how do breathalyzers work

How Does A Breathalyzer Work?

If you’ve ever been pulled over for suspicion of DUI in Maryland, there’s a good chance that you were asked to submit to a breathalyzer test. These devices may seem as if they magically measure the amount of alcohol content in your body, but there is some science inside those boxes. The result that a breathalyzer produces could influence an officer’s decision on your arrest, or it may validate an arrest that already took place.

How Alcohol is Detected on Your Breath

When a person has been drinking, alcohol can usually be smelled on their breath. This is something that’s highly subjective though, as the smell could be the same whether you have had one drink or many.

In contrast, a breathalyzer doesn’t “sniff” your breath but rather analyzes the presence of alcohol in your system at the molecular level. Alcohol molecules are so tiny that they will pass through your stomach’s wall into your blood stream. This happens within minutes after you begin drinking that wine, beer, or other cocktail. After it enters your bloodstream, the alcohol will also travel through your lungs, and some of it will evaporate into your outgoing breath.

How Does a Breathalyzer Work?

When you breathe into a breathalyzer, the device can measure the amount of alcohol in your breath, which translates to your blood alcohol content (BAC). In Maryland, the legal limit is 0.08, but the laws will vary for underage drinkers or those who have a commercial driver’s license. This mathematical estimation of your BAC can be provided by several types of breathalyzer technology.

  • Semiconductor Sensor Breathalyzers. If you have a personal breathalyzer, it is probably one of this variety. These relatively affordable devices will oxidize alcohol molecules using a low-voltage semiconductor that is created from metal When you breathe into the device, the breathalyzer will oxidize the molecules, and the affected electrical current will produce your BAC. Unfortunately, these machines are also prone to providing false positive results.
  • Fuel-Cell Breathalyzers. A police officer giving a breath test on the side of the road will most likely use one of these devices, which works in a similar fashion to a semiconductor breathalyzer. The difference is that these machines are specifically calibrated for alcohol, so they are more precise.
  • Infrared Spectroscopy Breathalyzers. This is a bulkier and more expensive unit that you will most likely find sitting in a police station. When you breathe into one of these breathalyzer machines, it measures your BAC by sending your breath through infrared light. Alcohol molecules absorb light differently, so they can be identified and then measured.

Are Breathalyzers Accurate?

Some breathalyzers are more accurate than others, but none of them are infallible. This is just one of the reasons why you should speak with a qualified DUI attorney who can put forth the proper defenses in your case.

There is a margin of error with most breathalyzers, and there are certain factors that can cast doubt on a positive result. These sensitive machines are supposed to be calibrated at least annually, so failure to do this could result in a test being disqualified. Some breathalyzers may give false results due to such things as acid reflux, blood in the mouth, and body temperature. Natural chemicals such as “ketones” have also been mistaken for alcohol in the bloodstream and returned positive results.

Should You Agree to Take a Breathalyzer Test in Maryland?

There are some things to consider when deciding on whether to agree to take a breathalyzer in Maryland. First, all CDL drivers must know that the penalties for refusing to take this test are very high, regardless of whether you are in a commercial vehicle at the time. For other drivers, while the penalties are not as severe for a refusal, it should also be fully understood that there may be consequences associated with this decision.

If you’ve been charged with a DUI you should not take on this battle alone. A qualified attorney can help you to get a more favorable outcome for your case. Jonathan Fellner, Attorney at Law, has been representing DUI clients in Maryland for over 15 years. Contact our office in Rockville now to discuss your case at (301) 309-2000!

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