Carbonyl Compounds in Mainstream Smoke of Hemp Cigarettes

Abstract

Introduction: CBD is a major phytocannabinoid in hemp (Cannabis sativa containing less than 0.3% THC). Hemp cigarettes are a combustible form of hemp consisting of dried and smokable flowers, which represent 2% of the overall CBD market, and the market is expected to grow. Combustion and pyrolysis of organic material are associated with the production of carbonyl compounds, which are known toxicants and are associated with adverse health outcomes. Concentrations of carbonyl compounds in mainstream hemp cigarette smoke are unknown. Materials and Methods: We analyzed and compared carbonyl concentrations in the mainstream smoke produced by a hemp cigarette (Brand B), a premium hemp cigarette (Brand A), Marlboro Red tobacco cigarette, and a research reference tobacco cigarette using high-performance liquid chromatography. We measured carbonyl concentrations in lg per puff and mg per cigarette. Carbonyls investigated were formaldehyde, acetaldehyde, acetone, acrolein, propionaldehyde, crotonaldehyde, 2-butanone, and butyraldehyde. Significance was determined using Tukey's test. Results: We observed that Brand B had significantly higher butyraldehyde than any cigarette. No significant differences were observed in crotonaldehyde concentration in the cigarettes. For the remaining carbonyls, Brand A had consistently lower concentrations in mainstream smoke than tobacco cigarettes. Hemp cigarettes emit carbonyls in a lower concentration in lg/puff than tobacco cigarettes, but the magnitude of significance generally decreases when normalized to mg/cigarette. Conclusions: Smoke from hemp cigarettes contains carbonyls at biologically significant concentrations. Opportunities may exist to reduce carbonyl production in these products, and identified potential risks must be considered when balancing the harms and benefits of hemp cigarettes when used for therapeutic purposes.

An Automated “Hands-Off” Method for Sampling Mainstream Smoke from Cannabis Cigarettes

“…Although we did not collect samples from the tobacco cigarettes for PAH analysis, a comparison to published data for several types of unfiltered tobacco [18] indicates that the emissions are comparable, as shown in Figure 5a for the high-flow topography condition. We also compared our chemical analysis results to the limited number of similar data for cannabis that have been published [7,18,19]. As shown in Figure 5a,b, we measured similar or higher concentrations of PAHs, except naphthalene.…”

“…Among the measured chemical compounds in this study and the literature, formaldehyde, acetaldehyde, and benzo[a]pyrene (BaP) were selected for risk estimation because they are the most hazardous compounds based on a previous tobacco smoke risk study, contributing more than half of the risk associated with hazardous and potentially hazardous compounds in cigarette smoke [20]. The observed concentrations from this current study and literature values [7,18,19] were combined to obtain emitted average formaldehyde, acetaldehyde, and BaP concentrations from tobacco, marijuana, and hemp (µg/m 3 ). The reference concentration (RfC; µg/m 3 ) and cancer unit risk [(µg/m 3 ) −1 ] were obtained from the EPA CompTox Version 2.3 database.…”