In 146 countries around the world, smoke-free now means exactly that.

As well as agreeing to draw up international laws against cigarette smuggling, officials at a major World Health Organization (WHO) anti-tobacco meeting adopted stringent definitions of what it means to have a smoke-free bar or office.

The guidelines, which are not legally binding, stipulate that there is no safe level of exposure to tobacco smoke, adding explicitly that half-way measures such as designated smoking areas, air filtration or ventilation do not work.

These guidelines are important to counteract some of the industry myths, Douglas Bettcher, head of the WHO's Tobacco-Free Initiative, told a news conference on Friday.

The tobacco industry knows that if you ban smoking entirely in public places and work places it will encourage smokers to reduce their consumption and encourage them to quit. It also reduces the chances that people will initiate the habit.

The industry says second-hand smoke is a nuisance. It's not a nuisance. It's deadly. It's lethal. It's a Class A carcinogen, Bettcher said.

The guidelines do not apply in the United States, Russia or Indonesia, three countries that are not members of the WHO's Framework Convention on Tobacco Control (FCTC).

However, anti-tobacco campaigners hope they will still act as a benchmark by which national, state and municipal rules in the three countries will be judged.

WHO officials said they were also optimistic that Russia would accede to the FCTC soon following a recent demonstration of political will in Moscow to address the chronic public health problems in Russia caused by tobacco and alcohol.

The week-long conference in the Thai capital also started to lay the groundwork for international laws against cross-border tobacco advertising as part of a global masterplan to get the world to kick the habit.

One billion people would die of tobacco-related diseases this century unless governments in rich and poor countries alike got serious about preventing smoking, Bettcher said at the start of the conference.

However, if they introduced tried-and-tested policies such as aggressive taxation, banning cigarette advertising and establishing totally smoke-free public places, global smoking rates could halve by 2050, he said.