ALVEOLAR AIR
Alveolar air is the part of the exhaled air that is derived directly from the lung cavities, so called alveoli, where the exchange between blood and air takes place.
BAC = Breath Alcohol Concentration
The sample is taken by exhaling breath.
The BAC is measured in milligram per litre of exhaled breath. (mg/l) with the temperature of the exhaled breath in the mouth being 34° C on average.
BAC -Valuation = valuation of Breath Alcohol Concentration
The breath alcohol analysis measures in milligram per litre of exhaled breath (mg/l).
BAL = Blood Alcohol Level
The amount of alcohol in your blood stream is referred to as Blood Alcohol Level (BAL). The necessary blood sample is normally taken from the elbow vein. The determination is carried out from the blood serum that will be extrapolated to a full blood value in the basis of a divisor (1.20). This divisor has been fixed after the principle "in dubio pro reo“.
BAL Valuation = valuation of Blood Alcohol Level
The Blood Alcohol Level (BAL) is recorded in grams per mille (g/l) / ‰
These are always Breath Alcohol Concentration measuring results and not, as often wrongly believed, Blood Alcohol Level results.
To be able to get specifications about the BAC in correlation to the BAL, it is possible to calculate the results in comparable units. For this purpose, the results in per mille can be extrapolated with a given factor (1:2,1) into the unit milligrams of ethanol per litre of exhaled air (mg/l).
However, there might be variations of the correlation factor depending on the level of concentration. There are also slight differences in the factor in different countries.