The effect of external conditions on indoor air quality in new buildings

The development of indoor air quality was studied in three newly finished buildings in Helsinki, Finland during the years 2000-2002. The concentration of volatile organic compounds (VOC), formaldehyde and ammonia, for which the Finnish Classification of Indoor Climate 2000 gives target values, in indoor air as well as the air exchange rate, relative humidity and temperature were determined for the newly finished buildings and 6- 12 months after the buildings had been taken in use. A total of five measurement sites in three residential buildings, representing the present construction practice in Finland, were chosen for investigation. Low-emitting surface materials according to the Finnish Classification of Building Materials were used at all sites.The results showed that the type of ventilation system used seemed to affect by most the concentration of the total amount of volatile organic compounds (TVOC) in the newly finished building. The TVOC- concentration decreased during the first 6 months to a level of