San Francisco is ordering everyone to wear masks in public, with violators subject to possible fines or jail time

• San Francisco will start requiring residents to wear a mask in public.
• While the law will require residents to wear masks at essential businesses such as grocery stores and takeout restaurants, residents will not have to wear them when outdoors for exercise — though they should have one on hand, the city says.
• The city is again relying on voluntary compliance, although noncompliance is considered a misdemeanor punishable by fines, jail time, or both.
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San Francisco will start requiring people to wear a mask when they leave their homes for essential needs.

Based on guidelines issued by the Centers for Disease Control and Prevention, the city's new order will require residents to have a mask covering their nose and mouth at essential businesses, public facilities, and on public transit. That includes waiting in line to enter a grocery store or picking up food from a restaurant. Essential workers are also required to cover their faces.

However, people are not required to wear face coverings while outdoors walking, hiking, bicycling, or running. They're instead recommended to have one on hand.

The mask does not need to be an N-95 or surgical mask — it can be a homemade mask, bandanna, scarf, or a towel. The order is part of the city's efforts in preparing for eventual relaxed shelter-in-place restrictions.

"As we look to a time where we can begin to ease the Stay Home Order, we know that face coverings will be part of that future – and we want San Franciscans to become more comfortable with this new normal," Mayor London Breed said in a press release. "We know it will take some time to get used to, but it will help save lives."

The order, issued by County Health Officer Tomás Aragón, is effective going into Saturday, but will not be enforced until April 22. A similar order was announced by New York Gov. Andrew Cuomo on Wednesday.

The coronavirus disease, known as COVID-19, is transmissible through respiratory droplets. Wearing a mask can help prevent sick people from infecting others as well as healthy people who aren't exhibiting symptoms from passing it onto others.

San Francisco was one of six counties in the Bay Area that enacted a shelter-in-place order on March 17.