The Technology & Misconceptions Related to How Breathalyzers Work

Breathalyzers are a common tool used by police officers every day in dealing with cases of real or suspected drunk driving. Along with the field sobriety test, it’s one of the first tools the police have for determining immediately if someone is intoxicated. A result on the breathalyzer indicating a level of alcohol above the legal limit for driving immediately gives the police officer probable cause to arrest the driver, which makes it very important. But how do breathalyzers actually work? Many don’t fully understand how this seemingly simple instrument works or what the legal implications are around its use.

The Technology

As the name suggests, the breathalyzer analyzes your breath. Alcohol you ingest passes into your blood and will then be picked up on your breath as well. You blow into the breathalyzer over three seconds, and the machine will test the breath as it enters, distinguishing the breath from your throat from the breath coming from deeper in your lungs. If you have a significant amount of alcohol in your blood, the air in your lungs will have a higher concentration of alcohol.

To test the air itself, the breathalyzer uses infrared radiation, which will reveal the ethanol found in the air. Then the breathalyzer assesses the estimated concentration of alcohol in your blood by measuring how much alcohol is present in your breath. This result is called blood-alcohol concentration, or BAC. The usual level of BAC required for it to count as driving while intoxicated is .08 percent.

The Misconceptions

While breathalyzers themselves are very common and most people understand the basics of what they are supposed to do, there are numerous breathalyzer myths that aren’t true. Many people, perhaps because of an incomplete understanding of the law or of how breathalyzers work, assume that breathalyzers can be tricked or avoid in various ways.

Some people believe that simply drinking more water will dilute the alcohol picked up by the breathalyzer and give you an artificially low result. Drinking water after a night of alcohol is good for you and your body, and you won’t regret it, but it won’t do anything to lower your BAC as measured by the breathalyzer. Chewing gum or rinsing with mouthwash won’t do anything to get you a lower result either. The breathalyzer doesn’t measure the actual smell of alcohol in your mouth but its presence in the air from your lungs. If anything, mouthwash with trace amounts of alcohol may skew your results by boosting them slightly.

Many also underestimate the legal consequences of a breathalyzer test. While some individuals may suggest that you can just refuse a breathalyzer test when a police officer asks for one, it’s not that simple. Depending on the state you live in, there may be serious legal consequences for refusing to take the test, and it will make any subsequent legal case difficult to pursue. Many states have laws stating that by legally driving a car, you have given “implied consent” to be tested for alcohol. You may also have heard that breathalyzer results can’t be used against you in court. This depends on the particular breathalyzer, however, and the type of sensor it uses. More and more breathalyzers these days are made with more advanced technology that can be legally used against you as evidence. The only way to really avoid being busted for driving while intoxicated is to not do it.

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