How schools are making informed classroom ventilation choices

Epuni School student Mercy holding one of the portable CO2 monitors used to help assess ventilation

Good ventilation is an important tool in the armoury of defence from transmission of Covid-19, and especially valuable in a classroom setting.

The amount of CO2 in a space generally gives an indication of how well-ventilated it is, with lower levels of CO2 meaning there is more fresh air. It’s a useful metric, which is why every state or state-integrated school in
Aotearoa has now received at least one portable CO2 monitor (unless it opted-out due to already having fixed CO2 monitors), with more to be distributed over the next couple of months to schools with rolls of more than 250 students.

Portable CO2 monitors have been used by schools in a number of ways, including being incorporated into lessons and appointing students to record results. One school that has used the information provided by its portable CO2 monitor to improve its approach to ventilation is Epuni School in Lower Hutt.

Harnessing data to inform change

Principal Janet Evans says her school has used the data from their portable CO2 monitor to inform the way different spaces are used and adapt their approach as required, leading to good results.

“Our staff and students are monitoring and recording the CO2 level in their classrooms throughout the day to track the impact of opening different combinations of windows and doors. What they’ve seen in real time is the
positive effect of natural ventilation letting clean, fresh air into the room.”

Janet says one of the first steps for the school was taking stock of what it already had in terms of windows and doors that could be used to improve ventilation, including those that had been overlooked or forgotten about.

“There are fire exit doors in our cloak bays that weren’t often used before, which have been helpful for increasing airflow now that they’re frequently open. We also made a point of fixing windows that were broken or stuck so that we could open them,” she says.

The school has noticed the positive cumulative impact of lots of little tweaks, including some minor property improvements and changes to the day-to-day use of spaces.

“Teachers have been diligent about opening windows, which has a big impact. Things that seem small, like taking a class outside for a five-minute fresh air break, can make a significant difference to the CO2 levels in a classroom too. We’ve also moved activities like singing, dancing and eating lunch outside.

“In the current environment, understanding the science behind ventilation and the impact of opening windows and doors has given our students a sense of control – the knowledge has been empowering for them. They can take home what they’re learning about good ventilation and share it with their whānau too.”

Epuni School principal Janet Evans shows ākonga how the CO2 monitor works.

Backed by science

Most schools in Aotearoa are designed for natural ventilation which means they have lots of windows and doors that can be opened to allow the flow of fresh air.

As Epuni School has found, this is the fastest and best way to ventilate a space and it’s an approach that aligns with a recent study by the National Institute of Water and Atmospheric Research (NIWA), as well as other local and international research and expert opinion.

Dr Ian Longley from NIWA says their recent study found that good ventilation could be achieved in most of the classrooms by opening windows and doors, with the most effective ventilation achieved by opening windows and doors on different sides of the room to create a crossflow of air where this is possible.
“Our study has endorsed the evidence-based approach to ventilation that’s been taken in New Zealand schools from the start. While we’ve now verified the role of natural ventilation and fresh air, we’ll be using this study as a
basis for some more research looking at other ventilation improvement tools for schools like extractor fans and assisted natural ventilation systems,” says Ian.

Heading into the cooler months it will be important for schools to continue self-assessing the CO2 levels in spaces that may be more challenging to ventilate well so any issues can be raised with its Ministry property advisor and resolved.

To assist with this, there will soon be additional CO2 monitors distributed to larger schools. The Ministry has also started deploying portable air cleaners to some schools throughout New Zealand, which in most cases will be a temporary or interim targeted solution for use in areas with specific ventilation challenges. By May all schools will be eligible to receive one or more portable air cleaners, for use in areas that may have higher Covid-19
airborne transmission risk due to the nature of their use, like staff rooms, music rooms and high-use meeting or break-out rooms.

• For ventilation advice, including more information about portable CO2 monitors, portable air cleaners and guidance for cooler weather, schools can visit education.govt.nz/ventilation(external link).
  
  
• For further ventilation assistance and support schools should contact their Ministry property advisor or ventilation.mailbox@education.govt.nz.