What Is Mainstream Smoke?

Close up young man smoking a cigarette.
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What Is Mainstream Smoke?

Mainstream smoke is the smoke that a person exhales after they take a puff of a cigarette. It is considered a type of secondhand smoke, as is sidestream smoke, which is the smoke that wafts off the end of a lit cigarette.

This article defines mainstream smoke and discusses the harmful chemicals found in mainstream smoke as well as the potential health risks of inhaling it. It also discusses safety precautions to take to avoid these health hazards.

Chemicals in Mainstream Smoke

There are many carcinogens (cancer-causing chemicals) in mainstream smoke. Some of them are:

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

Health Risks of Mainstream Smoke

There are many health risks associated with smoking cigarettes and secondhand smoke, both of which include inhaling mainstream smoke. Mainstream smoke contains nicotine, which is an addictive substance. In addition, mainstream smoke contains cancer-causing chemicals.

Smoking increases a person's risk of:

  • Cancers (including bladder, liver, lung, mouth, pancreas, and stomach cancers)
  • Chronic obstructive pulmonary disease (COPD), including emphysema and chronic bronchitis
  • Diabetes
  • Eye diseases such as glaucoma
  • Heart disease
  • Lung disease
  • Rheumatoid arthritis
  • Stroke
  • Tuberculosis

Secondhand smoke is made up of both mainstream and sidestream smoke. Breathing in mainstream smoke means that a person is also inhaling sidestream smoke that is lingering in the air. There is no way to breathe in one without the other. So, the risks of inhaling secondhand smoke overlap with the risks of inhaling mainstream smoke.

Unfortunately, secondhand smoke can be fatal to those who breathe it in. Children, especially, face serious health risks when they are exposed to secondhand smoke, including sudden infant death syndrome (SIDS), respiratory infections, middle ear disease, asthma, and slowed lung growth.

How to Protect Yourself From Secondhand Smoke

If you smoke, the best way to protect yourself and your loved ones from the mainstream smoke and sidestream smoke that make up secondhand smoke is to quit smoking. There is no safe level of secondhand smoke exposure. However, there are precautions you can take in the meantime.

Avoid smoking inside your home or inside your car. Secondhand smoke can be more damaging in enclosed spaces. Make sure that no one smokes near your children.

Most schools, daycare centers, and restaurants must be smoke-free by law, but you may still encounter smoking outside. Make sure that you and your children aren't standing nearby if someone is smoking.

It's especially important to avoid secondhand smoke if you have heart disease, respiratory disease, or if you are pregnant.

How to Quit Smoking

There are many different ways to quit smoking. Talk to a healthcare provider, and together, you can lay your personal roadmap for your quit journey. Some methods of quitting include:

NRT comes in lozenges, mouth sprays, gum, and a patch for your skin, among other forms. It may be especially helpful for people who have trouble quitting cold turkey.

A doctor may prescribe you a medication for quitting such as Chantix (varenicline) or Zyban (bupropion). These medications may help reduce the urge to smoke. However, these medications can cause mild to severe side effects in some people. Be sure to consult a doctor if you notice any unusual emotional, behavioral, or physical symptoms when taking Chantix or Zyban.

You might also find it helpful to talk with a therapist who can help you understand your personal triggers to smoke and can teach you healthy coping mechanisms to use instead.

Many people find support groups and quit smoking apps helpful. These resources can help you maintain the motivation to quit as well as teach tips for managing cravings.

A Word From Verywell

It can be frightening to learn about the dangerous health conditions linked with mainstream smoke and cigarette smoking in general. If you or a loved one is looking to quit smoking, don't be afraidNicotine addiction can manipulate a person's thoughts, making them think they can't live without cigarettes—but the opposite is true. Once you've recovered, you'll experience the many physical and mental health benefits of leading a smoke-free life.

7 Sources
Verywell Mind uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
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  2. Centers for Disease Control and Prevention. How tobacco smoke causes disease: The biology and behavioral basis for smoking-attributable disease: A report of the surgeon general.

  3. Centers for Disease Control and Prevention. Smoking and tobacco use: Health effects.

  4. Pérez-de-Arcelus M, Toledo E, Martínez-González MÁ, Martín-Calvo N, Fernández-Montero A, Moreno-Montañés J. Smoking and incidence of glaucoma: The SUN CohortMedicine (Baltimore). 2017;96(1):e5761. doi:10.1097/MD.0000000000005761

  5. Centers for Disease Control and Prevention. How to protect you and your loved ones from secondhand smoke.

  6. Wadgave U, Nagesh L. Nicotine replacement therapy: An overviewInt J Health Sci (Qassim). 2016;10(3):425-435.

  7. MedlinePlus. Varenicline.

By Terry Martin
Terry Martin quit smoking after 26 years and is now an advocate for those seeking freedom from nicotine addiction.