obacco smoke is a mixture of gases and aerosols with a variety of toxicologically active substances such as tar constituents as PAH, carbon monoxide, formaldehyde, benzene, heavy metals, and nicotine.

In contrast to the self-determined inhalation of the active smoker, the passive smokers inhaling the tobacco smoke involuntarily are also exposed to the increased health risks as the smoker. While the smokers themselves the "mainstream smoke" and "sidestream smoke" is actively inhaled, his fellows are mainly the " sidestream smoke " or " cold smokeIt contains many pollutants in multiples of concentrations that the smoker inhales in the " mainstream smoke " or " hot smoke ." Even after a long time in a room is no longer smoked remains a high Concentration of pollutants, as curtains, carpets or other textiles from smoker's rooms first bind certain pollutant components which they later release, and the concentrations from this source are particularly high in interiors such as offices, hotels, airplanes, and taxis 

Tobacco smoke is seen as an enhancer of almost all other everyday poisons like car exhaust, Alcohol, asbestos, heavy metals, solvents, dioxins and furans.
The inhaled tobacco smoke is by far the most significant pollutant from the environment. The deposition takes place down to the finest ramifications of the lungs, where it unfolds its damaging potential. Smoking also harms the immune system, among other things. Besides the heavy effects on the respiratory organs such as chronic bronchitis (smoker's cough), emphysema, laryngeal, bronchial and lung are other typical diseases due to the additional damage to the blood vessels: atherosclerosis (arteriosclerosis), heart attack by occlusion of the coronary arteries, stroke by arteriosclerosis in the brain and the so-called "smoker's leg", whereby the limbs die off by occlusion of the blood vessels. Tobacco smoke is partly responsible for the increasing occurrence of allergic diseases. The heavy metal cadmium in the smoke, especially in women promoted the tendency to osteoporosis.

Unborn children in the womb "smoke" with; if the mother herself is a smoker, the child absorbs all tobacco contaminants through the common bloodstream. The consequence is an impairment of the mental and physical development of the child. Newborns of smokers have at birth on average 100 to 300g less weight than non-smokers. There is also a higher prematurity and malformation risk. But even smoking the father can already burden the unborn child.