It is abundantly clear that many schools support unacceptable mold burdens. However, what is less clear from the literature on school biocontamination problems is whether all schools support the same types of molds and where the most common mold amplifying sites are likely found. Since 1992, I have been involved in the study of 631-school environments for mold contaminants and analyzed some 5000 air and substrate samples from schools throughout the Atlantic Provinces. Objectives of this presentation are threefold. The first is to compare mold burdens and dominant species assemblages in "normal" and "contaminated" school environments. The second is to show that mold species assemblages vary widely with the school construction type and amplifying sites and; the third is to evaluate the effect of ongoing inspections in schools for mold contaminants. In normal school environments, like in other buildings in temperate zones, airborne mold burdens follow clear seasonality patterns that are quantitatively and qualitatively similar to that found outdoors. Schools suffering from mold contamination problems most frequently support high focal and sometimes widespread spore loads and growth of a variety of species including the indicator species Acremonium spp., Aspergillus fumigatus, A. niger, A. ustus, A. versicolor, Chaetomium spp., Paecilomyces variotii. Penicillium brevicompactum, P. aurantiogriseum complex, P. variabile, Phoma spp., Stachybotrys chartarum, Trichoderma harzianum and T. viride. However, indicator species assemblages recovered from contaminated school sites vary considerably reflecting school age and construction, and the composition and water activity of the amplifying substrate material. The most common contamination sites in descending order of occurrence are classrooms and administration sites, especially peripheral-wall cavities and ceiling plenum, libraries, gymnasiums, basements/crawl spaces, ventilation systems, janitor/mechanical rooms and portable classrooms. The most commonly encountered contaminated substrates in schools are drywall, dust, ceiling tiles, structural wood, insulation, carpets, concrete wall surfaces, and, amongst others, that have been exposed to chronic water infiltration, condensation and/or wicking problems. School inspections for mold contamination, which have been ongoing since 1993, have resulted in a reduction in the number of schools suffering from widespread contamination problems. However, the number of schools suffering from focal problems, especially in inapparent sites, has remained approximately the same. Prompt abatement action to remove amplifiers once they have been detected, and better communication outlining potential exposure risks, have helped to allay heightened occupant and parent anxiety.

• fungi: molds in buildings
• ventilation - Air Infiltration and Ventilation in Buildings