Submitted to: International Symposium on Air Quality and Waste Management for Agriculture
Publication Type: Abstract Only
Publication Acceptance Date: September 16, 2010
Publication Date: September 16, 2010
Citation: Moore, K., Reese, E., Martin, R., Marchant, C., Wojcik, M., Going, C., Pfeiffer, R.L., Prueger, J.H., Hatfield, J.L. 2010. Preliminary ammonia measurements and emission calculation results from a California dairy [abstract]. International Symposium on Air Quality and Waste Management for Agriculture, Sept. 13-16, 2010, Dallas, TX. CD-ROM.
Gaseous ammonia (NH3) is an important basic chemical species in the atmosphere, most notably for its combination with nitrous and sulfuric oxides to form fine particles, which negatively impact air quality and human health. The agricultural sector is estimated to be the largest source of US NH3 emissions, largely due to biological degradation of manure. A one week field campaign was carried out in California's San Joaquin Valley to quantify NH3 and particulate matter emissions. This presentation will focus on the preliminary results of the NH3 measurements and emissions calculations, while a companion study will present preliminary results for particulate matter. The dairy milked about 950 cows with a total animal count of 1,885. Milking cows were housed in combination free stall/open lot pens, while all others were housed in open lot pens. Free stall lanes were flushed daily to remove manure; flushing water was sent to a solids separator basin then to a lagoon. Open lot pens were scraped once per week and stored in piles within each pen. Ammonia concentrations were measured using passive filters and open path infrared spectroscopy (FTS). Twenty-five Ogawa passive samplers were deployed around the dairy for thirteen 12-hr sample periods. Two FTS units were employed, one nominally upwind and nominally one downwind, and ran continuously throughout the study. The upwind FTS was a stationary system, while the downwind instrument was a scanning system with six retroreflectors at different distances and elevations along the edge of the dairy. Comparison of passive and FTS measured concentrations showed good results downwind of pens, with greater differences found downwind of the lagoon, separator basin, and pens. Emission rates based on passive sampler measurements were calculated using inverse modeling with ISCST3 and AERMOD. Emission rates from the FTS data were calculated using both inverse modeling with ISCST3 and AERMOD and vertical radial plume mapping.