To generate the samples for carbonyl testing, an Aspire Atlantis 2 tank was filled with the thinning agent being tested and coupled to an Evolv DNA 200 vaporizer controller containing a nickel coil.
PEG 400 produced the greatest levels of formaldehyde and acetaldehyde, followed by PG. VG and MCT produced low levels of formaldehyde and acetaldehyde, including levels that did not reach the limit of quantitation (LOQ) for acetaldehyde (VG only) and formaldehyde (both VG and MCT). None of the thinning agents produced acrolein at levels that reached the LOQ.
Compared with the other agents, PEG 400 produced the largest amounts of acetaldehyde and formaldehyde. The amount of formaldehyde was particularly high, with levels that were nearly four times greater than that produced by PG, more than 226 times higher than that produced by MCT, and almost 242 times greater than that produced by VG. Relative to the other agents, PG produced moderate levels of acetaldehyde and formaldehyde. Both VG and MCT produced low levels of acetaldehyde and formaldehyde. All agents produced low levels of acrolein.
To provide a context for exposure to the carbonyls produced by the four agents, we compared the levels of acetaldehyde and formaldehyde to occupational exposure limits defined by the Occupational Safety and Health Administration (OSHA). Leveraging calculations conducted by Gillman et al., the daily OSHA limits for acetaldehyde and formaldehyde are 2,088,000 and 5300 mg, respectively. Given acetaldehyde’s greater exposure limit, a cannabis user inhaling the byproducts of heated thinning agents would not be exposed to a significant percentage of their daily limit. For example, one inhalation of PEG 400 heated to 230C, which produced the greatest amount of acetaldehyde, exposes an individual to 0.00125% of the daily limit. However, for individuals with a variant ALDH2 gene, any exposure to acetaldehyde may cause adverse effects, including an increased risk of UADT cancers.
Exposure to formaldehyde represents a much greater potential risk. One inhalation of PEG 400 would expose an individual to 1.12% of the daily limit of formaldehyde. Comparatively, smoking one cigarette exposes an individual to 1.42%to 2.35%of the daily limit of formaldehyde. Although not as high as PEG 400, one inhalation of PG exposes an individual to 0.30% of the daily limit. In comparison, one inhalation of MCT or VG would result in an exposure of 0.0050% and 0.0046% of the daily limit, respectively.
Although in practice only a small amount of PEG400 or PG is used to dilute cannabis oil (compared with the isolates used in the present study), these results suggest that consumers potentially expose themselves to health risks when using such products, as formaldehyde inhalation has been linked to increased incidence of myeloid leukemia and nasopharyngeal cancer.
For two reasons, the results may have differed if a cannabis oil-thinning agent mixture were tested. First, the mixture may have produced a different amount of carcinogenic byproducts than the thinning agents alone. A mixture of two components may have boiling and combustion points that are different from either of the components separately. Thus, vaporizing the mixture may increase or decrease carbonyl production. Second, the botanical and chemical compounds found in cannabis oil may affect carbonyl production during vaporization. Cannabis contains hundreds of cannabinoids, terpenoids, and antioxidants that may affect the oxidation of the thinning agents and inhibit or exacerbate the formation of carcinogenic compounds. Unfortunately, due to federal restrictions, in the present study, we were not able to examine carbonyl production in cannabis oil-thinning agent mixtures.
Finally, although acetaldehyde, acrolein, and formaldehyde are the carbonyls that are the most commonly tested for in prior research, thinning agents may produce other potentially harmful compounds. Future work may extend the findings of this study by testing agents for other carbonyls.
If you would like more detail I can set aside some time later to look back at the study and give you the info (busy now). I do recall that the study found greater levels of the offending compounds at greater voltages. Also dual coil ecig tanks tended to produce lower volumes of the offending compounds than single coil ecigs at the same voltage, due to the voltage/current being dispersed across a greater surface area, resulting in lesser overall temp.
Sorry, but the burden of proof is on that wanna-be Dexter who wrote that post on ICMag, making those wholly, unsubstantiated claims. 
