Dynamics of airborne fungal populations in a large office building

The increasing concern, with bioaerosols in large office buildings prompted this prospective study of airborne fungal concentrations in a newly constr ucted building on the Gulf coast. We collected volumetric culture plate air samples on 14 occasions over the 18-month period immediately following bui lding occupancy. On each sampling occasion, we collected duplicate samples from three sites on three floors nf this six-story building and an outdoor sample. Fungal concentrations indoors were consistently below those outdoor s, and no sample clearly indicated fungal contamination in the building, al though visible growth appeared in the ventilation system during the course of the study. We conclude that modern mechanically ventilated buildings pre vent the intrusion of most of the outdoor fungal aerosol, and that even rel atively extensive air sampling protocols may not sufficiently document the microbial status of buildings.