Significant Differences in Ultrafine Particle Concentrations and Size Distributions between Cannabis Cultivation and Processing Facilities

DAVI DE FERREYRO MONTICELLI, Cynthia Pham, Sahil Bhandari, Angela Eykelbosh, Sarah Henderson, Amanda Giang, Naomi Zimmerman, University of British Columbia

     Abstract Number: 769
     Working Group: Indoor Aerosols

Abstract
Cannabis cultivation and cannabis processing are emerging industries with poorly understood emissions. Information about ultrafine particles (UFP) is scarce and size distribution information has not been widely reported. In this study we deployed a Fast Mobility Particle Spectrometer (FMPS, model 3091, from TSI Instruments) in different rooms within a cannabis cultivation facility and processing facility. For 16 days across June-July 2023, we sampled in the Mother, Vegetation, Grow (early stage), Packaging, and Storage rooms of a cultivation facility and in the Grinding, Ethanol, Distillation, Formulation, Pre-Roll, and Packing room of a extraction and processing facility, covering almost the full life cycle from early plant development to final product. At least one day of continuous sampling was taken per room. While the constant action of mechanical ventilation, dehumidifiers and charcoal filters in cultivation rooms significantly reduced the UFP concentrations (most of the time to <1000 #/cm3), in the processing rooms which had a single exhaust that operated in cycles, concentrations were much higher (in some cases above 100,000 #/cm3). The one-minute average shape of distributions (i.e., unimodal, bimodal, multimodal) and peak modes (p-mod) in the cultivation facility rooms were: Mother (bimodal, p-mod = 80nm and 450nm), Vegetation (unimodal, p-mod = 80nm), Grow no pesticides (unimodal, p-mod = 124nm), Grow with pesticides (unimodal, p-mod = 6nm), Storage (bimodal, p-mod = 6nm and 124nm), Packing (unimodal, p-mod = 107nm). For the processing facility rooms: Grinding (bimodal, p-mod = 6nm and 45nm), Ethanol (unimodal, p-mod = 93nm), Distillation (unimodal, p-mod = 45nm), Formulation (unimodal, p-mod = 93nm), Pre-Roll (unimodal, p-mod = 34nm), and Packing (unimodal, pmod = 60nm). Understanding these effects will support policy makers and facility managers to coordinate efforts towards reducing exposure for workers and overall improved air quality.