Understanding Breathalyzers: What They Detect and How They Work

A breathalyzer estimates blood alcohol content (BAC) from alveolar breath analysis. Name: "breath" + "analyzer". Developed 1950s, first used in US 1954.

Principle: Alcohol absorbed into bloodstream from stomach/lungs, transported to lungs, excreted in breath. Breath alcohol concentration is directly proportional to blood alcohol concentration.

Device components: Mouthpiece, sampling tube, reaction chamber, analyzer. Subject blows into mouthpiece; air sample drawn into reaction chamber where alcohol reacts with chemical solution, causing color change. Analyzer detects color change, converts to electrical signal, processes and displays BAC reading.

Widely used by law enforcement for drunk driving detection; also in workplace safety, school safety, healthcare.