An assessment of airborne fungi exposure risk level in air-conditioned offices

The exposure to airborne fungi has not been included in many regular indoor air quality (IAQ) assessments of air-conditioned (A/C) offices. This study examined the feasibility of using a proposed relative index of fungal exposure (RIFE) as a quantitative measure to specify the enclosure effect of an indoor environment in 82 Hong Kong A/C offices. The airborne fungi count ranged from 2 to 92CFU •m-3. Yeast, Aspergillus, Cladosporium, and Penicillium were reported as dominant in the offices. The RIFE of Yeast, Aspergillus, and Penicillium were 1.26, 1.21, and 1.02, respectively, and it would confirm a higher indoor exposure risk relative to that of outdoors. The RIFE of the common outdoor fungi Cladosporium was 0.48. This study presents a useful index for IAQ assessment regarding relative risk exposure of airborne fungi in A/C offices.