Towards a Verifiable Ammonia Emissions Inventory for Cattle Feedlots in the Great Plains

EPA Grant Number: R834551
Title: Towards a Verifiable Ammonia Emissions Inventory for Cattle Feedlots in the Great Plains
Investigators: Ham, Jay M , Johnson, Kristen , Lamb, Brian , Pressley, Shelley N.
Institution: Colorado State University , Washington State University
EPA Project Officer: Chung, Serena
Project Period: April 1, 2010 through March 31, 2013 (Extended to March 31, 2014)
Project Amount: $499,875
RFA: Novel Approaches to Improving Air Pollution Emissions Information (2009) RFA Text |  Recipients Lists
Research Category: Air Quality and Air Toxics , Air


Collectively, beef cattle feedlots in the Great Plains may be the nation’s single largest source of atmospheric ammonia. Unfortunately, the large uncertainty around these emissions not only affects the U.S. ammonia inventory, but also undermines attempts to understand and mitigate livestock-related air quality impacts on the environment. As of January 2009, the EPA requires cattle feedlots greater than 1,000 animals to report ammonia emissions to state and local authorities; however, no verifiable method has been developed to estimate these emissions on a site-specific basis. If feedlot managers had an software tool for predicting ammonia emissions that took into account climate, livestock diet, manure management, etc., the summation of these reports could be used to significantly improve the U.S. feedlot emissions inventory. The goal of this study is to use novel field measurements, new modeling approaches, and feedback from stakeholders to develop and evaluate an software tool for predicting site-specific beef feedlot ammonia emissions.


The overall goal of this proposal is to use novel measurement and modeling methods that will result in a software tool for predicting site-specific feedlot NH3 emissions. The use of this predictive tool within the current EPA reporting framework will lead to a verifiable NH3 inventory for feedlots in the High Plains. Furthermore, improved measurement and modeling of ammonia emissions from feedlots will also provide science based information to address other environmental questions linked to feedlot nitrogen dynamics, including: how do ammonia emissions affect nitrogen content of manure and potential water quality effects during storage or land application, are there correlations between ammonia and emissions of nitrous oxide, an important greenhouse gas; and how might environmental factors like climate change impact feedlot ammonia losses in the future.


The experimental approach will include: 1) micrometeorological measurements of ammonia emissions from commercial cattle feedlots in CO and KS. Data will be obtained using a unique form of relaxed eddy accumulation; 2) mass balance studies of feedlot nitrogen will be conducted to constrain the ammonia measurements and relate emissions to feeding and animal growth data; and 3) field data will be used to development a new type of feedlot nitrogen balance and emissions model where fate and transport of nutrients will be modeled as a series of continuous flow tank reactors (i.e., chemical engineering analog). This model will become the foundation for the new software tool to be used by feedlot managers to estimate their site specific emissions and evaluate how management might reduce ammonia losses.

Expected Results:

Field measurements and modeling of emissions will help quantify the contribution of cattle feedlots to the nation’s ammonia inventory and possibly indicate points of intervention where emissions can be reduced. Results from this effort also will be used to develop an online emissions tool for feedlot managers to predict their actual ammonia emissions on a seasonal site-specific basis. Once this tool is developed and becomes widely used, the EPA mandated ammonia reporting information from each feedlot can be used as a database for constructing county, state, and regional ammonia inventories on an annual basis.

Publications and Presentations:

Publications have been submitted on this project: View all 11 publications for this project

Journal Articles:

Journal Articles have been submitted on this project: View all 2 journal articles for this project

Supplemental Keywords:

agriculture,livestock,atmosphere,Front Range,Midwest,reactive nitrogen,transport,measurement methods,

Progress and Final Reports:

  • 2010 Progress Report
  • 2011 Progress Report
  • 2012 Progress Report
  • Final Report