AIR EMISSIONS From Animal Feeding Operations

Current Knowledge, Future Needs

Ad Hoc Committee on Air Emissions from Animal Feeding Operations

Committee on Animal Nutrition

Board on Agriculture and Natural Resources

Board on Environmental Studies and Toxicology

Division on Earth and Life Studies

NATIONAL RESEARCH COUNCIL OF THE NATIONAL ACADEMIES

THE NATIONAL ACADEMIES PRESS
Washington, D.C. www.nap.edu



The National Academies | 500 Fifth St. N.W. | Washington, D.C. 20001
Copyright © National Academy of Sciences. All rights reserved.
Terms of Use and Privacy Statement



Below are the first 10 and last 10 pages of uncorrected machine-read text (when available) of this chapter, followed by the top 30 algorithmically extracted key phrases from the chapter as a whole.
Intended to provide our own search engines and external engines with highly rich, chapter-representative searchable text on the opening pages of each chapter. Because it is UNCORRECTED material, please consider the following text as a useful but insufficient proxy for the authoritative book pages.

Do not use for reproduction, copying, pasting, or reading; exclusively for search engines.

OCR for page R1
Air Emissions from Animal Feeding Operations: Current Knowledge, Future Needs AIR EMISSIONS From Animal Feeding Operations Current Knowledge, Future Needs Ad Hoc Committee on Air Emissions from Animal Feeding Operations Committee on Animal Nutrition Board on Agriculture and Natural Resources Board on Environmental Studies and Toxicology Division on Earth and Life Studies NATIONAL RESEARCH COUNCIL OF THE NATIONAL ACADEMIES THE NATIONAL ACADEMIES PRESS Washington, D.C. www.nap.edu

OCR for page R1
Air Emissions from Animal Feeding Operations: Current Knowledge, Future Needs THE NATIONAL ACADEMIES PRESS 500 Fifth Street, N.W. Washington, DC 20001 NOTICE: The project that is the subject of this report was approved by the Governing Board of the National Research Council, whose members are drawn from the councils of the National Academy of Sciences, the National Academy of Engineering, and the Institute of Medicine. The members of the committee responsible for the report were chosen for their special competences and with regard for appropriate balance. This study was supported by Contract No. 68-D-01-69 between the National Academy of Sciences and the U.S. Environmental Protection Agency and Grant No. 59-0790-2-106 between the National Academy of Sciences and the U.S. Department of Agriculture. Any opinions, findings, conclusions, or recommendations expressed in this publication are those of the author(s) and do not necessarily reflect the views of the organizations or agencies that provided support for the project. International Standard Book Number: 0-309-08705-8 Library of Congress Control Number: 200310401 Additional copies of this report are available from the National Academies Press, 500 Fifth Street, N.W., Lockbox 285, Washington, DC 20055; (800) 624-6242 or (202) 334-3313 (in the Washington metropolitan area); Internet, http://www.nap.edu Copyright 2003 by the National Academy of Sciences. All rights reserved. Printed in the United States of America

