Author Description

In winter, multi-stage scrubbers reduced emissions of airborne total bacteria by between 46% and 85%, PM10 by between 61% and 93%, PM2.5 by between 47% and 90%, and ammonia by between 70% and 100%. The EU reference dust sampler with an impaction pre-separator, which was designed for sampling dust in ambient air, could not be used to sample PM2.5 in livestock houses where dust concentrations were high, because overloading occurred. A sampler with a cyclone pre-separator was more tolerant of dust loads in livestock houses and was validated as a reference equivalent sampler. The method for evaluating the efficiency of bioaerosol samplers for airborne microorganisms was appropriate. It calculated the physical and biological sampling efficiencies separately, by excluding the viability losses in the non-sampling processes. The Andersen six-stage impactor, the All Glass Impinger (AGI-30) and the MD-8 had higher physical efficiencies than the OMNI-3000. The Andersen impactor and the AGI-30 had high (100%) biological efficiencies on sampling all five aerosolized microbial species (Enterococcus faecalis, Escherichia coli, Campylobacter jejuni, Mycoplasma synoviae and Gumboro vaccine virus). C. jejuni and Gumboro vaccine virus were inactivated by the OMNI-3000 during sampling, whereas E. coli and C. jejuni were inactivated by MD8. As a result, these two bioaerosol samplers had lower biological efficiencies. Although recipient broilers became infected, no culturable airborne Campylobacter were detected by the Andersen impactor, the AGI-30 and the OMNI-3000 in an airborne transmission of Campylobacter in broilers.