[Recommendation for a legally valid breath alcohol measurement]

Evidential breath-alcohol analysis requires measuring devices which cannot yet be obtained from industrial manufacturers. In order to avoid the influence of environment and breath techniques and to relate the breath-alcohol concentration to a standard temperature of 34 degrees C it is necessary to measure the breath temperature with a special device. The required reliability of measured results can only be obtained with two measuring systems operating independently from each other. When two measuring systems of different analytical specificity towards interfering substances are used, the infrared method allows a widely selective determination of ethanol. This is a prerequisite for the legal calibration of breath-alcohol analysers.