Emissions and ventilation rates (VRs) in naturally ventilated dairy barns (NVDBs) are usually measured using indirect methods, where the choice of inside and outside sampling locations (i.e. sampling strategy) is crucial. The goal of this study was to quantify the influence of the sampling strategy on the estimation of emissions and VRs. We equipped a NVDB in northern Germany with an extensive measuring setup capable of measuring emissions under all wind conditions. Ammonia (NH3) and carbon dioxide (CO2) concentrations were measured with two Fourier-transform infrared spectrometers. Hourly values for ventilation rates and emissions for ammonia over a period of nearly a year were derived using the CO2 balance method and five different sampling strategies for the acquisition of indoor and outdoor concentrations were applied. When comparing the strategy estimating the highest emission level to the strategy estimating the lowest, the differences in NH3 emissions in winter, transition, and summer season were +26%, +19% and +11%, respectively. For the ventilation rates, the differences were +80%, +94%, and 63% for the winter, transition and summer season, respectively. By accommodating inside/outside concentration measurements around the entire perimeter of the barn instead of a reduced part of the perimeter (aligned to a presumed main wind direction), the amount of available data substantially increased for around 210% for the same monitoring period.

中文翻译：

---

通风率和氨排放量的计算：自然通风奶牛舍的采样策略比较

自然通风牛舍 (NVDB) 中的排放和通风率 (VR) 通常使用间接方法进行测量，其中内部和外部采样位置（即采样策略）的选择至关重要。本研究的目的是量化采样策略对排放量和 VR 估算的影响。我们为德国北部的 NVDB 配备了广泛的测量装置，能够在所有风力条件下测量排放。氨 (NH3) 和二氧化碳 (CO2) 浓度使用两个傅立叶变换红外光谱仪进行测量。使用 CO2 平衡方法推导出近一年时间内氨的通风率和排放的每小时值，并应用五种不同的采样策略来获取室内和室外浓度。当比较估计最高排放水平的策略与估计最低排放水平的策略时，冬季、过渡和夏季的 NH3 排放差异分别为 +26%、+19% 和 +11%。对于通风率，冬季、过渡和夏季的差异分别为 +80%、+94% 和 63%。通过在谷仓的整个周长周围进行内部/外部浓度测量，而不是周长的减少部分（与假定的主风向对齐），在同一监测期内，可用数据量显着增加了约 210%。冬季、过渡和夏季的差异分别为 +80%、+94% 和 63%。通过在谷仓的整个周长周围进行内部/外部浓度测量，而不是周长的减少部分（与假定的主风向对齐），在同一监测期内，可用数据量显着增加了约 210%。冬季、过渡和夏季的差异分别为 +80%、+94% 和 63%。通过在谷仓的整个周长周围进行内部/外部浓度测量，而不是周长的减少部分（与假定的主风向对齐），在同一监测期内，可用数据量显着增加了约 210%。