What peer review studies mean is that when a scientist concludes a research project, they write the results up in the form of a paper which includes the hypothesis of the study, a literature review of related studies, the methods used, sources or origin of the data, the amount of data, the way the data was analyzed, the conclusions from the analysis and submits it to a scientific journal, a board of his peers will sit review and pick apart if need be anything they may think falls short of sound research methods. This is done to assure that the quality of the information is sound because that information will be review and used by other scientists in furthering the research and knowledge within that field. The fact that the University of Washington author used (referenced) 21 separate studies in writing this gives it more credence than most of the non reference crap that is publish on the net nowadays,
My background in science is in biology and agriculture. I made my living as a plant breeder and through the years wrote and submitted many papers of my own to journals.
Dispute what you want, but the fact of what cannabis smoke contains is easily proven with the use of mass spectrometry and has been known for years.