Ventilation requirements in houses and flats. Ventilationskrav i en-och flerfamilyshus.

Reports study of the ways in which different ventilation levels affect people part 1 of the study took place in Gavle. Air change rates, the amounts of radon and its derivatives were measured. Finds that ventilation installations are often poorly adjusted giving a wide variation between flats in the levels of air change. Amounts of radon and daughters were also higher than expected, due mainly to the poor ventilation. Concludes that lowering ventilation to present recommended level of 0.5 changesper hour cannot be recommended without further investigation. Part 2 of study investigated whether a problem connected with formaldehyde in single family houses in Skorde could be solved by increasing the ventilation. Measurements showed that ventilation would have to be unrealistically high if the level of 0.3 ppm as recommended by the local health authorities was to be attained.