Carbon dioxide monitors could warn of unsafe Covid transmission indoors, scientists say

Sarah Knapton
·2-min read
coronavirus -  Jeff Gilbert
coronavirus - Jeff Gilbert

Carbon dioxide monitors could warn when indoor areas are reaching unsafe Covid-19 transmission levels, government scientists have said.

A 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, and could be checked using Co2 detectors.

The scientists conclude that measuring elevated levels of carbon dioxide would be an effective way to spot if air flow levels have reached a level where the coronavirus is more likely to spread. 

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

There have been several outbreaks in factories where workers have to shout to be heard and in singing groups. In Washington State, in the US, 53 out of 60 members of the Skagit County choir caught coronavirus. 

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

“However preliminary research suggests that in spaces where the same group of people regularly attend (e.g. offices, schools), 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).

However areas with singing, loud speech or aerobic activity may pose a substantially higher risk and ventilation rates should aim to maintain CO2 below 800ppm, the report states.

The researchers recommend that people working in indoor areas such as offices and schools for several hours should be given regular breaks, with the room purged of air before they return.

They also advise opening doors and windows, and said fresh air levels could be monitored with detectors.