THE WELSH GOVERNMENT will spend £6m on 30,000 CO2 sensors and 1,800 ozone disinfecting machines in a bid to improve ventilation in schools, colleges and universities.

Welsh doctors have welcomed the move having long-advocated air flow as a way to significantly reduce the risk of spreading Covid in enclosed places.

Using the technology, developed by Swansea University, will bring Wales in line with England after the UK government announced last week that CO2 monitors would be provided to all English state schools.

However there is growing concerns about toxic chemicals contained within the ozone disinfecting machines.

Developed at Swansea University, the machines convert oxygen in a room to ozone, a chemical that kills Covid in the air and on surfaces, along with other viruses and bacteria. Once a room has been disinfected, the machine, each the size of a suitcase, converts the ozone back to oxygen.

Ozone is so toxic that no one will be allowed inside the room when the machine is operating, according to Dr Chedly Tizaoui, who was part of the design team.

Plaid Cymru has raised questions about toxic chemicals contained within the technology. And campaigners questioned why the Welsh government was turning to a harmful substance in schools when safer alternatives are available.

Announcing the initiative, Rebecca Evans, the minister for finance and local government, said: “By investing in new technology such as ozone disinfecting machines, we’re ensuring learners can stay in school and colleges as Wales moves beyond the pandemic.”

But Dr Eilir Hughes, a GP on the Llŷn peninsula and a member of the Fresh Air Wales campaign, was not convinced. He said: “If you have to put in place a lot of health and safety guidelines in rolling it out then it really needs to be worth it.

“Adding a toxic substance to the environment raises concerns about how it will react to chemicals particularly in soft furnishings. Is it sensible to be testing this in schools?”

In an article published online on Monday in Nation Cymru he wrote: “Using ozone to disinfect does seems counterintuitive. In an attempt to lower the risk of harm to human health, we are using toxic chemicals when safer alternatives are available.

“And suggesting that disinfecting potentially infected air when no one is present to breath it is an insult to our intelligence.”

Hughes argued that better ventilation in schools was safer and a more effective means of tackling Covid in the classroom.

He said: “Instead of rolling out expensive, untried, unnecessary technology that has the potential of being damaging to the environment and dangerous to human health, we should place our efforts on interventions that provide the greatest benefit in reducing risk … If natural ventilation is provided for indoor settings, transmission reduces by up to 70%.”

Plaid Cymru’s education spokesperson, Siân Gwenllian, said: “The use of ozone disinfecting machines is controversial to say the least and we all need to be satisfied that Welsh government is absolutely certain that they are a safe option before introducing them.”

A Welsh government spokesman said the machines were only for disinfecting empty indoor spaces. He said: “These machines have been developed to speed-up the decontamination of classrooms following a confirmed outbreak of covid-19 only, and not as a form of air purification for occupied indoor spaces.”

The Welsh government will also be providing CO2 sensors to schools, colleges and universities to improve ventilation, after a similar move in England.