Ajax Bay
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Thank you for responding.cyclingnews - belgian-study-on-safe-distancing-while-exercising-goes-viral
They found that with a slipstream, a much larger distance is needed to avoid exposure - up to five metres (16 feet) at a fast walking pace.
"The results indicate that the largest exposure of the trailing person to droplets for walking and running is obtained when this person is in line and with leading person and positioned in the slipstream of this person.
"Exposure increases as the distance between leading and trailing person decreases."
But surely this is just common sense though isn't it? I don't get the debate you're trying to push. Is your point that 2 metres is fine, no matter what you're up to? No matter what pace?
By the way, your gleeful targeting of my "I felt" as just mere, ignorant opinion is undermined somewhat by your own use of "I think", they're the same thing of course. You think my opinion is b****cks, and I'm calling yours the same. Just pure, unadulterated "I'll do what suits me" and sod everyone else" b*llocks.
From the article you quote (Cycling News summary): "The Blocken paper is an interesting study that can serve as a guideline for exercising outside but what it is not is any evidence whatsoever that SARS-CoV-2 is spread by aerosols in the outdoors."
This paper has been widely criticised, not least because it was shared on social media (Linked-in) with no peer-review, presumably for (Eindhoven University of Technology aerodynamic department) publicity purposes. The Daily Mail has been responsible for hyping its validity up - there's a recommendation. Make the right assumptions and a mathematical simulation can prove anything (eg lead mouth at 168cm).
From an epidemiologist at US Communicable Disease Dynamics: "virality of Blocken's research is harmful"
"Where the droplets are is much less relevant than the amount of transmission that occurs via this route"
the overall risk of transmission appears to be less outdoors. Transmission depends on a host of factors; scientists believe an important one of these is “viral load,”
"On the epidemiology side—where the droplets are is much less relevant than the amount of transmission that occurs via this route," "Advice on physical distancing is really about *reducing* the risk of transmission rather than eliminating it altogether."
US CDC said studies like this are "not really useful. Not to epidemiologists anyway. The amount of transmission from this route even if it is possible will be dwarfed by that from others."
I've done a little more 'work' on this and, yes, I think that the level of risk is as low as practical (ALARP) at 2 metres. Cycling along we just don't know whether a greater distance is required to achieve the same level of risk (ALARP). Intuitively it'd be more than 2m but 4m, 6m? I note that Audax Australia have reintroduced audaxes, but require 10m between riders (one behind the other), but without any apparent scientific basis for that distance. The Blocken social media post suggests that riding in echelon (and not because of a cross-wind) reduces the concentration of the lead cyclist's exhalation particles.
The corresponding WHO SD guideline is to keep distance to one metre (increasingly being adopted by countries as they forge a path out of 'lockdown'. So the UK 2m already has a 100% safety margin built in.
From the summary: "The virus has to get to your mucous membranes - your nose, mouth, or eyes. Even if you're in the slipstream of someone who coughs and is infected, science has not yet determined how many virus particles are needed to cause disease."
And from the article: "Airborne [as opposed to droplet] transmission is very unlikely in regular outdoor environments like parks, hiking trails, because they are not in a closed space."
I have due respect what you feel, of course. I think (feel) that your inference that people shouldn't be associating with another person (even if SD limited) unless they're a relative or 'close friend' is
It's sunny down here today so I'll be out for a long cycle. I'll be wearing gloves; I'll not be going into shops or toilets; and I'll be washing my hands on return. What's the effect on the virus of sunscreen PF30, I wonder?
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