[Evaluation and requirements of natural room ventilation]. / Beurteilung und Erfordernisse der natürlichen Raumlüftung.

The current application of the carbon dioxide standard ("Kohlensäuremassstab") of 0.1 vol.-% CO2 given by Pettenkofer 140 years ago is assessed in order to evaluate tolerable indoor air and sufficient indoor air ventilation. For this purpose, criteria by Pettenkofer were contrasted by currently valid criteria. It was found that an actual guidance value should be clearly higher than the one given by Pettenkofer. As confirmed by recent measurements this actual guidance value should be around 0.15 vol.-% CO2. By means of a few examples requirements for indoor aeration of living rooms and classrooms are made evident. The corresponding calculations are based on the indoor air guidance value (i.e. actualised value of Pettenkofer) of 0.15 vol.-% CO2 and are based on respiration rates compiled in "Standards of exposure assessment" by the health authorities of the German federal states. The calculated number of complete renewals of air achieved by circulation shows that recent values given by others concerning the permitted indoor self aeration were set too low and require correction. Applying the demonstrated requirements for indoor ventilation many of the well known problems of indoor air can be minimised or even solved.

[Organic-chemical air pollutants indoors--aspects of environmental toxicologic evaluation]. / Organisch-chemische Luftverunreinigungen in Innenräumen--Aspekte der umwelttoxikologischen Beurteilung.

Indoor air pollution is characterized by a wide range of concentrations of many, mainly organic substances. To avoid adverse health effects it is necessary to develop indoor air quality standards. Standards should reflect the way and time of exposure and the fact that health risks might be possible especially to sensitive people. The toxicological basis for regulating indoor air quality is discussed. Special attention is given to organic substances with a cancerogenic and accumulating potential. An approach in setting standards of indoor air quality for frequent organic substances like toluene, xylene, styrene, dichloromethane, 1.1.1-trichloroethane, trichloroethene, tetrachloroethene, pentachlorophenol and PCB is presented, incorporating adequate protection margins. The results of this approach are compared with the WHO air quality guidelines and the German MIK values.