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Indoor Air Quality (IAQ)

Secondhand Smoke and Smoke-free Homes

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What is Secondhand Smoke?

Secondhand smoke is a mixture of the smoke given off by the burning of tobacco products, such as cigarettes, cigars or pipes and the smoke exhaled by smokers. Secondhand smoke is also called environmental tobacco smoke (ETS). Exposure to secondhand smoke is sometimes called involuntary or passive smoking. Secondhand smoke, classified by EPA as a Group A carcinogen, contains more than 7,000 substances. Secondhand smoke exposure commonly occurs indoors, particularly in homes and cars. Secondhand smoke can move between rooms of a home and between apartment units. Opening a window or increasing ventilation in a home or car is not protective from secondhand smoke.

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What are the Health Effects of Secondhand Smoke?

The health effects of secondhand smoke on nonsmoking adults and children are harmful and numerous. Secondhand smoke causes cardiovascular disease (heart disease and stroke), lung cancer, sudden infant death syndrome, more frequent and severe asthma attacks, and other serious health problems. Several landmark health assessments regarding secondhand smoke have been conducted.

Key findings:

  • There is no risk-free level of exposure to secondhand smoke.
  • Since the 1964 Surgeon General’s Report, 2.5 million adults who were nonsmokers died because they breathed secondhand smoke.
  • Secondhand smoke causes nearly 34,000 premature deaths from heart disease each year in the United States among nonsmokers.
  • Nonsmokers who are exposed to secondhand smoke at home or work increase their risk of developing heart disease by 25-30%.
  • Secondhand smoke causes many lung cancer deaths among U.S. nonsmokers each year.
  • Nonsmokers who are exposed to secondhand smoke at home or at work increases their risk of developing lung cancer by 20-30%.
  • Secondhand smoke causes numerous health problems in infants and children, including more frequent and severe asthma attacks, respiratory infections, ear infections, and sudden infant death syndrome. 

Learn more about the health effects of secondhand smoke from the Centers for Disease Control and Prevention (CDC). 

Secondhand smoke poses particular health risks to children with asthma. 

  • Secondhand smoke is a universal asthma trigger and can elicit an asthma attack or make asthma symptoms more severe.
  • Asthma is a chronic disease that affects the airways of the lungs and can lead to coughing, trouble breathing, wheezing and tightness in the chest.
  • Asthma is the most common chronic childhood disease affecting, on average, 1 in 13 school aged children.
  • Exposure to secondhand smoke may cause new cases of asthma in children who have not previously shown symptoms.
  • More than half of US children with asthma are exposed to secondhand smoke (quinto, 2013).

Read EPA’s 1999 health assessment, Respiratory Health Effects of Passive Smoking:  Lung Cancer and Other Disorders.

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What Can You Do to Reduce Exposure to Secondhand Smoke?

Eliminating secondhand smoke in the indoor environment will reduce its harmful health effects, improve the indoor air quality and the comfort or health of occupants. Secondhand smoke exposure can be reduced through mandated or voluntary smoke-free policy implementation.  Some workplaces and enclosed public spaces such as bars and restaurants are smoke-free by law.  People can establish and enforce smoke-free rules in their own homes and cars.  For multifamily housing, smoke-free policy implementation could be mandatory or voluntary, depending on the type of property and location (e.g., ownership and jurisdiction).  

  • The home is becoming the predominant location for the exposure of children and adults to secondhand smoke.  (Surgeon General’s Report, 2006)
  • Households within buildings with smoke-free policies have lower PM2.5 compared to buildings without these policies. PM2.5 is a unit of measure for small particles in the air and is used as one indication of air quality. High levels of fine particles in the air can lead to negative health impacts. (Russo, 2014)
  • Prohibiting smoking indoors is the only way to eliminate secondhand smoke from the indoor environment. Ventilation and filtration techniques can reduce, but not eliminate, secondhand smoke. (Bohoc, 2010)

Many resources are available to assist you in implementing smoke-free policies and to quit smoking:

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How Much Progress Has Been Made Nationally in Reducing Exposure to Secondhand Smoke?

January 2018 marked the 25th anniversary of the landmark EPA health assessment, “Respiratory Health Effects of Passive Smoking:  Lung Cancer and Other Disorders.” To learn about progress over the years, read: 

Reducing Exposure to Secondhand Smoke – U.S. Progress Since EPA’s 1993 Landmark Report.

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Scientific Resources

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