- 1. How does the device work?
- 2. What percentages of alcohol are allowed?
- 3. Is it possible to cheat the breathalyzer?
- 4. Why can alcohol be measured in exhaled air?
- 5. Is the result always reliable?
The breathalyzer is a device capable of measuring the percentage of alcohol in the blood, making it possible to assess whether the person is capable of doing more complex tasks that can be life-threatening, such as driving or operating heavy machinery.
Thus, this type of device is widely used by police to quantify the blood alcohol levels of people who appear to be drunk or just as a routine test.
1. How does the device work?
In most breathalyzers, when you blow into the device, it collects about 1 mL of exhaled air and places it on a reactive cell. When reacting, the cell releases a small electrical discharge, which is measured by the device.
According to the size of the reaction and the discharge, the breathalyzer is able to identify the amount of alcohol that is present in the exhaled air and then makes a new assessment to indicate what percentage of alcohol this amount represents in 100 mL of blood.
2. What percentages of alcohol are allowed?
According to the National Traffic Council, the maximum limit for a person not to be fined is 0.05 mg of alcohol for each liter of air, assessed by a breathalyzer. If a blood test is performed, this value is 2 dg for each liter of blood.
3. Is it possible to cheat the breathalyzer?
The breathalyzer is an extremely sensitive device that uses chemical reactions to produce the result, so techniques such as chewing gum, drinking vinegar or sucking on ice do not change the result, and can even cause injury to the body.
4. Why can alcohol be measured in exhaled air?
Alcohol in beverages is known scientifically as ethanol and has a very small molecule, which can easily pass through the walls of the stomach and reach the blood vessels, passing quickly into the blood.
Once the body is at a temperature of approximately 37ºC, the alcohol evaporates and, when that happens, it is transported to the pulmonary alveoli, where it is then eliminated through the exhaled air.
Thus, the greater the amount of alcohol ingested, the greater the concentration of ethanol in the lungs and, consequently, in the exhaled air.
5. Is the result always reliable?
The breathalyzer should be calibrated regularly to ensure that the result is reliable. For this, a bottle of compressed air is used that contains an exact percentage of 0.08 mg of alcohol. When this air is expelled and the breathalyzer gives a different result, it must be evaluated by the company that produced it.
Thus, whenever a breathalyzer test is performed, there must be a sheet that ensures that the device has been calibrated regularly.
