The influence of CO2 in the measurements of mass concentration of alcohol in exhaled breath using dual IR & EC technology

Romania, as a member state of European Union, started to develop together with its National Institute of Metrology, efficient measures to detect drivers under influence with accurate results and to assure the traceability of mass concentration of alcohol in exhaled breath. The paper describes the influence of carbon dioxide in the measurements of mass concentration of alcohol in exhaled breath using a set of 7 standard solution (mass concentration of alcohol in distilled water) with traceability of LNE France and the complete system used for testing of ethylometers performance, also. The expanded uncertainty for the complete simulator system (including gravimetric preparation, wet simulator system and breath analyser) was calculated taking into consideration all input quantities which have noticeable contribution to the final uncertainty: uncertainties budget of mass concentration of alcohol in distilled water, of the wet simulator system and of the breath analyser.