AAAR 37th Annual Conference October 14 - October 18, 2019 Oregon Convention Center Portland, Oregon, USA
Abstract View
Heterogeneous Ozonolysis of THC and Nicotine
AARON WYLIE, Christopher Lim, Jonathan Abbatt, University of Toronto, Canada
Abstract Number: 88 Working Group: The Air We Breathe: Indoor Aerosol Sources and Chemistry
Abstract Smoking is responsible for over 7 million deaths per year worldwide, with almost 1 million of these deaths caused by second-hand smoke. An additional cause for concern is third-hand smoke, which leads to exposure via partitioning of surface-bound smoke constituents to the immediate atmosphere after smoking has ceased. While little is known of the nature of third-hand smoke, less is known about how its constituents temporally evolve with respect to oxidation by atmospheric oxidants such as O3 and OH. With the recent trend of recreational cannabis legalization in developed countries, understanding the nature of cannabis smoke in the indoor environment is paramount to public health. The temporal evolution of Δ9-tetrahydrocannibinol (THC) and nicotine, major constituents of cannabis smoke and tobacco smoke respectively, with respect to O3 reaction on model indoor surfaces is presented. THC films of known thickness on a glass surface were exposed to clean air containing O3 of various mixing ratios and different relative humidity (RH) values in a flowtube, and THC concentration and product formation were monitored by offline HPLC-ESIMS. The oxidation of THC followed pseudo first-order reaction kinetics independent of RH with first-order dependence on O3 mixing ratio. Oxidized condensed-phase products were separated and putatively identified, and include secondary ozonides, epoxides and dicarbonyl products of oxidative cleavage. Product formation was heavily dependent on RH, with the presence of water favouring formation of dicarbonyl products. The surface behaviour of nicotine, both as a pure compound and within cigarette smoke extract (CSE), on glass and cotton surfaces is evaluated with respect to whether oxidation by O3 can compete as a loss process with volatilization.