"Dr. Jennings also pointed to chemical analyses of marijuana smoke showing that it is inherently more toxic even than cigarette smoke."

Tired old stat that is only a half truth.  Google " donald tashkin ucla marijuana study" - the largest ever study on smoked marijuana and its effect on lungs.  His findings paint a far different picture:

"..smoking marijuana, even regularly and heavily, does not lead to lung cancer....
what we found instead was no association at all, and even a suggestion of some protective effect....marijuana also contains the chemical THC, which he said may kill aging cells and keep them from becoming cancerous."  

So not only does smoking marijuana not hurt your lungs, it actually helps protect you from acquiring various cancers.  And if you are unfortunate enough to get cancer, smoking marijuana will help you deal with the nausea and pain inducing effects of chemotherapy.  It will also help the appetite and the ability to hold food down. It does all this better than just about any pharmaceutical product that exists - with far less side effects.

This "article" is nothing more than the dying last gasps of prohibitionist propaganda.  Dr. Jennings sees the writing on the wall - with less addicts of traditional dangerous prescribed pharmaceuticals -  trillions of dollars will no longer go to the pharmaceutical industry.  
  You only need look at the policing and prison systems, and big alcohol to see similar tripe coming from their directions.  These half-truths and outright lies they come up with - may have worked in a pre-Internet world - but its outright insulting that they continue to bank on the ignorance of the populace.  
  Your lies don't work anymore.