Space and time: Why 6 feet isn't enough


By Bob Hembree
Lake Powell Chronicle

Each exhale from an infected person contains millions of coronavirus particles.


University of San Francisco research scientist Jeremy Howard said, “Recent research from (the Massachusetts Institute of Technology) and Stanford has shown that when we speak, little saliva microdroplets come flying out of our mouth, 6-feet or more. It depends how loud we talk; it depends what specific thing we’re saying, but there’s always this little stream of droplets. Those droplets, if you’re infected, contains millions of particles of virus.”


Droplets linger in the air.


According to Dr. Linsey Marr, an aerosol scientist at Virginia Polytechnic Institute and State University, “Droplets are larger respiratory particles that are 5 to 10 micrometers in size. Those are considered “big,” even though a 5-micrometer particle would still be invisible to the naked eye.” Mar added, “Even a 5-micrometer droplet can linger in the air. “If the air were perfectly still, it would take a half-hour to fall from a height of 6 feet down to the ground. And, of course, the air isn’t perfectly still. “It can easily be blown around during that time and stay in the air for longer or shorter.”


Marr said she believes transmission by inhalation of virus in the air is happening.
Coughs and sneezes increase the danger. They create turbulent clouds of gas that can propel respiratory particles well beyond 6 feet.


Dr. Sui Huang, a molecular and cell biologist at the Institute for Systems Biology in Seattle, Washington, said, “If we are soon loosening the lockdown due to the political pressure to sustain the economy, perhaps encouraging face masks to be worn in the public would be a good compromise between total lockdown and total freedom that risks resurgence of the invisible enemy. There is now a robust scientific basis for putting an end to the officials’ anti-surgical mask hysteria and to recommend or even mandate a broad use of masks as in Asian countries that have bent the curve.”





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