Characterisation of exposure to airborne fungi: Measurement of ergosterol

Abstract In order to gain a clearer understanding of the level of fungal air contamination in indoor environments, we have adapted and tested a method to evaluate fungal biomass. Liquid phase chromatography (HPLC) of ergosterol, a component of the cell membrane of microscopic fungi, was employed. This method permits the detection and identification of ergosterol molecules at a concentration of 40 μg/ml ( n  = 33, σ  = 5). By combining this assay with a rotating cup collection apparatus, it was possible to measure fungal flora levels with a limit of quantification of 0.4 ng/m 3 or a theoretical value of 150 spores per cubic meter (m 3 ). Measurements of ergosterol levels performed on different sites showed that this method reflected the different situations of exposure of occupants to airborne fungal flora.