Microbial growth was studied in six damp buildings. Mesophilic fungi, especially Penicillium spp., yeasts, and species of Cladosporium and Aspergillus, occurred most abundantly on building constructions. Thermophilic fungi and mesophilic actinomycetes were occasionally found. A toxigenic fungus, Stachybotrys sp., was also detected on cellulose-based materials. In a cytotoxicity test, 23% of samples were positive. Spore counts varied considerably on materials, but no correlation between counts and the substrate or its water activity (aw) was observed. In experiments a rapid increase in CO2 production and spore propagule count was observed in all materials incubated at a relative humidity (RH) (RH=0ˇ¤01*water activity) of 96-98ˇă. Some differences were noted between materials in CO2 evolved, but not in propagule counts.

• fungi: assessment, sampling and analysis
• fungi: growth and growth model

1. Air pollution exposure in European cities: The "EXPOLIS" study
2. Fungal microcolonies on indoor surfaces an explanation for the base-level fungal spore counts in indoor air
3. Significance of air humidity and air velocity for fungal spore release into the air
4. Temporal and spatial variation of fungal concentrations in indoor air  

1. Growth and volatile metabolite production of Aspergillus versicolor in house dust
2. Microbial growth and metabolism in house dust