THC was detected in 80% of breath samples collected 1 hour after cannabis smoking using an impaction filter device, but baseline detection rates suggest the technology needs refinement.
Forensic toxicologists, law enforcement technology developers, and impaired driving researchers.
80% post-use detectionof THC in breath 1 hour after smoking, but 31-36% baseline detection rates complicate interpretation
What the researchers found
THC was quantified in 80% of 1-hour post-use breath samples, 36% of baseline-experimental samples, and 31% of baseline-intake samples, indicating detectable but inconsistent breath THC levels.
Why it matters
A reliable cannabis breathalyzer could be crucial for impaired driving enforcement, but this pilot study shows significant technical challenges remain before such a device is practical.
The numbers in context
42 breath samples from 18 participants over 1+ year. Cannabis flower ~25% THCa. THC detected in 31% baseline-intake, 36% baseline-experimental, 80% post-use samples. Analyzed by LC-MS/MS.
How the study worked
Pilot study using impaction filter breath collection device before and after legal cannabis flower smoking. THC quantified by liquid chromatography-tandem mass spectrometry.
Who was studied
18 participants who smoked legal market cannabis flower (~25% THCa) in their residences.
What this study cannot tell us
Small pilot study (18 participants). THC detected in 31-36% of baseline samples raises specificity concerns. No verified abstinence before baseline. Single post-use time point. Cannabis use occurred at participant residences.
How to read the evidence
Small pilot study providing proof-of-concept; much larger studies with verified abstinence needed.
When this study was published
Recent pilot study spanning over 1 year of data collection.
The bigger picture
While alcohol breathalyzers are mature technology, a cannabis equivalent faces fundamental challenges because THC is carried in breath aerosol particles rather than vapor, requiring entirely different detection approaches.
Replication
Small pilot; larger studies with verified abstinence and multiple time points needed.
Funding
Not specified in abstract
Conflicts of interest
Not specified in abstract
Questions still open
- Can baseline THC detection be eliminated with verified abstinence periods?
- What post-use time window would be appropriate for a cannabis breathalyzer?
Read the original research
THC in breath aerosols collected with an impaction filter device before and after legal-market product inhalation-a pilot study.
Journal of breath research, 17(3)
Citation
Jeerage, Kavita M; Beuning, Cheryle N; Friss, Adam J; Bidwell, L Cinnamon; Lovestead, Tara M. (2023). THC in breath aerosols collected with an impaction filter device before and after legal-market product inhalation-a pilot study.. Journal of breath research, 17(3). https://doi.org/10.1088/1752-7163/acd410