Minimum ventilation rates as a function of the use and frequency of use of rooms. Mindestluftwechsel in abhangigskeit von nutzungsart und -intensitat.

From a hygienic viewpoint, optimum indoor air quality can be characterized as the complete absence of pollutants. The most important sources of such pollutants are reviewed, including those entering a room from outside, those generated by human activity and those emanating from various materials. Thebasic requirement is for all emissions to be as low as possible. For CO2 and formaldehyde the existing standards are reasonable. For most of the other substances it is not recommended to define tolerable limit values since such definition may decrease the efforts to attain a zero level. Furthermore, minimum ventilation rates for indoor environments are a variable parameter and have to be defined taking account of the health effects and toxicological relevance of all possible indoor pollutants.