Date Full Report Received


Date Abstract Report Received



Primary Investigator:

The air emission data from the National Air Emissions Monitoring Study (NAEMS) is used by the U.S. Environmental Protection Agency (USEPA) to determine the regulatory responsibilities of animal feeding operations and to develop emissions-estimating methodologies, and it was collected from 2007 to 2009. Over the past decade, feed formulations have changed and nutrient use efficiencies have improved. The U.S. pork industry is experiencing continuous changes and refinements driven by technology, which enable producers to be more competitive and efficient, while being good stewards of the environment and promoting the well-being of their animals. The U.S. pork industry needs to be informed, whether the changes since 2009 in the technological and management practices employed at pork production facilities have a material effect on the suitability of the NAEMS data for modeling emissions today and over the next few years.

The goal of the project is to gather solid information through comprehensive literature review, survey, and meta-analysis, for an evaluation of the representativeness of air emissions monitoring data collected from swine operations under NAEMS relative to emissions from the predominant swine production systems in use today and in the next few years, and to provide scientific evidences for an estimation of the nature and size of the changes in emissions today relative to the NAEMs results.

Over the past decade, feed conversion efficiency in the U.S. pork industry have improved continuously due to improved feed formulations, genetics and management practices. As a result, for the same amount of animal product, the manure amount and air emissions per unit of animal product are likely reduced by 18% from 2010 to 2019, and could further be reduced with further improvement in feed conversion efficiency. One direct effect of change in diet formulation on air emissions is the increasing use of DDGS in swine diet. Increased DDGS content in the diets can result in higher odor and hydrogen sulfide emissions, but its effect on ammonia emission is uncertain. Another trend that directly affect manure characteristics is that, development in watering technology makes thicker manure and thus can reduce ammonia and odor emissions in swine houses.

Controlled-environment buildings and systems approaches are increasingly used for swine operations to maximize the well-being and productivity of both animals and workers. Data in recent literature indicated that although the recent ammonia emission rates for finishing swine houses were similar with the finishing swine house emission rates in the NAEMS report, the recent ammonia emission rates for gestation swine houses were much lower than the gestation swine house emission rates in the NAEMS report. Similarly, although the recent ammonia emission rates for swine houses with deep-pit systems were similar with the deep-pit swine house emission rates in the NAEMS report, the recent ammonia emission rates for swine houses with pit recharge systems were much lower than the pit recharge swine house emission rates in the NAEMS report.

The NAEMS ammonia emission rates for finishing swine houses with deep pit may still be representative in today’s condition, but the NAEMS data on ammonia emission rates for gestation houses or for pit recharge systems may overestimate emissions by 2 to 4 times higher. As DDGS are increasingly used in practice as a partial replacement for corn-soybean meal to reduce feed cost, the NAEMS hydrogen sulfide emission rates for swine house may underestimate emissions in cases when DDGS diet are used.

Emission measurement from lagoons/basins at swine operations have high uncertainties due to variety of environmental conditions and measurement technologies. Based on recent data in literature, The NAEMS emission rates for lagoons/basins at swine operations could overestimate ammonia emissions by three times higher, and overestimate hydrogen sulfide emissions by 7 to 11 times higher.
Results from this project provided scientific evidences to assist the U.S. pork industry to participate in the discussion on its regulatory responsibilities with regarding to environmental restrictions.

Contact information: Zifei Liu, 785-532-3587, zifeiliu@ksu.edu