[The prevalence of bacterial and fungal aerosol in homes, offices and ambient air of Upper Silesia. Preliminary results].

Quantitative criteria of microbiological air quality in homes and offices are needed for practical reasons. The purpose of this study was to obtain the preliminary characteristic of bacterial and fungal aerosols in healthy buildings. It was analysed the concentrations levels and size distributions of the investigated bioaerosols. The obtained data can be treated as a first step in the direction of determining so called normal level for different bioaerosols in homes and offices in Poland. The concentrations of airborne bacteria and fungi were measured using 6-stage Andersen impactor. The Trypcase Soy Agar were applied for bacteria and 2% Malt Extract Agar for fungi. The bacteria samples were incubated for 2 days at 37 degrees C and the fungi samples respectively for 4 days at 25 degrees C. The indoor levels of bacterial aerosol (homes: 212-888 cfu/m3, offices: 136-542 cfu/m3) were higher than the outdoor levels (respectively: 42-386 cfu/m3 and 13-115 cfu/m3). The fungal aerosol concentrations were lower indoors (homes: 81-383 cfu/m3, offices: 18-133 cfu/m3) than outdoors (94-625 cfu/m3). There were distinctly higher concentrations of the investigated bioaerosols in homes than in offices. The aerodynamic diameter of most bacterial particles were higher than 7 microns, both in indoor air (homes: 57-260 cfu/m3, offices 19-118 cfu/m3) and outdoor air (respectively: 9-145 cfu/m3 and 0-71 cfu/m3). The maximum for fungal spore levels were observed in the size range 3.3-4.7 and 2.1-3.3 microns in the instance of homes (respectively: 12-155 cfu/m3 and 19-154 cfu/m3) and in the size range 2.1-3.3 microns in the instance of offices (6-55 cfu/m3). Largest numbers of this bioaerosol in outdoor air were isolated in the size range 2.1-3.3 microns (25-208 cfu/m3). Although there are some proposals for an upper limit of the normal indoor concentration of airborne bacteria and fungi, but due to different climate and housing conditions we can expect other normal range of fungal and bacterial aerosol in Polish homes.