Grantee Research Project Results

2012 Progress Report: Atmospheric Ammonia Emissions from the Livestock Sector: Development and Evaluation of a Process-based Modeling Approach

EPA Grant Number: R834549
Title: Atmospheric Ammonia Emissions from the Livestock Sector: Development and Evaluation of a Process-based Modeling Approach
Investigators: Adams, Peter
Institution: Carnegie Mellon University
EPA Project Officer: Chung, Serena
Project Period: May 1, 2010 through April 30, 2014 (Extended to November 30, 2015)
Project Period Covered by this Report: May 1, 2012 through April 30,2013
Project Amount: $483,827
RFA: Novel Approaches to Improving Air Pollution Emissions Information (2009) RFA Text |  Recipients Lists
Research Category: Air Quality and Air Toxics , Air

Objective:

The objective of this project is to build an improved atmospheric ammonia emissions inventory for U.S. livestock by developing and evaluating a process-based approach that accounts for regional and temporal variations in weather and farming practices. We will accomplish this by pursuing the following goals and tasks:

• Develop process-based models of ammonia emissions from beef cattle, swine, and chickens that account for differences in farming practices as well as seasonal and diurnal variability
• Assess the uncertainty in livestock ammonia emissions and suggest sources of data that can help reduce this uncertainty
• Test process-based models at the farm scale against NAEMS multi-year measurements
• Develop a revised national emissions inventory based on these results
• Test the performance of the revised national emissions inventory in a CTM against ambient measurements of NH₃ and NH₄+ concentrations and deposition
• Assess the sensitivity of inorganic PM_2.5 to NH₃, SO₂, and NO_x emissions under current and future policy regimes

Progress Summary:

The goals of the project have not changed, and the project is on schedule. In the past year, farm emissions models (FEMs) for beef have been completed, those for swine are nearly complete, and poultry will be completed soon (Task 1). All the FEMs show skill at explaining variability in the observed emissions factors reported in the literature. The FEMs for swine in housing perform better in this regard than for beef on feedlot, and we hypothesize this is due to the more controlled conditions that prevail in swine production, where animals are housed indoors. Our results point to the importance of knowing the “context” of emissions measurements, including meteorology, manure management practices, and animal diet. Our model performance for beef on feedlots is noticeably higher when the model is constrained with these key inputs, which are not always reported in emissions studies. Our results also suggest that, for purposes of estimating national ammonia emissions, we need better emissions measurements for beef cows in pasture. While their emissions factors are lower, the majority of beef cows at any given time are in pasture, so the emissions of feedlot and pasture beef cows are comparable.

Future Activities:

Work over the next year will focus on completing the poultry farm model, writing up a manuscript describing all the FEMs, and then comparing them against NAEMS data. With a no-cost extension, we will then develop an improved national emissions inventory, perform chemical transport modeling to evaluate it against ambient data, and assess implications for PM_2.5.

Journal Articles:

No journal articles submitted with this report: View all 3 publications for this project

Supplemental Keywords:

Acid deposition, particulate matter, ecosystem, agriculture;

Progress and Final Reports:

Original Abstract

2010 Progress Report

2011 Progress Report

2013 Progress Report

2014 Progress Report

Final Report