Abstract. Air emissions from animal feeding operation (AFO) facilities have been of increasing concern. While the EPA was pressured to put more stringent regulations on the AFO industry, there was an absence of suitable emission data to support regulatory decisions for different AFOs due to limitations of past studies and the absence of standard measurement protocols that link an emission rate to the different activities responsible for the emissions. In 2005, the EPA announced the AFO Air Quality Compliance Agreement, under which a two-year National Air Emissions Monitoring Study (NAEMS) was initiated. The NAEMS Southeast Layer Site was designed to collect baseline air emissions from high-rise tunnel-ventilated layer houses. The target emissions at this site were ammonia (NH 3 ), hydrogen sulfide (H 2 S), carbon dioxide (CO 2 ), volatile organic compounds (VOCs), and particulate matter (PM), including PM 2.5 , PM 10 , and total suspended particulate (TSP). In addition, operational and environmental variables (e.g., animal activity, room temperature and relative humidity (RH), house ventilation rate, ambient temperature and RH, wind speed and direction, and solar radiation) were monitored to address their impacts on the emissions. Information about house inventory and major farm management activities was also collected. This article documents site characteristics and monitoring methods for the NAEMS at the Southeast Layer Site. Baseline emissions of PM and gaseous pollutants, house ventilation rates, and apparent impacts of farm management activities are reported in parts II through VI of this series.