Pittsburgh may have the world's largest "green" convention center, but it could soon be in big trouble. A growing number of professional associations ranging from the Girl Scouts to the American Public Health Association are refusing to hold national meetings in cities that permit smoking in public places. While the city and its airport are poised for greatness on the convention front, and bookings have continued to grow in recent years, this bright future may be in jeopardy.

Every day at the Hillman Cancer Center and the other UPMC Cancer Centers throughout Western Pennsylvania, my colleagues treat the tragic human consequences caused by years of smoking. Too many people, who started smoking as young teenagers, find themselves struggling to breathe by the time they reach middle age.

Women appear especially vulnerable to the hazards of smoking. Lately, more and more otherwise healthy women, such as Dana Reeves, the wife of the late actor Christopher Reeves, are developing cancer even though they never smoked themselves. In many cases, lung cancer in nonsmokers can result simply from having the misfortune of either growing up or working with smokers.

When it comes to the consequences of smoking, we are all paying a heavy price. In a report this past summer, the Society of Actuaries asserted that, in the United States alone, the cost for medical bills and lost work due to tobacco-related health problems amounts to $10 billion each year.

We see the medical consequences of tobacco at UPMC Cancer Centers, and we also see the human and emotional toll caused by smoking, a completely avoidable cause of illness and death. While we have made tremendous progress in our ability to find cancers earlier and treatments have become less toxic, the fate of those with lung cancer remains problematic. Early in my research career, I discovered natural killer cells, remarkable immune cells in the blood that can sometimes destroy tumors. We are still learning how to stimulate the immune system for cancer therapy. Unfortunately, lung cancer is still a very difficult disease to cure.

Smoking remains fundamentally a public health threat. We must address it as part of an overall strategy to protect public health, with laws and regulations, as the surgeon general and many officials have repeatedly advised.

Growing numbers of physicians and cancer researchers, and a wide array of other stakeholders concerned about cancer, across the state and the nation agree that we must take a position against tobacco smoking. The Pennsylvania Cancer Control Consortium, which I chair, includes the leaders of all the state's major cancer research and treatment centers plus key representatives of the health insurance industry, pharmaceutical and biotech industries, community hospitals, foundations and cancer survivors. We are convinced of the need for social policy to control this serious health hazard.

The leaders of PAC3 have taken an extraordinary, unanimous position. We recommend that the state act now to ban smoking in public places. Very similarly, C-Change, the national organization of cancer-related stakeholders of which I am a member, has issued a Call to Action. The time for debate is long past. More than 10 other states have already taken this action, as have the nations of Italy, Ireland, Iran, Sweden, Norway, Uganda and Australia. Even the French are moving ahead on this front.

Several major U.S. cities, including New York, San Francisco and Denver have banned smoking from restaurants and bars. Contrary to the warnings that businesses would suffer after restrictions on smoking in public places were put in place in these cities, business has boomed. According to a one-year review report released by the New York City Department of Finance in March 2004, business tax receipts in restaurants and bars were up 8.7 percent and employment in these establishments was increased by 11,600 since the law was enacted on June 23, 2003.

Growing revenues in the restaurant and entertainment industry are easy to quantify. What cannot be counted as easily are the dramatic health benefits that have resulted from banning smoking indoors. These include fewer workdays lost by those forced to work in the smoky hazes of bars and restaurants, lowered health care costs and premiums for all of us and reduced costs of cleaning up cigarette butts.

Scientists have amassed considerable proof through natural experiments that have been conducted in these various locales. If you want to improve public health, it's simple -- restrict smoking in indoor public spaces. Fewer people will smoke. Fewer still will be exposed to the dangers of passive smoke as innocent bystanders.

According to government estimates, implementation of the U.S. Clean Air Act from 1970 to 1990 saved a quarter of a million lives and about $22 trillion. Every dollar spent enforcing this act, produced about $40 in benefits, ranging from reduced hospital admissions for asthma to fewer deaths from stroke and heart attack. At the center of the Clean Air Act are standards that limit daily average levels of exposure to fine particles of 50 micrograms per cubic meter, based on the latest scientific evidence from government and private sector experts. Fines can be issued against polluters who exceed permitted levels of pollution.

Wherever smoking is allowed indoors, levels of particulate air pollution can be three times as high as those that are banned under the Clean Air Act. Yet, there are no penalties in Pennsylvania for restaurants or workplaces where conditions routinely violate outdoor standards for particles.

We must confront this issue in Pittsburgh and in the Commonwealth. Tobacco revenues currently fund a host of activities aimed at reducing smoking through voluntary efforts, and these are certainly having a significant impact. However, we are missing the boat if we fail to forge ahead also with mandatory actions, like those already taken in so many other parts of the country and the world.

We have made immense strides to transform Pittsburgh from the city described in years past as "hell with the lid off," in part because of laws that curtailed many sources of old pollution. By tackling indoor public smoking, our city can extend its legacy to protect the public's health now and in the future. We also will preserve the potential of our convention center to attract new businesses, as growing numbers of clients insist on smoke-free environments.