Understanding involuntary indoor THC exposure

Amirashkan Askari
Amirashkan Askari, PhD student supervised by Professor Arthur Chan.

Amirashkan Askari, a PhD student supervised by Professor Arthur Chan, has been Modeling the Fate and Involuntary Exposure to Tetrahydrocannabinol (THC) Emitted from Indoor Cannabis Smoking. His research will soon be published in a special issue of Environmental Science: Atmospheres, which will be dedicated to indoor air quality studies. This journal is governed by the Royal Society of Chemistry (RSC).

Recent data shows that cannabis consumption, especially through smoking, has become more frequent in Canada following the legalization of cannabis recreational use in 2018. Indoor spaces, such as apartments, restaurants, and bars are potential venues where cannabis smoking emissions may adversely impact indoor air quality. Experimental measurements concerning cannabis smoking emissions are sparse, making modeling studies valuable.

“To the best of our knowledge, our research has been the first to investigate the detailed and dynamic fate of THC, which is the psychoactive ingredient of cannabis, within a generic indoor space,” says Amirashkan.

The study reveals that airborne THC from cannabis smoking tends to absorb on indoor surfaces like carpet fibers, countertops, and walls. The project characterizes indoor residents’ involuntary exposure to THC from cannabis smoking.

“We realized that while adults’ exposure happens primarily through inhaling airborne THC, toddlers are exposed by touching indoor spaces and putting their contaminated fingers in their mouths. This latter mechanism, called non-dietary ingestion, makes toddlers’ exposure rates to THC even higher than adults,” explains Amirashkan.

In partnership with Professors Arthur Chan (ChemE) and Frank Wania (Department of Chemistry), Amirashkan examined several methods to alleviate involuntary exposure to THC. Their collaborative findings showed that filtering the room’s air from airborne particles, enhancing ventilation, and leaving space during the smoking period can reduce involuntary exposure to THC up to 50%.

Their project, funded by NSERC and EMHSeed, serves the public health sector by inspecting and characterizing an emerging source of indoor air pollution. People spend a considerable amount of time indoors. Poor indoor air quality can lead to a range of health problems, including respiratory illnesses, allergic reactions, headaches, fatigue, and more. It is particularly problematic for vulnerable populations, such as children, the elderly, and those with pre-existing health conditions. Understanding indoor air pollution is essential for protecting our health and well-being.