Spatial Gradients of Fungal Abundance and Ecology throughout a Damp Building

Dampness and fungal (mold) growth in buildings are persistent environmental health problems. This study sought to determine the extent to which fungi grown on damp materials are distributed throughout a single-family home. Samples were collected from fungi growing directly on building materials in the basement (direct mold), and as a proxy for indoor and outdoor air, settled dust was collected from the top of door frames (basement, first and second floor, and exterior). Direct mold in the basement influenced both the fungal richness and ecology of air throughout the building. Fungal communities clustered by sample type (ANOSIM R = 0.62; p = 0.001) and floor (indoor samples; ANOSIM R = 0.58; p = 0.001) with the direct mold ecologies dominated by taxa (i.e., Sterigmatomyces, Stachybotrys, and Aspergillus) associated with mold growth on building materials and not present in outdoor samples. The relative abundances of these highly enriched direct mold taxa were also found to be inversely correlated to the distance to mold growth, decreasing by >70% between the basement and second floor. Through intense spatial characterization of the fungal community of one home, this study illustrates that fungal growth in a single location can significantly influence the fungal communities and human fungal exposure throughout the building.