In a recent study published by the journal Chemical Research in Toxicology, Health Canada researchers found higher levels of certain toxins in marijuana smoke than in tobacco smoke. The researchers used a smoking machine to compare cigarettes made from Players brand fine-cut tobacco with cigarettes made from cannabis produced by Prairie Plant Systems of Saskatoon, which grows medical marijuana under contract with Health Canada. The marijuana smoke had 20 times as much ammonia and five times as much hydrogen cyanide and nitrogen oxides, possibly due to higher levels of nitrate fertilizer traces in the marijuana. Then again, only the tobacco smoke contained the potent carcinogens known as tobacco-specific nitrosamines, and it had “moderately higher levels” of potentially hazardous compounds such as formaldehyde, acetaldehyde, and polycyclic aromatic hydrocarbons. Guess which comparison was emphasized in the press coverage.
Jacob Sullum also points out that tobacco ends up being more dangerous because tobacco smokers smoke much more tobacco per day than pot heads smoke cannabis per day. They don’t mention the whole “pot nowadays is so much stronger than when we were kids” hype. Stronger pot is safer because it requires less smoking.