The Egg Industry Center (EIC) recently completed an in-depth evaluation of EPA’s draft models developed to create air emissions factors for layer operations. The models were developed using data collected during the 2007-2010 National Air Emissions Monitoring Study (NAEMS).

The EIC’s findings raise questions about the accuracy of those draft models, as they generated widely varying estimates of per hen emissions from hen houses with inventories that are smaller or larger than those generated from the hen inventory numbers in the houses studied by NAEMS.  The EIC also used EPA’s models to estimate ammonia emissions for 12 locations which were representative of the wide range of weather conditions around the U.S. and found the estimates to be considerably higher than those in the research literature.

When provided with these results in a meeting with the EIC, UEP and others from the egg sector, EPA acknowledged the validity of these questions and indicated a strong willingness to improve the performance of its models. They noted that other animal sectors had raised similar questions over the performance of the EPA’s models.

The EIC’s study was funded by the American Egg Board, which, also funded the original collection of the monitoring data on layer operations during the NAEMS effort. EPA is expected to continue improving and refining its estimation models over the next several months and publish proposed air emissions factors for the layer, broiler, swine and dairy sectors sometime in 2023.  EPA will take formal comments on those proposed factors and intends to finalize emissions factors sometime in 2024.

UEP will remain fully engaged with EPA and the other animal agriculture groups throughout this process. UEP’s Environment and Sustainability Committee was briefed this week on the findings of the EIC report and the conversations with EPA.  Please contact Tom Hebert if you have questions.