It has a very obvious link to lung cancer. Over 90% of all lung cancer and 60% of all types of cancer is caused by smoking. The tar in cigarettes can block the bronchioles provoking asthma and other respiratory related diseases. Upon 25 years of smoking, your body could've received over 10 litres of tar. Other brutal chemicals inside cigarettes include formaldehyde (poison gas, used for sterilization), carcinogen (cancer causer), carbon monoxide (car exhaust) and nicotine (used in insecticide). The Carbon Monoxide that is inhaled can cause several toxic effects on our bodies. First, it impairs the oxygen transportation in our blood. This impairs muscular performance and may even affect our vision at high altitudes. Therefore smokers are slower, reach exhaustion earlier and reach lower goals in terms of fitness. Gangrene is the death of tissue in the body due to lack of blood supply to the area. Smoking causes Gangrene because it forces the blood vessels to contract and it obstructs the blood circulation. 70% of all leg amputations are because of gangrene. Smoking can cause such horrific diseases that it makes people sometimes wonder if a life where you can't even put your clothes to wash without a tank of oxygen beside you and running out of breath is worth living. Passive smoking is when someone else involuntarily inhales the fumes of someone else's" tobacco smoke. It also has a variety of bad effects, for we inhale it directly, without a filter. A filter is a small circular net around the butt of the cigarette that prevents some chemicals of the cigarette to be inhaled. Passive smoking increases the probability of obtaining lung or heart diseases by 25% and there have been several cases of deaths due to passive smoking. Smoking can also affect our aesthetics by rotting our teeth and causing premature ageing and wrinkles Smoking also pollutes. Sunny beaches can be filled cigarette butts, creating an unpleasant environment for others.