Now that the scientific wisdom has come around to the evidence that the coronavirus is spread through aerosolized droplets that could come from just talking or exhaling, some cities and counties have started making the wearing of facial coverings in public the law, with fines and possible arrests attached. But if Laredo, Texas is already doing this, why isn't San Francisco?

Sonoma County became the first locality in the Bay Area to make entering public spaces without a facial covering illegal by order of the county health officer on Monday. County Health Officer Dr. Sundari R. Mase wrote in the order, which goes into effect on Friday, "The age, condition, and health of a significant portion of the population of the County places it at risk for serious health complications, including death, from COVID-19." And, "COVID-19 is spread through respiratory droplets that are produced when an infected person coughs, sneezes or talks... [and it] has been shown to attach to surfaces for days and remain viable in the air for up to three hours after the infected person has left. When properly worn by the user, these facial coverings have the potential to slow the spread of the virus by limiting the spread of these droplets."

Violations of the Sonoma County order are misdemeanors "punishable by fine, imprisonment, or both."

The federal government and the CDC reversed their position on facial coverings almost two weeks ago, after spending two months telling Americans that only people who are sick or those in healthcare roles needed to be wearing them. And this came with warnings from the director of the CDC that as many as 25 percent of COVID-positive people are asymptomatic — i.e. not coughing at all and potentially unaware that they're infected — but are still able to spread the virus in public.

Since then, as the Washington Post reports, Los Angeles Mayor Eric Garcetti mandated facial coverings in public last week, and the city of Miami issued their own, similar order. Also, Montgomery County, which is home to one million people just outside Washington, D.C., issued a similar order with fines imposed on businesses as well for not enforcing social-distancing among waiting customers; New York governor Andrew Cuomo just issued a statewide face-mask order today; and Laredo, Texas imposed a fine of up to $1,000 over a week ago for failing to wear a face mask in public.

Grocery store owners and others tell the Post that county- and city-mandated orders like this make it easier to convince their workers to actually come to work at essential businesses. One store owner told the paper that he already had five employees refusing to come in for fear that they will be infected with the virus.

San Francisco stores like Bi-Rite and Safeway have installed sneeze guards to protect cashiers, but what if those aren't enough? Shouldn't everyone who steps into a grocery store in San Francisco — which has had seven times as many confirmed COVID-19 cases as Sonoma County thus far — be masked at this point in order both to protect themselves and protect vulnerable people in case they themselves are infected and asymptomatic?

The Chronicle published a Q&A Wednesday on whether people should be wearing masks in public, noting that AC Transit has already begun encouraging riders to wear masks on East Bay buses — though they're not required. And the concern seems to still be that people will hoard N95 and surgical masks that are critically needed right now for healthcare personnel. So, if you don't have a mask yet, refer to the tutorial below on making one at home out of an old t-shirt, no sewing required.

Previously: CDC Director: 25 Percent of Infected People May Be Asymptomatic