The Impact: Marijuana Grows and Extraction Labs Harm Our Air, But Here’s How Pollution is Being Mitigated | Marijuana

The Impact: Marijuana Grows and Extraction Labs Harm Our Air, But Here’s How Pollution is Being Mitigated


The Impact is a weekly series that looks at how the growing cannabis industry affects our environment. Each week, we examine and explain the environmental impact of cannabis, for better or worse. Writer Greg Heilers speaks with Jeremy Neustifter and Kaitlin Urso about the cannabis industry’s impact on air quality.

Inhale. Exhale.

Was that tinge of cannabis in the air from the open jar next to you, or a massive emission of volatile organic compounds escaping from a grow operation a block away?

Cannabis consumers who have been concerned with the plant’s effects on their lungs have traditionally focused on the act of smoking. The growing popularity of extracts, such as live resin and shatter — there is now even a “710” holiday celebrating oils — may have reduced our concern with smoking carcinogens.  The effects of vaporizing concentrates remain, however.

Regardless, the burgeoning industry is now shifting its attention toward how the cultivation and extraction processes, critical to the production of both flower and extracts, may be affecting the air quality for everyone — not just smokers.

To get a clearer picture of just how the cannabis industry is affecting our air quality, reached out to Jeremy Neustifter and Kaitlin Urso of the Colorado Department of Public Health and Environment (CDPHE). Their work in the Air Pollution Control Division, and more specifically the CDPHE’s program on cannabis sustainability, is to “raise awareness on the environmental impacts of growing cannabis and establish best practices for the industry to reduce their environmental footprint.”

Clearing the Haze: Is There a Problem?

As with most issues within cannabis, its status as a Schedule I narcotic has made researching associated emissions difficult. Urso explained that typically, the US Environmental Protection Agency (EPA) quantifies air quality impacts of emerging industries.

Given cannabis’ illegal status federally, the EPA has not done so in this case. As such, CDPHE will conduct a study from October 2018 to September 2019 to quantify volatile organic compound (VOC) emissions from cannabis cultivation in Colorado.

According to Urso, what we do know today is that, “The main pollutant of concern is a VOC.”

There are two sources of VOCs:

  1. Cultivation of the plant: As plants grow, they naturally emit terpenes. People typically associate terpenes with the aromatic compounds of marijuana. However, these odors are VOCs, which react with other types of pollution to create ground-level ozone.
  2. Solvents used to extract marijuana concentrates: A lot of solvents in use are VOC-based. During extraction processes, a certain amount of solvent evaporates. While many facilities have closed-loop extraction systems, those have limitations. Sometimes, 30 percent of solvents are lost to evaporation.

Wherever VOCs are released into the air and exposed to sunlight, they combine with nitrogen oxide (NOx) to form ground-level ozone. According to the EPA, ground-level ozone has been linked to “a variety of health problems, particularly for children, the elderly, and people of all ages who have lung diseases such as asthma.”

Just how much ground-level ozone is being created in areas surrounding cannabis cultivation and extraction operations is unknown.

On top of VOCs, cannabis cultivation sites using diesel generators also generate nitrogen oxide. Plus, as previously reported, indoor grows’ energy consumption in cannabis states, such as California and Colorado, that produce a high volume of cannabis, already account for 10 percent or more of household energy use. Additionally, that energy often comes from fossil fuel burning power plants.

Photo courtesy of CDPHE – Air Pollution Control Division

Because of the uncertainty of the environmental impacts associated with cannabis cultivation and extraction operations, organizations like the CDPHE have come onto the scene by performing research, making best-practices suggestions, as well as helping cannabis companies with troubleshooting and tracking their progress.

Best Practices for Reducing Air Quality Impact

Neustifter explained that “emissions from the marijuana industry are just not that well understood, and we’re only really starting to better understand them in the recent years.” He added that the CDPHE is working hard to develop “innovative strategies and tools to assist the cannabis industry in becoming more environmentally friendly” through research conducted over the next year.

In addition, the organization is helping develop Greener Grows, an industry tool meant to help share metrics and find cost effective, environmentally friendly solutions. Greener Grows is expected to be open to the public in the fall.

Urso assured that any individual business’ data entered into the benchmarking tool will never be shared with the government and will remain anonymous. CDPHE — subject to the Colorado Open Records Act — deliberately constrained itself to a consulting role with Greener Grows, owned by a private company; having the tool owned and developed by a private company ensures data security.

That allows for anonymous, aggregated data to be used in creating industry trend reports shared publicly on the website. Companies interested in keeping up with the industry can use these trend reports to make business decisions surrounding environmental impact.

At the time of the interview, Urso recommended carbon filtration as “the gold standard.” Depending on how carbon filtration systems are installed and operated, they are able to “remove 50 to about 98 percent of VOC emissions.” Many growers already have to comply with odor control ordinances, which include carbon filtration.

A brief checklist of CDPHE’s current recommended cannabis operation best practices:

  • Regularly inspecting and replacing carbon filters
  • Making sure exhaust goes through filters, and doesn’t escape out of an open door
  • Regularly maintaining heating and ventilation systems
  • Having documented system in place to respond to odor complaints
  • Purchasing a scentometer or nasal ranger to better measure odor intensity
  • Optimizing carbon filtration and other odor control systems
  • Avoiding high-emission activities during high ozone periods, particularly during layight in summertime
  • Developing a training for staff to ensure best practices are being implemented
  • Deploying neutralizing agents, which prevent VOCs from reacting to form ozone

A Big, Clean Sigh of Relief?

Individuals living near cannabis cultivation and extraction sites may not yet be able to take a big sigh of relief. Though the public, and federal government, have up until now focused mainly on the dangers of firsthand cannabis smoke, there are also other concerns — those documented, and those currently under study.

To reduce emissions, public and private groups across the industry are continuing to investigate the quantities of VOCs released by cultivation sites, as well as determine grow and extraction operation best practices.

About Author

Greg Heilers is an environmentally conscientious writer living in the San Francisco Bay Area.

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