Ed Gollar has a bachelors degrees in physics and electrical engineering, as well as 20 years of experience in the design of breathalyzers, including breath alcohol ignition interlock devices and consumer breathalyzers. He is currently the managing director of OmegaPoint Systems, LLC.
How does a breathalyzer device work?
Alcohol is absorbed into your bloodstream primarily through the stomach and intestines. Deep within your lungs there are tiny blood capillaries that serve as the interface between your blood and the air in your lungs. This is where the alcohol in your bloodstream is evaporated into your exhaled breath. The breathalyzer then determines the concentration of alcohol in your breath.
Any type of breathalyzer depends on an alcohol gas sensor to measure the concentration of alcohol in your breath. Most professional breathalyzers use a fuel cell alcohol sensor, while most consumer breathalyzers use a less expensive semiconductor sensor. The concentration of alcohol in your breath is assumed to be directly proportional to that in your blood. Once the gas sensor determines the concentration of alcohol in your breath, a microprocessor then converts the sensor reading into a % BAC (blood alcohol concentration) for display.
How accurate are breathalyzer tests?
Professional quality breathalyzers, such as the ones that the police use, are accurate to within 0.005% BAC at a concentration of 0.100%. The better consumer breathalyzers are accurate within 0.010% BAC at 0.100% BAC. This means that if your BAC is 0.100%, the breathalyzer can read anywhere from 0.090% BAC up to 0.110% BAC. The lower quality consumer breathalyzers can be off by as much as 0.050% BAC at 0.100% BAC, or even worse.
Are there any significant differences between the breathalyzer devices that law enforcers use versus the devices for sale to consumers?
Besides being more accurate, the professional breathalyzers used by law enforcement can cost anywhere from $500 to several thousand dollars. Most consumer breathalyzers range from about $50 to $150. Professional breathalyzers sold in the US are required to be certified by the Department of Transportation (DOT) for accuracy and reliability. Consumer breathalyzers sold in the US are required to be certified by the Food and Drug Administration (FDA) to ensure that they do what they claim to do. But even though all consumer breathalyzers are required to be certified by the FDA, many are not.
What are some advantages to a consumer owning a personal breathalyzer?
Most people who go out for a few drinks have no idea what their breath alcohol level is. Since alcohol tends to impair your judgment, you may feel like you are safe and under the legal limit (0.080% BAC), even though you may later be pulled over by the police and tested to be over the limit. Personal breathalyzers are meant to give you an objective measurement of your blood alcohol level, so that you can make an informed decision about your own personal safety as well as that of others.
How do alcohol breath tests differ from other testing methods(i.e. blood or urine)? Is one method more accurate than another?
Taking a blood sample and testing it for alcohol content is the most accurate means available. Taking a urine sample is less accurate, since the amount of alcohol that transfers from your blood system into your urine is not exactly the same in each person. Since neither of these methods is very practical, a breath alcohol tester is a quick an non-invasive way of determining your BAC. However it is not as accurate; the amount of alcohol that vaporizes from your blood into your exhaled breath is assumed to be the same for all people, even though it actually varies from person to person. So the concentration of alcohol that a breathalyzer measures in your breath may not exactly reflect the concentration in your blood.
What advice can you give to people who wish to purchase their own breathalyzer?
Go ahead and spend a little extra on a quality breathalyzer, and make sure that it is FDA certified. And even though a personal breathalyzer can provide you with useful information, the result of a breathalyzer test should not be used on its own to determine if you are safe to drive. Even a small amount of alcohol in your body (as low as 0.040% BAC, or half the legal limit) can affect your motor skills and coordination. Remember that it is always safest when you do not drink and drive.
For more on breathalyzers, see our Breathalyzer Test Directory. To learn more about breathalyzer tests, read our Breathalyzer Test Guide.
