The Chemistry Behind Breathalyzer Tests

Breathalyzers measure alcohol in your breath, translating it into a blood alcohol concentration (BAC) reading.
They rely on chemical reactions, typically oxidizing ethanol to produce a detectable signal.
Early devices used potassium dichromate, which changes color when it reacts with alcohol.
Modern breathalyzers often use fuel cell sensors, generating an electrical current proportional to alcohol levels.
The reaction is precise and fast, giving almost instant BAC readings.
Temperature and calibration matter, ensuring results are accurate and reliable.
They detect alcohol molecules, not water vapor, distinguishing ethanol from other compounds in breath.
Law enforcement uses them widely, helping prevent drunk driving and improve road safety.
They’re a practical application of analytical chemistry, turning chemical reactions into real-world measurements.
At its core, a breathalyzer converts molecules into numbers, showing how chemistry directly protects lives.