How Does a Breathalyzer Work?

The History of the Breathalyzer

How many drinks have you had tonight? This is a question police officers ask motorists every day as license checks are set up across the nation. In addition to catching someone driving illegally, they are also checking for the smell of alcohol. Suspicious behavior or unstable movement can lead to a night in jail and one might find themselves standing on the side of the road blowing into a breathalyzer. When alcohol is consumed, it passes from the stomach to the small intestines, where it is absorbed into the blood stream and goes through the whole body. Alcohol goes through the body so fast that it affects the central nervous system even when it is ingested in small amounts.

History

As far back as 1874, researchers have suspected breath could be used for alcohol testing. They realized that trace amounts of alcohol were excreted in breath. In 1827, W.D. McNalley, a Chicago chemist, invented a breathalyzer in which the breath changed colors when it moved through
chemicals in water. Housewives came up with a useful use of the breathalyzer: to test for alcohol on their husband's breath before they would let
me in the house.

Drunkometer

The drunkometer, invented by Rolla Harger in 1938, was the first roadside breather-tester that was intended for the police to use. The machine collected a sample of the driver's breath directly into a balloon in the machine and pumped through a solution of acidified potassium. If there was
alcohol in the breath, the solution changed colors. The bigger the color change, the more alcohol that was in the sample.
In 1954, A police captain in Indiana, who later became a professor at a university in Indiana, Dr. Robert Borkenstein, is credited as the first person to invent a device that can measure a driver's blood alcohol level based on a sample of their breath. It provided the police with a test that would give them immediate results as to a driver's alcohol concentration in their breath.

How Do They Work?

Since the air in the deepest part in the lungs give the most accurate results, the person issuing the test will tell the driver to blow as hard as they can into the breathalyzer for about two to four seconds. The breath sample bubbles into a vial with potassium chromate. If there is any ethanol present it will react with the potassium chromate and cause the solution to switch to a golden yellow color as a result. This mixture is then compared to another vial that has potassium chromate but not ethanol which will make it a bright orange color. The color difference in these vials will give an the person issuing the test an indication of the amount of ethanol in the person's breath. The device then gives a readout that states the degree of color change and the level of alcohol in their breath.
Breathalyzers are not the only method for determining levels of intoxication. Intoxilyzers, and Alcosensers are two other devises to measure someone's intoxication.

About the Author - Gordon Weber is a guest blogger.  His interest in how Breathalyzers work led him to thesandiegoduiattorneys.com website of Chris P Sohovich.