Clarifying recent reports comparing marijuana smoke and tobacco smoke

Colleagues,

An intriguing study was published last week in the journal Chemical Research
in Toxicology assessing the concentrations of respiratory pollutants
produced by marijuana combustion to those produced by smoking tobacco.
Fortunately, folks can download the entire text of the study and read it for
themselves here:

"A comparison of mainstream and sidestream marijuana and tobacco cigarette
smoke produced under two machine smoking conditions"


Unfortunately, it appears that few if any reporters actually did this before
penning widely disseminated articles such as this one:

Study Shows Toxins In Marijuana Smoke

Dec 17, 2007

(WebMD) 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.

The nitrogen-based fertilizer used on the marijuana plants -- which all came
from the same batch of Canadian pot plants -- may have affected the results.
The temperatures used to burn the cigarettes may also have been a factor.

Marijuana smoke and tobacco smoke shared many of the same chemicals. But the
two types of smoke weren't identical.

For instance, marijuana doesn't contain nicotine. And tobacco doesn't
contain cannabinoids, which include THC, marijuana's active ingredient

Tobacco has long been linked to cancer and other health problems. Marijuana
smoke hasn't been tied to cancer in the past, note the
researchers, who included David Moir of the Safe Environments Programme in
Kitchener, Ontario.

Moir and colleagues report their findings in the advance online edition of
Chemical Research in Toxicology.

They promise to compare the toxicity of marijuana smoke and tobacco smoke in
animals in another study.

By Miranda Hitti
Reviewed by Brunilda Nazario
©2007 WebMD, Inc. All rights reserved.

A few comments responding to this news item that are apparent reading the
study:

1) Investigators reported that mainstream marijuana smoke contained lower
levels of selected polycyclic aromatic hydrocarbons (cancer causing agents)
compared to tobacco.

2) Nicotine, tobacco-specific nitrosamines, arsenic, and lead were not
present in marijuana smoke.

3) HCN forms from protein at temperatures above 700 degrees C, and would
likely be reduced or eliminated by vaporization.

4) Clinical trials have shown that vaporization -- whereby marijuana is
heated to a temperature where active cannabis vapors form, but below the
point of combustion -- can greatly reduce or eliminate the presence of many
polycyclic aromatic hydrocarbons. Most recently, investigators at San
Francisco General Hospital reported in the journal Clinical Pharmacology &
Therapeutics that the "vaporization of marijuana does not result in exposure
to combustion gases, ... and is preferred by most subjects compared to
marijuana cigarette." A previous clinical trial published in 2006 in the
Journal of Pharmaceutical Sciences reported that vaporization is "safe and
effective" cannabinoid delivery system that "avoid[s] the respiratory
disadvantages of smoking.²

5) The higher presence of ammonia, HCN, and aromatic amines
(nitrogen-related chemicals) in marijuana were likely all due to the fact
that Prairie Plant Systems cultivated the pot used in the trial with a high
nitrate fertilizer. (By contrast, the tobacco used in the study was not
treated with a similar fertilizer.) I know that in the past Philippe
Lucas/The VICS has been outspoken in his criticism of Prairie Plant Systems
grow techniques, and I'd imagine that these latest findings will only add
fuel to his fire.

Best Regards,
--
Paul Armentano
Senior Policy Analyst
NORML | NORML Foundation
paul [at] norml.org

PS: Folks can look for a full review of this study in Thursday's NORML
weekly media advisory, as well as on the NORML podcast.
(http://www.normlaudiostash.com/)