EPA drops livestock emissions models and moves to end 2005 agreement
The National Milk Producers Federation (NMPF) welcomed the announcement, describing it as a step towards clearer regulation for American dairy producers. Dairy farms and other livestock businesses participating in the National Air Emissions Monitoring Study (NAEMS) had awaited a final outcome for more than two decades. The federation had previously questioned the proposed models for estimating emissions from dairy operations.
The agreement was established to produce scientifically credible ways of calculating emissions from animal feeding operations. Monitoring for NAEMS took place during 2005–07 at 25 operations in ten states. The study gathered measurements of four categories of pollutants: ammonia, hydrogen sulfide, particulate matter and volatile organic compounds. Those observations provided the dataset for the emissions-estimation methods that EPA subsequently developed.
EPA concluded that the measurements were too dated and their coverage too limited to provide reliable estimates for present-day livestock production. Changes to livestock housing, the size of herds, approaches to handling manure and technologies used on farms had reduced the dataset's relevance to current operations. The agency's decision reflected its concerns about both the age of the observations and how well they represented the industry.
NMPF's objections included the proposed dairy models' dependence on observations from just five dairy farms. Its technical review found that estimated emissions per cow varied substantially according to herd size. It also identified estimates that became negative when temperatures fell below freezing. The federation said the models gave limited consideration to advances in animal feed and genetics, manure-handling practices and technology for controlling emissions.
EPA will contact the operations covered by the arrangement and carry out termination under the agreement's provisions. Its implementation of the Clean Air Act remains unchanged, and livestock businesses remain subject to other applicable environmental requirements. The agency also plans further work with the US Department of Agriculture, land-grant universities and agricultural producers on practical approaches, grounded in science, to understanding farm air emissions and reducing them.
NMPF indicated that it would maintain collaboration with government agencies, universities and dairy cooperatives to support environmental improvements in the dairy sector.
