What does the BrAC curve graphically represent?

The BrAC curve graphically represents the change in alcohol level during exhalation. This curve illustrates how the concentration of alcohol in the breath changes over time as the subject exhales. Initially, the breath alcohol concentration rises as alcohol from the bloodstream diffuses into the lungs and is expelled in the breath. As exhalation continues, the BrAC level may peak and then decline, reflecting the dynamics of alcohol absorption and elimination from the body.

This representation is crucial for understanding how breath alcohol tests work, as it allows for the identification of the most accurate moment to measure breath alcohol concentration. Analyzing the BrAC curve aids in determining the appropriate measurement point to ensure accurate results, which is critical in the context of evaluating intoxication and determining legal limits.