Smoking is a practice where a substance, most commonly tobacco, is burned and the smoke tasted or inhaled. This is primarily done as a form of recreational drug use, as combustion releases the active substances in drugs such as nicotine and makes them available for absorption through the lungs. Do you know that the air pollution emitted by cigarettes is 10 times greater than diesel car exhaust, suggests a controlled experiment, reported in Tobacco Control? Environmental tobacco smoke produces fine particulate matter, which is the most dangerous element of air pollution for health.