Second-hand Smoke

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Maggie Hampshire RN, BSN, OCN
The Abramson Cancer Center of the University of Pennsylvania
Last Modified: June 21, 2002

With special commentary by: Gregory Tino, MD, Assistant Professor of Medicine Pulmonary-Critical Care and Director of Pulmonary Outpatient Practices at the Hospital of University of Pennsylvania

The problem of "second-hand smoke" which is also called environmental tobacco smoke (ETS) is an emotionally charged personal and public health issue. Non- smokers have many negative comments about being forced to breathe toxin filled air. Smokers, on the other hand, feel that their "rights" are infringed upon by non-smokers seeking regulations to inhibit their smoking habits. The fact remains that scientists estimate that every year more than 3,000 deaths from lung cancer in non-smokers are caused by second-hand smoke.

What is Second-hand Smoke?

Second-hand smoke is made up of about 80 percent "sidestream smoke" (the smoke which comes from the lit end of the cigarette and does not pass through the filter) and 20% "mainstream smoke" (the smoke which is exhaled by the smoker).

It has been proven, by laboratory analysis, that sidestream and mainstream smoke contain different amounts of toxic substances. Sidestream smoke is actually the more dangerous of the two, as it contains higher concentrations of toxins and cancer-causing chemicals. This smoke is not inhaled by the smoker--only by those around him or her.

How dangerous is second-hand smoke?

Second-hand smoke is a major source of dangerous indoor air pollution in the United States. It contains almost 5,000 chemicals. The Environmental Protection Agency (EPA) and the Department of Health and Human Services have compiled a list of the Top 20 Hazardous Substances. Seven out of the twenty toxins listed are found in cigarette smoke. Remarkably, about 75 percent of a cigarette's nicotine, (another noxious and addictive substance) goes into the air, for others to passively inhale via sidestream smoke. There is no safe exposure level for the cancer-causing agents found in second-hand smoke.

The EPA classifies second-hand smoke as a known -- not just a "probable" or "possible" -- human Class A carcinogen. This distinction has been used by EPA for only 15 other pollutants, including asbestos, radon, and benzene. Studies, of non-smoking spouses living with smokers, conclude that long-term exposure to second-hand smoke increases the risk of lung cancer in the spouse who has never used tobacco.

According to Gregory Tino, MD, Assistant Professor of Medicine Pulmonary-Critical Care and Director of Pulmonary Outpatient Practices at the Hospital of University of Pennsylvania, "Advice to avoid second-hand smoke should take its place beside the usual advice to avoid the use of all tobacco products."

What can be done to limit exposure to second-hand smoke?

It is not easy to avoid second-hand smoke because it is estimated that about one in four people in the U.S. smoke. In order to limit exposure:

  • Do not allow others to smoke in your home.
  • Do not smoke if children are present.
  • If exposure to second-hand smoke cannot be avoided, increase ventilation in the area where smoking takes place.
  • The American Lung Association has published the following list of tips on how to protect yourself and your family from exposure to second-hand smoke.


Federal, state, and local levels of government have already begun to enact laws, which attempt to limit exposure to second-hand smoke. The federal government has banned smoking on the sites of federally assisted programs for children and on domestic airline flights. Forty-eight states and the District of Columbia have enacted laws that, in some way, restrict smoking in public places. As more people become aware of the dangers of second-hand smoke, they put pressure on their government officials to enact tougher legislation. A recent example of this response is the suggestion for stricter regulations on second-hand smoke made by the Presidential Task Force On Environmental Tobacco Smoke.

Non-smokers are now beginning to voice their opinions. The Department of Labor ruled that the widower of a former Veterans Adminstration hospital nurse should receive compensation due to her second-hand smoke-related cancer death. And the first class action lawsuit has recently been filed against the tobacco industry by 60,000 flight attendants. They allege that their illnesses, including lung cancer, have been caused by second-hand smoke.

The fact remains that most Americans, smokers and nonsmokers alike, are wary of tighter governmental regulations on any issue. But, most will agree that we do have a "right" to breathe clean air. It seems, however, that we can not seem to agree on exactly what constitutes air pollution. This is illustrated by an experience I had several years ago. I attended a town meeting in my area to express my opinion about a proposal to build a trash to steam plant in the middle of our neighborhood. When I entered the church hall filled with other "concerned citizens" I was shocked. -- The room was filled with cigarette smoke. When will we learn?


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