjects can work with articles related to the topic.
- In philosophical subjects, the following questions can be discussed: "How do we deal with a risk that is not yet fully known?", "Do we choose energy-efficient heating (save the planet) or do we choose more ventilation (save ourselves)?”
- Also involve the support staff in the project (opening or closing windows and doors, adjusting and maintaining the ventilation system, etc.). The handyman can play a very crucial role. Make use of his/her expertise, let him/her work together with the pupils.
- Dare to ask for support from the parents' committee, the school board, the school association, the municipality, ... when planning structural measures.
- Invite a ventilation expert (or pay him/her a visit).
- Involve the (grand)parents in the project. Ask about their experiences. Make a link between the air quality in school and at home.
- Report on your experiment and your conclusions.
- Communicate your findings through Smartschool, information boards, etc.
- Present your findings at a staff meeting and to the prevention advisor.
CO2 is a greenhouse gas and therefore contributes to global warming, but that is not the subject of this action sheet. CO2 concentrations help us to get a good idea of the air quality in a room.
A person breathes out an average of 18 litres of CO2 per hour. CO2 concentrations in the classroom are not usually so high that they become dangerous. So why do we measure CO2 concentration?
CO2 concentration is relatively easy and cheap to measure and gives a good idea of the air quality and the amount of air exchange. If the concentration remains below 900 ppm, then you can be sure that other more harmful substances are also adequately ventilated. Other hazardous substances are e.g. formaldehydes, methane and, since a while, very relevant: virus particles, ...
Watch out!
Sustainable behavioural change takes time and patience. Habits that have become ingrained are not easy to forget. Therefore, repeat and evaluate on a regular basis, and adjust if necessary. Do this in dialogue with the pupils.
Golden tip!
MOS provides free energy suitcases. In it you will also find instruments to set up an air quality study together with the pupils (including a manual, worksheets,...)
The Agency for Care and Health recommends a CO2 concentration of < 900 ppm (parts per million, 900ppm means 900 particles of CO2 per million particles of air).
