TY - JOUR AU - Mitloehner, Frank M. AU - Sun, Huawei AU - Karlik, John F. TI - Direct measurements improve estimates of dairy greenhouse-gas emissions JF - California Agriculture JO - Calif Agr Y1 - 2009/04/01 VL - 63 IS - 2 SP - 79 EP - 83 PB - University of California Agriculture and Nature Resources SN - 0008-0845 UR - http://dx.doi.org/10.3733/ca.v063n02p79 L3 - 10.3733/ca.v063n02p79 AB - California is the leading dairy state in the United States, producing 21% of the nation's milk supply. The state's highest concentration of dairies is in the San Joaquin Valley, a region that violates federal limits for ozone and particulate matter in the air. Volatile organic compounds and greenhouse-gas emissions from dairies contribute to regional air-quality challenges and also play a role in climate change. We used an environmentally controlled chamber to monitor greenhouse-gas emissions from dairy cattle over a 24-hour period, and we measured the emissions from waste slurry using a simulated dairy waste lagoon. This research helps to quantify emissions from dairies in California and suggests possible approaches for their mitigation.