Local research is contributing to other national efforts to determine how cannabis grow facilities may impact air quality. The Desert Research Institute and Washoe County Health District tested air quality in four Nevada and California grow facilities.
Results suggest that butane and cannabis itself release enough biogenic volatile organic compounds (BVOCs) that it could be harmful to workers at the facilities. Concentrations may also be high enough to contribute ground-level ozone in the atmosphere.
“The concentrations of BVOCs and butane that we measured inside of these facilities were high enough to be concerning,” said lead author Vera Samburova, an associate research professor of atmospheric science at DRI. “In addition to being potentially hazardous to the workers inside the cannabis growing and processing facilities, these chemicals can contribute to the formation of ground-level ozone if they are released into the outside air.”
Volatile organic compounds (VOCs) are emitted by cannabis plants and solvents used to extract THC, according to the Colorado Department of Public Health and the Environment.
“When we went to these facilities, of course, the smell is really, really strong, and we were really surprised that there was no [use of] personal protective equipment there.”
Plants in general produce VOCs used “to perform a variety of tasks, as different as: indirect plant defense against insects; pollinators attraction; plant-to-plant communication; thermo-tolerance and environmental stress adaptation; [and] defense from predators,” according to a 2017 study published in Nature.
VOC emissions are dependant upon the type of plant, and some plants can remove VOCs, but that doesn’t necessarily mean house plants filter the air.
According to research detailed earlier this year in The Atlantic, “more than 107 million Americans live in areas with unhealthy amounts of ozone, according to the Environmental Protection Agency. Unfortunately, houseplants can’t do much about that, either. The researchers found that even the most effective plants barely reduced the level of ozone in indoor spaces.”
Where cannabis fits in
Cannabis’ distinctive and potent odor comes from terpenes that emit VOCs.
“[These] organic chemical compounds … participate in atmospheric photochemical reactions that create smog/ozone,” said Kaitlin Urso of the Colorado health department.
In particular, terpenes react with nitrogen to form ground-level ozone. Those compounds would evaporate under normal indoor atmospheric conditions, but in pot facilities, as DRI found, concentrations of VOCs were considerably higher, raising the alarm about increased ozone within facilities and, potentially, around the region.
Elevated ozone can cause health problems, such as breathing difficulties and cardiovascular problems, and Washoe County has exceeded ozone air-quality standards more than once this year.
“Here in our region, unfortunately, we already exceeded the national air quality standard for ground-level ozone quite a few times per year,” Samburova said. “That’s why it is so important to answer the question of whether emissions from cannabis facilities are having an added impact.”
Colorado, because of its legal cannabis industry, is studying the issue, and DRI researcher Samburova says more studies need to be conducted before these results are definitive.
“We can just speculate that the grow facilities…can have an impact on air quality because the concentrations [of VOCs] are extremely high,” she said.
Moreover, workers in grow facilities may need protective equipment.
“When we went to these facilities, of course, the smell is really, really strong, and we were really surprised that there was no [use of] personal protective equipment there,” Samburova said. “Each facility can have hundreds of plants releasing VOCs into the air, which is why we need to look at that carefully.”