Fungal contribution to size-segregated aerosol measured through biomarkers

Fungal spores are the dominant biological component of air. Although ubiquitous in outdoor air, they are scarcely measured due to the inadequacy of measurement methods. The use of biomarkers as tools for the determination of fungal contribution to bioaerosol has often been suggested, and ergosterol, arabitol and mannitol have been associated to fungal spores as tracers. In the present paper, the fungal component of aerosol was studied at suburban/rural and at urban sites. Ergosterol, arabitol, and mannitol contents in airborne particulate matter, even at different sizes, were determined. Literature conversion factors and calculated conversion factors correlating ergosterol, arabitol, and mannitol masses to fungi mass were applied and compared to each other. The obtained fungal spore concentrations were different depending on the marker utilized both with the conversion factors found in literature and the calculated ones. Size-segregated marker distribution suggested different sources for the three tracers indicating ergosterol as the only reliable biomarker at our latitudes. The fungal spore concentrations were higher at the suburban/rural location and respectively inversely and directly proportional to temperature and relative humidity.

► Fungi-containing aerosols were studied by means of chemical biomarkers.
► Ergosterol, arabitol, mannitol were used as tracers for fungal spores.
► Fungal component of aerosol was studied even at different sizes of PM10.
► Arabitol and mannitol can overestimate fungal spore concentrations in atmosphere.
► Ergosterol remains the only reliable biomarker.