ISSUE 30: How are these ammonia emissions from livestock being estimated ?
RESPONSE: There are some measurement data in the literature and scientists are also conducting limited measurements here in North Carolina. Some type of factor is usually generated from these measurements that can then be used to estimate ammonia emissions from animal population statistics. Unlike industries, extensive databases of actual measurements of ammonia emissions from animal production are unavailable. The amount of emissions will also vary with type and size of the operation; e.g., cattle feedlot versus pasture, e.g., swine slurry manure handling systems versus liquid manure handling. In more confined animal operations, the amount of feed and its nitrogen content can be used to calculate nitrogen inputs, and the nitrogen composition of the animals and their products such as milk can be calculated for those outputs. The difference between feed inputs and product outputs approximates the nitrogen excretion, which approximates an upper limit for potential ammonia, not the actual