"Tar" is the term used to describe the toxic chemical residue left behind from burning cigarettes.
The concentration of tar in a cigarette determines its rating:
- High-tar cigarettes contain at least 22 milligrams (mg) of tar
- Medium-tar cigarettes from 15 mg to 21 mg
- Low-tar cigarettes 7 mg or less of tar
In solid form, tar is also known as third-hand smoke. It is the brown, tacky substance left behind on the end of the cigarette filter. It stains a smoker's teeth and fingers brown and coats everything it touches with a brownish-yellow film. Imagine that settling into the delicate pink tissue of your lungs.
Tar is present in all cigarettes and tends to increase as the cigarette is burnt down, which can mean that the last puffs on a cigarette may contain as much as twice the amount of tar as the first puffs.
Tar in cigarette smoke paralyzes the cilia in the lungs, and contributes to lung diseases such as emphysema, chronic bronchitis, and lung cancer.
Are Light Cigarettes Less of a Risk for Smokers?
"Up In Smoke: The Truth About Tar and Nicotine Ratings" May, 2000. The U.S. Federal Trade Commission.
"A Vision for the Future." Surgeon General's Report 1981 Section 8. Centers for Disease Control.
"Low-Tar Cigarettes Do Not Cut Cancer Risk." 14 January, 2004. MIT News Office.