OCR for page R1
Air Emissions from Animal Feeding Operations: Current Knowledge, Future Needs THE NATIONAL ACADEMIES Advisers to the Nation on Science, Engineering, and Medicine The National Academy of Sciences is a private, nonprofit, self-perpetuating society of distinguished scholars engaged in scientific and engineering research, dedicated to the furtherance of science and technology and to their use for the general welfare. Upon the authority of the charter granted to it by the Congress in 1863, the Academy has a mandate that requires it to advise the federal government on scientific and technical matters. Dr. Bruce M. Alberts is president of the National Academy of Sciences. The National Academy of Engineering was established in 1964, under the charter of the National Academy of Sciences, as a parallel organization of outstanding engineers. It is autonomous in its administration and in the selection of its members, sharing with the National Academy of Sciences the responsibility for advising the federal government. The National Academy of Engineering also sponsors engineering programs aimed at meeting national needs, encourages education and research, and recognizes the superior achievements of engineers. Dr. Wm. A. Wulf is president of the National Academy of Engineering. The Institute of Medicine was established in 1970 by the National Academy of Sciences to secure the services of eminent members of appropriate professions in the examination of policy matters pertaining to the health of the public. The Institute acts under the responsib-ility given to the National Academy of Sciences by its congressional charter to be an adviser to the federal government and, upon its own initiative, to identify issues of medical care, research, and education. Dr. Harvey V. Fineberg is president of the Institute of Medicine. The National Research Council was organized by the National Academy of Sciences in 1916 to associate the broad community of science and technology with the Academy’s purposes of furthering knowledge and advising the federal government. Functioning in accordance with general policies determined by the Academy, the Council has become the principal operating agency of both the National Academy of Sciences and the National Academy of Engineering in providing services to the government, the public, and the scientific and engineering communities. The Council is administered jointly by both Academies and the Institute of Medicine. Dr. Bruce M. Alberts and Dr. Wm. A. Wulf are chair and vice chair, respectively, of the National Research Council. www.national-academies.org

OCR for page R1
Air Emissions from Animal Feeding Operations: Current Knowledge, Future Needs This page intentionally left blank.

OCR for page R1
Air Emissions from Animal Feeding Operations: Current Knowledge, Future Needs AD HOC COMMITTEE ON AIR EMISSIONS FROM ANIMAL FEEDING OPERATIONS PERRY R. HAGENSTEIN (Chair), Institute for Forest Analysis, Planning, and Policy, Wayland, Massachusetts ROBERT G. FLOCCHINI (Vice Chair), University of California, Davis, California JOHN C. BAILAR III, University of Chicago, Chicago, Illinois CANDIS CLAIBORN, Washington State University, Pullman, Washington RUSSELL R. DICKERSON, University of Maryland, College Park, Maryland JAMES N. GALLOWAY, University of Virginia, Charlottesville, Virginia MARGARET ROSSO GROSSMAN, University of Illinois at Urbana-Champaign, Urbana, Illinois PRASAD KASIBHATLA, Duke University, Durham, North Carolina RICHARD A. KOHN, University of Maryland, College Park, Maryland MICHAEL P. LACY, University of Georgia, Athens, Georgia CALVIN B. PARNELL, JR., Texas A&M University, College Station, Texas ROBBI H. PRITCHARD, South Dakota State University, Brookings, South Dakota WAYNE P. ROBARGE, North Carolina State University, Raleigh, North Carolina DANIEL A. WUBAH, James Madison University, Harrisonburg, Virginia KELLY D. ZERING, North Carolina State University, Raleigh, North Carolina RUIHONG ZHANG, University of California, Davis, California Consultant MICHAEL OPPENHEIMER, Princeton University, Princeton, New Jersey Staff JAMIE JONKER, Study Director CHAD TOLMAN, Program Officer TANJA PILZAK, Research Assistant JOE ESPARZA, Project Assistant STEPHANIE PADGHAM, Project Assistant BRYAN SHIPLEY, Project Assistant PETER RODGERS, Intern FLORENCE POILLON, Contract Editor

OCR for page R1
Air Emissions from Animal Feeding Operations: Current Knowledge, Future Needs COMMITTEE ON ANIMAL NUTRITION GARY L. CROMWELL (Chair), University of Kentucky, Lexington, Kentucky C. ROSELINA ANGEL, University of Maryland, College Park, Maryland JESSE P. GOFF, United States Department of Agriculture/Agricultural Research Service, Ames, Iowa RONALD W. HARDY, University of Idaho, Hagerman, Idaho KRISTEN A. JOHNSON, Washington State University, Pullman, Washington BRIAN W. MCBRIDE, University of Guelph, Guelph, Ontario, Canada KEITH E. RINEHART, Perdue Farms Incorporated, Salisbury, Maryland L. LEE SOUTHERN, Louisiana State University, Baton Rouge, Louisiana DONALD R. TOPLIFF, West Texas A&M University, Canyon, Texas Staff JAMIE JONKER, Program Officer JOE ESPARZA, Project Assistant

