World of Beer in Rockville already bans smoking in its outdoor dining area, but many restaurants and bars do not. The Rockville City Council will vote Monday on whether to ban all outdoor smoking in sidewalk cafes and outdoor dining establishments. (BT/Bill Turque/The Washington Post)

In an increasingly smoke-free world, the outdoor restaurant table has become a kind of last redoubt for lighting up in public.

But on Monday, the Rockville City Council is expected to eliminate that refuge by passing a ban on smoking or vaping in outdoor dining areas and bar patios.

The suburban Maryland city of 66,000 would become the largest Washington-area locality to snuff out the practice and would join a lengthening list of jurisdictions nationwide.

As of last month, more than 230 cities and counties, four states (Hawaii, Maine, Michigan and Washington) and the Commonwealth of Puerto Rico mandated smoke-free outdoor dining and drinking, according to Americans for Nonsmokers’ Rights, a lobbying group. That includes just one other community in the Washington region — La Plata, Md., population 9,000, about 35 miles south of the nation’s capital in Charles County.

While the health risks posed by secondhand smoke have been well understood for many years, much of the focus has been on indoor exposure. A growing body of more recent research indicates that, under certain conditions, outdoor tobacco smoke can be just as harmful, both to nonsmokers and workers who wait tables. Some studies show that air quality inside “smoke-free” restaurants also suffers from outdoor smoke.

“I think people have this false sense of security that when they are outside, exposure to secondhand smoke isn’t much of an issue,” said Rockville City Council member Julie Palakovich Carr, the bill’s sponsor and a biologist by training. “I think it’s an important health issue for our community.”

The ordinance would cap more than a decade’s worth of measures by Rockville, Montgomery County and Maryland to ban smoking in government buildings, workplaces, parks, playgrounds, and inside drinking and dining establishments. Effective in 2018, the U.S. Department of Housing and Urban Development will prohibit smoking in all public housing units and common areas.

Smoke-free space has become so much the norm it is widely assumed that the ban covers virtually every public area. That is especially true in Montgomery, which has built a reputation — and drawn some criticism — as a nanny state, with laws mandating healthy vending machine offerings and barring trans fats from restaurant menus.

“I guess you can still smoke in this county, if you dig a bunker a couple hundred feet below the surface and nobody’s around and you make sure it’s enclosed,” quipped Montgomery Circuit Court Judge Terrence J. McGann, a nonsmoker, during a hearing last week on another health-related law, this one barring the use of certain pesticides on private lawns in the county.

A walk through Rockville Town Square during lunchtimes and happy hours last week found few smokers at outdoor tables, most of them not eager to talk about the issue — and some under the impression that a ban on smoking in outdoor dining areas was already in place.

“I didn’t know you could do that,” said Madison Bump, 26, a smoker who works for a nonprofit in downtown Rockville, who added that he is extremely cautious about where he lights up.

“I think among our generation, many smokers feel ostracized. We’re like lepers,” he said.

While Carr is sponsoring the ordinance, the real energy behind the proposal is Adam Zimmerman, a Rockville resident who became concerned about his young daughter’s exposure to secondhand smoke during outings on the square.

In 2013, he lobbied the council for a ban on smoking in city parks — including the civic green on the town square — which the council passed two years later. Then he turned his attention to the outdoor tables bars and restaurants that line the square.

“When we walk inside of a restaurant we’d be shocked if someone was smoking a cigarette inside,” said Zimmerman, 35, a senior associate for a communications firm that works with nonprofits. “We should have the same expectation on an outdoor patio.”

The measure has drawn only modest opposition from Rockville bar and restaurant proprietors. They are less concerned about protecting smokers than with what they see as the latest in regulations that plague small businesses.

“My main concern is that we have too many laws. Too many laws and spending a lot of money enforcing them,” said Sudhir Seth, who owns Spice Xing, an Indian restaurant on Gibbs Street off the Town Square.

Seth, 59, who smoked for 37 years before quitting a year ago, said Rockville officials should be more concerned about expensive parking and the lack of top-line retail stores downtown. “This will be another nail in the coffin,” he said.

There is stronger pushback from owners and customers of Rockville’s hookah lounges, which are also covered under the proposal. The state’s clean-air law treats them as tobacco retailers, because they usually serve no food. But the Centers for Disease Control and Prevention says secondhand smoke from hookahs, flavored tobacco smoked through a water pipe, also poses health risks to nonsmokers.

The owners of Sam’s Hookah Bar & Cafe on Rockville Pike have collected 200 signatures on a petition opposing the ordinance. The business is wedged into a shopping strip. The outdoor tables, which owner Marvin Motaghi said generate important extra income, look out onto a driveway next to a mattress store, where pedestrian traffic is rare.

“I don’t agree with it whatsoever,” Motaghi, whose family has been in business for 18 years, said of the ordinance.

Without an outdoor smoking area, “we’re going to barely make ends meet,” he said. “We’re not a franchise where we can grab money from one store and put it into another.”