Dec. 14, 2007 -- New research from Canada shows that some toxins may be more abundant in marijuana cigarettes than tobacco cigarettes.
The researchers burned 30 marijuana cigarettes and 30 tobacco cigarettes on a machine in their lab, measuring levels of chemicals in the smoke.
Ammonia levels were up to 20 times higher in marijuana smoke than in tobacco smoke. Levels of hydrogen cyanide and nitrogen-related chemicals were three to five times higher in marijuana smoke than in tobacco smoke. Read more.