With the marijuana industry growing at a rapid pace in the U.S. and other countries around the world there is a race going on outside of the industry to see who can develop the first effective THC breathalyzer test. Current tests are not able to be performed during a traffic stop or are just not accurate in calculating impairment, but there's one company who may be on the right track. Hound Labs is currently developing a simple device that can be used by police officers almost exactly like a BAC breathalyzer for alcohol, but to detect if a driver is impaired from THC. Instead of detecting how much THC is in someone's blood, which could be there for weeks, this test is strictly looking for THC in the breath which will likely have dissipated after a few hours, typically how long it takes for a high to wear off. The development of this breathalyzer is racing against the clock to beat the new year when several new state's legal marijuana programs will go into effect.
Research shows the level of THC in someone’s breath rises right after smoking, and then trails off after a few hours. Those first few hours are when someone is most likely to be impaired, according to the National Highway Traffic Safety Administration. That’s why a marijuana breathalyzer would be a big improvement from blood and urine tests — which aren’t sensitive enough to determine whether someone smoked marijuana right before driving, or days ago at a party.
Some states where it is legal to smoke pot for medicinal or recreational purposes, like Colorado and Montana, have selected a limit of five nanograms for THC in blood. But scientists disagree on what amount — whether in blood or breath — indicates someone is too high to drive.
Kara Lynch, an Associate Professor of Laboratory Medicine at the University of California San Francisco said there will need to be studies to correlate levels of breath with impairment to establish a standard.