Study on behalf of ADEME - 06/12/2010

The project included three phases: first intended to study methods and choose those which would be described more precisely. A second which aimed to compare various measurement methods for manure storage and animal housing. The third phase intended to evaluate the possibilities to apply methods described in various countries. Complementary projects, associating the French actors of project ADEME and the Agricultural Colleges of Brittany (CASDAR, PITE, RMT) helped to fund other measurement works and software development.

The study of the methods showed that the emission measurement is always based on the observation of a variation of concentration (inside-outside) combined with a ventilation measurement. There are multiple situations, from a few square decimeters measuring chamber to a transmitting source of several thousands square meters. In all the cases, a great caution in the use of the results is necessary because of errors resulting from the heterogeneity of the concentrations near the source, of the possible presence of multiple entries and exits of air having each different concentration, of temporal variability due to the climate or animal evolutions, of the disturbances possibly caused by the device of measurement itself.

The experimental phase of comparison of the methods in the house on one hand, with the storage of slurry on the other hand showed important differences between measurement methods, wether it is in the house or with storage. It is thus advisable to be particularly careful in the use of results deduced from only one measurement method, not confirmed by one second independant method. By increasing the number of measurements in animal farm (temporal representativeness) and implementing complementary methods (no experimental bias), one can distinguish the animal farms strongly or slightly transmitters. Mass budget of the animal farm, deduced from measurements or references on the animals, their food and their manure can be used as parapets with emission measurements. Thus three levels of quality can be distinguished: (I) the qualitative evaluation compared to a reference; (II) intermittnt measurement with a risk of bias; (III) the measurement continuous with a risk of error minimized in so far as the device of measurement does not interfere with the processes of emission.

The evaluation of the possibilities to apply the methods showed the diversity of the national situations and the difficulty of quantifying uncertainty inherent in specific measurements in animal farm. Methodological work and the international exchanges should thus continue, parallel to house measurements and with storage in order to harmonize the methods, to standardize some of them, of going towards a certification of the emissions, while making progress the knowledge of the real animal farms emissions. the appropriation of these results by livestock industries will enable them to suggest objectives of evolution based on their possibilities of measurement of results and their economic outlooks.

The whole of the results, about fiften procedures described in French and English, is available.