A UBC researcher has developed a marijuana breathalyzer that measures THC levels in hopes it will be used to combat impaired driving as the debate over legalization continues.

UBC Okanagan engineering professor Mina Hoorfar and PhD student Mohammad Paknahad began developing the microfluidic breath analyzer three years ago.

Prof. Hoorfar said the device can detect tetrahydrocannabinol (THC), the psychoactive ingredient in cannabis, on a person's breath.

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"The device is so sensitive it can even measure sub ppm, particle per million, up to a higher concentration.

"THC is a big molecule and it stays on the breath for hours," she said.

The device is non-invasive and differs from other methods of THC detection, which typically require saliva and blood samples.

A 3-D printer was used to form the tiny channels needed to analyze breath in the hand-held device. It cost just $15 to produce and once in mass production, Prof. Hoorfar anticipates production costs per unit to be less than $5.

An app will be developed to accompany the breathalyzer and Bluetooth technology will be used to transmit data.

"The device comes with a clinical bag. It's just a bag you blow into.

"You attach the bag to the sensor, the sensor will send a signal to your cellphone, to an app on your cellphone, and it will give you the level of THC in your breath," Prof. Hoorfar explained.

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The breathalyzer is portable, about the size of two fingers, and weighs less than 10 grams. It consists of a micron-sized polymer channel fit with an electrochemical gas sensor that reacts with gas to send an analysis.

The technology is set apart, she said, by its ability to avoid false positives and negatives by controlling for temperature and humidity, and to be selective to any gas found on the breath.

"It can detect the THC accurately among other gases. That's a unique factor I haven't seen in any other breath analyzers in the market."

The technology also has the capability to measure ketones, a biomarker of diabetes, which Prof. Hoorfar hopes will be developed further for use by diabetes patients. And the technology also has capabilities to test gas leaks via drones, Prof. Hoorfar said.

The breathalyzer has been tested on THC in a lab and clinical field tests will launch this summer. Prof. Hoorfar hopes it will be on the market within a year or two.

She also hopes people will use the device to regulate their intake and avoid impaired driving.

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Vancouver-based company Cannabix Technologies, led by former RCMP officer Kal Malhi, announced the development of a THC breathalyzer in 2014.

In a release sent out at the end of March, the company said that they anticipate the completion of a portable device for field tests in the coming months.

Constable Brian Montague, media-relations officer with the Vancouver Police Department, said testing for drug-impaired driving presents unique challenges.

"We train special officers as drug-recognition experts to conduct field sobriety tests for those suspected of operating a motor vehicle while under the influence of a variety of drugs, not just marijuana," he said, adding any instrument or technology introduced to assist police in detecting drug impairment would need to be authorized through the Police Services Division of the provincial government.

In Washington and Colorado, where marijuana was legalized in 2014, the legal THC blood limit to drive is five nanograms per millilitre of blood. In both states, most police have been trained in advanced roadside detection of impaired behaviour.

"We've been giving our officers more training in detecting not only marijuana, but other drugs that impair people beyond the standard roadside sobriety test," Colorado State Patrol public affairs officer trooper Nate Reid said.

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A blood sample is ordered if an officer suspects a driver is under the influence and alcohol is ruled out.

"Those results take some time to get back; we don't have labs in the back of the car," he said. "After the test, it has to do with the courts and how they prosecute and it's kind of out of our hands."

In a March, 2016, report from the Colorado Department of Safety, marijuana-only DUI summons decreased slightly from 2014 to 2015, from 354 to 347.

Lieutenant Rob Sharpe, section commander of Washington State Patrol Impaired Driving Unit in Seattle, said if alcohol impairment is ruled out during a roadside test, a drug recognition expert is called in – an officer who is trained to perform batteries of tests that look at psycho-physical and clinical indicators.

"They'll look at blood pressure, pulse rate, pupils' reaction to light, muscle tone, injection sites, they inspect the oral and nasal cavities," Lt. Sharpe said.

If drug use is suspected, a search warrant must be submitted by the officer to draw a blood sample at a facility for analysis at a toxicology lab.