DEAR ABBY: On Thursday, Nov. 16, millions of smokers will take part in the American Cancer Society’s Great American Smokeout. During the last 30 years, we have learned that the combination of a smoke-free community and smoking cessation support is vital to helping smokers quit.

Abby, I need your help. Although people are aware of the dangerous effects of tobacco use on a smoker’s own health, there has been debate about the impact of secondhand smoke.

Earlier this year, the U.S. surgeon general issued the first report in 20 years on the health effects of involuntary exposure to secondhand tobacco smoke. We hope the following information from that report will help your readers to better understand the harmful effects of secondhand smoke on their health – as well as the importance of smoke-free workplaces:

• Secondhand smoke causes premature death and disease in children and adults who do not smoke.

• Children exposed to secondhand smoke are at an increased risk for Sudden Infant Death Syndrome (SIDS), acute respiratory infections, ear problems and more severe asthma. Smoking by parents causes respiratory symptoms and slows lung growth in their children.

• Exposure of adults to secondhand smoke has immediate adverse effects on the cardiovascular system and causes coronary artery disease and lung cancer.

• The scientific evidence indicates that there is no safe level of exposure to secondhand smoke.

• An estimated 126 million Americans, both children and adults, are still exposed to secondhand smoke in their homes and workplaces – despite substantial progress in tobacco control.

• Eliminating smoking in indoor spaces fully protects nonsmokers from exposure to secondhand smoke. Separating smokers from nonsmokers, “cleaning” the air and ventilating buildings cannot eliminate the exposure of nonsmokers to secondhand smoke.

Abby, please help us spread the word about the importance of not exposing yourself or your loved ones to secondhand smoke. In addition, remind your readers that quitting smoking is one of the healthiest decisions they can make.

The American Cancer Society has helped thousands of Americans to quit smoking. Smokers who quit by age 35 will avoid 90 percent of the risk attributed to tobacco. Smokers who quit by age 50 will reduce the overall risk of dying prematurely in the next 15 years by 50 percent. – RICHARD C. WENDER, M.D., PRESIDENT, AMERICAN CANCER SOCIETY

DEAR DR. WENDER AND DEAR READERS: This is an important column, about a cause that has been embraced by my family for decades. Smoking remains the leading preventable cause of death in the United States. It has been responsible for nearly one in five deaths in 2006. Smoking will cause about 30 percent of the estimated 570,280 cancer deaths this year.

For those of you who smoke, it is my hope that the Great American Smokeout will motivate you – as well as give you an opportunity – to quit. I urge smokers to contact the American Cancer Society for help in making a plan to quit smoking. I am also urging you to advocate for smoke-free communities.

The American Cancer Society has helped thousands of Americans throw away their cigarettes for good. For more information on quitting smoking, lung cancer or any other information, call toll-free at 800-227-2345 (the number is staffed 24/7), or visit online at www.cancer.org.

Dear Abby is written by Abigail Van Buren, also known as Jeanne Phillips, and was founded by her mother, Pauline Phillips. Write Dear Abby at www.DearAbby.com or P.O. Box 69440, Los Angeles, CA 90069.