We
studied microbial growth inside exterior walls as a possible biocontamination
source for indoor air. Microbial contamination (mesophilic fungi,
actinobacteria and other bacteria) of the insulation layer was measured in
cfu/g of mineral wool. Quality of indoor air was studied from flats next to
analysed panels having different degree of microbial contamination in the insulation.
Generalised Linear Mixed Models were used to analyse indoor air spora using microbial
contamination of insulation, other microbial sources (e.g. outdoor air), and
environmental variables as explaining factors. Actinobacterial contamination in
the insulation layer was shown to affect indoor air quality. An analogous
linkage with other bacteria or fungi was not found. The moisture content of
indoor air (g/m3) affected significantly airborne counts of all three microbial groups.