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).

historyTOSeries   As many of you already know, the EN 13725 was published in February 2022. There are many new provisions in the new text that needs to be reviewed in detail, but maybe one of the most impacting in the day-to-day operations of the over 400 laboratories around the world is the one of the minimal recovery rate accepted for olfactometers.

   With the new standard in hand, no olfactometer can be used for odour measurement under the EN 13725 accreditation scheme, unless recovery rates of 70 % or higher has been tested for four test gases: hydrogen sulphide, n-butanol, propanoic acid and dimethyl sulphide. That means that any olfactometer in the world needs to pass this test if an accreditation is needed. And this is no cheap test.

Weber-Fechner Curve    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.

   The method includes using the Odor Profile Method to identify each odor character and intensity and using olfactometry as an odor dilution system to determine the persistency of the odor, i.e., the rate of decrease of an odor with dilution. The results showed that air coming from the EDF can pose a rancid and sweet odor nuisance for the community near the EDF and possibly a weak musty odor nuisance for the area further away from the EDF. 

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