Tobacco: Behind the Smoke


About Smoking, Your Body, and You!

Smokers, and everyone around them, are exposed to toxic chemicals contained in tobacco smoke.

There are over 4,000 chemicals in tobacco smoke, including:

  • Tar
  • Hydrogen cyanide
  • Formaldehyde
  • Carbon monoxide
  • Nicotine
  • Benzene

Did you know?

Two-thirds of the tobacco smoke is not inhaled by the smoker but is found in the air surrounding him or her.

There are different ways of being exposed to the chemicals from tobacco smoke.

  • Mainstream smoke: directly inhaled by the smoker.
  • Second-hand smoke: a mixture of the smoke exhaled from a smoker and the smoke released from the end of a burning cigarette. Second-hand smoke can be inhaled by the non smoker and the smoker.

When smoke is inhaled, it initially passes by the mouth. Then, it is absorbed through the lungs.

Once absorbed through the lungs, the toxic chemicals are transferred to the bloodstream.

Then, they are distributed to the entire body by the heart's pumping action.

Exposure to the chemicals in the tobacco smoke can cause a number of health effects, including:

Lung cancer

Lung cancer is the leading cause of death due to cancer in Canada. Smoking is the single most important preventable cause of lung cancer. Smoking causes genetic changes in the cells of the lung; these changes lead to the development of cancer.

Bladder, pancreatic and other forms of cancer

Research shows that smoking tobacco can lead to respiratory and upper digestive tract cancers, particularly cancer of the mouth, throat (pharynx), voice box (larynx) and esophagus. Research also indicates that smoking tobacco is a contributing cause of leukemia and cancers of the bladder, stomach, kidney and pancreas. Female smokers are at greater risk for developing cervical cancer.

Emphysema and other respiratory diseases

Smoke absorbed through the lungs

The respiratory diseases associated with smoking are often grouped together and referred to as "chronic obstructive pulmonary disease" or "COPD". These diseases include emphysema, chronic bronchitis and asthmatic bronchitis. Smoking is also linked to an increased risk of respiratory symptoms, including coughing, phlegm, wheezing and difficult breathing (dyspnea).

Heart diseases, strokes and other cardiovascular diseases

Cardiovascular diseases are diseases and injuries of the heart, the blood vessels of the heart, and the system of blood vessels (veins and arteries) throughout the body and brain. Cardiovascular diseases caused by smoking include heart attacks and angina (coronary heart diseases), blockages in the legs (peripheral vascular diseases) and strokes (cerebrovascular diseases).

Premature death

Half of all long-term smokers will eventually be killed by tobacco, and of these, half will die during middle age, losing 20 to 25 years of life. Also, a Canadian dies every 12 minutes of a tobacco related disease.

True or False?

The health effects caused by smoking only occur after long-term exposure to cigarette smoke (mainstream or second-hand).

False.
The health effects linked to cigarette smoke can manifest themselves at any time, both immediately and in the longer term. What is more, smoking affects the entire body (skin, hair, etc.).


In summary, all plants, including tobacco, are composed of chemicals.

When a cigarette burns, the chemicals in tobacco are changed into new chemicals. Many of these new chemicals are toxic.

The exposure to the chemicals in tobacco smoke can cause a number of health effects.

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