Impact on Adults Make an Appointment Ask a Question Search Conditions The U.S. Surgeon General has concluded that breathing even a little secondhand smoke poses a risk to your health. Secondhand smoke (SHS) exposure causes heart disease and lung cancer in nonsmoking adults. Nonsmokers who are exposed to SHS at home or work increase their heart disease risk by 25–30 percent and their lung cancer risk by 20–30 percent. SHS is estimated to cause 22,700 to 69,600 premature deaths from heart disease each year in the United States among nonsmokers. Breathing SHS causes immediate harm to the cardiovascular system and increases the risk of heart attacks. People who already have heart disease are at especially high risk. Even a short time in a smoky room can cause your blood platelets to become stickier. Even brief SHS exposure can damage the lining of blood vessels. Adults who breathe 5 hours of SHS daily have higher levels of the bad cholesterol that can clog the arteries of the heart. SHS causes approximately 3,000 lung cancer deaths among U.S. nonsmokers each year. SHS causes lung cancer in adults who have never smoked. Even brief SHS exposure can damage cells in ways that set the cancer process in motion. As with active smoking, there is a dose-response relationship between SHS exposure and lung cancer—the longer the duration and the higher the level of exposure, the greater the risk of developing lung cancer. SHS exposure appears to also cause breast cancer and head and neck cancer. SHS exposure also can cause many types of both acute and chronic breathing problems. There is no risk-free level of SHS exposure. Even brief exposure can be dangerous. References The health consequences of smoking – 50 years of progress: a report of the Surgeon General. – Atlanta, GA. : U.S. Department of Health and Human Services, Centers for Disease Control and Prevention, National Center for Chronic Disease Prevention and Health Promotion, Office on Smoking and Health, 2014. California Environmental Protection Agency. Proposed Identification of Environmental Tobacco Smoke as a Toxic Air Contaminant. Sacramento, California: California Environmental Protection Agency. This information has been approved by Amy Lukowski, PsyD (August 2015).