Most in Florence may assume that roadside breathalyzer tests are actually the chemical breath tests referred to in the state’s implied consent law (and thus may also believe that they are compelled to submit to them). Breathalyzer tests are actually preliminary alcohol screenings that are not as accurate as chemical testing (indeed, research data shared by the National Motorists Association shows that they have an error rate as large as 50 percent). Because of this wider margin for error, drivers are not required to take them. Yet understanding which breath tests are required by law may be secondary to an even larger question: How does one’s breath offer a clue as to what is in their blood?
BAC does stand for blood-alcohol content. Therefore, a blood test would likely yield the most accurate measurement of how much alcohol is in one’s system. Once alcohol is in the body, however, one of the methods through which it leaves is actually through one’s breath. According to The Alcohol Pharmacology Education Partnership, ethanol molecules (ethanol being the form of alcohol used in drinks) are able to pass through the membranes of the stomach and intestines after consumption and enter the bloodstream. Capillaries then carry them to the heart, where they are then is pumped into the lungs via the right ventricle. Upon coming in contact with oxygen molecules in the lungs, some of the ethanol molecules are vaporized into a gaseous form. That gas is then exhaled with each breath. The remaining molecules continue to make the same round trip through the body, with more being vaporized as others are exhaled to remain in a state of equilibrium.
This process shows how, with each breath, one’s BAC is changing. Its dynamic nature may make it easier to challenge the validity of breath test measurements.