People who Don't Wear Masks in a Pandemic are Absolute Morons

How though?

The study, titled “Estimated Inactivation of Coronaviruses by Solar Radiation,” looked at how effective UVB rays had been at inactivating coronavirus at various locations around the world.

The new study also suggests that shelter-in-place orders and similar lockdown plans could be counterproductive for anyone sharing a roof with multiple people.

“Healthy people outdoors receiving sunlight could have been exposed to lower viral dose with more chances for mounting an efficient immune response,” it said.

ABSTRACT

Using a model developed for estimating solar inactivation of viruses of biodefense concerns,we calculated the expected inactivation of SARS-CoV-2 virus, cause of COVID-19 pandemic, byartificial UVC and by solar ultraviolet radiation in several cities of the world during different times ofthe year. The UV sensitivity estimated here for SARS-CoV-2 is compared with those reported forother ssRNA viruses, including influenza A virus. The results indicate that SARS-CoV-2 aerosolizedfrom infected patients and deposited on surfaces could remain infectious outdoors for considerabletime during the winter in many temperate-zone cities, with continued risk for re-aerosolization andhuman infection. Conversely, the presented data indicate that SARS-CoV-2 should be inactivatedrelatively fast (faster than influenza A) during summer in many populous cities of the world,indicating that sunlight should have a role in the occurrence, spread rate, and duration of coronaviruspandemics.

Estimated time for inactivation of SARS-Co V-2 virusTable 2 shows reported solar virucidal flux at solar noon together with the estimated minutes ofsunlight exposure needed at various populous North American metropolitan areas to inactivate 90%of SARS-CoV-2. The (+) sign in Table 2 indicates that 99% of SARS-CoV-2 may be inactivatedwithin the two hours period around solar noon during summer in most US cities located south ofLatitude 43oN. Also 99% of the virus will be inactivated during two hours midday in several citiessouth of latitude 35oN in Fall, but only Miami and Houston will receive enough solar radiation toinactivate 99% of the virus in spring. During winter, most cities will not receive enough solarradiation to produce 90% viral inactivation during 2-hours midday exposure (underlined values inTable 2).

The objective of the present study was to evaluate the influence of simulated sunlight and suspension medium on the persistence of SARS-CoV-2 on surfaces and provide data needed to inform assessment of the exposure risk associated with contaminated outdoor surfaces.

The light spectrum was designed to represent natural sunlight, specifically in the ultraviolet (UV) range (280–400 nm), and closely matched model spectra from the National Center for Atmospheric Research’s (NCAR) tropospheric ultraviolet and visible (TUV) radiation model in this range [15] (Figure 2). A previous study demonstrated that light in the UVA portion of the spectrum (315–400 nm) did not damage SARS-CoV-1 at doses similar to those used in the present study [16]. Therefore, the integrated irradiance in the UVB portion of the spectrum (280–315 nm) was utilized to quantify exposure. The intensity of the light was controlled through the use of neutral density filters and adjustment of the power supply to the lamp. Three different intensity levels, approximating integrated UVB irradiance levels for different times of day and year, were utilized in testing (Figure 2 and Figure 3). Spectra produced by the solar simulator were measured immediately outside of the chamber window using a spectroradiometer (OL756; Gooch & Housego) equipped with a 2-inch diameter integrating sphere light receptor (IS-270; Gooch & Housego), and corrected for transmission losses through the window.

In contrast to simulated sunlight, no significant decay was observed in darkness over the 60-minute test duration, which is consistent with previously published data with both SARS-CoV-2 and SARS-CoV-1 [4, 5, 9, 20]. van Doremalen et al [4] reported half-lives of 5.6 and 6.8 hours for SARS-CoV-2 on nonporous stainless steel and plastic surfaces, respectively, under indoor conditions, or approximately 18 to 23 hours for a 90% reduction in infectivity. Chan et al [9] reported that it took 3–5 days to lose 90% of infectivity of SARS-CoV-1 dried on a surface under indoor conditions.

The present study provides the first evidence that sunlight may rapidly inactivate SARS-CoV-2 on surfaces, suggesting that surface persistence, and subsequently exposure risk, may vary significantly between indoor and outdoor environments. However, in order to fully assess the risk of exposure in outdoor environments, information on the viral load present on surfaces, the transfer efficiency of virus from those surfaces upon contact, and the amount of virus needed to cause infection are also needed.