MADISON, WI, DECEMBER 8, 2008 Animal feeding operations are an important emission source of air pollutants including methane and carbon dioxideknown greenhouse gases. Recent inventories suggest that animal manure makes a significant contribution to global methane emissions. As a consequence, greenhouse gas emissions can potentially become a limiting factor in the development and sustainability of animal production and technologies are needed to mitigate pollutant gas emissions. Oil spray has been used as a mitigation technique to reduce pollution from animal buildings. However, little is known about its effect on greenhouse gas emissions.
Scientists at Purdue University and the University of Missouri have investigated oil spray on air pollutant emissions from pig barns in northern Missouri. Specifically, they studied the quantity and characteristics of methane and carbon dioxide emissions from two commercial pig finishing barns and tested three oil spray techniquesvegetable oil sprinkling, essential oil misting, and misting of essential oil with waterto reduce these emissions. Results from the study were published in the November-December issue of Journal of Environmental Quality.
The study revealed average emissions of 32.5 g methane and 15.8 g carbon dioxide per day per animal unit (500 kg animal live weight) from the two barns. Treatments of oil sprinkling, misting of essential oils, and misting of essential oils with water reduced the average emissions of methane by 20% and of carbon dioxide by 19%. Barn methane and carbon dioxide concentrations and emission rates were affected by diel and seasonal fluctuations of ambient temperature. Methane was produced from decomposing manure and released from recycled lagoon effluent during barn gutter flushing. Carbon dioxide was produced from pig exhalation, manure decomposition, and combustion heaters and was also released from recycled lagoon effluent. The flushing lagoon effluent was resp
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American Society of Agronomy