## 3 Results
### Farm Scale Evaluations as the Outputs of the AGEM-S  
The results are presented in a pie chart showing the total calculated ammonia emissions from the farm, subdivided into emissions from housing, storage, field application, and additional nitrogen fertilization. The following bar chart depicts the on-farm nitrogen flow, which can be used to monitor how the TAN content of nitrogen excreted by animals decreases during the time of housing and subsequently in storage and application (Figure 2). Farm evaluation is an illustrative tool for demonstrating the total nitrogen flow in the pig farm, providing a realistic picture of NH\({}_{3}\) emissions from livestock operation based on the results of a properly completed model. The selected graphical view gives a visual representation of the decreasing TAN content in each module, which together with the total nitrogen content provides a good picture of the changes in the nutrient content of manure. In addition to reducing ammonia emissions, the higher the nitrogen content that remains in manure, the more beneficial for crop production, as it contributes to higher crop yields. The principle for assessing each module is similar. The amount of NH\({}_{3}\) emissions achieved without any abatement measures is determined in parallel with the amount of ammonia emissions realized using most techniques simultaneously (e.g., application) or using the most efficient abatement techniques. These levels form the two endpoints of a \"quantitative\" scale. The actual reduction achieved should be assessed in proportion to this. This also means that the scale is relative, as each technology element has a different emission reduction potential. However, it is not a disadvantage for the overall assessment, as it will direct the attention of farmers towards technologies with a higher emission  
Figure 2: Ammonia emission and N flow on the farm in the AGEM-S (example). reduction potential. The application of the principle allows NH\({}_{3}\) emissions to be assessed per module or even within a module (feed per age category, housing technology per livestock building, or other technologies). It is very beneficial for the farmers, giving visibility to the technological elements within the farm that need to be improved the most. For example, in the case of livestock buildings, the introduction of a technology with the highest correction factor does not necessarily result in the lowest ammonia emission if the number of animals is considered. In the majority of farms, the growing/finishing stock is the largest emitter, so even a small reduction in emissions affecting these age groups can lead to significant operational reductions. A good example of the complexity of judging by the correction factor is the assessment of air purifiers in the model. Air filtration equipment proved to be effective in trapping ammonia in the air released from the stable. Acid scrubbers are 70-90% effective in filtering NH\({}_{3}\), depending on pH, and bio-drip filters are 70-75% effective in capturing odor and particulate loads in the barn [1]. Since the use of the AGEM-S model has the dual purpose of determining ammonia emissions and monitoring the amount of nitrogen remaining in manure as a source of nutrients that can be further used, the use of air purifiers cannot be evaluated as the best emission reduction technique from this point of view. Although their impact on ammonia emissions is undebatable, the bound nitrogen is removed from the farm-level N flow system and does not follow the pathway mapped in the model. The evaluation system therefore follows a unique bottom-up logic. Once the values of each technological element have been determined, a weighted aggregation gives the value of the module. Weighting is done by the rate of the emission reduction potential of each element, so that technologies with a higher reduction potential are weighted more heavily (Figure 3). The figures are explained in detail to further understanding. The results of the modules are totaled in the score of the farm.