Not long ago, nonsmoking airplane passengers had no choice but to breathe clouds of smoke as other passengers lit up cigarettes in the next row. Restaurant patrons smelled acrid tobacco smoke along with their meals, and many employees in shared workspaces had to share air clouded with second-hand smoke.

This casual acceptance of smoking was the norm when the American Cancer Society’s Great American Smokeout went nationwide 31 years ago. Those three decades have marked dramatic changes in the way society views tobacco promotion and tobacco use. Many public places and work areas are now smoke-free, which protects non-smokers and supports smokers who want to quit, according to information from the American Cancer Society.

The Great American Smokeout has helped to spotlight the dangers of tobacco use and the challenges of quitting, but more importantly, it has set the stage for the cultural revolution in tobacco control that has occurred over this period.

Because of the efforts of individuals and groups that have led anti-tobacco efforts, there have been significant landmarks in the areas of research, policy, and the environment:

— In 1977, Berkeley, Calif., became the first community to limit smoking in restaurants and other public places.

— In 1983, San Francisco passed the first strong workplace smoking restrictions, including bans on smoking in private workplaces.

— In 1990, the federal smoking ban on all interstate buses and domestic flights of six hours or less took effect.

— In 1994, the state of Mississippi filed the first of 24 state lawsuits seeking to recuperate millions of dollars from tobacco companies for smokers’ Medicaid bills.

— In 1999, the Department of Justice filed suit against cigarette manufacturers, charging the industry with defrauding the public by lying about the risks of smoking.

— In 1999, the Master Settlement Agreement was passed, requiring tobacco companies to pay $206 billion to 45 states by the year 2025 to cover Medicaid costs of treating smokers. The MSA agreement also closed the Tobacco Institute and ended cartoon advertising and tobacco billboards.

“Those are just a few of the remarkable changes in the age-old acceptance of smoking as our cultural norm,” said Dileep G. Bal, national president of the American Cancer Society. “What we have been doing can be characterized as the denormalization of smoking as an acceptable behavior.”

An estimated 46 million adults in the United States currently smoke, and it is estimated approximately half will die prematurely from smoking. Lung cancer is the leading cause of cancer death for men and women, and more than 80 percent of lung cancers are thought to result from smoking. Smoking causes one in five deaths from all causes.