Methane (CH₄) emissions from dairy housings, mainly originating from enteric fermentation of ruminating animals, are a significant source of greenhouse gases. The quantification of emissions from naturally ventilated dairy housings is challenging due to the spatial distribution of sources (animals, housing areas) and variable air exchange. The inverse dispersion method (IDM) is a promising option, which is increasingly used to determine gaseous emissions from stationary sources, as it offers high flexibility in the application at reasonable costs. We used a backward Lagrangian stochastic model combined with concentration measurements by open-path tunable diode laser spectrometers placed up- and downwind of a naturally ventilated housing with 40 dairy cows to determine the CH₄ emissions. The average emissions per livestock unit (LU) were 317 (±44) g LU⁻¹ d⁻¹ and 267 (±43) g LU⁻¹ d⁻¹ for the first and second campaign, in September – October and November – December, respectively. For each campaign, inhouse tracer ratio measurements (iTRM) were conducted in parallel during two subperiods. For simultaneous measurements, IDM showed average emissions which were lower by 8% and 1% than that of iTRM, respectively, for the two campaigns. The differences are within the uncertainty range of any of the two methods. The IDM CH₄ emissions were further analysed by wind direction and atmospheric stability and no differences in emissions were found. Overall, IDM showed its aptitude to accurately determine CH₄ emissions from dairy housings or other stationary sources if the site allows adequate placement of sensors up- and downwind in the prevailing wind direction. To acquire reliable emission data, depending on the data loss during measurements due to quality filtering or instrument failure, a measuring time of at least 10 days is required.

奶牛舍的甲烷 (CH ₄ ) 排放主要来自反刍动物的肠道发酵，是温室气体的重要来源。由于来源（动物、饲养区）的空间分布和可变的空气交换，自然通风乳牛舍的排放量化具有挑战性。逆分散法 (IDM) 是一种很有前景的选择，它越来越多地用于确定固定源的气体排放，因为它以合理的成本在应用中提供了高度的灵活性。我们使用了一个反向拉格朗日随机模型，并结合了浓度测量，这些光谱仪放置在一个自然通风的牛舍的上风和下风处，有 40 头奶牛，以确定 CH ₄排放。9 月至 10 月和 11 月至 12 月的第一次和第二次活动的每个牲畜单位 (LU) 的平均排放量为 317 (±44) g LU ^-1 d ^-1和 267 (±43) g LU ^-1 d ^-1， 分别。对于每个活动，内部示踪剂比率测量 (iTRM) 在两个子周期内并行进行。对于同时测量，IDM 显示两个活动的平均排放量分别比 iTRM 低 8% 和 1%。差异在两种方法中任何一种的不确定性范围内。IDM CH ₄通过风向和大气稳定性进一步分析了排放，未发现排放差异。总体而言，如果现场允许在盛行风向的上风向和下风向充分放置传感器，IDM 显示了其准确确定来自乳品房或其他固定源的CH ₄排放的能力。为了获得可靠的排放数据，根据质量过滤或仪器故障导致的测量数据丢失，至少需要 10 天的测量时间。