OCR for page R1
Air Emissions from Animal Feeding Operations: Current Knowledge, Future Needs BOARD ON AGRICULTURE AND NATURAL RESOURCES HARLEY W. MOON (Chair), Iowa State University, Ames, Iowa SANDRA BARTHOLMEY, Quaker Oats Company, Barrington, Illinois DEBORAH BLUM, University of Wisconsin, Madison, Wisconsin ROBERT B. FRIDLEY, University of California, Davis, California BARBARA GLENN, Federation of Animal Science Societies, Bethesda, Maryland LINDA GOLODNER, National Consumers League, Washington, D.C. W.R. (REG) GOMES, University of California, Oakland, California PERRY R. HAGENSTEIN, Institute for Forest Analysis, Planning, and Policy, Wayland, Massachusetts CALESTOUS JUMA, Harvard University, Cambridge, Massachusetts JANET C. KING, University of California, Davis, California WHITNEY MACMILLAN, Cargill, Incorporated, Minneapolis, Minnesota PAMELA A. MATSON, Stanford University, Stanford, California TERRY MEDLEY, DuPont Biosolutions Enterprise, Wilmington, Delaware ALICE PELL, Cornell University, Ithaca, New York SHARRON S. QUISENBERRY, Montana State University, Bozeman, Montana NANCY J. RACHMAN, Novigen Sciences, Incorporated, Washington, D.C. SONYA SALAMON, University of Illinois, Urbana-Champaign, Urbana, Illinois G. EDWARD SCHUH, University of Minnesota, Minneapolis, Minnesota BRIAN STASKAWICZ, University of California, Berkeley, California JACK WARD THOMAS, University of Montana, Missoula, Montana JAMES TUMLINSON, United States Department of Agriculture, Agricultural Research Service, Gainesville, Florida B.L. TURNER, Clark University, Worcester, Massachusetts Staff CHARLOTTE KIRK BAER, Director STEPHANIE PADGHAM, Senior Project Assistant

OCR for page R1
Air Emissions from Animal Feeding Operations: Current Knowledge, Future Needs BOARD ON ENVIRONMENTAL STUDIES AND TOXICOLOGY GORDON ORIANS (Chair), University of Washington, Seattle, Washington JOHN DOULL (Vice Chair), University of Kansas Medical Center, Kansas City, Missouri DAVID ALLEN, University of Texas, Austin, Texas THOMAS BURKE, Johns Hopkins University, Baltimore, Maryland JUDITH C. CHOW, Desert Research Institute, Reno, Nevada CHRISTOPHER B. FIELD, Carnegie Institute of Washington, Stanford, California WILLIAM H. GLAZE, University of North Carolina, Chapel Hill, North Carolina SHERRI W. GOODMAN, Center for Naval Analyses, Alexandria, Virginia DANIEL S. GREENBAUM, Health Effects Institute, Cambridge, Massachusetts ROGENE HENDERSON, Lovelace Respiratory Research Institute, Albuquerque, New Mexico CAROL HENRY, American Chemistry Council, Arlington, Virginia ROBERT HUGGETT, Michigan State University, East Lansing, Michigan BARRY L. JOHNSON, Emory University, Atlanta, Georgia JAMES H. JOHNSON, Howard University, Washington, D.C. JAMES A. MACMAHON, Utah State University, Logan, Utah PATRICK V. O’BRIEN, Chevron Research and Technology, Richmond, California DOROTHY E. PATTON, International Life Sciences Institute, Washington, D.C. ANN POWERS, Pace University School of Law, White Plains, New York LOUISE M. RYAN, Harvard University, Boston, Massachusetts JONATHAN M. SAMET, Johns Hopkins University, Baltimore, Maryland KIRK SMITH, University of California, Berkeley, California LISA SPEER, Natural Resources Defense Council, New York, New York G. DAVID TILMAN, University of Minnesota, St. Paul, Minnesota CHRIS G. WHIPPLE, Environ Incorporated, Emeryville, California LAUREN A. ZEISE, California Environmental Protection Agency, Oakland, California Staff JAMES J. REISA, Director RAY WASSEL, Program Director MIMI ANDERSON, Senior Project Assistant

