Environmental tobacco smoke (ETS) is also known as “second-hand smoke”, “passive smoking” or “involuntary smoking” (breathing in the smoke from nearby smokers).
Passive smoking is a universal and almost unavoidable problem, as nonsmokers can be exposed at home, in public places, at work, etc.
The smoke inhaled by the smoker first, and then exhaled, is called mainstream smoke. The smoke that goes directly into the air from the end of a burning cigarette is called sidestream smoke. ETS is composed of side-stream smoke from smouldering cigarettes and from mainstream smoke exhaled by smokers.
Tobacco smoke contains over 4,000 chemicals, including hazardous air pollutants and hazardous waste, more than 100 toxic chemicals and 50 carcinogens.
Side-stream smoke contains larger amounts of some toxic constituents.
Even if side-stream smoke is diluted it is still dangerous; there is no safe level of exposure.
ETS is a proven risk factor for lung cancer, asthma attacks in those already affected and worsening symptoms of bronchitis in adults.
It is also responsible for recurrent respiratory illnesses, asthma and lung function impairment in children.
It is estimated that approximately one third of lung cancers in nonsmokers result from passive exposure to cigarette smoke.
ETS can also cause shortness of breath, airway irritation and coughing.
The risk of developing respiratory disease in children increases in direct relationship to parental smoking habits, with the greatest risk being when both parents smoke.