摘要：Federal policy on manure management has focused on water-quality protection. However, animal agriculture is an important source of ammonia-nitrogen and other air emissions, increasing attention on air-quality concerns. Policies to address air emissions would influence both the costs of meeting water-quality objectives and environmental tradeoffs. We consider hypothetical policies at a regional level.
关键词：manure management;confined animals;water quality;air quality;regional optimization;Chesapeake Bay
