Marijuana joints produce 3.5 times as much secondhand smoke as a Marlboro.

• Pollution levels as fine particulate matter in the air and how long they persistent was compared with marijuana joint, the bong with its bowl, the glass pipe, electronic vaping pen, and a Marlboro cigarette inn 60 controlled experiments. Cannabis joints were the most polluting – 3.5 times that of a Marlboro. The emission rate for a cannabis bong was 67% that of a joint; the glass pipe’s emission rate was 54% of the joint, and the vaping pen’s emission rate was 44% of the joint, as polluting as a cigarette, but hung around longer.

Ott WR. et al. Measuring indoor fine particle concentrations, emission rates, and decay rates from cannabis use in a residence, Atmospheric Environment: X, Volume 10, 2021,100106,ISSN 2590-1621,https://doi.org/10.1016/j.aeaoa.2021.100106.