Background concentrations of airborne, culturable fungi and dust particles in urban, rural and mountain regions

Geographic location and meteorological factors can affect the content of bioaerosol concentrations. This study was conducted to determine the natural background concentrations of culturable fungal spores and dust particles in three different geographical areas. Focus was given to the dominant airborne genera Cladosporium, Penicillium, Aspergillus and the species Aspergillus fumigatus. The influence of weather conditions on the microorganism concentrations in urban, rural and mountain regions were examined. Possible correlations between particle counts and culturable fungal spore concentrations were investigated. 125 measurements of the air were conducted using the air sampler MAS–100NT® and the particle counter Alphasense OPC–N3. The analyses of the collected samples were based on culture methods using different media. The highest median of fungal spore concentrations was detected in the urban region and was of 2.0 × 103 CFU/m3 for xerophilic fungi and 1.7 × 103 CFU/m3 for the genus Cladosporium. The concentrations of fine and coarse particles in rural and urban regions were the highest of 1.9 × 107 pa/m3 and 1.3 × 107 pa/m3, respectively. Little cloud cover and slight wind had a positive influence on the concentration of fungal spores. Furthermore, correlations were observed between air temperature and the concentrations of xerophilic fungi as well as the genera Cladosporium. In contrast, relative humidity correlated negatively with total fungi and Cladosporium and no correlation was found with the other fungi. For the region of Styria in summer and early autumn, the natural background concentration for xerophilic fungi ranged between 3.5 × 102 and 4.7 × 103 CFU/m3 air. No significant differences were detected between the fungal spore concentrations in urban, rural and mountainous regions. The data of this study could be used as a reference to compare the natural background concentrations of airborne culturable fungi in further studies concerning air quality assessment.