Supplementary figure for: "UVA radiation could be a significant contributor to sunlight inactivation of SARS-CoV-2"

Supplementary Figure 1 for https://www.biorxiv.org/content/10.1101/2020.09.07.286666 

Summary of sunlight inactivation mechanisms for viruses, based on [1,2]. Solid yellow line: example of solar spectral irradiance reaching the Earth’s surface [3]. In principle, UVC light is most effective at damaging nucleic acid, leading to direct, endogenous inactivation; however, it is completely blocked by atmospheric ozone. Some UVB reaches the Earth’s surface, and may also damage nucleic acid. However, its effectiveness is lower than for UVC, and falls rapidly as wavelength increases (as shown by the white dashed line). Sunlight in the UVA range reaches the ground in larger amounts than for UVB, but does not interact directly with nucleic acid. However, UVA can be absorbed by natural or engineered sensitizers in the suspending medium, thereby creating photo-produced reactive intermediates that can damage viruses, leading to indirect, exogenous inactivation.

* Corresponding author: pfegiz [at] ucsb [dot] edu

1. Nelson KL, Boehm AB, Davies-Colley RJ, et al. Sunlight-mediated inactivation of health-relevant microorganisms in water: a review of mechanisms and modeling approaches. Environ Sci Process Impacts. 2018; 20(8):1089–1122.

2. Lytle CD, Sagripanti J-L. Predicted inactivation of viruses of relevance to biodefense by solar radiation. J Virol. 2005; 79(22):14244–14252.

3. Tropospheric Ultraviolet and Visible (TUV) Radiation Model [Internet]. [cited 2020 Sep 2]. Available from: https://www2.acom.ucar.edu/modeling/tropospheric-ultraviolet-and-visible-tuv-radiation-model

Funding statement:

This work was supported by the University of California, Santa Barbara [Vice Chancellor for Research COVID-19 Seed Grant] and by the Army Research Office Multi University Research Initiative [W911NF-17-1-0306 to P.L.-F.].