What Mainstream Smoke is and Why It's so Harmful

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What is Mainstream Smoke?


What's in Mainstream Smoke?

Toxic chemicals in mainstream smoke include:

The composition of mainstream smoke is affected by how the smoker inhales and exhales, so it will vary from person to person. The frequency of puffs, duration and volume all contribute to the chemical makeup of mainstream smoke.

How Does Mainstream Smoke Differ from Sidestream Smoke?

Sidestream smoke is smoke that wafts off the end of a lit cigarette. This smoke is usually laden with higher concentrations of some chemicals than mainstream smoke due to incomplete burning. The temperature of a smoldering cigarette averages 400 degrees centigrade, while it's closer to 900 degrees centigrade during a puff. Some of the chemicals present in higher amounts due to this process are 2-naphthylamine, N-nitrosodimethylamine, 4-aminobiphenyl, and carbon monoxide. Sidestream smoke is the most toxic of the two types of cigarette smoke. 

Mainstream smoke and sidestream smoke are the components of environmental tobacco smoke, also known as ETS.  Approximately 85 percent of ETS is sidestream smoke. 

Non-smokers who breathe in ETS in an enclosed space are doing what is known as passive or involuntary smoking.

ETS and Your Health

Breathing in ETS is associated with an increased risk of heart disease and a number of cancers, including:


There is no safe level of exposure to secondhand smoke.

It is toxic air and should be avoided at all costs.

See Also:  Secondhand Smoke Facts

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National Institutes of Health. National Center for Biotechnology Information. How Tobacco Smoke Causes Disease: The Biology and Behavioral Basis for Smoking-Attributable Disease: A Report of the Surgeon General. http://www.ncbi.nlm.nih.gov/books/NBK53014/. Accessed January, 2016.

Government of Canada. Canadian Centre for Occupational Health and Safety. Environmental Tobacco Smoke (ETS): General Information and Health Effects. https://www.ccohs.ca/oshanswers/psychosocial/ets_health.html

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