Lack of classroom CO2 monitors may increase Covid-19 risk

Nearly 85% of classrooms across the country do not have their own carbon dioxide monitors, potentially increasing the risk of students catching Covid-19.

By Farah Hancock of rnz.co.nz

High levels of carbon dioxide in a space can indicate poor ventilation and an environment where aerosol particles from people’s breath can linger, increasing the risk of infection if someone in the room is sick.

From whom do you breathe the breath of RNZ? The project tested carbon dioxide levels in a typical middle school classroom and found that on a cold day when the windows were closed, indoor CO2 levels reached 1373 parts per million.

To combat Covid-19, the Ministry of Education has asked teachers to open doors and windows when CO2 levels exceed 8:00 a.m. and leave the room briefly if the level exceeds 12:51 p.m.

“Ideally, every classroom should have a carbon dioxide monitor,” said Julie Bennett, senior researcher at the University of Otago’s Department of Public Health.

Bennett said while it’s “fantastic” the ministry has set guidelines, few classrooms have a CO2 monitor in place at all times so they can act at increasing levels.

“It’s very difficult to know when the CO2 is building up until the levels get really high – when you can feel the room is really stuffy and people are starting to fall asleep. Often at this point, they went well above 800 parts per million,” Bennett said.

The Department for Education says 1,000 rooms have built-in monitors and it has provided 5,400 CO2 monitors to schools, but there are around 42,000 teaching spaces in New Zealand. This equates to approximately one portable monitor shared between eight classes.

Departmental property manager Sam Fowler said the portable monitors help schools assess ventilation in different spaces.

“Generally, the methods employed to manage ventilation and CO2 levels in a learning space will be applicable in similar teaching spaces.”

Over the next year, another 8,000 rooms are expected to receive indoor environmental monitors, which monitor CO2.

He did not respond to a question asking why the ministry had not provided CO2 monitors for all rooms.

Central Otago parent Andrew Dickinson took matters into his own hands and bought several monitors for his children’s school.

In his son’s classroom, which was a new building, the monitor made it easy for teachers and students to manage the air quality when the monitor’s LED screen alerted them.

“You could see the impact immediately. The CO2 will reach the orange level, and they will open a window and it will drop immediately.”

Managing CO2 in her daughter’s classroom, located in an older building, was more difficult.

“It’s steadily going up to 1200 or more and they’re fighting it all morning. So all morning they’re trying to keep the room warm enough and get enough ventilation to bring the CO2 down.”

Dickson shared the data with the Department of Education, and the school received air purifiers for older classrooms. These can help remove virus particles from the air and are particularly useful if schools cannot properly ventilate classrooms by opening doors and windows.

Fowler said the ministry has so far sent 8,250 air purifiers to schools nationwide.

“More air purifiers are available for schools in need, which the ministry will provide free of charge, to help address ventilation issues. Schools and other education sector entities can also purchase monitors of CO2 and additional air purifiers at a discounted rate directly from ministry suppliers.

In addition to CO2 monitors in all rooms and air purifiers if needed, Bennett and University of Otago epidemiologist Amanda Kvalsvig would like to see mask mandates reintroduced.

“New Zealand schools need a Vaccines Plus approach, using layered protections because no single measure can protect 100%,” Kvalsvig said.

“The situation is now urgent. Some protections could be reinforced tomorrow, including wearing masks and staying at home if you feel unwell.”

The Vaccines Plus approach was outlined in an open letter signed by more than 150 doctors and scientists, who sent it to government officials in April. Suggestions included continuing masking in schools over winter and for the ministry to provide CO2 monitors and air filtration units to all classrooms.

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