BAC stands for blood alcohol concentration, which is the amount of alcohol in a person’s blood. BrAC stands for breath alcohol concentration, which is the amount of alcohol in a person’s breath. Both BAC and BrAC are used to measure the level of intoxication of a person who has consumed alcohol.
BAC and BrAC are not exactly the same, because alcohol is not evenly distributed throughout the body. Alcohol is absorbed into the bloodstream from the stomach and intestines, and then distributed to various organs and tissues. The lungs are one of the organs that receive alcohol from the blood, and some of it evaporates into the air that a person exhales. The ratio of alcohol in the breath to alcohol in the blood is called the partition ratio, and it varies from person to person and from situation to situation.
The partition ratio is usually assumed to be 2100:1, which means that for every 2100 milliliters of blood, there is 1 milliliter of alcohol in the breath. This is the basis for calculating BAC from BrAC using breathalyzers, which are devices that measure the amount of alcohol in a person’s breath. However, this assumption may not be accurate for everyone, and factors such as body temperature, humidity, medication, and health conditions can affect the partition ratio.
Therefore, BAC and BrAC are not always equivalent, and there may be some discrepancy between them. BAC is considered to be more accurate and reliable than BrAC, because it directly reflects the amount of alcohol in the blood. However, BAC can only be measured by taking a blood sample, which is more invasive and time-consuming than taking a breath sample. BrAC is more convenient and less intrusive than BAC, but it may not reflect the true level of intoxication of a person.