Chinese health experts estimated that passive smoking has affected about 540 million people out of the country's 1.3 billion population.

Passive smoking, especially in public place, has been a serious health problem in China, said Li Hengyuan, deputy secretary-general of the All-China Environment Federation (ACEF), a leading environmental non-governmental organization, on Tuesday.

Passive smoking, meaning involuntary inhalation of smoke from tobacco products, could increase the incidence of cardiovascular and respiratory diseases and even lead to lung cancer.

"The only way to protect the public from passive smoking is to completely ban smoking in public and working places," Li said.

The Chinese capital Beijing will start a smoking ban in public places from May 1.

The city government announced a regulation banning smoking in some public places on April 10 to replace an old one adopted in 1995.

"It is the first time that a ban is imposed on offices," said Rao Yingsheng, official with a health commission under the city government.

The ban also covers hospitals, schools, restaurants, pubs, cafes, gyms, air ports, railway stations, hotel rooms and parks, Rao said.

But, Monday's China Daily reported that the new rules were a step back from a blanket smoking ban in restaurants. Instead, business owners are asked them to separate smoking and non-smoking areas.

Li suggested that the smoking ban should be written into laws and the government encourage NGOs to supervise the implementation.

"We should work, step by step, to realize a full ban against smoking, including abandoning smoking rooms," he said.

The country has about 350 million smokers, 14.28 percent of whom are teens, according to a report issued by the Ministry of Health in 2006.

It estimated that about two million Chinese will die of smoking in 2020 and half of them aged between 35 and 64.

(Xinhua News Agency April 16, 2008)