|Follett, Ronald - Ron|
Submitted to: Western Dairy Management Conference
Publication Type: Proceedings
Publication Acceptance Date: 4/1/2006
Publication Date: 6/1/2006
Citation: Marcillac, N.M., Hanan, N.P., Lee, T., Follett, R.F., Stanton, T.L., Collett, J.L., Johnson, D.E. 2006. Air emissions from dairy CAFO's: multi-scale measurements and process based modeling. Western Dairy Management Conference. Interpretive Summary: Preliminary results show that the concentration of each compound varies spatially with location downwind of the farm and height , as well as seasonally. To date, not enough data has been collected to show any significant diurnal variation in emissions.
Technical Abstract: Emission of ammonia from animal agriculture has been heavily studied lately due to its large output from CAFO’s and rapid reaction with strong atmospheric acids (nitric and sulfuric acid) to produce ammonium salts, also know as PM2.5’s. PM2.5 has been linked to reduced atmospheric visibility and negative health effects. In addition to its atmospheric reactions, ammonia can be dry deposited near its source contributing to soil acidification and decreased dissolved oxygen levels in streams and lakes. Due to its short lifetime (24 h to ~10d), it is generally regarded as a local problem, rather than a global one. The emission of ammonia is greatly effected by management techniques and season. Gases like methane, nitrous oxide and carbon dioxide are regarded as global problems due to their long lifetimes (>100yr), low volatility, and contribution to global warming. Methane sources from CAFO’s have been well characterized for cattle, but other sources such as anaerobic lagoons, compost, and others are variable with season and management. The exact contribution of dairies to the emission of nitrous oxide is uncertain. It has been estimated that animal wastes and fertilizer account for about 8% of the global emissions, but other on farm practices are not estimated in the global budget. Methane, nitrous oxide, and carbon dioxide pose difficulties in modeling due to variations in management and ambient conditions, so direct measurement of there emissions is necessary for accurate estimates.