Mold Found in Home Air Research

Many fungi can develop on building material in indoor environments if the moisture level is high enough. Among species that are frequently observed, some are known to be potent mycotoxin producers. This presence of toxinogenic fungi in indoor environments raises the question of the possible exposure of occupants to these toxic compounds by inhalation after aerosolization. This study investigated mycotoxin production by Penicillium brevicompactum, Aspergillus versicolor, and Stachybotrys chartarum during their growth on wallpaper and the possible subsequent aerosolization of produced mycotoxins from contaminated substrates. We demonstrated that mycophenolic acid, sterigmatocystin, and macrocyclic trichothecenes (sum of 4 major compounds) could be produced at levels of 1.8, 112.1, and 27.8 mg/m², respectively, on wallpaper. Moreover, part of the produced toxins could be aerosolized from the substrate. The propensity for aerosolization differed according to the fungal species. Thus, particles were aerosolized from wallpaper contaminated with P. brevicompactum when an air velocity of just 0.3 m/s was applied, whereas S. chartarum required an air velocity of 5.9 m/s. A. versicolor was intermediate, since aerosolization occurred under an air velocity of 2 m/s. Quantification of the toxic content revealed that toxic load was mostly associated with particles of size ≥3 μm, which may correspond to spores. However, some macrocyclic trichothecenes (especially satratoxin H and verrucarin J) can also be found on smaller particles that can deeply penetrate the respiratory tract upon inhalation. These elements are important for risk assessment related to moldy environments.