Abstract

Studies have compared the chemical properties of tobacco smoke to those of cannabis smoke,
with the objective of identifying the chemical attributes responsible for the mutagenicity and
carcinogenicity of cannabis smoke. Comparative studies have included small sample sizes and
produced conflicting results. The aim of this study was to assess the major chemical and
physical variations of cannabis smoke across a range of cannabis samples of different potencies
and origins, sourced from the illegal market in New Zealand. Twelve cannabis samples were
studied ranging from 1.0% to 13.4% delta-9-tetrahydrocannabinol (D9THC) content. A smoking
machine was used to smoke “joints” (cannabis cigarettes) and the chemical/physical properties
of the smoke assessed. The chemical constituents of the smoke extracts were analysed by gas
chromatography/mass spectrometry. A range of different chemical constituents (in addition to
D9THC) were identified and their concentrations estimated. Terpenoids were identified as the
major variable in cannabis smoke, showing a 40-fold range in total terpenoid content. Analysis
of the total particulate matter showed that significantly different levels of particulate matter
were produced between the different cannabis samples, ranging from 14.6 to 66.3 mg/g of
cannabis smoked. The D9THC delivery efficiency during smoking was also investigated and
produced consistent results showing a mean and median of 12.6% and 10.8%, respectively, of
the theoretically available D9THC (ranging from 7.2% to 28.0%).