A new discovery about carbon dioxide is challenging decades-old ventilation doctrine
17 June 2024 • Article Summary
Topic: Carbon Dioxide
STAT News
No sensor can monitor how many infectious aerosols are swirling around us in real time. But carbon dioxide, or CO2, can act as a convenient proxy. People exhale it when they breathe, and in spaces that aren’t well ventilated, the gas accumulates. High CO2 concentrations can provide a warning sign that a lot of the air you’re inhaling is coming out of other people’s respiratory tracts.
In fact, CO2 levels play a critical role in determining how long viruses can stay alive in the air: The more CO2 there is, the more virus-friendly the air becomes. Haddrell and his team proposed that pH, more than temperature and humidity, was the driving force behind viral decay in respiratory particles.
Increasing the CO2 concentration to just 800 parts per million, a level widely identified as being a marker of good ventilation, significantly extended the life spans of multiple SARS-CoV-2 variants. At higher concentrations — like those you might expect to find in a crowded, poorly ventilated room — Haddrell’s team found that 10 times as much virus remained infectious after 40 minutes when compared to clean air.
Quote: “By increasing the CO2 in the air, we’re getting rid of a
natural means by which viruses become inactivated,” said Allen
Haddrell, an environmental chemist at the University of Bristol
Aerosol Research Center.
“It’s (CO2) moving from a role of being just a proxy to being
understood as an enhancer, if we can use this term, for infection.”
Professor Morawska.