Ammonia and other microclimatic conditions at an Australian pre-export sheep assembly depot

Noxious gases produced at hazardous concentrations in animal housing systems may affect the health and wellbeing of both animals and workers. In order to determine if the gaseous emissions from a pre-export assembly depot for sheep constituted a risk, atmospheric ammonia was measured in eight sheep buildings at an Australian assembly depot. Additionally, meteorological variables and distance from excreta were measured to determine their influence on ammonia, carbon dioxide and hydrogen sulfide concentrations. Repeat measurements were made at 12 sites in each building on 4 separate days, and four buildings were mapped using longitudinal and latitudinal transects. Concentrations of ammonia, carbon dioxide and hydrogen sulfide were all below the recommended safety thresholds for humans and livestock. There were positive correlations between ammonia and the following variables: ambient temperature and moisture content, and negative correlations with distance from animal excreta. Understanding these relationships will help to understand the reasons for ammonia accumulation in such buildings.