The Paradoxical Role of far-Ultraviolet C (far-UVC) in Inactivation of SARS-CoV-۲: The Issue of Droplet Size

The Omicron variant is spreading at a rate we have never observed with any previous variant. A lot of efforts have been taken to inactivate SARS-CoV-۲, especially the omicron variant. Specific wavelength ranges of electromagnetic radiation can be exploited to inactivate coronaviruses. Previous studies show that ۲۲۲-nm far-Ultraviolet C (far-UVC) light inactivates airborne influenza virus efficiently. Considering the similar genomic sizes of all human coronaviruses, other human coronaviruses, such as SARS-CoV-۲, would be expected to be inactivated by far-UVC with a similar efficacy. Taking this into account, it is concluded that exposure to far-UVC can be introduced as a safe method that significantly reduces the ambient level of airborne coronaviruses in crowded places. Biomolecules, particularly proteins, strongly absorb ultraviolet radiation at a wavelength of around ۲۰۰ nm. Given this consideration, far-UVC has a limited ability to permeate biological materials. Thus, for example, in only around ۰.۳ mm of tissue, the intensity of ۲۰۰-nm UV radiation is decreased by half, compared to tissue penetration of about ۳ mm at ۲۵۰ nm. This paper aims to answer the key question of whether far-UVC can penetrate SARS-CoV-۲ inside inhalable respiratory droplets (with diameters up to ۱۰۰ µm).

کلیدواژه ها:

Ultraviolet rays ، COVID-۱۹ ، SARS-CoV-۲ ، Disinfection ، Pneumonia