Potential of Solar UV Radiation for Inactivation of Coronaviridae Family Estimated from Satellite Data

Abstract

The pandemic COVID‐19 disease affects people dramatically overall the globe by illness and death. Several strategies are applied to restrict the spread of this disease such as lockdown, adequate social distance in different activities, hand disinfection and the use of masks. Potential hazard outdoors comes from released viruses, which may remain in the air for a while and settle down afterward and contaminating surfaces. Solar ultraviolet radiation (UVR) is known to act as a natural environmental virucide. The virucidal effectivity of UVR depends on a first order on the sensitivity of the virus against UVR as well as on the amount of incoming UVR. Here, we present estimates of the potential of solar UVR in inactivating SARS‐CoV‐2 in the environment. This is done by combining DNA‐damaging surface solar UVR retrieved by satellites and the available information on fluence for inactivation of Coronaviridae. Our results show that solar UVR has a high potential to inactivate these viruses, but the degree depends strongly on location and season. In the subtropics (Sao Paulo, 23.5°S), the daily survival fraction is lower than 10−4 during the whole year, while close at norther latitudes (Reykjavik, 64°N), such a reduction can be found in June and July only.

Investigating the Potential for Ultraviolet Light to Modulate Morbidity and Mortality From COVID-19: A Narrative Review and Update

“…However, viral inactivation may not be possible in low UV environments, including at levels experienced in many European cities around the winter solstice (89). These findings have been largely reproduced in other modeling studies (90,91). While germicidal UVC is likely more effective, there is evidence that other wavelengths of light have germicidal properties, including, far-UVC (222 nm), UVB, UVA, visible (400-700 nm) and infrared (92).…”

Solar UV-B/A radiation is highly effective in inactivating SARS-CoV-2

“…In particular, about 10% of the photons emitted by the Sun in the range 290–315 nm (UV-B) and as much as 95% of those in the range 315–400 nm (UV-A), reach the Earth . The effect of these photons on Single- and Double-Stranded RNA/DNA viruses 10 – 13 and the possible role they play on the seasonality of epidemics 14 – 25 , are nevertheless little studied and highly debated in alternative or complementarity to other environmental causes 23 , 26 – 39 . Notably though, the effects of both direct and indirect radiation from the Sun needs to be considered in order to completely explain the effects of UV radiations in life processes (with e.g.…”

Survey of Home‐Use UV Disinfection Products†

“…Solar UV is the primary natural viricidal agent (4–6) which may help reduce viral load outdoors. However, seasonal changes in Europe with diminishing contribution of sun exposure to viral control (7,8) and people moving indoors for occupational, educational and most of their recreational activities, has shifted the emphasis to the deployment of affordable measures to abate COVID‐19 transmission including the use of artificial UV radiation in public places and at home.…”