Travelers were required to wear masks inside Philadelphia’s main airport terminal Tuesday, but not after boarding many airplanes. They had to mask up to enter stores in the city, but not to ride the commuter rails.

As local and federal COVID-19 safety requirements changed yet again this week, Philadelphia stood out for rules that often came into conflict inside the city’s most crowded locations.

Philadelphia started the week by becoming the first large U.S. city to reinstate an indoor mask mandate, which some businesses are suing to block. Then late Monday, regional transit authorities SEPTA and PATCO dropped their longtime mask requirements after a Florida judge struck down a federal mask mandate for public transportation. Some airlines have allowed passengers to remove masks, no matter how packed their flight is, though they will be required to mask up when they arrive at the far more spacious terminals of Philadelphia International Airport to comply with the city’s mandate.

Similarly, you don’t need a mask to ride within the confines of a Regional Rail car, or to walk through Jefferson Station in Center City. But cross the threshold into the adjoining Fashion District mall — with its wide open spaces and soaring ceilings — and you need to slap that mask on your face.

The shifting pandemic safety guidelines from local and federal authorities have left many confused about what the rules are and how best to protect themselves. Two years into the pandemic, the policy patchwork also showcases the struggles of public health agencies to offer easily understood information and actionable guidelines.

“This was inevitable,” said Georges Benjamin, executive director of the American Public Health Association, of the confusion over the morass of pandemic guidelines. “Public health is governed at the local level, and as long as it’s governed at the local level you’re going to get this degree of difference in opinions.”

Yet all these layers of public health agencies — federal, state, county, municipal — left people like Latoya Maddox feeling vulnerable.

Maddox, who uses a wheelchair and plans to keep wearing her mask, said entities like SEPTA should still consider keeping their mask mandates. Many people with disabilities have underlying health conditions that make them susceptible to severe illness from the virus.

“A full busload or trainload of people, some with masks on, some without, for a person with a disability, it can cause a lot of confusion, a lot of anxiety,” said Maddox, a lead organizer at the disability-rights organization Philly ADAPT. “It’s not fair for those with disabilities and vulnerable populations.”

Nicole Kligerman, the Pennsylvania director for the National Domestic Workers Alliance, said SEPTA’s decision to drop mask requirements ignores how domestic workers, house cleaners, nannies, and caregivers often have no choice but to take public transportation to work. Most NDWA workers, she noted, are women of color and many are undocumented.

“Domestic workers have never been able to rely on the government to make sane public policy to protect them as workers. It comes as no surprise that the left foot and the right foot are walking in fully different directions,” she said of the differing standards across the region.

At the Philadelphia airport, most passengers still wore masks, and many accepted the contradictions as part of a new normal.

“It’s kind of just par for the course. Right? I mean, you go to a place that says put on a mask, you put on a mask,” said Media’s William Pohlhaus, 47, who is immunocompromised and was nervous about being in a plane with recirculated air. “You go to a place that says you don’t need a mask, then that’s your option, right?”

Traveler Julie Fowler, 49, who had been visiting family in Philadelphia, wasn’t wearing a mask but had one in her bag ready if anyone made a fuss as she prepared to fly home to Panama City Beach, Fla.

Wearing a mask “should be a choice at this point,” Fowler said. “I’m ready to get back to normal.”

‘Failure of communication’

When strategizing a response to a health threat, public health departments must consider whether people will actually be able to follow the recommendations, said Michael Siegel, a professor in the department of community health sciences at the Boston University School of Public Health.

He said the differing mandates “just seems very haphazard.” While some new guidelines seem designed to best protect people’s health, others seem motivated by a desire to return to normal life and restore the economy, he said.

“That’s the biggest failure of communication — people are being told to do things, but not why or what the goal is,” he said. “I would argue we don’t have a public health strategy. A strategy is something you can articulate and I cannot articulate any particular strategy.”

Philadelphia City Councilmember Allan Domb said many of his constituents are confused about the city’s mask mandate.

“Why would the city require them when no other municipality does? They don’t understand, and I don’t understand it either,” he said.

The answer to that question is complicated, said Keri Althoff, an epidemiologist at the Johns Hopkins Bloomberg School of Public Health.

The CDC makes recommendations based on national data, but instructs states and local jurisdictions to tailor those guidelines to fit their communities’ unique needs. Local public health agencies better understand health needs and trends in their area, she said.

“Our local public health guidance is where we really need to be focused right now,” Althoff said. “The community may not necessarily agree with all the guidance,” but local health officials are making decisions based on the risk factors, infection levels, and the socioeconomic background of their residents, she said.

Benjamin thinks public health agencies everywhere should send clearer messages at a time when people tend to think of a return to mask-wearing as a step backward.

He compared a periodic need for masking when case counts increase to wearing a rain jacket during a storm — when it passes, you can take it off.

“People have to think about this as an environmental condition,” he said. “The problem is we haven’t really sat down and said it that way.”

Olivia Ponce, a lab technician who works with the Garces Foundation’s COVID-19 testing operation, said she and other members of Philadelphia’s Latino community are frustrated by conflicting mandates, and still worried about the virus.

”Members of my community are on the front lines for every work: the restaurants, construction, we are cleaning,” she said. “I’m wearing my face mask, but what happens if you don’t want to wear a face mask?”

“I don’t want to get COVID again,” she said.

Staff writers Rodrigo Torrejon, Marina Affo, and Catherine Dunn contributed to this article.