Cannabis farms in the US could be causing chronic air pollution

Cannabis farms, traffic emissions and the Californian sunshine could be creating the ‘perfect storm’ for air pollution, according to research published by the Desert Research Institute (DRI).

Since California and Nevada legalised cannabis for recreational use in 2016 and 2017, there has been a proliferation of new farms popping up across the two states but a pilot study, published in Journal of the Air & Waste Management Association, suggests this is having a negative impact on air quality.

Researchers visited four cannabis growing farms and found that cannabis plants emit biogenic volatile organic compounds (BVOCs) during growth and reproduction, which when mixed with nitrogen oxide (NOx) traffic emissions and sunlight creates ozone (O3), a toxic air pollutant which is harmful to humans.

They also found very high levels of butane, a volatile organic compound (VOC) that is used during the oil extraction process.

The team measured emission rates over time, to learn about the ozone-forming potential of each individual plant. The results show that the BVOCs emitted by each cannabis plant could trigger the formation of ground-level O3 at a rate of approximately 2.6g per plant per day.

Vera Samburova, Ph.D, and lead author of the study said: ‘The concentrations of BVOCs and butane that we measured inside of these facilities were high enough to be concerning,

‘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.’

Mike Wolf, permitting and enforcement branch chief for the WCHD Air Quality Management Division added: ‘With so much growth in this industry across Nevada and other parts of the United States, it’s becoming really important to understand the impacts to air quality.’

The team at DRI now say they hope to find funding for a similar study on a wider scale