Smoking in Beijing is now prohibited in all indoor public places, including offices, shopping malls and airports, as well as at outdoor stadiums, school grounds and public parks. Beijing's main airport terminal will close its three smoking rooms.
Fines for violators have been raised to 200 yuan ($32), up from the 10 yuan ($1.60) charged under the former partial ban, and for the first time owners of restaurants and other businesses are responsible for ensuring compliance and can face fines up to 10,000 yuan (about $1,600) if they fail to do so.
While members of the public generally expressed support for the ban Monday, it remained to be seen how uniformly the new rules would be heeded and enforced.
"Of course (smoking) influences our health because secondhand smoking is more damaging than smoking," said Xu Jiawen, a housewife and the mother of a 4-month-old baby. "I think it's best for everyone to stop smoking in public places."
The World Health Organization says that 300 million Chinese smoke, including about half of all men, and that 740 million Chinese are exposed to secondhand smoke. The group says lung cancer kills more than 1.3 million people in the country each year — a third of the global total.
Other cities have issued partial smoking bans and cigarette sales to minors are technically forbidden, although enforcement has been spotty at best.
China had long been reluctant to fully crack down on smoking, partly because of the tax revenue that cigarette sales bring in. However, official attitudes have evolved along with the realization that the public health costs far outstrip tobacco's contribution to the public purse.
Amid worsening pollution and growing affluence, cancer is now the leading cause of death in China, with lung cancer at the head of the list.
Beijing, meanwhile, has been seeking to promote civilized behaviour on a par with its aspirations to become a major world capital. Smoking in public places is seen by many as a drag on quality of life, alongside complaints over heavy traffic, line-jumping and the city's notorious air pollution.
While many restaurants appeared to be enforcing the new rules and more than the usual amount of people could be seen going outside of buildings to smoke Monday, enforcement seemed to be nonexistent at one downtown coffee shop, where smokers continued to puff away.
World Health Organization anti-smoking expert Angela Pratt said that, if properly enforced, the smoking ban could help change the general acceptance of smoking as routine.
"That's what we have seen all over the world when strong smoke-free laws are adopted and there is strong enforcement effort. The social norms changed," Pratt said.
Tobacco shop owner Sun Jinhua said he expected the ban would cut into his business and convince more smokers to quit.
"Many of my old customers want to quit smoking because there is nowhere to smoke," Sun said.
However, along with the general tolerance of smoking, the habit is supported by low taxes that keep the price of cheaper brands at as little as $1 per pack. At around 43.4 per cent, China's cigarette tax is almost 20 per cent less than the rate in Japan and Singapore, two Asian countries with high rates of smoking.
That helps keep China's smoking rates on the rise, especially among the young, although women are far less likely to smoke than men.
According to the official Xinhua News Agency, more than 50 million cartons of cigarettes were sold in China last year, an increase of 37 per cent over the previous year.
Xinhua also cited a study by the disease control and prevention centre of Beijing's Chaoyang District that found cigarettes for sale within 100 metres (yards) of two-thirds of Beijing's 87 middle schools.
Only 38 per cent of shops selling cigarettes displayed signs banning sales to minors, and inspectors who wore school uniforms while trying to buy cigarettes were blocked less than 20 per cent of the time.
Associated Press journalists Isolda Morillo and Christopher Bodeen contributed to this report.