THC Breathalyzers are Coming

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by Dan Larkin.

THC breathalyzers are coming. But, are they the right law enforcement tool? Let’s take a look at what these breathalyzers do. Maybe we can see if they are an answer to a problem or a reinforcement of a misguided, yet well-intentioned idea about cannabis consumption.

What are THC breathalyzers and how do they work?

THC breathalyzers are being designed to perform much like alcohol breathalyzers. Basically, they’ll measure the level of THC that’s present in your body. Scientists at the University of Pittsburgh are working on the technology right now.

“We envision that this sensor can be produced as a breathalyzer like an alcohol breathalyzer.”

Alexander Starr-lead researcher & professor at University of Pittsburgh

You would breathe into the device and tiny carbon nanotubes inside the unit would detect the level of THC in your body. How, you ask? Well, let’s get science-y for a minute.

Your breath has electrical molecules in it. Those molecules would bind to the nanotubes. Oh, and these nanotubes are tiny. I’m talking about 100,000 times thinner than a human hair. Since the molecules all travel at different speeds, the breathalyzer would be set-up to detect THC molecules. Pretty cool, really.

So, if you’re wondering if the readings will be accurate, the short answer is yes. I say that because right now the tests are matching the accuracy of mass spectrometers. And that is considered the gold standard of potency testing in the cannabis industry.

But, what does the THC breathalyzer reading really mean?

Ah, this is the big question, isn’t it? Does the presence of THC in your system mean that you are impaired? Does it mean you shouldn’t drive? Will medicinal cannabis users be arrested for trying to legally treat their ailments? Will you be arrested even though you aren’t impaired? What exactly denotes impairment from THC?

Phew! There are more questions than answers associated with a THC breathalyzer, for sure. But, let’s be clear. If someone is impaired to the point where they can’t safely operate a motor vehicle, heavy equipment, or perform duties that require no acceptable level of impairment (think brain surgeon, for instance) they should be stopped from doing so.

No one is advocating for that. But, is the level of THC in the body the right measurement to use to make a determination of impairment? I think not. Sure, it is certainly a possible clue, but in and of itself, shouldn’t be used to arrest cannabis consumers.

Why? Well, for one thing, THC can stay in your body for up to 20-30 days for regular users. But the “impairment” from the THC will only last for a few hours. Do you see the issue there?

What about breathalyzers for other substances?

If we’re going to measure THC that way, then don’t we also need a breathalyzer that measures the level of opioids in your body too? What about sleep-aid medication or even over the counter meds that can make you drowsy?

Do you see my point? Everyone’s body and brain are different. We have different tolerances. So, the level of THC that impairs me may be very different than the level of THC that impairs you.

I get it though. If you are against cannabis use or you are simply uninformed or misinformed about it you may think the only real goal of consuming it is to “get high”. So, if you have THC in your system, you are “high” and thus, shouldn’t be driving.

If you regularly consume cannabis you know that just isn’t the case. You may very well consume cannabis to get a lift or high. You may also consume it to relieve anxiety or PTSD. Maybe you use it for pain or to improve your appetite after cancer treatment. Again, the point is, one size does not fit all and a THC breathalyzer set to some specific detection level isn’t going to do what it is being designed to do.

“There is zero scientific data addressing the question of correlating the detection of THC or its metabolites in breath with psychomotor impairment, nor am I aware of any serious scientific investigations that have sought to do so,”

Paul Armentano, deputy director of NORML

Even the AAA and the National Highway Transportation Association (NHTSA) have said they oppose the imposition of such a per se limit, according to Paul Armentano of NORML


As currently envisioned, THC breathalyzers would take us backward towards unjust arrests. It supports the stigmas that have been created around cannabis use. It doesn’t, on its own, solve any actual problem.

A better idea would be for law enforcement to develop well tested and researched methods of testing drivers for physical and/or mental impairment. That should be the gold standard for determining whether someone is fit to drive or operate machinery or perform surgery. Set specific performance measurements for use in evaluating individuals.

Let’s all work together to continue to educate those who don’t have enough information about what cannabis is, and what it isn’t. We need to erase the stigma and explain the benefits. We can and will eventually normalize cannabis, but it will take all of our efforts.

Want to read more from CannabisIRL on cannabis testing? Click here.

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