Why look for your BAC in your breath?

You may often hear stories of people in Charlotte challenging the validity of results produced by a roadside breath test. It only makes sense, then, that if you find yourself facing charges for driving under the influence, that you would also raise the same questions. Often at the heart of disputes over sobriety test results is how is that your breath is able to offer an accurate measurement of the alcohol content of your blood? Understanding the answer to this question tells you how law enforcement officials rely on such results to verify your intoxication. At the same time, it also may give you the information needed to question the results of your breath test.

According to the Alcohol Pharmacology Education Partnership, the type of alcohol ingested in drinks is ethanol. This is a water-soluble compound that is able to permeate and pass through membranes through a process known as passive diffusion. Thus, as ethanol travels through your gastrointestinal tract, it passes through the lining of the stomach and small intestine and ends up in the bloodstream.

Once in your blood, it eventually will be transported to your lungs, which (as you know) contain oxygen. That oxygen causes some of the ethanol molecules to vaporize into a gas, which is then expelled from your lungs as your breath. This lowers the ethanol concentration in the blood, which causes more of it to vaporizes in order to maintain equilibrium. With each breath, more ethanol escapes your body, and more is then vaporized in your lungs.

The static nature of this process means that your body’s blood-alcohol content lowers with every breath. That may allow you to ask the question of how reliable can a breath test be if the result is ever-changing.