pyrene

Perhaps your intended reference, however, is to the other toxic components of cigarette smoke, such as benzo[a]pyrene.

The substance with the formula C20H12 is one of the benzopyrenes, formed by a benzene ring fused to pyrene.

You really don't want benzo[a]pyrene floating around your system, it's a potent carcinogen that's been firmly established by many studies.

Preliminary findings suggest that marijuana smoke activates cytochrome P4501A1, the enzyme that converts polycyclic hydrocarbons, such as benz[a]pyrene, into active carcinogens.

> B[a]P: Benzo[a]pyrene Benzo[a]pyrene is a product of incomplete combustion and is basically found wherever organic stuff (in the carbon containing sense) is burned with low available oxygen.

Despite the tobacco industry's decades-long effort to deny the link between lung cancer and smoking tobacco, it seems well-understood that the combustion product benzo[alpha]pyrene plays a major role.

Any time there is incomplete combustion of carbon compounds like cooking oil, carcinogenic molecules like benzo-a-pyrene are formed, which appears to cause or contribute to skin, lung, and bladder cancer.

Specifically benzo[a]pyrene has been shown to form DNA adducts, which can alter replication and generate cancer cells by damaging DNA elements involved in cell cycle control, or by damaging components of the immune system involved in normal detection and elimination of cancer cells.

Bibracte near Autun in Burgundy — the city Julius Ceasar had to conquer — is built at the top of a 900 meter hill; Pyrene/Heuneburg built on a rocky spur overlooking the Danube in southern Germany is considered the first real city north of the Alps.