Final answer:
Peak blood ethanol concentration is determined by individual factors such as age, sex, metabolism rate, and the amount of alcohol dehydrogenase in the liver. The rate of metabolism is a zeroth-order reaction and can be influenced by the presence of food. Breathalyzers measure BAC non-invasively through breath ethanol concentration.
Step-by-step explanation:
The peak blood ethanol concentration (BAC) can be influenced by several factors, including the individual's age, sex, body composition, health conditions, and whether the alcohol was consumed with food. For instance, a person's metabolism rate plays a significant role in how quickly ethanol is broken down in the liver; men typically metabolize alcohol faster than women. The rate at which alcohol is metabolized is a zeroth-order reaction, meaning it occurs at a constant rate regardless of ethanol concentration until all the alcohol has been metabolized.
Alcohol dehydrogenase, an enzyme in the liver, is critical for breaking down alcohol, with variations in levels affecting BAC. Contrary to popular belief, substances like caffeine have no impact on the oxidation of ethanol. The use of a Breathalyzer provides an immediate, non-invasive measure of BAC, correlating the concentration of ethanol in the breath to that in the blood.
Due to the variance in metabolism, diagnosis of alcohol intoxication often considers the history of events and physical examination, supported by witness testimonials and the precise BAC, which is legally defined at different thresholds.