Grantee Research Project Results

2012 Progress Report: 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 , Pressley, Shelley N. , Lamb, Brian , Johnson, Kristen
Current Investigators: Ham, Jay M , Lamb, Brian , Johnson, Kristen , 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 Period Covered by this Report: April 1, 2012 through March 31,2013
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

Objective:

The goal of this study is to use novel field measurements, new modeling approaches, and feedback from stakeholders to develop and evaluate a method for predicting site-specific beef feedlot ammonia emissions in the Great Plains.

Progress Summary:

1. A new type of conditional sampler network was perfected that uses Radiello passive ammonia samplers. Deployment of the cartridges is robotically controlled so the samplers are only exposed to air under a user-defined set of weather conditions. The use of passive conditional samplers in combination with inverse modeling provides a very low cost method for estimating NH3 emissions from feedlots.
2. A network of the robotic Radiello samplers were deployed on the upwind and downwind edges of a 25,000-head feedlot near Fort Morgan, CO. Concentration data were then used in an inverse dispersion model (FIDES) to estimate the areal NH₃ emissions from the feedlot. The fraction of fed nitrogen lost the air as NH₃ ranged from 70% in October to 40% in January with an overall average of 53%. This fractional loss of fed nitrogen is very similar to data reported in other studies from Canada and Texas.
3. Data analysis was completed of a field campaign to survey the nitrogen isotopic signatures at feedlots, dairies, and other strong NH₃ along the front range of Colorado. The isotope data showed that most agricultural sources have very similar levels of fractionation; especially beef feedlots, dairies, and cropland. Results show that isotopes might be useful for studying residence times in the atmosphere but likely will not be a practical way to trace / fingerprint the different sources of ammonia at the point of deposition.
4. Mechanistic modeling of NH₃ volatilization from feedlot pens showed that simulated emissions were very sensitive to submodels used to estimate the Henry constant (Kh) and ammonium acid dissociation constant (Ka). A novel laboratory study was conducted to study the effect of temperature and ionic strength on Kh and Ka in feedlot pen soil-manure-slurries in order to improve our current understanding and modeling of ammonia loss from feedlots.

Future Activities:

1. Continue to compare NH₃ measured by the Radiello samplers with that measured by the long path IR laser (Boreal Laser, www.boreal-laser.com/) at a 25,000 head feedlot.
2. In the fall of 2013, a study will be conducted in collaboration with Princeton University to compare NH₃ emissions estimated by our inverse modeling techniques with eddy covariance measurements of flux.  
3. Better quantify “typical” feedlot diets at large and small operations in the High Plains.  Emphasis will be placed on getting good crude protein numbers. Feed samples will be analyzed from several feedlots.
4. Develop a simple “top down” model of beef feedlot emissions that use feeding data and location dependent climatological information.

Journal Articles:

No journal articles submitted with this report: View all 11 publications for this project

Progress and Final Reports:

Original Abstract

2010 Progress Report

2011 Progress Report

Final Report