Question by petweasel: How does a breathalyzer measure alcohol in the blood?
Just interested in the science here. If someone drinks a single shot of whiskey then immediately does the breathalyzer, does that alcohol register via ‘fumes’? Or does the device somehow differentiate and only register the actual acohol that’s absorbed into the blood? How?
Best answer:
Answer by J.D.
It actually measures the amount of alcohol in the air from your lungs. This is from whatever amount you drank earlier that has already been metabolized in your system.
While fairly accurate, the most sure-footed measurement of blood-alcohol level in the body is an outright blood test.
What do you think? Answer below!
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There is a mathematical relationship between the amount of alcohol in the lungs and the amount of alcohol in the blood, and it can be manipulated to determine how much alcohol is in the blood without actually drawing any. All BAC testing equipment measures alcohol in the breath and uses this formula to calculate how much alcohol is in the blood. Accordingly, all the devices have a mouthpiece through which the test subject blows air and a sample chamber to hold the air.
The Breathalyzer detects alcohol by monitoring a chemical reaction that produces a color change. Besides the mouthpiece and sample chamber, it consists of two glass vials to contain the chemical reaction and a system of photocells connected to a meter. The air is bubbled through one vial containing a chemical mixture and into another vial. From that vial, the air is passed over the photocells so the meter can measure the color change and calculate the BAC.