Assessment of the inverse dispersion method for the determination of methane emissions from a dairy housing

• Methane (CH 4 ) emission measurements were conducted at a housing with 40 dairy cows. Inverse dispersion method (IDM) was compared an “inhouse” tracer ratio method. Differences between means of 1-8% are within the uncertainty range either IDM CH emissions 317±44 and 267±43 g LU −1 day for two campaigns. An analysis suggests measurement duration least 10 days IDM. from housings, mainly originating enteric fermentation ruminating animals, significant source greenhouse gases. The quantification naturally ventilated housings is challenging due to spatial distribution sources (animals, areas) variable air exchange. inverse promising option, which increasingly used determine gaseous stationary sources, as it offers high flexibility in application reasonable costs. We backward Lagrangian stochastic model combined concentration by open-path tunable diode laser spectrometers placed up- downwind cows emissions. average per livestock unit (LU) 317 (±44) d 267 (±43) first second campaign, September – October November December, respectively. For each inhouse (iTRM) parallel during subperiods. simultaneous measurements, showed lower 8% 1% than that iTRM, respectively, differences any methods. further analysed wind direction atmospheric stability no found. Overall, its aptitude accurately or other if site allows adequate placement sensors prevailing direction. To acquire reliable data, depending on data loss quality filtering instrument failure, measuring time required.