Secondhand Smoke Is Bad News

Secondhand Smoke
Secondhand Smoke. Ozan El/EyeEm/Getty Images

Secondhand smoke is tobacco smoke inhaled by nonsmokers. It consists both of smoke exhaled by smokers, and of the “sidestream” smoke given off by smoldering cigarettes, cigars or pipes. Experts now agree that secondhand smoke poses a health hazard to nonsmokers, and that therefore, it makes good sense to take whatever steps may be necessary to protect nonsmokers from exposure to secondhand smoke.

    What Is In Secondhand Smoke?

    In environments where there are people smoking, the air you breathe contains several products of tobacco combustion, including nicotine, carbon monoxide, benzene (a carcinogen), and numerous small particles which the EPA classifies as air pollution. In fact, the concentration of air pollution particles in homes with smokers is generally twice as high as in homes without smokers.

    What’s worse, the toxic components of tobacco combustion can actually be measured in the blood and urine of nonsmokers exposed to secondhand smoke. (For this reason, even libertarians should be alarmed by secondhand smoke.)

    Health Consequences of Secondhand Smoke

    Is is much more difficult to quantify the long-term toxic exposure experienced by nonsmokers than smokers, and this has made it difficult to “prove” that secondhand smoke causes disease. However, the evidence accumulated over the past few decades is now quite convincing.

    Several studies have now shown that people exposed to secondhand smoke have a significantly increased risk of lung cancer, and that the increase in risk is directly related to the cumulative “dose” of your exposure to secondhand smoke. The spouses, children and co-workers of smokers in particular have a significantly increased risk of lung cancer.

    People with asthma and chronic obstructive lung disease will tell you that their breathing is effected by exposure to secondhand smoke, and analysis tells us that the particulate matter in secondhand smoke is just the right size to reach the lungs and cause damage. The lung function of asthmatics exposed to secondhand smoke has been measured to decline acutely by up to 20%.

    Secondhand smoke also affects the cardiovascular system in several ways, including: making platelets stickier, causing inflammation, reducing HDL cholesterol levels, increasing LDL cholesterol levels, and increasing insulin resistance. (There is even evidence that secondhand smoke increases the risk of developing diabetes.)

    Furthermore, large epidemiological studies show that people chronically exposed to secondhand smoke have as much as a 20% increase in the risk of coronary artery disease or cardiac death. There is also a correlation between smoking spouses and the risk of stroke.

    Controlling Secondhand Smoke

    Those of us who are above a certain age and live in the U.S. have already seen a major reduction in our exposure to secondhand smoke over the past 20 years.

    Indeed, the only place today where you are regularly exposed to indoor secondhand smoke is in the home of a smoker. Smoking has been virtually eliminated from most enclosed public spaces.

    However, secondhand smoke remains a major risk factor for lung cancer and cardiovascular disease, especially among the spouses and children of smokers. Smokers (who love their husbands, wives and children as much as anyone else) ought to take this very unpleasant fact into strong consideration.


    US Department of Health and Human Services (USDHHS). The health consequences of involuntary exposure to tobacco smoke. Centers for Disease Control and Prevention, Rockville, MD, 2006.

    Samet JM, Wang SS. Environmental Tobacco Smoke. In: Environmental Toxicants: Human Exposures and Their Health Effects, Lippmann M (Ed), Van Nostrand Reinhold Company, Inc., New York 2000. p.319.

    Japuntich SJ, Eilers MA, Shenhav S, et al. Secondhand tobacco smoke exposure among hospitalized nonsmokers with coronary heart disease. JAMA Intern Med 2015; 175:133.

    Kim CH, Lee YC, Hung RJ, et al. Exposure to secondhand tobacco smoke and lung cancer by histological type: a pooled analysis of the International Lung Cancer Consortium (ILCCO). Int J Cancer 2014; 135:1918.

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