Size-selective assessment of airborne particles in swine confinement building with the UVAPS

The ultraviolet aerodynamic particle sizer (UVAPS) is a novel aerosol counter for real-time monitoring of viable bioaerosols. The previous validation studies on the UVAPS were either laboratory based or were conducted outdoor with the artificially generated aerosols. In this study, the spectrometer was applied to investigate particulate pollution inside a swine confinement building (SCB). Real-time capabilities of the instrument were used to investigate the effect of on-farm-activities, such as an effluent flushing with recycled water, on aerosols load inside the SCB. In addition to the UVAPS, monitoring of viable bioaerosols (bacteria and fungi) was simultaneously conducted with the six-stage Andersen microbial impactor and the AGI-30 impingers. The UVAPS measurements showed that the concentrations of both viable (fluorescent) and total (fluorescent and non-fluorescent) particles inside the SCB were in order of 10(6)- 10(7) particles m(-3). These concentrations were approximately seven times the outside concentrations for total particles and up to 12 times for viable particles. Approximately 95% of both total and viable particles were respirable (< 7 mum) and approximately 60% of total and 50% of viable particles accounted for the fine particle fraction (< 2.5 mum). The concentration of culturable bacteria and fungi ranged from 1.12 x 10(5) to 5.17 x 10(5) CFU m(-3) and from 1.12 x 10(3) to 2.79 x 10(3) CFU m(-3), respectively. Approximately 50-80% of airborne particles which carried culturable fungi were within the respirable size range. The concentration of viable particles measured with the UVAPS was at least one order of magnitude higher than the concentration of the culturable microorganisms measured with the AGI-30 impingers. Nevertheless, the trends in the concentration changes of viable bioaerosols measured with the UVAPS followed the trends in the concentration changes of the culturable airborne microorganisms quite adequately. Thus, it was concluded that the UVAPS is an appropriate method for investigating the dynamic of viable bioaerosols in the SCBs. The results obtained in this study assist in advancing an understanding of the UVAPS performance in the real-life agricultural settings. In addition, the data provide a new insight on the particles size distribution inside the SCB, depending on their nature. (C) 2004 Elsevier Ltd. All rights reserved.