Concentration and size distribution of bioaerosols in an outdoor environment in the Qingdao coastal region

Bioaerosol particles in the atmosphere were collected from the coastal region of Qingdao from Jul. 2009 to Jun. 2010. The concentrations of microorganisms (including culturable, nonculturable, terrestrial and marine microorganisms) were measured. Average concentrations of airborne terrestrial bacteria, marine bacteria, terrestrial fungi, marine fungi and total bioaerosol were in the ranges of 33-664 CFU/m³, 63-815 CFU/m³, 2-777 CFU/m³, 66-1128 CFU/m³ and 85,015-166,094 Cells/m³, respectively. The nonculturable microbes accounted for 99.13% of the total microbes. In addition, there were more culturable marine microbes than culturable terrestrial microbes, and more airborne fungi than bacteria. The concentration of airborne bacteria showed a skewed distribution pattern, while unimodal size distributions were observed for the concentrations of fungi and total microbes. The airborne microbes mainly existed in > 2.1 μm coarse particles. Pearson correlation analysis between the concentrations and meteorological parameters showed that the meteorological parameters had different effects on different kinds of microbes. Sandstorms increased the concentrations of both culturable microbes and total microbes in the bioaerosol.