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Re: Joe skipper criticised for taking a bike ride [apmoss] [ In reply to ]
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Runners should be 10m away, says research
(https://www.bbc.com/.../live/world-52225173)
Anna Holligan
BBC News reporter cycling in The Hague

"On the basis of these results, the scientists advise that those on the move should be given more of a social distance. Walkers should get at least four metres, runners 10 metres and cyclists at least 20 metres."

Results at: https://twitter.com/.../1247540735001251841



"By the way this is aerodynamics work, not virology." - Bert Blocken

That's a really important distinction.


https://www.vice.com/...not-actually-a-study
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Re: Joe skipper criticised for taking a bike ride [tessar] [ In reply to ]
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We know COVID-19 is transmitted airborne through aerosols


https://www.nature.com/...s/d41586-020-00974-w


It sounds like there's some debate on whether Covid really is airborne. I can understand assuming it is until we know otherwise, but it doesn't sound like that's something we know for certain.
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Re: Joe skipper criticised for taking a bike ride [tessar] [ In reply to ]
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Thanks, this is the study I previously read and generally its a great path, but the limitations relative to the real world are still there. This was the key item that somewhat decoupled it from the reality of the real world:


"The study is subjected to a number of limitations that will give rise for further work. Further work will consider the effect of head wind, tail wind and cross-wind. Cross-wind will cause the slipstream to be not straight but obliquely positioned behind the runners, and while it is expected that also in this case the droplets will mainly remain entrained in the slipstream, this should be confirmed by future simulations. External wind will also increase the turbulence intensity and might cause stronger mixing of the droplets in the slipstream, and potentially also allow a small fraction droplets to escape the slipstream. Further work can also consider walkers and runners at different velocities overtaking each other and runners crossing each other. "


The study definitely covers the exposure to aerosol droplets in still air (which may or may not result in infection and death). From there, add crosswinds and actual risk of infection increasing and we have it all.


Again, to be clear, I am distancing as asked by my government in all activities.
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Re: Joe skipper criticised for taking a bike ride [devashish_paul] [ In reply to ]
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Generally science is about "decoupling from the real world" in order to break it down into smaller problems that are solvable or understandable. Newton's theory of gravity? Outright wrong on so many levels, but it's a very good approximation.

Yes, the study has limitations just like every study does. But it shows evidence that scaling distances to account for velocity is more than just a thought experiment.

ZONE3 - We Last Longer
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Re: Joe skipper criticised for taking a bike ride [tessar] [ In reply to ]
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tessar wrote:
Generally science is about "decoupling from the real world" in order to break it down into smaller problems that are solvable or understandable. Newton's theory of gravity? Outright wrong on so many levels, but it's a very good approximation.

Yes, the study has limitations just like every study does. But it shows evidence that scaling distances to account for velocity is more than just a thought experiment.

I totally get how science and studies work (I have a company filled with data scientists and their models are used in the real world to predict and control things in real life....and you have to start somewhere). But we're always adjusting to reality as the fitting of the actions to the data has a learning period where you reiterate.

Intially you have a void of info and need to make some assumptions and then you take actions extrapolating a bit based on the proven knowledge at hand.

This study WAS NOT PEER REVIEWED and has several holes and I pointed out to you the biggest hole that does not take into account cross winds and turbulence. it does not even take into account the concentration of infectable particles that you may or may not be exposed to.

As such, a non peer reviewed WHITEPAPER (not a proper study) is put out as fact, it goes viral and it is used by the rest of the world to shame joggers, runners and cyclists in an "us vs them" battle, when we're all fighting about something where there is hardly any risk.

Here as a counter point on the same article being treated as gospel:

https://www.vice.com/...l3sAFdWxz43G0PszArjM

One part of the text:

Crucially, scientists are still unsure how well the coronavirus spreads in the air, and many have cautiously speculated that the overall risk of transmission appears to be less outdoors. Globules and droplets do likely carry the virus, but that doesn’t mean that anyone who gets a droplet on them from someone’s breath is going to be infected. Transmission depends on a host of factors; scientists believe an important one of these is “viral load,” which is a measure of how much of the virus is present.
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