Since the announcement of the saliva tester for drugs last week, many people have been wondering if there is an effective replacement for saliva testing. The concerns that people have around saliva testing include temperature sensitivity, that the device has difficult operating procedures, and that THC stores in the body over a long period, so the device is not testing actual impairment.
Among many other concerns.
Some have said that a marijuana breathalyzer will eliminate most of these concerns. After all, a marijuana breathalyser will not produce a piece of evidence, containing a person’s DNA. It will not take as long to take a sample, and it’s a roadside procedure with which we are already generally comfortable and familiar. And California has now unveiled the first marijuana breathalyzer ready for law enforcement use.
But the marijuana breathalyzer suffers from flaws too.
The underlying principle in breath testing is a scientific law called Henry’s Law. Henry’s Law states that at a given temperature, the saturated vapour above a solution contains a concentration of solute proportional to the concentration of the solute in the solution. If you’re scratching your head and going “huh?” this is it simply: when you make a liquid into a gas, the gas has a proportional amount of everything in the liquid, provided it is at a specific temperature.
For breath alcohol testing, the breathalyzer assumes that 2100 parts of deep lung air contain the same as 1 part of blood. This is known as a partition ratio, 2100:1. And while there are a number of inherent flaws in partition ratio that are likely to be the subject of another blog post one day, it's at least something that is arguably fair. Every solution has a partition ratio, so blood with THC in it will have its own THC partition ratio. The marijuana breathalyzer works on the same underlying scientific principle about partition ratio.
So how does this translate into a fatal flaw in marijuana breath testing? While the privacy considerations are certainly mitigated, and the operating procedures are roughly the same as the breath testing for alcohol, the flaw in testing for THC in the blood stream remains. A marijuana breathalyzer detects the same THC that saliva testing looks for. It detects the same substance just in a different manner.
This means that the concerns about people who are not impaired but are releasing THC from their lipid cells into their blood stream remain with a marijuana breathalyzer. The problem really comes down to this: we are treating cannabis as though it is alcohol, and it is simply not the same.
No piece of technology is going to change anything when it comes to THC and the blood stream. What needs to change is the legislation. And yet, despite hearing expert testimony on this topic, the House of Commons Justice Committee kept the blood drug concentration regulations as part of Bill C-46. So as of October 17, 2018, people who are tested – whether it is by way of a marijuana breathalyzer or saliva testing – will face the same problem. And until the laws change, the mechanism of penalizing people for blood drug concentrations will be unfair and unjust, at least when it comes to THC.
Vancouver Criminal Lawyer with a focus on impaired driving, cannabis legalization and related issues, and immediate roadside prohibition defence.