How do temperature, humidity, and air saturation state affect the COVID-19 transmission risk?

Environ Sci Pollut Res Int. 2023 Jan;30(2):3644-3658. doi: 10.1007/s11356-022-21766-x. Epub 2022 Aug 11.

Abstract

Environmental parameters have a significant impact on the spread of respiratory viral diseases (temperature (T), relative humidity (RH), and air saturation state). T and RH are strongly correlated with viral inactivation in the air, whereas supersaturated air can promote droplet deposition in the respiratory tract. This study introduces a new concept, the dynamic virus deposition ratio (α), that reflects the dynamic changes in viral inactivation and droplet deposition under varying ambient environments. A non-steady-state-modified Wells-Riley model is established to predict the infection risk of shared air space and highlight the high-risk environmental conditions. Findings reveal that a rise in T would significantly reduce the transmission of COVID-19 in the cold season, while the effect is not significant in the hot season. The infection risk under low-T and high-RH conditions, such as the frozen seafood market, is substantially underestimated, which should be taken seriously. The study encourages selected containment measures against high-risk environmental conditions and cross-discipline management in the public health crisis based on meteorology, government, and medical research.

Keywords: Air saturation state; COVID-19; Relative humidity; Respiratory tract deposition; Temperature; Transmission risk model.

MeSH terms

  • COVID-19*
  • Cold Temperature
  • Humans
  • Humidity
  • Temperature
  • Virus Inactivation