If you've ever had a few drinks at a party and needed to quickly gauge your sobriety before driving, you've probably wondered to yourself, "how does a breathalyzer work?" Does it only capture the alcohol on your breath? How easy is it to fool the machine? How accurate are the readings, anyway?
Many have been pulled over or rolled into a routine traffic stop and desperately wanted to remove the smell of alcohol from their breath. Even if a breath mint or a piece of chewing gum might fool the nose of a police officer, if he or she suspects that you've been drinking, they probably won't rely on their intuition. They'll use a breathalyzer to learn whether you're inebriated and if so how inebriated.
When you blow into the device, the officer presents you with a blood alcohol level or BAC. The legal limit of intoxication is almost universally 0.08, though in some states the threshold is lower. This number probably sounds rather small. Most people can have 1-2 drinks before nearing this limit. But this isn't a hard and fast rule. Gender, weight, and height, are all factors that influence a person's BAC. Some people get drunk more easily than others.
The legal limit means that if your BAC is 0.07, then you're legally allowed to drive a car. But many argue that limit should be lowered to make a BAC of 0.05 punishable by law. Since the penalty for a DWI or DUI, both terms referring to driving with a BAC over the limit varies from state to state, the punishment may be rather lenient or quite severe.
If you think you can evade a DUI by reading tips or tricks that will help beat the breathalyzer, think again. But if you're curious about how these devices work and how they differ from each other, read on to find out, "how does a breathalyzer work?"
What Is a Breathalyzer?
A breathalyzer isn't just one device. It's actually many different devices that work on different principles but perform the same function. If you're at home, having a few drinks, and you want to know whether you are sober enough to drive, then you might reach for a semiconductor oxide-based tester. These testers are inexpensive enough for consumers to own and take anywhere.
Some semiconductor oxide-based testers are small enough to fit into the palm of your hand and might cost as little as $30. These testers are great for personal use and some business owners might even keep them in the office in the event that an employee shows signs they might be abusing alcohol.
Bar owners, police or others who need to test a lot of people in a short span of time will typically opt for fuel cell testers. They're reliably accurate and they're also portable. They tend to be more expensive than semiconductor breathalyzers, but they will perform well in any circumstance and can give a consistently accurate reading.
Another method is to use infrared light to test a person's alcohol consumption. The infrared light passes through the ethanol particles and the machine can use this reading to determine the amount of alcohol that's been absorbed by a person's system. These devices are too large to be portable. Most sit on desks at police stations and are used to measure a person's blood alcohol level after the arrest.
Why Are They Used?
If you've ever had an alcoholic beverage, and especially if you've had a few in quick succession, you understand how your capacity for rational decision making becomes impaired when you drink. Alcohol lowers your inhibitions and you are statistically much more likely to make rash or uninformed decisions.
Imagine you're approaching a yellow light about to turn red. Do you slow down or speed up to make it through the light? Your answer may depend on whether or not you're inebriated. You're more likely to take risks you might not otherwise if you've had one or several drinks. Also, your reaction time is reduced, meaning you're slower to react to new stimuli.
While alcohol has been consumed since the dawn of civilization, the pressing need to regulate its consumption came with the introduction of automobiles. Now suddenly people had the power to inflict lethal damage on themselves and others by getting behind the wheel of a car. Strict laws were introduced to curb incidences of drinking and driving.
How Does a Breathalyzer Work to Reduce Traffic Accidents?
Before the invention of breathalyzer tests, there was no accurate way to assess a person's alcohol consumption. Police used sobriety tests devised to measure a person's coordination and recall, walking a straight line or reciting the alphabet backward for example. The problem with tests like these is that they're subjective, and people with blood alcohol levels above the limit could evade detection.
Because roughly 40% of traffic fatalities involved alcohol consumption, there was a strong incentive to create an unbiased test that could accurately measure a person's blood alcohol level quickly. Out of this need, the breathalyzers tests were created in 1954. Now it was possible to accurately test the level of alcohol in a person's blood without having to draw blood to do it.
While breathalyzers mean that you can't fool a police officer into thinking you're below the limit, it can offer a hidden advantage. Before it was possible to assign a quantifiable number to a person's level of intoxication, the designation of "too drunk to drive" was open to interpretation. A police officer could exercise their own judgment, which meant you might have gotten a DUI even if you weren't impaired.
Breathalyzers are now standard tools of law enforcement and are used by police all around the country to catch drunk drivers. So long as they use a breathalyzer, there's a standardized method for measuring intoxication. But if the device is measuring the alcohol in your blood, but uses your breath to do it, then how does a breathalyzer work?
How Do They Work?
Each tester works on slightly different principles, so to answer the question "how does a breathalyzer work?" you've got to first clarify what type of breathalyzer you're talking about. A semiconductor oxide-based test is used specifically to measure the ethanol levels in a person's system. Ethanol molecules pass through a tin oxide electrode to create a measurable chemical reaction.
Fuel cell breathalyzers also work by creating a chemical reaction that generates an electrical current. Breath passes through platinum electrodes and is then oxidized into electrons and other particles. The electrons pass through a copper wire which generates the current. The strength of that current is measured by the device and uses this data to generate a BAC, or blood alcohol level.
Infrared breathalyzers, also known as intoxilyzers, work by measuring the vibration of ethanol molecules. When molecules form bonds they absorb light at distinct wavelengths. By sending infrared light through a breath sample and then measuring for wavelengths that betray the presence of ethanol using a microprocessor, it's possible to accurately assess how drunk a person is.
The Lungs Give It Away
Regardless of which device is used, a breathalyzer can measure a person's blood alcohol level by testing their breath because of how alcohol is absorbed by the lungs. When you take a drink of an alcoholic beverage, it's not just absorbed by your gut, there are membranes in your mouth and throat which absorb it too. From there, it passes into the bloodstream.
Once it passes into your bloodstream, it begins circulating throughout your body, including your lungs. A breathalyzer works when a person holds the mouthpiece to their mouth and blows a steady, continuous breath into the sample chamber. The device then takes the breath and uses it to measure the amount of alcohol held in your lungs.
This is how your breath can be used to accurately gauge your blood alcohol level. For the alcohol to be present in your lungs it has to have passed through your blood first. So if you're curious, "how does a breathalyzer work" and you don't know why you can't fool the machine by rinsing your mouth out or brushing your teeth, there's your answer.
The machine isn't testing for the amount of alcohol in your mouth or throat. This number wouldn't accurately measure your level of inebriation, anyway. The level of blood toxicity strongly correlates to how much alcohol passes through your brain, affecting coordination and state of mind.
Now that you can answer "how does a breathalyzer work" you'll be able to dismiss the urban myths and misconceptions surrounding breathalyzers. While eating and drinking water can help to reduce your BAC over the course of several hours, it won't help to rinse out your mouth or drink a lot of water just before taking a breathalyzer test.
What matters is how much alcohol is in your blood, and your BAC can only go down as blood is removed from your system. To help avoid accidentally driving when over the legal limit, it's a good idea to purchase a small, inexpensive breathalyzer that you can carry with your in your glove box. If you do, you can take a cab or Uber instead of risking a DUI.