Ventilation Does Not Effectively Protect Nonsmokers from Secondhand Smoke
Secondhand smoke is the combination of smoke from the burning end of a tobacco product and the smoke breathed out by the user. Secondhand smoke contains more than 7,000 chemicals; hundreds are toxic, and about 70 can cause cancer.1,2 There is no risk-free level of secondhand smoke, and even brief exposure can cause immediate harm.2 Establishing a 100% smokefree environment is the only effective way to fully protect nonsmokers from secondhand smoke.2,3,4
Expert Conclusions on Ventilation
U.S. Surgeon General
In 2006, the U.S. Surgeon General released a report entitled The Health Consequences of Involuntary Exposure to Tobacco Smoke: A Report of the Surgeon General.2 The report stated that the scientific evidence now supports the following major conclusion:
“Eliminating smoking in indoor spaces fully protects nonsmokers from exposure to secondhand smoke. Separating smokers from nonsmokers, cleaning the air, and ventilating buildings cannot eliminate exposures of nonsmokers to secondhand smoke.”2
This conclusion was substantiated, in part, by the following facts:
- Conventional air cleaning systems can remove large particles but not the smaller particles or the gases found in secondhand smoke.
- Current heating, ventilating, and air conditioning systems alone do not control secondhand smoke exposure. In fact, these systems may distribute secondhand smoke throughout a building.
- Even separately enclosed, separately exhausted, negative-pressure smoking rooms do not keep secondhand smoke from spilling into adjacent areas.
World Health Organization (WHO)
In 2007, WHO released a report entitled Protection from Exposure to Secondhand Tobacco Smoke: Policy Recommendations.3 In light of the available scientific evidence on ventilation, the report made the following recommendation to protect workers and the public from exposure to secondhand smoke:
"Remove the pollutant—tobacco smoke—by implementing 100% smokefree environments. This is the only effective strategy to reduce exposure to tobacco smoke to safe levels in indoor environments and to provide an acceptable level of protection from the dangers of secondhand smoke exposure. Ventilation and smoking areas, whether separately ventilated from nonsmoking areas or not, do not reduce exposure to a safe level of risk and are not recommended."
The American Society of Heating, Refrigerating and Air-Conditioning Engineers (ASHRAE)
ASHRAE is the national standard-setting body for indoor air quality, including ventilation issues. In 2010, ASHRAE released a report entitled ASHRAE Position Document on Environmental Tobacco Smoke.4 The report included the following major conclusions:
“At present, the only means of effectively eliminating health risks associated with indoor exposure is to ban smoking activity.”
“No other engineering approaches, including current and advanced dilution ventilation or air cleaning technologies, have been demonstrated or should be relied upon to control health risks from environmental tobacco smoke exposure in spaces where smoking occurs.”
“Because of ASHRAE’s mission to act for the benefit of the public, it encourages elimination of smoking in the indoor environment as the optimal way to minimize environmental tobacco smoke exposure.”
- U.S. Department of Health and Human Services. A Report of the Surgeon General: How Tobacco Smoke Causes Disease: What It Means to You. Atlanta: 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, 2010 [accessed 2014 Apr 25].
- U.S. Department of Health and Human Services. The Health Consequences of Involuntary Exposure to Tobacco Smoke: A Report of the Surgeon General. Atlanta: U.S. Department of Health and Human Services, Centers for Disease Control and Prevention, Coordinating Center for Health Promotion, National Center for Chronic Disease Prevention and Health Promotion, Office on Smoking and Health, 2006 [accessed 2014 Apr 25].
- World Health Organization (WHO). Protection from Exposure to Secondhand Tobacco Smoke: Policy Recommendations. WHO Press, 2007 [accessed 2014 Apr 25].
- American Society of Heating, Refrigerating and Air-Conditioning Engineers (ASHRAE). ASHRAE Position Document on Environmental Tobacco Smoke. Atlanta: ASHRAE, 2010 [accessed 2014 Apr 25].
For Further Information
Centers for Disease Control and Prevention
National Center for Chronic Disease Prevention and Health Promotion
Office on Smoking and Health
Media Inquiries: Contact CDC's Office on Smoking and Health press line at 770-488-5493.
- Page last reviewed: February 18, 2016
- Page last updated: April 25, 2014
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