Ten years ago, Ireland became the first country in the world to ban smoking in the workplace. On 29 March 2004, the air cleared in Ireland's bars, restaurants and other buildings - and there was hardly any backlash. The pub-loving nation became the model for a global health revolution. In the decade since, countries across the world have passed smoke-free laws of their own. In this programme, the BBC's former Ireland Correspondent Denis Murray looks at the impact of this type of anti-smoking legislation across Europe - and considers the future of tobacco. Denis's journey begins in Dublin, where he recalls how radical a move the smoking ban was at the time. His old haunt, Mulligan's bar, used to be memorable for its blue, reeking fug. And the success of the ban in Ireland made international news - leading other countries to follow suit. So Denis travels to two very contrasting cities to compare attitudes to smoking ten years on. The Czech Republic has the most liberal smoking laws in the European Union. In Prague, going to a bar can feel like stepping back in time - many of them permit smoking. France, so long synonymous with romantic movies featuring characters speaking to each other through clouds of smoke, has followed Ireland's lead and banned smoking in public places. Paris is a city with a fascinating relationship with tobacco - where the debate is often about philosophy as much as science. In a journey across three countries, with a cast list of doctors, politicians and businesspeople - with the odd musician and philosopher thrown in - "Clearing the Air" poses and answers many questions about the effect which smoke-free laws are having on health and society. Producer: Chris Page.