A comprehensive experimental study of aerial pollutants in and emissions from livestock buildings. Part 2: Results

Comprehensive measurements of aerial pollutants were carried out in a mechanically-ventilated fattening piggery and in a naturally-ventilated (Louisiana-type) broiler house. In the piggery, ventilation rate was directly measured using fan-wheel anemometers and indirectly estimated by a CO2 balance method. Over 24 h, the indirect CO2 method underestimated the direct method by approximate to 6.5%. Concentrations of inhalable dust and of the gases NH3 and CO2 were monitored quasi-continuously in both buildings. In the piggery gravimetric and wet chemical measurements were used to investigate the spatial variation of dust and ammonia concentration, respectively; only towards the walls were significant variations found. Seasonal influences were detected for inhalable dust concentration in the broiler house and for ammonia concentration in the piggery. Altogether, the comprehensive study showed that the results of a related field survey, which used an array of measuring positions in the central cross-sectional plane of each livestock building, were comparable and sufficiently representative. (C) 1998 Silsoe Research Institute.