Cattle farms consist of various spatially extended odour-emitting areas representing ground-level diffuse odour sources. These include loose-housing systems with outdoor exercise areas, the supplied diet, and storage areas for silage, slurry and solid manure. The aim of this study was to identify relevant odour sources on cattle farms and to compare the odour concentrations of individual sources, bearing in mind descriptive parameters.
Compared with hay and sugar beet pulp (mean: <750 OUE m−3), higher odour concentrations resulted from the cut surface of grass silage (3990 OUE m−3) and maize silage (1690 OUE m−3) in the stores as well as from the mixed ration with silage on the feed table (2955 OUE m−3). Samples from the solid floors in the cattle housing (feeding and cubicle access aisles, outdoor exercise area) and from solid manure stores showed higher odour concentrations (1485 resp. 1845 OUE m-3) than littered areas such as cubicles and deep-bedded areas (<500 OUE m−3).
As many of you already know, the EN 13725 was published in 
An Energy Development Facility (EDF) has been evaluated as an odor source to optimize the evaluation of odor persistency. The objectives were to identify the odor characteristics and intensity from the EDF and to determine the relative contribution and variability of the different odors emitted.