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Stricter regulations on volatile organic compounds and hazardous air pollutants have increased the demand for abatement technologies. Biofiltration, a process in which contaminated air is passed through a biologically active bed, can be used to remove these pollutants from air streams. In this study, a fungal vapor-phase bioreactor containing a strain of the dimorphic black yeast, Exophiala lecanii-corni, was used to treat a gas stream contaminated with toluene. The maximum toluene elimination capacity in short-term tests was 270 g m(-3) h(-1), which is 2 to 7 times greater than the toluene elimination capacities typically reported for bacterial systems. The fungal bioreactor also maintained toluene removal efficiencies of greater than 95% throughout the 175-day study. Harsh operating conditions such as low moisture content, acidic biofilms, and nitrogen limitation did not adversely affect performance. The fungal bioreactor also rapidly reestablished high toluene removal efficiencies after an 8-day shutdown period. These results indicate that fungal bioreactors may be an effective alternative to conventional abatement technologies for treating high concentrations of pollutants in waste gas streams.

Global urbanization, combined with evidence of increased prevalence of mental illness in urban environments, highlights a need to investigate potential connections between the built environment and mental health. Previous research has shown that the built environment may impact occupant mental health through its effects on connection to nature, personal control and indoor air quality. Contact with the natural environment has physiological and psychological benefits; consequently, reduced contact or exposure leads to negative mental health outcomes. The control an occupant has in the built environment can alter the mental health of individuals through direct pathways, such as prevention of exposures to environmental stressors and indirect pathways, such as social connections to others. Indoor air quality is connected to the mental health of built environment occupants, as particulate matter, malodorous irritants and toxins have all been shown to alter mental well-being. Opportunities for architects and engineers to optimize building designs that improve occupant mental health include planned urban greenspace, personalized temperature control and building ventilation. To understand optimization targets, interdisciplinary research utilizing controlled experiments are needed to confirm causality and improve our current understanding of mechanisms underlying the association between the built environment and mental health.