Chemical Constituents and Oxidative Potential of Fine Particulate Matter in a Cannabis Consumption Lounge: A Case Study

Cannabis consumption lounges represent an emerging indoor microenvironment where secondhand cannabis exposure may pose potential health risks. However, understanding of particle composition and oxidative potential (OP) in these settings remains limited. In this case study, we quantified PM 2.5, black carbon (BC), metals, cannabinoids, and OP in a cannabis consumption lounge and assessed spatial variability across three sampling locations: the smoking cabin, retail entrance, and street front. Mean (±SD) PM 2.5 concentrations during busy hours (12 pm–10 pm) reached 92 (±100) μg/m 3 in the smoking cabin. Weekly mean PM 2.5 concentrations were 63 (±3.3) μg/m 3 in the smoking cabin and decreased by 62% and 79% at the entrance and street-front, respectively. BC averaged 11.0 (±1.8) μg/m 3 in the smoking cabin and decreased by 76% and 87%. In contrast, total cannabinoids reached 1560 (±580) ng/m 3 in the smoking cabin but decreased more sharply by 98% and 99%. OP metrics showed assay-dependent spatial patterns: OP v OH decreased by 46% and 64%, whereas OP v DTT did not follow the same monotonic decrease. These findings suggest that chemical constituents exhibited distinct spatial behaviors and were not fully confined to the smoking cabin, providing exploratory evidence to inform future engineering controls and regulatory guidance for cannabis consumption lounges.