Researchers are trying to create a weed breathalyzer to pop drivers for cannabis DUIs, but it’s pretty darn challenging
As the cannabis industry continues to flourish nationwide, concerns over impaired driving due to cannabis consumption have become a growing issue in most states. While a large number of states have legalized the use of cannabis for medical or recreational purposes, ensuring roadways remain safe remains a top priority for law enforcement and policymakers.
And one potential solution lies in the development of a cannabis breathalyzer that accurately detects THC, the psychoactive component of cannabis, in the breath of drivers who are suspected to be impaired on the ol’ weed plant. However, creating such a device presents significant challenges due to the unique nature of cannabis aerosols and their THC content.
The quest for a cannabis breathalyzer
Developing a breathalyzer for alcohol is a well-established and straightforward process since alcohol is exhaled in substantial amounts after consumption. However, cannabis poses a different challenge. THC is believed to be carried within aerosol particles in exhaled breath, and the total volume of these aerosols can be quite small, making it difficult to measure their THC content accurately. Unlike alcohol breathalyzers, no standard method currently exists for cannabis breath detection.
A step toward progress
Researchers at the National Institute of Standards and Technology (NIST) and the University of Colorado Boulder have taken a significant step towards developing a reliable cannabis breathalyzer. Their study, published in the Journal of Breath Research, involved collecting breath samples from participants both before and after smoking high-THC cannabis. The goal was to establish a protocol that yields consistent and reproducible results—a crucial prerequisite for creating a validated field-based method.
A challenging research process
To ensure compliance with federal laws, the research team employed a mobile lab, a comfortable white van conveniently parked outside participants’ homes.
All participants used a consistent type of high-THC cannabis obtained from a licensed dispensary in Boulder, Colorado. This approach allowed researchers to analyze THC in breath without directly handling cannabis.
The study involved participants providing a pre-use breath sample and a blood sample before smoking cannabis. Immediately after consumption, they provided a second blood sample to confirm recent use. An hour later, a second breath sample was collected. To analyze THC concentration, participants blew into a tube with an “impaction filter” that captured aerosols from their breath. In the lab, researchers extracted the material from the filter and used liquid chromatography with tandem mass spectrometry to measure THC and other cannabis compounds.
Challenges and results
While the study was a protocol development experiment and lacked statistical weight due to its small participant size
(18 individuals), it highlighted important findings. Contrary to expectations, THC concentrations in breath samples collected an hour after consumption did not significantly differ from pre-use samples. This indicates that the current method might not reliably detect recent cannabis consumption.
The road ahead
Despite these challenges, the importance of developing a cannabis breathalyzer cannot be overstated. Impaired driving, whether due to alcohol or cannabis, poses serious risks to public safety. The study’s results underscore the need for further research and a larger participant pool to produce more statistically significant data.
The National Institute of Justice has already granted additional funding of $1.5 million over three years to continue research in this area. The upcoming study will involve a larger group of at least 40 participants, providing over a thousand breath samples, to strengthen the results and move closer to a viable cannabis breathalyzer.
The quest for a reliable cannabis breathalyzer remains ongoing, and researchers at NIST and the University of Colorado Boulder are diligently working towards this goal. With the rising acceptance of cannabis use, ensuring road safety is paramount. While challenges persist, continued research and funding will play a crucial role in developing an accurate and effective cannabis breathalyzer. Once achieved, this technology will be a game-changer in keeping impaired drivers off the road and making our highways safer for everyone.
