Evidence Hub

Polycyclic aromatic hydrocarbons and cannabinoids in secondhand cannabis smoke

Tang X, Huang AS, Russell ML, Helen GS, Jacob P, Destaillats H, Schick SF

Environment international, 2026

Abstract

The legalization of cannabis is exposing more people to secondhand smoke (SHS) generated during cannabis use. Given the serious health effects caused by tobacco SHS, there is a need to assess the potential health effects of exposure to cannabis SHS. As a step toward this, we measured the concentrations of cannabinoids, nicotine and polycyclic aromatic hydrocarbons (PAHs) in air samples collected in public places where cannabis was being consumed. These were compared with concentrations in exhaled aerosols from cannabis smoking and vaping, and in tobacco SHS. Tetrahydrocannabinol concentrations were 22 to 255 µg/m3 in field samples, below the threshold for psychoactive effects. Nicotine concentrations in field samples did not exceed 1 µg/m3. The total PAH concentrations in field samples were from 3.2 to 80.5 ng/m3, depending on location type. By contrast, PAH levels averaged 72 ng/m3 in tobacco SHS and 220 ng/m3 in the more concentrated, exhaled cannabis aerosols. A total of 22 different PAHs were identified in field samples of cannabis aerosols, from which benz[a]anthracene (B[a]A) was present in the highest concentrations. The PAH profile of cannabis aerosols was different from that of tobacco SHS. A preliminary cancer risk evaluation showed that the dose associated with inhalation of cannabis SHS during an 8-h work shift exceeded the California No Significant Risk Level for B[a]A at all venues where cannabis was consumed primarily via smoking. In summary, the consumption…

Read the paper

Related studies

Go deeper in Evidence Hub

Evidence Hub adds a study data sheet (design, sample size, evidence level, key numbers), an AI summary and a chat grounded in the paper's text.

Open this study Sign up free