Abstract
Studies of the time course of breath alcohol concentration (BAC) in relation to the expired volume flow and the exerted pressure were carried out to obtain data to specify the features of breath alcohol measuring devices. Similar experiments were devoted to the influence of the ventilation pattern on the rise of the BAC. The temperature of the breath in the mouth piece was simultaneously recorded. The findings confirmed a need for a small sample chamber with low back pressure allowing an even flow of breath to ensure undiluted breath samples of the end-expiratory phase.