In this post, we focus on whether breath testing—as opposed to blood or urine testing—is (or should be) protected by the Fourth Amendment. Why would there be a difference and what are the implications?
Towards the end of the oral arguments in State v. Bernard, Justice David Stras asked Bernard’s attorney, “I know blood can be used to obtain DNA . . . but can breath be used to tell more about a person than just their blood-intoxication level?” The Court also asked questions along the line of whether breath is “personal property.”
Because the question went unanswered, and because the Court seems to be intrigued by this issue as a potential way not to rule on the criminalization of refusal itself, we take it on today. Spoiler Alert: you can learn a ton about someone by their breath, not just whether they’ve recently consumed alcohol (or had onions or garlic for lunch).
While it seems like breath is a harmless way to test someone’s alcohol concentration, breath has been has associated with individual health for centuries. Apparently, the first person to recognize this phenomenon was the namesake of the Hippocratic oath himself: Hippocrates (460 B.C. to 377 B.C.). That’s right, the father of medicine believed that bad breath was a symptom of disease. And, as it turns out, a couple thousand years later, we now know this to be true. Let’s skip ahead to today.
According to John Hopkins University, they can currently use breath testing to diagnose: lactose intolerance, inflammation-causing bacteria, fructose intolerance, and bacterial overgrowth syndrome (source here). Other applications have allowed doctors to determine the effectiveness of asthma treatment. Cancer diagnosis, in one test, was found to be 90% accurate!
How is this possible? The answer lies in the same reason that we have a strong privacy interest in our breath: each person's breath makes up a unique "blue print." This blue print comes from the fact that breath can contain from 4,000 to 6,000 different compounds, and the ratios and numbers of those compounds reveal an awful lot about a person’s health, habits, and diet.
This scientific reality is especially relevant because the government’s breath testing equipment is intended to measure a certain type of air: deep-lung or “alveolar” air, which is far more likely to contain “blue print”-like information.
So, the short answer to the question “can breath be used to tell more about a person than just their blood-intoxication level?” is not only “yes,” but, further, “yes, and breath testing tells us more and more about a person, for good and potentially harmful purposes, every year.”
In sum, while it may feel like breath is “non-invasive,” the information it contains is certainly invasive, and thus certainly worthy of constitutional protection.
*Unsolicited advice: Do chew gum if you eat onions or garlic for lunch, folks.