THE IDENTITY TEST: The breath is tested with a mechanism similar to a breathalyzer. The diffference is that a breathalyzer relies on chemical oxidation, and therefore requires a dangerous reangent, while a mechanism using an IR test (for example, a CMI INTOXILIZER), uses the unique response of alcohol to infrared radiation.

Different compounds within alcohol (and other substances) resonate and absorb radiation only at specific wavelengths. The intoxilizer or other IR mechanism compares the resonance and absorption of infrared radiation from the breath in one chamber to the same properties in a second chamber, which contains air.