Effect of wet deposition on the transmission of aerosolized SARS-CoV-2: Facts and mechanisms

Abstract

Objectives: Rapid spreading of COVID-19 (coronavirus disease 2019) causes increasing morbidity and mortality worldwide. Researchers believe that SARS-CoV-2 (severe acute respiratory syndrome coronavirus 2) uses the airborne mode of transmission. Airborne transmission is crucial because in this way viral particles are dispersed maximum in the air. SARS-CoV-2 can be present in respiratory droplets and atmospheric aerosols. Aerosols having a diameter <10 μm can easily penetrate deep inside the lung and interact with alveolar epithelial cells. Thus, the accumulation of infectious aerosols in the air may rapidly spread COVID-19. Therefore, clearance of aerosols from the air is crucial to minimize airborne transmission of SARS-CoV-2.

Methods/Results: In this review, the latest and peer-reviewed publications obtained from Pubmed, Google Scholar, Web of Science, Scopus are evaluated to understand the underlying mechanisms of wet deposition and aerosolized SARS-CoV-2 dispersion. Infectious respiratory droplets may undergo the process of evaporation to produce respiratory droplet nuclei (≤5 μm in diameter), which is capable to suspend in the air for a long time. However, low relative humidity, high temperature, and speed of air are factors to influence aerosolized virus dispersion. Rain or precipitation is useful to remove air particulate matter to provide good air quality. It is reported that COVID-19 cases are less during monsoon. The wet deposition also affects the downward flux of aerosolized virus particles.

Conclusion: Overall, precipitation may reduce the airborne SARS-CoV-2 transmission by removing aerosolized virus particles by wet deposition. However, rain intensity and total days of rainfall are crucial in this case.