Seasonal, diurnal and spatial variations of environmental variables in Australian livestock buildings

摘要

To identify the most practical and representative sampling locations for air quality and environmental variables inside intensive piggery buildings, the variation in the spatial, diurnal and seasonal concentration of major airborne pollutants, and related environmental parameters, were analysed over a 2.5-day period at several locations within different piggery buildings. Major airborne pollutants including, ammonia, carbon dioxide, and airborne particles were monitored along with environmental parameters of airspeed, temperature and humidity. To determine the air quality within each building, cyclone attachments were installed to measure particles of less than 5 μm along with a seven hole sampler attachment to measure inhalable airborne particles. An Osiris optical particle counter also monitored the concentrations of airborne particles. Ammonia and carbon dioxide were monitored using a multi-gas monitoring machine and airspeed was measured using a hot-wired anemometer. Interesting patterns in the concentration of carbon dioxide, dust and ammonia were observed over time and space. Carbon dioxide, airspeed and dust concentration demonstrated an obvious circadian pattern. The difference in the concentrations of ammonia and carbon dioxide was not statistically significant at alternative sampling locations inside each building. However, the gravimetric measurements indicated that the concentrations of inhalable particles were not uniform throughout the buildings and proved to be higher above the walkways. Ammonia and respirable particle concentrations were significantly higher in summer when compared to winter conditions. These results combined, identified the most appropriate sampling times and sampling places for reliable evaluation of air quality in intensive livestock buildings.