Breath Testing 101 – The Principles Behind The Use Of A Breathalyzer

by Dan Christie December 01, 2015

Breath Testing 101 – The Principles Behind The Use Of A Breathalyzer

Drivers who have imbibed too many alcoholic drinks pose a hazard to themselves, their passengers, and even to other road users. Suffice it to say that drink drivers should be kept out of the roads lest they cause road accidents and hurt themselves and other people. As such, authorities are vigilant against road users who have a high blood alcohol level.

It is not unusual for drivers who have had one drink too many to pass road test sobriety tests. In order to really determine the level of alcoholic intoxication of a driver, police authorities rely on the Breathalyser. But how exactly does a Breathalyzer work?

There are a couple of ways to determine the blood alcohol concentration or BAC level in a person. These include blood tests and urinalysis. Despite the effectivity of these methods, these can be impractical out on the field and authorities do not want civilians to cry out against the practice of invading a suspect's body through tests. Such tests require lab analysis, which can take a substantial amount of time.

Breathalyzers were invented by Dr. Robert Borkenstein from the Indiana State Police and have become one of the most widely used devices by numerous police forces around the world.

When a person consumes alcohol, it is absorbed through various body parts including the mouth, stomach and intestines, eventually winding down to the bloodstream.

When you drink (say, a mug of beer or a glass of wine), your body does not immediately digest alcohol nor does it chemically alter it upon reaching the bloodstream. After drinking an alcoholic drink, the blood which has traces of alcohol, circulates around various parts of the body, including the lungs. As the blood passes through the lungs, traces are left in the air sacs or alveoli. The alcohol, because of its volatile nature, evaporates, and traces can be found in the breath exhaled by a person. Breathalyzers determine BAC levels by analyzing the alcohol content of the breath thus, eliminating the need for blood or urine tests while on the field. Take note that there is a correlation between the alcohol concentration in a suspect's breath and the alcohol concentration in his blood.

Acceptable BAC levels will vary from one country to another. In the United States for example, the acceptable limit is 0.08. In Australia, the legal limit is 0.05. And if you have a learner's or probationary driver’s licence, your BAC level should be zero.

Dan Christie
Dan Christie


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