Most people today recognize the health risks of inhaling tobacco smoke, even secondhand. Fewer are aware of the dangers of cannabis smoke. However, new research from Berkeley’s School of Public Health finds that secondhand smoke from marijuana bongs, in particular, is more harmful than from cigarettes.
In the study, which was published in March in JAMA Network Open, authors S. Katharine Hammond, a professor of environmental health sciences, and Patton Khuu Nguyen ’18, MPH ’19, compared tobacco smoke from hookah pipes and cigarettes to cannabis smoke from bongs. The researchers, who asked study participants to bring their own weed and paraphernalia, found that fine particulate matter from the cannabis smoking was at least four times greater and took longer to dissipate. After one session, the fine particulate matter concentration still measured 10 times greater than background levels 12 hours after smoking had stopped.
The authors note that while nearly a third of young adults believe secondhand pot smoke to be safe, it actually has “several hundred toxic chemicals, carcinogens, and fine particulate matter (PM2.5), many at higher concentrations than tobacco smoke.”