Aerosols Formed during Simulated Cannabis Vaping and Dabbing

XIAOCHEN TANG, Clément Gambier, Vi Rapp, Marion Russell, Lara Gundel, Hugo Destaillats, Lawrence Berkeley National Laboratory

     Abstract Number: 531
     Working Group: Indoor Aerosols

Abstract
Vaporizable cannabis concentrates (VCCs) consumed as a liquid (vaping) or a waxy solid (dabbing) are becoming increasingly popular. Major constituents of VCCs are semivolatile monoterpenes, sesquiterpenes and terpene alcohols, along with high molecular weight (HMW) compounds (MW > 300) that include the active cannabinoids and co-extracted plant metabolites. In addition, the HMW illicit additive vitamin E acetate (α-tocopheryl acetate) was found in many of the e-cigarettes associated with the outbreak of vaping product-associated lung injury (EVALI) in 2019 and 2020, and is considered to be a key factor associated with the disease. Despite the growing amount of research on chemical emissions from cannabis use, little is known about the influence of HMW compounds on the generation of ultrafine particles (UFPs) and thermal degradation byproducts during vaping or dabbing.

This study systematically explored how VCC formulation affects the number and mass concentration of UFPs and their chemical composition, by generating vaping aerosols from liquids of different composition under standardized conditions in a 20-m³ environmental chamber. A mixture consisting of common terpenoids found in cannabis extracts was incrementally enriched in HMW constituents, including cannabinoids (trans-Δ9-tetrahydrocannabinol, cannabidiol and cannabinol), plant metabolites (lignans, flavonoids, triterpenes), and vitamin E acetate. Aerosol particles between 8 and 2,500 nm in size, generated by heating mixtures of various compositions, were monitored in real time with a Fast Mobility Particle Sizer spectrometer, an Optical Particle Sizer and an Aerodynamic Particle Sizer. In addition, airborne species were collected in sorbent tubes and analyzed by gas chromatography/mass spectrometry, and volatile carbonyls were sampled in dinitrophenylhydrazine-coated cartridges, extracted and analyzed by liquid chromatography. These results were used to determine the UFP yield, byproduct formation rate, and the UFP carrying capacity of HMW compounds. Users’ daily intake and indoor levels of toxicants and UFPs were estimated in typical scenarios.