OCR for page R1
Air Emissions from Animal Feeding Operations: Current Knowledge, Future Needs Acknowledgments This report represents the integrated efforts of many individuals. The committee thanks all those who shared their insights and knowledge to bring the document to fruition. We also thank all those who provided information at our public meetings and who participated in our public sessions. During the course of its deliberations, the committee sought assistance from several people who gave generously of their time to provide advice and information that were considered in its deliberations. Special thanks are due the following: JOHN ALBERTSON, Duke University, Durham, North Carolina C. RICHARD AMERMAN, United States Department of Agriculture, Beltsville, Maryland BOB BOTTCHER (Deceased), North Carolina State University, Raleigh, North Carolina GARTH BOYD, Murphy-Brown LLC, Warsaw, North Carolina LEONARD BULL, Animal and Poultry Waste Center, Raleigh, North Carolina TOM CHRISTENSEN, United States Department of Agriculture, Beltsville, Maryland JOHN D. CRENSHAW, Eastern Research Group, Research Triangle Park, North Carolina TONY DELANY, National Center for Atmospheric Research, Boulder, Colorado RALPH ERNST, University of California, Davis, California MICHAEL FITZGIBBON, California Environmental Protection Agency, Sacramento, California

OCR for page R1
Air Emissions from Animal Feeding Operations: Current Knowledge, Future Needs ERIC GONDER, Goldsboro Milling Company, Goldsboro, North Carolina ALEX GUENTHER, National Center for Atmospheric Research, Boulder, Colorado ELLEN HANKES, Environmental Management Solutions, LLC, Des Moines, Iowa LOWRY HARPER, United States Department of Agriculture, Watkinsville, Georgia BRUCE HARRIS, United States Environmental Protection Agency, Research Triangle Park, North Carolina TOM HORST, National Center for Atmospheric Research, Boulder, Colorado DONALD JOHNSON, Colorado State University, Fort Collins, Colorado RENEE JOHNSON, United States Environmental Protection Agency, Washington, D.C. RAY KNIGHTON, United States Department of Agriculture, Beltsville, Maryland GARY MARGHEIM, United States Department of Agriculture, Washington, D.C. JOHN H. MARTIN, JR., Hall Associates, Dover, Delaware F. ROBERT MCGREGOR, Water and Waste Engineering, Incorporated, Denver, Colorado DEANNE MEYER, University of California, Davis, California BOB MOSER, ConAgra Beef, Kersey, Colorado DANIEL MURPHY, National Oceanic and Atmospheric Administration, Boulder, Colorado BRENT NEWELL, California Rural Legal Assistance Foundation, Sacramento, California ROY OOMMEN, Eastern Research Group, Research Triangle Park, North Carolina JOSEPH RUDEK, Environmental Defense, Raleigh, North Carolina GARY SAUNDERS, North Carolina Department of Environment and Natural Resources, Raleigh, North Carolina SUSAN SCHIFFMAN, Duke University, Durham, North Carolina SALLY SHAVER, United States Environmental Protection Agency, Research Triangle Park, North Carolina MARK SOBSEY, University of North Carolina, Chapel Hill, North Carolina JOHN SWEETEN, Texas A&M University, Amarillo, Texas DAVID TOWNSEND, Premium Standard Farms Research and Development, Kansas City, Missouri RANDY WAITE, United States Environmental Protection Agency, Research Triangle Park, North Carolina JOHN T. WALKER, United States Environmental Protection Agency, Research Triangle Park, North Carolina

