Carbon dioxide helps extend the life of airborne viruses like COVID

O carbon dioxide (CO_two) plays a vital role in determining the lifespan of airborne viruseslike SARS-CoV-2, the virus that caused COVID-19, a new study revealed.

The study, which was published in the journal Nature Communicationsalso highlights the importance of control CO levels_two to reduce virus survival and minimize the risk of infection.

CELEBS technology

The researchers developed a unique bioaerosol technology called CELEBS (Controlled Electrodynamic Levitation and Extraction of Bioaerosols on a Substrate) to show how CO2 is a factor that contributes to prolonging the life of SARS-CoV-2 variants.

CELEBS technology allows measure the survival of different variants of SARS-CoV-2 in particles in the air generated in a laboratory and designed to mimic exhaled aerosol. By varying the concentration of CO_two in the air between 400 parts per million (ppm), the level of normal outdoor air, and 6,500 ppm, the team confirmed a link between increased concentrations of CO_two and the aerostability of different SARS-CoV-2 variants.

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“We knew that SARS-CoV-2, like other viruses, spreads through the air we breathe. But this study represents a breakthrough in understanding exactly how and why this happens and, crucially, what can be done to stop it,” explains lead author Dr Allen Haddrell, a researcher in aerosol science at the University of Bristol.

Haddrell says research also shows that opening a window “may be more powerful than originally thought, especially in poorly ventilated roomsas fresh air will have a lower concentration of CO_twowhich will cause the virus is inactivated much more quickly“.

Superspreader events

The increase in CO concentrations_two to just 800 ppm, a level considered well ventilated, resulted in increased viral aerostability. After 40 minutes, about 10 times more viruses remained infectious when the air had a concentration of CO_two similar to that of a crowded room (3,000 ppm) compared to clean air.

“This relationship sheds important light on why superspreader events can occur under certain conditions,” explains Haddrell. “O Elevated pH of exhaled droplets containing the SARS-CoV-2 virus is likely an important factor in the loss of infectivity“, he said.

The CO_two behaves like an acid when interacting with droplets. This causes the pH of the droplets to become less alkaline and, in turn, the virus within them is inactivated at a slower rate.

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He says that’s why open a window is an effective mitigation strategy: it physically removes the virus from the room and makes aerosol droplets more toxic to the virus.

Climate research

Recent scientific studies on the climate suggest that, by the end of the century, the CO concentration_two in the atmosphere should reach more than 700ppm.

“These findings therefore have broader implications not only for our understanding of respiratory virus transmission, but also for how changes in our environment may exacerbate the likelihood of future pandemics,” Haddrell said.

The study data suggests that rising CO levels_two in the atmosphere may coincide with an increase in the transmissibility of other respiratory viruses, by prolonging the time they remain infectious in the air – said Haddrell.

“Although there is still much we don’t understand, we are now getting a much more complete picture of the role that exhaled respiratory aerosols play in transporting infectious viruses between people, and the mechanisms that control their survival,” adds Jonathan Reid, professor at University of Bristol. “These discoveries can serve as a scientific basis for designing mitigation strategies that could save lives in any future pandemic“, he said.

News reference:

Haddrell, A. et al. Ambient carbon dioxide concentration correlates with SARS-CoV-2 aerostability and infection risk. Nature Communications2024