this is an excerpt from the book "Drugs and Society seventh edition" this book was from a college course i took when i was in school.


Marijuana is often smoked like tobacco and like tobacco can cause damage to the lungs. When smoking tobacco nearly 70% of the total suspended particles in the smoke are retained in the lungs. Because marijuana smoke is inhaled more deeply than tobacco smoke, even more tar residues may be retained with its use.
Smoke is a mixture of tiny particles suspended in gas, mostly carbon monoxide. These solid particles combine to form a residue called tar. Cannabis produces more tar (up to 50% more) than an equivalent weight of tobacco and is smoked in a way that increases the accumulation of tar.
More than 150 chemicals have been identified in marijuana smoke and tar. A few are proven carcinogens; many others have not yet been tested for carcinogenicity. The carcinogen benzopyrene, for example, is 70% more abundant in marijuana smoke than in tobacco smoke.

cannabis is a drug, and it can be dangerous.