Some evidence

Some evidence
Smoking causes 87% of lung cancer deaths and is responsible for most cancers of the mouth, larynx, pharynx, esophagus and bladder. In addition, contrary to general parrerii consumption of cigarettes "light" or "ultra-light" does not reduce the risk of lung cancer.

Passive smoking is responsible for approximately 3,000 lung cancer deaths among nonsmokers each year.
Some evidence
Tobacco smoke contains thousands of chemical compounds, among which 60 substances recognized as carcinogenic.
Some evidence
The risk of smoking-related cancers, and other diseases increases with exposure to cigarette smoke.
Some evidence
Quitting smoking shows major and immediate benefits, including reducing the risk of lung cancer and other cancers, heart attack, stroke and chronic lung disease.