Origin

• Tar in lungs is not the same tar that is used to manufacture tires or build roads. It is a sticky, dark brown chemical that is produced when tobacco is burned through smoking. Tar can damage the lungs and can stain teeth, fingers and clothing.
  
  

Inhalation

• The tar enters the lungs when the smoke is inhaled. The more a smoker smokes, the more tar he will inhale. When a smoker inhales the smoke from the cigarette, that dark tar is also inhaled into the lungs. When cigarette smoke is inhaled, it condenses and deposits cigarette tar in the lungs. The more a smoker smokes, the more tar that will coat his lungs. It will eventually interfere with the smoker's breathing.
  
  

Levels of Content

• High-tar cigarettes can contain up to 27 mg of tar. Medium tar cigarettes can contain anywhere from 15 to 21 mg of tar. Low tar cigarettes contain less than 7 mg of tar.
  
  

Buildup

• If a smoker smokes two packs of high-tar cigarettes each day, she will inhale 1 g of tar each day. This will build up to 1 qt. of dark brown tar into her lungs each year. This buildup is what causes lung cancer among smokers.
  
  

Filters

• In the 1950s, cigarette companies added filters to the cigarettes when consumers complained about tar inhalation. While filters do remove much of the tar, cigarettes still contain enough tar in them to be dangerous to the lungs of smokers.
  
  

Purification

• The lungs have a mechanism that cleans and purifies them. The "cilia" are tiny hairlike filaments that sweep away impurities. This process can take many years to fully remove tar from the lungs.