NEW YORK >> Eric Leventhal felt a sneeze coming and panicked.

The Brooklynite left his cloth face mask at home for a morning run in a park last week. Walking home, he turned toward an empty street and let the sneeze out, hoping no one would notice.

Too bad for him, there’s no hiding without a mask in virus-stricken New York City.

“I picked my head up and I caught eyes with a woman who was wearing a mask, an older woman,” Leventhal recalled recently. “She was just kind of shaking her head.”

Leventhal, 36, is caught in the middle of a debate over when and where, exactly, it is necessary to wear a mask in a city where COVID-19 has now claimed more than 20,000 lives.

Since April 17, everyone in New York state has been required to wear a face-covering in any place where they can’t stay at least 6 feet from people who don’t live with them. Only children younger than 2 and people with a medical excuse are exempt.

Similar rules are in place in New Jersey and Connecticut, and were recently put in place in Massachusetts. The British government told people to start covering their mouth and nose in shops, buses and subway trains just this week.

Yet, while the rule is clear, New Yorkers have adopted their own interpretation of when masks are required.

It isn’t unusual to see groups of park goers and essential workers — even police officers — leaving their masks dangling as they squeeze past people on sidewalks or chat with friends. They are perhaps most rarely used among people trying to exercise.

“Everything is fraught with life and death consequences, and it’s just hard to grapple with that at any one moment,” said Leventhal, the runner. “That’s a long way of saying, I should be wearing one, probably, but it’s difficult when you run, so I don’t.”

As warmer weather beckons people outside, more chances emerge for confrontations between mask believers and mask doubters.

Gov. Andrew Cuomo, who says people are fine not wearing a mask if they are out walking alone, but need to put one on if someone approaches, on Tuesday described confronting a maskless man he encountered while walking his dog.

“We were in a little bit of a disagreement and the situation, the conversation got a little tense. So I stopped the conversation,” Cuomo said.

Elissa Stein, a 55-year old activist and graphic designer living in Manhattan, went as far to make T-shirts with a more profane version of the message “Wear Your Mask.” Stein gets stares when she wears the shirt, but she said it’s worth it given the stakes.

“It shouldn’t be something that you take lightly,” she said. “This is not a joke.”

There are no fines, under the state rule, for not wearing a mask. Mayor Bill de Blasio has said he favors education over enforcement, pledging to distribute 7.5 million masks to the public.

There have been mixed messages from other politicians.

President Donald Trump has eschewed wearing a mask in public, though on Monday, the White House ordered anyone visiting the West Wing to wear one after some staff were infected with the virus. The Centers for Disease Control and Prevention advises using face coverings because they could help prevent people who have virus, but don’t know it, from transmitting it to others.

The personal politics of masks caught up to Norm Scott, 63, of Brooklyn, when he got heat on one website for saying studies show the risk of the virus spreading outdoors, compared to indoors, is minimal. Scott said he merely wanted to bring perspective to the situation.

“I’m not telling people to not wear a mask,” said Scott, who says he too wears one in public. But, he added, “posting on a public forums about how runners or millennials are going to infect us is ridiculous. … I believe in social responsibility. I don’t believe in social shaming.”

The scenes in New York City’s parks as the weather warmed up demonstrate the varying mores about covering faces in public. Among bikers and runners out one recent morning, some wore masks, some had face coverings pulled down around their necks and some — including a man running past a sign imploring park-goers to wear masks — were entirely maskless.

At a popular cupcake shop in Chelsea near the Manhattan park, a “mask required” sign on the window gave those standing in line an incentive to follow the rules — no mask, no cupcake.

In Brooklyn, Dovid Shlomo Halevi Kurtz, 69, said he doesn’t feel any guilt about being barefaced. He is confident in God’s plan. Also, the mask fogs up his glasses.

“I can’t breathe and then I can’t see, what good is that?” Kurtz said after finishing a walk in Prospect Park with gloves on, but no mask. “Should I wear it? No. I don’t have (COVID-19), I’m not giving it to anybody and I’m not getting it.”

Besides, he said, “It’s like a car accident, God forbid, or a lightning bolt. If God wants you to have it, you’ll have it. If God doesn’t want you to have it, you won’t have it.”

Actor Jon Michael Hill, 35, had a different approach as he ran in Manhattan wearing a mask. Health concerns aside, covering his face sends a message.

“Symbolically,” he said, “it’s about respect.”

Cuomo had a similar message for the barefaced man he encountered on his recent walk.

Masks, he said, say “I respect you. I respect your health” to the people around you.

“This mask says, ‘I respect the nurses and the doctors who killed themselves through this virus to save other people,’” he said. “This mask says, ‘I respect the essential workers who get up every day and drive the bus, or drive the train, or deliver the food, or keep the lights on so I can stay home and I can stay safe.’ And that is a statement that we should all be willing to make any day, but especially in the middle of this.”