Jul 21 2020

30 feet is the COVID Safe Unmasked Distance in Alameda County Rule

What is a Safe Social Distance?  Where did the 6 foot Rule Originate?

A Journal of the American Medical Association article by a particle fluid dynamicist at the Massachusetts Institutes of Technology suggests unmasked people might do well to stay more than 27 feet apart (8.2 meters) to avoid infecting one another.  It finds “wearing of appropriate personal protection equipment is vitally important for health care workers caring for patients who may be infected, even if they are farther than 6 feet away from a patient.”  See American Medical Association article here.

The World Health Organization recommends three-feet is wide enough social distancing based on the 1930s practice in treating tuberculosis.  But in 2003 it was found that SARS infections were communicated between people six feet apart—not three.  See December 2003 New England Journal of Medicine article here.

All of these distance reports focused on droplets, which fall.  However, the much smaller aerosols linger and move through the air as they are evaporating.

The Alameda County Public Health Officer ordered face coverings be worn at all times in public, if you are or are likely to be within 30 feet of another person outside of your household:

A person does not need to wear a Face Covering when outdoors alone or with a member of their Social Bubble and they have a Face Covering visible and immediately ready to cover the nose and mouth (such as hanging around their neck) and nobody else (other member of their own Social Bubble) is outdoors within 30 feet (10 yards) of them. It is recommended that people from the same household or living unit wear a Face Covering when outside, even if others are not nearby, any time others may appear without much notice.

Read the Alameda County Public Health Officer order on face coverings here.

On June 18, 2020  California’s Governor Newsom declared Californians must wear face masks in public under State coronavirus order.  A few days later the Governor threatened to withhold $2.5 billion in the upcoming budget from local governments if they don’t enforce the state’s orders on wearing masks, testing and other measures in place to slow the spread of COVID-19. 

One Response to “30 feet is the COVID Safe Unmasked Distance in Alameda County Rule”

  1. I walk a lot and it amazes me how many people in Piedmont don’t even carry (at least visibly) a mask. They walk past you and seem shameless.

    I wish PPD officers would start warning people.

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