Even I, for as COVID-cautious as I've been, have gotten pretty lax about outdoor events. A new study from China suggests we should be more careful. Three infected people attended a crowded night market, and they infected at least 131 other people. The market was crowded and there was little wind. Researchers found #COVID19 aerosols released by patients could suspend in ambient air up to 1 h 39 min and still be contagious. https://www.frontiersin.org/articles/10.3389/fpubh.2023.1153303/full
Important to note it was a *night* market, which means there was no benefit from UV radiation. A good reminder that outdoors isn’t magically safe, but is lower risk because of UV and the volume and mixing of air. But where those things aren’t present outdoors is just like indoors, and very risky when crowded.
@DavidM_yeg I believe your understanding of UV radiation from the sun is incorrect. I've seen several articles that indicated UVC rays can kill COVID, but that doesn't penetrate the atmosphere. The UV rays that reach us do not seem to impact COVID.
https://www.aad.org/public/diseases/coronavirus/can-sunlight-kill-coronavirus
Interesting… thanks for that, I’ll do some more digging!
I’ve read through what you linked and noticed the following:
- they focus on countering the idea that UV exposure (sunbathing) cures or prevents Covid
- they both warn that UV radiation generally can be harmful to humans
- that each say that UVC is more effective than UVB or UVA, not that the others have no effect
Neither addresses whether ambient outdoor UV impacts the risk of transmission.
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@DavidM_yeg @augieray Also the AAD site has a number of outdated pieces of information, like suggesting cloth masks and focusing on hand washing (nothing wrong with the latter but not generally thought to be all that important for covid anymore). So I don't think I'd put much stock in it personally (as a complete non-expert, of course).