OCR for page R1
Air Emissions from Animal Feeding Operations: Current Knowledge, Future Needs The committee is grateful to members of the National Research Council staff who worked diligently to maintain progress and quality in its work. The report has been reviewed in draft form by individuals chosen for their diverse perspectives and technical expertise, in accordance with procedures approved by the National Research Council’s Report Review Committee. The purpose of this independent review is to provide candid and critical comments that will assist the institution in making its published report as sound as possible and to ensure that the report meets institutional standards for objectivity, evidence, and responsiveness to the study charge. The review comments and draft manuscript remain confidential to protect the integrity of the deliberative process. We wish to thank the following individuals for their review of this report: DAVID T. ALLEN, The University of Texas, Austin, Texas WILLIAM BATTYE, EC/R Incorporated, Chapel Hill, North Carolina VAN C. BOWERSOX, Illinois State Water Survey, Champaign, Illinois ELLIS B. COWLING, North Carolina State University, Raleigh, North Carolina DANNY G. FOX, Cornell University, Ithaca, New York ROGENE HENDERSON, National Environmental Respiratory Center, Albuquerque, New Mexico KRISTEN A. JOHNSON, Washington State University, Pullman, Washington DEANNE MEYER, University of California, Davis, California GEORGE MOUNT, Washington State University, Pullman, Washington ROGER A. PIELKE, Colorado State University, Fort Collins, Colorado WENDY J. POWERS, Iowa State University, Ames, Iowa JOSEPH RUDEK, Environmental Defense, Raleigh, North Carolina MARGOT RUDSTROM, University of Minnesota, Morris, Minnesota Although the reviewers listed above have provided many constructive comments and suggestions, they were not asked to endorse the conclusions or recommendations, nor did they see the final draft of the report before its release. The review of this report was overseen by Bob Frosch, Harvard University, Cambridge, Massachusetts, and Albert Heber, Purdue University, West Lafayette, Indiana. Appointed by the National Research Council, they were responsible for making certain that an independent examination of this report was carried out in accordance with institutional procedures and that all review comments were carefully considered. Responsibility for the final content of this report rests entirely with the authoring committee and the institution.

OCR for page R1
Air Emissions from Animal Feeding Operations: Current Knowledge, Future Needs This page intentionally left blank.

OCR for page R1
Air Emissions from Animal Feeding Operations: Current Knowledge, Future Needs Preface The increasing concentration of food production—meat, eggs, milk—from animals in very large feeding operations has focused public attention on associated environmental issues. These include the effects of air emissions, especially those that come from the large quantities of manure produced by the animals. While concern has mounted, research to provide the basic information needed for effective regulation and management of these emissions has languished. This report, prepared by a committee appointed by the National Research Council, proposes two major ways to improve information and the nation’s ability to deal with the effects of these emissions. One is to change the way in which the rates and fate of air emissions are estimated and tracked. The proposal would replace the current “emission factor” approach with a “process-based modeling” approach. This can, if pursued vigorously, enhance both regulation and management of air emissions in the next two to five years. The other proposal is for a research program that views air emissions as one part of the overall system of producing food from animal feeding operations with the goal of eliminating the release of unwanted emissions into the environment. This “systems-based” proposal, if also pursued vigorously, would lead to fundamentally changed practices at animal feeding operations. The net result would be continued food production with greatly reduced adverse environmental effects. The 16-person committee that produced this report and an earlier interim report worked hard and well. The time allowed for producing the two reports was short, but committee members found time in their schedules to address what each sees as an important issue that needs attention. The project staff at the Board on Agriculture and Natural Resources, Jamie Jonker, study director, and Tanja Pilzak, research assistant, and the Board on Environmental Studies and Toxicol-

