What breathalyzer to choose?


Breathalyzers can be divided into product classes. The highest class is class A which forces out the application of the electrochemical sensor and the pressure sensor. These elements are also used in breath testers supplied to the police. In consideration of serious consequences which can result from errors in the breathalyzer’s indications, advice should be given against using devices of lower classes, whose indications may differ significantly from the actual alcohol level in the exhaled air.

Why should the test be delayed by about 20 minues after the alcohol consumption?

Just after alcohol consumption, its level in the exhaled air is very high. Therefore, it is necessary to wait at least 20 minutes for our organism to absorb the consumed alcohol. The premature performance of the test may also damage the sensor or speed up its wear-and-tear.

Why is smoking not allowed before the measurement?

Many factors have an impact on the correct measurement, and the cigarette smoke is one of them. In case of the Certen breathalyzers, it is of marginal importance, however, we recommend to wait at least 5 minutes from the last smoked cigarette before making the measurement, in order to avoid the risk of damaging the breathalyzer sensor.


What is calibration and what is it for?

The sensor of each electrochemical breathalyzer during the test is subjected to chemical reactions, which, as the number of measurements increases and the time passes by, gradually decrease the sensor’s sensitivity. This is a natural process, which also affects evidential breath testers supplied to the police. Find out more. (LINK TO CALIBRATION).


How does a breath alcohol test work?

The tester’s tube contains a reagent in the form of yellow crystals, which turn green, if the test subject has consumed alcohol. In case the limit of 0.2 ‰ in the exhaled air is exceeded, the green colour reaches the red line or exceeds it.


Why should you pick a breath alcohol test in which the air is breathed into the tester from a sack and not directly from lungs?

In case of breath alcohol tests whose use requires direct bringing of the tester’s tube closer to a person’s mouth, there is a risk that the air may withdraw while inflating the balloon. In this way, the toxic crystals may get into the lungs. The Certen breath alcohol test is designed with care for safety and health of the user, therefore, only the balloon is inflated and the tube itself has no contact with the mouth.

What alcohol limits are applicable in European countries?


What is the screening breathalyzer?

This is a breathalyzer which allows a great number of measurements to be performed in a short time. It is used in companies, institutions and offices which face the necessity of efficient testing of a large number of persons (e.g. employees).


What is the passive test and when is it used?

The passive test is a method of verifying the sobriety of a person who cannot blow in a sufficient amount of air into the breathalyzer (e.g. after an accident).


How to set the measurement time in Certen Professional?

Certen Professional breathalyzer allows the measurement time to be set within the range between 0.2 s and 2 s. The longer measurement time is selected, the more accurate the test is. In order to test a large number of persons efficiently, shorter settings, which can be increased at the moment of alcohol detection are usually applied in order to estimate the measurement result of alcohol content in case of a specific person.



Several basic principles must be observed in order to make the breathalyzer indicate the alcohol level in the exhaled air correctly.

Technical information

Types of alcohol sensors:

Semiconductor sensor – an alcohol sensor of low class. Its measurements are very unstable and depend on many factors (previously consumed food, smoked cigarettes). Moreover, the sensors of this type must be warmed up to high temperatures, which requires a lot of energy. Therefore, when the batteries are low, the sensor is not appropriately warmed up, which results in an incorrect measurement. The measurements indicated by this type of the sensor should never be taken into account when taking a decision on whether we can drive a car or other vehicle.

Electrochemical sensor – a high-class alcohol sensor used, among other things, in Certen breathalyzers. Its measurements are stable and depend on external factors to a much lesser extent. Moreover, the indicated measurement result is independent of the battery status. The sensors of this type are used in evidential breath testers which constitute the equipment of the police.

Spectrophotometric sensor – it is the most accurate sensor, however, because of its large size and high costs, it is used only in stationary equipment.

The second important factor while selecting the breathalyzer is the air flow sensor. In order to obtain an accurate measurement, the device must be provided with the information on the force of air blown into the sensor that measures the alcohol level.

Types of air flow sensors:

Thermistor – a resistor that reacts to heat. The sensor is heated to a high temperature. Then, depending on the force with which the user blows the air into the breathalyzer, the temperature of the thermistor decreases.

Electret microphone – depending on the force of the air that is blown in, the membrane built into the microphone vibrates with an appropriate force.

Pressure sensor – depending on the air blowing force, the pressure indicated by the sensor changes. This type of sensor is used in Certen breathalyzers as the most reliable measurement method.