Cannabis Cultivation Facilities: A Review of Their Air Quality Impacts from the Occupational to Community Scale

Abstract

This review addresses knowledge gaps in cannabis cultivation facility (CCF) air emissions by synthesizing the peer-reviewed and gray literature. Focus areas include compounds emitted, air quality indoors and outdoors, odor assessment, and the potential health effects of emitted compounds. Studies suggest that β-myrcene is a tracer candidate for CCF biogenic volatile organic compounds (BVOCs). Furthermore, β-myrcene, d-limonene, terpinolene, and α-pinene are often reported in air samples collected in and around CCF facilities. The BVOC emission strength per dry weight of plant is higher than most conventional agriculture crops. Nevertheless, reported total CCF BVOC emissions are lower compared with VOCs from other industries. Common descriptors of odors coming from CCFs include “skunky”, “herbal”, and “pungent”. However, there are few peer-reviewed studies addressing the odor impacts of CCFs outdoors. Atmospheric modeling has been limited to back trajectory models of tracers and ozone impact assessment. Health effects of CCFs are mostly related to odor annoyance or occupational hazards. We identify 16 opportunities for future studies, including an emissions database by strain and stage of life (growing cycle) and odor-related setback guidelines. Exploration and implementation of key suggestions presented in this work may help regulators and the industry reduce the environmental footprint of CCF facilities.

The Emerging Spectrum of Respiratory Diseases in the U.S. Cannabis Industry

“…39,40 While these measurements exceed the European Commission recommendations for overall indoor terpene concentrations (40-400 ppb), individual terpene components are generally below regulatory standards. 41 While terpenes themselves are considered to be relatively safe, they are highly reactive with oxidant species, such as hydroxyl radicals, ozone, and oxides of nitrogen. The heterogeneous products formed through these reactions include formaldehyde and ultrafine particles, which can act as upper and lower respiratory tract irritants and, in some cases, such as formaldehyde, as sensitizers.…”

“…People living in communities near cannabis cultivation facilities have reported nausea and eye irritation due to the strong smells, although it is unclear whether these symptoms are related to physiologic versus psychologic effects. 41 VOCs are also formed as byproducts of decarboxylation, a process in which plant material is heated in ovens to transform cannabinoids into activated 9-THC. In particular, 2,3-pentanedione and diacetyl-VOCs that have been shown to cause epithelial damage in laboratory studies and are linked to bronchiolitis obliterans in flavoring workers-have been detected in air samples near decarboxylation ovens.…”

“…39 40 While these measurements exceed the European Commission recommendations for overall indoor terpene concentrations (40–400 ppb), individual terpene components are generally below regulatory standards. 41…”

Odor Control in the Cannabis Industry: Lessons from the New Kid on the Block

“…To learn more about how neighbors of cannabis grows may be affected by odors, many of the same researchers who worked on that study authored a March 2022 review of the literature related to the air-quality impacts of these facilities. 27 …”

“…“Current studies suggest that cannabis cultivation facilities might already be changing the ozone concentration where they are located,” the Vancouver researchers wrote in their review. 27 For example, a 2019 study in Denver, Colorado, found that VOC emissions from local cannabis cultivation facilities could increase hourly ozone concentrations by up to 0.34 ppb in the morning and 0.67 ppb at night. 39 Review coauthor Naomi Zimmerman, an assistant professor of mechanical engineering at the University of British Columbia, says the significance of such changes depends on how close a region is to exceeding the National Ambient Air Quality Standard for ozone.…”