New York is introducing an outdoor smoking ban. But could the UK and other countries follow suit, asks Tom de Castella.
It is a city heralded for attracting incomers from around the world, but New York has just become less hospitable to one group - smokers.
Under measures approved by local authorities, swathes of outdoor public places including beaches, municipal parks and even Times Square have become tobacco-free.
And with smoking legislations, as with so much else, where New York leads, the rest of the world can find itself following.
After the city banned smoking in restaurants, bars and clubs in 2003 - itself following Los Angeles, which introduced similar curbs a decade earlier - it helped drive a global trend.
France, India, Ireland and Italy were among the nations which introduced bans after New York. Scotland prohibited smoking in enclosed public spaces in 2006 and the rest of the UK followed the year after.
So it is not surprising that the latest development in New York is attracting global interest.
The city's latest anti-smoking measures cover public golf courses and sports grounds as well as plazas like Herald Square.
Smoking will be allowed on pavements outside parks, and car parks in public parks. One area the ban does not cover is "median strips" - known as the central reservation in the UK - the sliver of land in the middle of a large road.
City authorities say they hope the new law will be enforced by New Yorkers themselves. But if someone refuses to stop, the public is advised to inform park wardens, and should someone refuse to stop smoking they could be fined.
The New York ban itself comes after Spain outlawed smoking near hospitals or in school playgrounds from January 2011. But whether other countries follow suit largely depends, of course, on whether the move proves effective.
New York Mayor Michael Bloomberg's office has cited studies suggesting that sitting three feet away from a smoker outdoors can expose people to the same passive smoking risk as would occur indoors.
Not all those who oppose smoking believe the ban is justified, however.
Michael Siegel, professor of community health sciences at Boston University, wrote in the New York Times that the ban was "pointless" from a public health perspective and could, in fact, increase the risk of passive smoking by creating "smoke-filled areas" near park entrances.
Whichever way the debate in New York is resolved, it will be watched closely abroad. Prof John Britton, chair of the Royal College of Physicians Tobacco Advisory Group, says the very existence of the ban could have an impact on countries like the UK.
He says the risks of second-hand smoke outdoors are "quite small unless you're right next to the smoker".
However, Prof Britton believes that seeing such a system in operation would convince those who might otherwise argue that such legislation would be unworkable.
"They did it when smoking on the London Underground was banned [in the 1980s]," he says. "Then they did it with the smoking ban in July 2007. But once it comes in, not only do people accept it, they say 'Why didn't we do it before?'"
Indeed, smoking bans are coming into effect in countries where observers would not have easily imagined citizens giving up their cigarettes.
China - home to one-third of the world's smokers - outlawed smoking in bars, restaurants and buses from 1 May 2011 and Russia plans to implement similar legislation from 2015.
This July will be the fourth anniversary of the ban on smoking in public places having reached all parts of the UK.
In the year following its introduction, more than two billion fewer cigarettes were smoked and 400,000 people quit, according to researchers at University College London.
As a result, the UK smoking lobby is watching developments across the Atlantic with trepidation.
Simon Clark, director of Forest, which campaigns against smoking bans, believes the New York initiative is "ludicrous" and that there is no evidence that anyone is at risk as a result of someone else smoking in the open air.
Some political leaders in the British Isles have already begun looking at tightening the law further.
In March 2011, the public health department in Jersey said it was considering whether to ban smoking in all motor vehicles on the island.
Martin Dockrell, director of research and policy at the campaign group Action on Smoking and Health (Ash), acknowledges that there is no clear evidence of a significant harm to health from second-hand outdoor tobacco smoke.
But he says there are compelling reasons for banning smoking in some outdoor areas, such as children's play parks, as a means of shifting long-term attitudes.
And he argues that if such a ban is put into place, it will not be due to the influence of New York - but because the tide of UK public opinion has hardened against smoking.
"It already has happened in the UK," he says. "Glasgow has smoke-free parks. In the north-west of England there are a number of parks that have gone smoke-free.
"We'll see more of this incrementally as more and more communities become non-smoking."
Smokers and non-smokers alike will make up their own minds in the months ahead.
What remains to be seen is not just whether the new ban can make it in New York, but whether it can make it anywhere.