What is the relationship between BrAC and BAC at equilibrium?

At equilibrium, BrAC (Breath Alcohol Concentration) and BAC (Blood Alcohol Concentration) do reach a defined proportion or balance based on physiological and environmental factors. This relationship is significant in the context of alcohol measurement in the body. When an individual consumes alcohol, it enters the bloodstream and subsequently affects both the blood and breath.

At equilibrium, there is a predictable ratio between the two concentrations due to the principles of alcohol distribution in the body. Typically, this is noted as a consistent ratio where the breath concentration reflects what is present in the blood because the alcohol diffuses between the blood and the alveolar air in the lungs. This dynamic relationship allows law enforcement and forensic experts to utilize breath testing as a reliable method for estimating blood alcohol levels based on breath samples.

Understanding that BrAC and BAC reach this defined proportion is crucial, especially when interpreting the results of breathalyzer tests like the Intoxilyzer 9000. It highlights the importance of calibration and accuracy in measuring these concentrations to ensure reliable and legally defensible results in impaired driving cases.