Pennsylvania Gov. Tom Wolf (D) on Friday afternoon asked residents to wear a mask outside of their homes to prevent the spread of the Chinese coronavirus.

“Two days ago, I amplified our social distancing efforts by instituting a statewide stay-at-home order, and today I am asking all Pennsylvanians to wear a mask any time they leave their houses,” Wolf said in a press conference. “Masks help prevent people from sharing illnesses. But, they don’t do a great job at keeping people from getting sick; and, they’re not foolproof, so it is critical that our first act is to ask ourselves if we really need to leave our house.”

“If we don’t really, truly need to leave, then we shouldn’t,” he added.

In addition to Wolf’s plea, the Pennsylvania Department of Health asked residents not to purchase masks, for healthcare professionals such as doctors and nurses face a shortage of masks across the country.

Pennsylvania remains under a “stay-at-home” Order through April 30. The state has 8,420 confirmed virus cases and 102 deaths.

“The continued rise in cases combined with our increasing deaths from COVID-19 reflects the seriousness of this situation,” Secretary of Health Dr. Rachel Levine said of the latest figures. “We need everyone to listen to the orders in place and to stay calm, stay home and stay safe. We know that these prolonged mitigation effects have been difficult for everyone, but it is essential that everyone follows these orders and does not go out unless they absolutely must.”

On Thursday, Los Angeles Mayor Eric Garcetti urged the city’s four million residents to don masks, homemade cloth masks, or a “tucked-in bandanna” to fight the spread of the coronavirus.

“I know this looks surreal,” Garcetti conceded, before adding: “We’re going to have to get used to seeing each other like this … This will be the look.”

Laredo, Texas, officials threatened this week that those who refuse to wear masks could face a fine of up to $1,000.