Morning-evening variation and determinants of bacterial and fungal aerosol concentration in historical objects in Krakow

摘要

Cultural heritage objects are very frequently visited by tourists, the presence of which is considered to affect the bacterial and fungal aerosol levels in these facilities. Therefore, this study had two main aims with the first to determine the morning/evening changes in the concentration of bacterial and fungal aerosol as well as particulate matter in the selected historical objects of Krakow: churches, crypts, libraries, and museums. The second aim was to establish the most possible factors affecting the quality of air in the examined sites using data mining techniques: principal component analysis (PCA) and cluster analysis (CA). Bacterial and fungal aerosol levels were measured in ten historical objects by six-stage Andersen impactor. Particulate matter (PM10, PM4, PM2.5 and PM1), temperature, and relative humidity (RH) were also assessed. Unlike dusts, the microbial aerosol concentrations were not always significantly lower in the morning than in the evening. For bacteria, these relationships varied depending on the site, while for fungi, the morning concentrations were mostly higher than the evening ones. Both PCA and CA indicated that the bacterial and fungal aerosol concentrations were not associated with the particulate matter levels, which might suggest different sources of those two air pollution components. Temperature and RH appear to be more important in shaping the microbial aerosol levels and fungi are more dependent on RH than bacteria.