Chinese health officials are warning that the number of lung cancer patients is skyrocketing as a result of tobacco use and air pollution. Experts say they expect a half million people to develop the disease by next year - a trend they blame on an economic boom that has put more cars on the streets and added plenty of stress to daily life for millions of urban Chinese.

Liao, a 55-year-old businessman from the southern industrial city of Guangzhou, lights a cigarette as he leaves an upscale restaurant in east Beijing.

He says smoking helps him relieve pressure when things get stressful. He says everyone knows that smoking is harmful. And, he says, if he refused a cigarette in a business setting, he would be viewed as antisocial. Experts say China now accounts for 40 percent of the world's new lung cancer cases. It is also the world's biggest consumer of tobacco; nearly two trillion cigarettes are sold in China each year - about one-third of all cigarettes produced worldwide.

Many Western nations have seen a drop in smoking rates as a result of anti-smoking campaigns and greater health awareness. But in China there is little public information on the dangers of smoking and the majority of men - including 60 percent of male doctors surveyed - use tobacco products.

The smoking trend is showing no signs of reversing, with government statistics showing more young people taking up the habit each year. Officials estimate 50 million of China's 350 million smokers are teenagers.

The new statistics on lung cancer confirm the worries of Chinese officials, who have been sounding the alarm about unhealthy lifestyles taking root alongside prosperity.

"China now is confronted with the problem of its own success," says Bob Dietz, who is the World Health Organization in Beijing. "We're seeing a whole new level of diseases come into play: diabetes, cardiovascular diseases, muscular-skeletal diseases, because people are leading inactive lifestyles."

In addition, in large cities such as Beijing and Shanghai, health experts say obesity and cholesterol levels are on the rise.

Lung cancer and other smoking-related diseases are expensive to treat - with medical costs for patients in the Western countries often topping $100,000. Experts fear China lacks the resources to care for the rising number of cases its medical system confronts.

After making great strides in life expectancy throughout the 1970s, improvements have stalled. Professor Liu Guo En, who heads the department of Health Economics at Peking University, says this is due to a lack of investment in public health.

"After [the] 1980s, as China transitioned to a market economy, we see the health trend gets stagnated, meaning the trend is not getting worse but it's not as good or as fast as before," he said.

Some Chinese officials have started to propose public health measures, including expanding nonsmoking areas in public places, restricting tobacco advertising, and imposing higher tobacco taxes - all long in use in the West. The WHO's Bob Dietz says Chinese leaders will have a hard time making these proposals stick.

"Tobacco becomes an incredibly sensitive political issue in which you have vested interests. It's a fundraiser for the state," he said. "You have tobacco-growing regions in China which are heavily dependent on tobacco production."

State-run media say China has promised to set limits on new tobacco companies and may take steps to ban tobacco-related joint-ventures - a move that may be challenged by foreign tobacco companies vying to get a foothold in the Chinese market.

In July, the government denied reports that it would allow the British American Tobacco Company to build a joint-venture factory that would have been the first foreign cigarette maker in China. Analysts at the time said China's reluctance to publicize such a deal had less to do with health concerns and more to do with fear of a backlash from domestic cigarette manufacturers.