How Does a Breathalyzer Work?

During a routine traffic stop, if a Maryland law enforcement officer suspects a motorist may be driving under the influence (DUI), the officer can do several different things in an attempt to determine the sobriety of a driver. One such tool to aid the law enforcement officer in making a decision regarding the arrest of the driver is to administer a breathalyzer test, but you may be wondering what this is and how it works in determining whether you are drunk behind the wheel.

First, a breathalyzer is an instrument designed to determine the amount of alcohol in the blood of a subject by analyzing the breath, and dozens of models exist. As the results of a breathalyzer test are frequently used as evidence in criminal courts, their performance and design are subject to stringent regulations. So how does a breathalyzer work in determining a motorist’s possible alcohol consumption?

Alcohol, in part, leaves the body via the breath, and as the percent of the total blood alcohol that exists this way is predictable and the alcohol content of the breath can be used to calculate a driver’s blood alcohol content (BAC). A hand-held breathalyzer model uses electromechanical fuel cell technology to identify the elements found in the sample taken, specifically searching for alcohol.

A driver’s BAC is then figured based on a partition ratio of anywhere between 1700 and 2400, which is the ratio of breath alcohol to blood alcohol. The output of the breathalyzer is ultimately a blood alcohol reading expressed as a percentage of the blood that is alcohol. A number of different factors, however, can influence the results of a breathalyzer, including a person’s body temperature, certain physical conditions and blood composition. Therefore, the results of this device may not always be accurate.

The St. Mary’s County DUI defense attorneys at the law firm of Alpert Schreyer have extensive experience defending individuals facing drunk driving charges and have the resources needed to thoroughly examine your arrest to determine if mistakes were made or the results of DUI-related tests were not accurate. A DUI conviction can seriously impact a person’s future, so in order to protect yours, call (800) 489-1577 to schedule a free case evaluation with our aggressive legal team.

About Andrew Alpert

+Andrew is one of the leading DUI and criminal defense attorneys in both the state of Maryland and the District of Columbia. He blogs about Maryland DUI law, has numerous videos on the subject and has been asked to appear on national television to offer his legal opinion on high-profile criminal cases.