OCR for page R1
Air Emissions from Animal Feeding Operations: Current Knowledge, Future Needs ogy, Chad Tolman, program officer, deserve special thanks for their long hours of very effective work. An informal editorial subcommittee that handled reviewer comments and provided enormous help throughout also deserves special thanks. The members were Chair Perry Hagenstein, Vice Chair Bob Flocchini, Jim Galloway, Rick Kohn, and, for the interim report, Wayne Robarge. Perry Hagenstein, Chair Robert Flocchini, Vice Chair Committee on Air Emissions from Animal Feeding Operations

OCR for page R1
Air Emissions from Animal Feeding Operations: Current Knowledge, Future Needs Contents     EXECUTIVE SUMMARY   1 1   INTRODUCTION   14      Basis for this Report,   14      Concerns with Air Emissions,   15      The Interim Report,   15      Scale and Impact of Emissions from Animal Feeding Operations,   17      Policy Context,   22      Science Context,   23      Challenges,   24      Structure of the Final Report,   24 2   LIVESTOCK AGRICULTURE AND ANIMAL FEEDING OPERATIONS   26      Introduction,   26      Livestock Agriculture,   26      Economics of Livestock Agriculture,   27      Summary,   49 3   AIR EMISSIONS   50      Introduction,   50      Species of Interest,   50      Factors Affecting Air Emissions,   57      Dispersion of Air Emissions—Meteorological considerations,   63

OCR for page R1
Air Emissions from Animal Feeding Operations: Current Knowledge, Future Needs      Potential Impacts,   65      Summary,   73 4   MEASURING EMISSIONS   74      Introduction,   74      Calibration, Sampling, and Concentration Measurements,   76      Measuring Concentrations and Compositions,   78      Measuring Emissions,   87      Air Quality Monitoring,   96      Summary,   96 5   APPROACHES FOR ESTIMATING EMISSIONS   98      Introduction,   98      Emission Factor Estimates,   99      Multiple Regression Approach to Develop Emission Factors,   102      Process-Based Modeling Approach,   103      Summary,   128 6   GOVERNMENT REGULATIONS AND PROGRAMS   129      Introduction,   129      Clean Air Act,   131      CERCLA and EPCRA,   138      Clean Water Act,   140      Coastal Zone Management Act,   145      The Role of USDA,   146      Summary,   151 7   IMPROVING KNOWLEDGE AND PRACTICES   152      Introduction,   152      Short-Term Research,   154      Long-Term Research,   161      Summary,   168 8   CONCLUSIONS   169      Setting Priorities,   170      Estimating Air Emissions,   171      Systems Approach,   172      Research Needs,   173     REFERENCES   176

OCR for page R1
Air Emissions from Animal Feeding Operations: Current Knowledge, Future Needs     APPENDIXES   195     A  Statement of Task   197     B  Acronyms and Glossary   198     C  Bioaerosols   205     D  Nitrogen and Sulfur Contents of Animal Products and Live Animals—Sample Excretion Predictions   207     E  Animal Units   214     F  Ammonia Emissions from Manure Storage   217     G  Regulatory Action Levels by Selected Atmospheric Pollutant   222     H  Regulatory Action Levels by Regulatory Requirement and Action Status   224     I  Emission Factors for a Feed Mill or Grain Elevator   226     J  Public Meeting Agendas   228     K  Geographic Distribution of Livestock and Poultry Production in the United States for 1997   234     L  Emission Factors in Published Literature   241     ABOUT THE AUTHORS   255     BOARD ON AGRICULTURE AND NATURAL RESOURCES PUBLICATIONS   261

OCR for page R1
Air Emissions from Animal Feeding Operations: Current Knowledge, Future Needs This page intentionally left blank.

