How does a breathalyzer work?

A breathalyzer is a device designed to estimate a person's blood alcohol content, commonly referred to as BAC, by analyzing their breath. The primary mechanism of a breathalyzer involves the detection of alcohol vapor in the breath. When an individual consumes alcoholic beverages, alcohol enters the bloodstream and is eventually expelled from the body through the lungs. As a person breathes out, the alcohol present in the blood is converted to vapor, which can be detected in their exhaled breath. The breathalyzer draws in a sample of this breath and typically uses either a fuel cell or infrared spectrometry to analyze the alcohol content. In a fuel cell breathalyzer, the breath sample comes into contact with a chemical reaction within the device that produces an electrical current proportional to the concentration of alcohol in the breath. This current is then translated into an estimated BAC reading. On the other hand, infrared spectrometry measures the specific wavelengths of light absorbed by the alcohol vapor in the breath to derive an alcohol concentration. Breathalyzers are widely used by law enforcement and individuals to promote responsible drinking and a better understanding of alcohol consumption.