Scientists discover critical factors that determine the survival of airborne viruses

Press release issued: 21 June 2023

Critical insights into why airborne viruses lose their infectivity have been uncovered by scientists at the University of Bristol. The findings, published in the Journal of the Royal Society Interface today [21 June], reveal how cleaner air kills the virus significantly quicker and why opening a window may be more important than originally thought. The research could shape future mitigation strategies for new viruses.

In the first study to measure differences in airborne stability of different variants of SARS-CoV-2 inhalable particles, researchers from Bristol's School of Chemistry show that the virus has become less capable of surviving in the air as it has evolved from the original strain through to the 'Delta' variant.

Through manipulating the gaseous content of the air, the team confirmed that the aero-stability of the virus is controlled by the alkaline pH of the aerosol droplets containing the virus. Importantly, they describe how each of the SARS-CoV-2 variants has different stabilities while airborne, and that this stability is correlated with their sensitivities to alkaline pH conditions.

The high pH of exhaled SARS-CoV-2 virus droplets is likely a major driver of the loss of infectiousness, so the less acid in the air, the more alkaline the droplet, the faster the virus dies. Opening a window may be more important than originally thought as fresh air with lower carbon dioxide, reduces acid content in the atmosphere and means the virus dies significantly quicker.

Read the full University of Bristol news item

Paper: 'Differences in airborne stability of SARS-CoV-2 variants of concern is impacted by alkalinity of surrogates of respiratory aerosol' by Allen Haddrell, Jonathan P. Reid et al. in the Journal of the Royal Society Interface [open access]