OCR for page R1
Air Emissions from Animal Feeding Operations: Current Knowledge, Future Needs Tables, Figures, and Boxes TABLES ES-1   Committee’s Scientific Evaluation of the Potential Importance of AFO Emissions at Different Spatial Scales,   5 1-1   Substances in AFO Emissions That the Committee Was Tasked to Address and Their Respective Classifications,   16 2-1   U.S. Per Capita Consumption of Meat, Dairy Products, and Eggs in 2001,   28 2-2   Leading Livestock Production States by Animal Sector,   33 2-3   Number of Animals per EPA Animal Unit,   34 3-1   Annual Anthropogenic Emissions of Constituents of Concern, 1990,   51 3-2   Measured Emission Fluxes of Ammonia from Primary Anaerobic Swine Lagoons as a Function of Measurement Method and Period,   58 3-3   Relationship of Management Practices on 4 percent Fat Corrected Milk and Nitrogen Utilization Efficiency,   62 3-4   Typical Lifetimes in the Planetary Boundary Layer for Pollutants Emitted from Animal Feeding Operations,   64 3-5   Short-Term Exposure to Ammonia,   66 3-6   Long-Term Exposure to Ammonia,   67 3-7   Committee’s Scientific Evaluation of the Potential Importance of AFO Emissions at Different Spatial Scales,   72

OCR for page R1
Air Emissions from Animal Feeding Operations: Current Knowledge, Future Needs 5-1   Maximum Methane Production Potential of Animal Manure as Affected by Different Diets,   120 6-1   Overview of Federal Statutes and Their Provisions,   131 8-1   Committee’s Scientific Evaluation of the Potential Importance of AFO Emissions at Different Spatial Scales,   170 D-1   Typical Nitrogen and Sulfur Content of Animal Products,   208 D-2   Nitrogen and Sulfur Content of Animal Live Weight Gain,   210 D-3   Sample Excretion Predictions Directly from Different Types of Food Production Animals,   211 L-1   Odor Emission Rates from Animal Housing as Reported in the Literature,   254 FIGURES 1-1   Mass flows (teragrams of nitrogen per year) of new reactive nitrogen in U.S. agriculture in 1997,   21 3-1   Relative excretion rate of nitrogen versus day in the life cycle of a grow-finish hog at a commercial swine production facility in the southeastern United States,   60 3-2   Nitrogen cascade,   70 4-1   Ammonia concentrations (averaged over a 68-m path) measured near a dairy wastewater lagoon,   76 4-2   Schematic illustrating the essential elements associated with measurement of emissions from agricultural sources that can be characterized as low-level point sources such as cotton gins, feed mills, grain elevators, and oil mills,   87 4-3   Schematic illustrating the essential elements associated with measurement of emissions from agricultural sources that can be characterized as ground-level area sources such as dairies, cattle feed yards, field operation, and agricultural burning,   88 4-4   Schematic illustrating the essential element associated with regulation of emissions from agricultural sources that can be characterized as low-level point sources such as tunnel-ventilated AFOs,   89 4-5   Schematic illustrating the essential element associated with regulation of emissions from agricultural sources that can be characterized as low-level point sources such as naturally ventilated AFOs,   91

OCR for page R1
Air Emissions from Animal Feeding Operations: Current Knowledge, Future Needs 5-1   A schematic representation of a process-based model of emissions from an animal production system,   104 7-1   Animal feeding operations system (animal plus associated cropland),   162 D-1   Change in body protein percentage as cattle mature,   209 K-1   Distribution of milk cows in 1997,   235 K-2   Distribution of cattle fattened on grain and concentrates and sold in 1997,   236 K-3   Distribution of hogs and pigs sold in 1997,   237 K-4   Distribution of broilers and other meat-type chickens sold in 1997,   238 K-5   Distribution of turkeys sold in 1997,   239 K-6   Distribution of layers and pullets, 13 weeks old and older in 1997,   240 BOXES ES-1   Findings from the Interim Report,   3 1-1   Findings and Discussion from the Interim Report,   18 2-1   Poultry Production in the United States,   33 5-1   Sample Calculations of Whole-Farm Nitrogen Balance,   116

OCR for page R1
Air Emissions from Animal Feeding Operations: Current Knowledge, Future Needs This page intentionally left blank.