estimating emissions for each component of the overall production process. In this approach, the origin and ultimate destination of each major chemical element (nitrogen, carbon, sulfur and phosphorus) in the animals’ feed is modeled. This chapter also compares the mass balance approach with other approaches for estimating emissions at the individual farm level, within regulatory and management contexts. Chapter 6 describes the legal and programmatic structure for managing—by public oversight and mitigation—air emissions from AFOs.
The information in Chapters 1-6 then serves as the basis for defining both short-term (4-5 years) and long-term (20-30 years) research programs in Chapter 7. The short-term program is designed to provide defensible estimates of air emissions that could be used to support responsible regulation. The long-term program views the animal feeding system more broadly in order to decrease AFO inputs, increase recycling of manure, and eliminate or greatly decrease adverse effects on health and ecosystems. Both the short-term and the long-term research programs are ambitious and will require cooperation and participation by the full range of the research community. Finally, Chapter 8 summarizes the committee’s major conclusions and recommendations.