What is secondhand smoke?

Secondhand smoke is also known as passive smoke. It is a mixture of 2 forms of smoke that come from burning tobacco: sidestream smoke (smoke that comes from the end of a lit cigarette, pipe, or cigar) and mainstream smoke (smoke that is exhaled by a smoker).

Non-smokers who breathe in secondhand smoke are called involuntary or passive smokers. Non-smokers who breathe in secondhand smoke take in nicotine and other toxic chemicals just like smokers do.

Tobacco smoke contains over 4,000 chemical compounds, and more than 60 of these are known or suspected to cause cancer. The more secondhand smoke you are exposed to, the higher the level of these harmful chemicals in your body.

Why is secondhand smoke a problem?

Secondhand smoke causes disease and death. Secondhand smoke is classified as a "known human carcinogen" by the U.S. Environmental Protection Agency, the U.S. National Toxicology Program, and the International Agency for Research on Cancer; a branch of the World Health Organization.

Secondhand smoke kills children and adults who don't smoke, and makes others sick.

In the United States alone, the are an estimated 46,000 deaths from heart disease in non-smokers who live with smokers, and about 3,400 lung cancer deaths in non-smoking adults.  Non-smokers who are exposed to secondhand smoke have more breathing problems, such as coughing, excessive mucus, chest discomfort, and reduced lung function.

There are 150,000 to 300,000 lung infections a year in children who are younger than 18 months of age. These infections in children leads to 7,500 to 15,000 hospitalizations annually. Secondhand smoke increases the number and severity of asthma attacks in 200,000 to 1 million children, and more than 750,000 middle ear infections in children.

Separating smokers from non-smokers, cleaning the air, and ventilating buildings cannot keep non-smokers from being exposed to secondhand smoke.

The only way to fully protect non-smokers from exposure to secondhand smoke indoors is to prevent all smoking in that indoor space or building.

What about smoking odors?

There is no research in the medical literature about the cancer-causing effects of cigarette odors. Research shows that secondhand tobacco smoke gets into hair, clothing, and other surfaces. Researchers call this "thirdhand" smoke referring to the toxic particles left in the air after smoke can no longer be seen.

Over time, it settles on surfaces and can be measured long after the person is done smoking. Though unknown, the cancer-causing effects would likely be very small compared with direct exposure to secondhand smoke, such as living in a house with a smoker. However, this is an active area of tobacco research.

A smoke-free home protects your family, your guests, and even your pets.  Any family member can develop health problems related to secondhand smoke.

We spend more time at home than anywhere else.

In the United States, 35% of children live in homes where residents or visitors smoke in the home on a regular basis.

50% to 75% of children in the U.S. have detectable levels of nicotine in their blood.

Infants exposed to secondhand smoke are at an increased risk of sudden infant death syndrome (SIDS), and pregnant women exposed to secondhand smoke are also at increased risk of having low birth-weight babies.

We spend a lot of time in cars, and smoking there can cause hazardous levels of smoke to build up quickly. This can be especially harmful to children. 

Children are especially sensitive to secondhand smoke. 

Asthma, lung infections, and ear infections are more common in children who are around smokers. Some of these health problems in children can be serious and even life-threatening.

Secondhand smoke health issues may seem like small problems, but they add up quickly. Think of the money spent on doctor visits and medicine, the lost school time and lost work time for the parent who must take their children to the doctor.

The 2006 U.S. Surgeon General's report reached these important conclusions:

Secondhand smoke causes premature death and disease in children and in adults who do not smoke, and causes acute respiratory infections, ear problems, and more severe asthma.

Smoking by parents causes breathing (respiratory) symptoms and slows lung growth in their children.

Secondhand smoke immediately affects the heart and blood circulation in a harmful way. Over a long time it also causes heart disease and lung cancer.

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