Tobacco smoking kills nearly about 420,000 people a year, making it more lethal than AIDS, accidents, homicides, suicides, drug overdoses, and fire. Smokers are also inhaling other chemicals including cyanide, benzene, formaldehyde, methanol (wood alcohol), acetylene (the fuel used in torches), and ammonia. Smoke also contains nitrogen oxide and carbon monoxide, which are harmful gases. 
Reduces Sperm Density

Men’s sexual and reproductive health is not immune from the effects of smoking. Heavy smoking is frequently cited as a contributory factor in impotence because it decreases the amount of blood flowing