CARBON dioxide monitors could warn people if indoor areas are reaching unsafe Covid-19 transmission levels, scientists say.

A report by Government scientists suggests that the threat of airborne transmission could be checked using CO2 monitors, as elevated carbon dioxide levels mean reduced air flow.

The report produced by Sage’s Environmental and Modelling Group (EMG) suggested that fresh air plays a significant role in keeping the virus at bay indoors.

Early in the pandemic, scientists believed that Covid-19 largely spread on surfaces, but there is increasing evidence it is airborne and people can breathe the virus in and out.

“Continuous CO2 monitoring is not likely to be a reliable proxy for transmission risk in most environments,” the scientists concluded.

“However preliminary research suggests that in spaces where the same group of people regularly attend, for example schools, universities and offices, continuous monitoring may be possible to use as a transmission risk indicator.”

The report suggests that a space with 20 people would be unsafe once it reached carbon dioxide levels greater than 1500ppm (parts per million).

“It has been recognised, even before Covid, that carbon dioxide monitoring is a key indicator as to whether a room is properly ventilated,” explained Steve Swinden, CEO of Birchwood-based Flamefast, a manufacturer of CO2 monitors in the UK.

He added: “We propose installing CO2 monitors with an easy-to-follow traffic light indicator.

“These are already widely used in schools and offices, and whilst they do not necessarily solve the ventilation problem, they provide the occupants with the information to safely manage the air quality.

“Fresh air levels can be measured with CO2 monitors and doors and windows opened at regular intervals.”

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