Attorneys Representing Clients In

New Hampshire And Massachusetts

Here’s how a chemical Breathalyzer determines BAC

On Behalf of | Oct 18, 2023 | Criminal Defense

If a New Hampshire police officer makes a traffic stop for suspected intoxication, the driver will probably be requested to step out of the vehicle. The driver may be asked whether they consumed any alcohol. A preliminary breath test or field sobriety test may also be requested. Compliance is not obligatory. However, if a driver complies and fails the test, arrangements will be made for a chemical Breathalyzer test to be administered. 

This test is different than a preliminary roadside test. Refusing a chemical test automatically activates a driver’s license suspension. In these circumstances, it is helpful to understand how a chemical Breathalyzer device works and what police can do with the results.  

Alcohol in your lungs correlates to alcohol in your bloodstream 

A chemical Breathalyzer test device detects the presence of alcohol when a person breathes into it. A chemical known as potassium dichromate, which is present in an orange solution in a Breathalyzer device, turns the solution green if alcohol vapors from someone’s breath come into contact with it. Every 2,100 ml of alcohol in a person’s breath equals 1 ml of alcohol in the bloodstream. This ratio is used to determine blood alcohol content (BAC).  

A BAC of .08 or higher is evidence of DUI 

In New Hampshire, it is illegal to operate a motor vehicle if a driver’s BAC is .08 or higher. Prosecutors may use BAC test results as evidence in court. Numerous issues can cause skewed test results, such as if the device was not properly calibrated. This is why it is best to seek immediate legal support following a DUI arrest. An attorney can review the process that occurred and determine whether there are grounds for requesting a dismissal of the case or for ruling test results inadmissible as evidence. 

FindLaw Network