Characterization of Ammonia, Methane, and Nitrous Oxide Emissions from Concentrated Animal Feeding Operations in Northeastern Colorado

Abstract

Atmospheric emissions from animal husbandry are important to both air quality and climate, but are hard to characterize and quantify as they differ significantly due to management practices and livestock type, and they can vary substantially throughout diurnal and seasonal cycles. Using a new mobile laboratory, ammonia (NH), methane (CH), nitrous oxide (NO), and other trace gas emissions were measured from four concentrated animal feeding operations (CAFOs) in northeastern Colorado. Two dairies, a beef cattle feedlot, and a sheep feedlot were chosen for repeated diurnal and seasonal measurements. A consistent diurnal pattern in the NH to CH enhancement ratio is clearly observed, with midday enhancement ratios approximately four times greater than nighttime values. This diurnal pattern is similar, with slight variations in magnitude, at the four CAFOs and across seasons. The average NH to CH enhancement ratio from all seasons and CAFOs studied is 0.17 (+0.13/-0.08) mol/mol, in agreement with statewide inventory averages and previous literature. Enhancement ratios for NH to NO and NO to CH are also reported. The enhancement ratios can be used as a source signature to distinguish feedlot emissions from other NH and CH sources, such as fertilizer application and fossil fuel development, and the large diurnal variability is important for refining inventories, models, and emission estimates.

Emissions of volatile organic compounds (VOCs) from concentrated animal feeding operations (CAFOs): chemical compositions and separation of sources

“…Six different CAFOs were studied, including two dairy farms, two beef feed yards, one sheep feed yard and one egg-laying chicken farm (Table S1 in the Supplement). Among the six CAFOs, emissions of NH 3 , N 2 O and CH 4 in four facilities (the two dairy farms, one beef cattle feed yard and the sheep feed yard) have been measured previously using an instrumented van (Eilerman et al, 2016). We added a new VOC instrument to the payload, and performed mobile measurements in wintertime (February, 2016) for the six CAFOs by sampling at their downwind flanks 1-2 times for each facility.…”

Separation of Methane Emissions From Agricultural and Natural Gas Sources in the Colorado Front Range

“…A few other studies that have apportioned (Peischl et al, 2018;Petron et al, 2014;Townsend-Small et al, 2016) or quantified (Eilerman et al, 2016;Fried et al, 2015;Gilman, 2017;Tzompa-Sosa et al, 2017;Yuan et al, 2017) CH 4 in the DJB study area exist, but none have attempted to source apportion CH 4 based on excess columns. These results can be used to assess how the concept of excess columns compares with results based on in situ observations.…”

Observations of VOC emissions and photochemical products over US oil- and gas-producing regions using high-resolution H<sub>3</sub>O<sup>+</sup> CIMS (PTR-ToF-MS)

“…4), although there was higher variability in organic acids and formaldehyde. The highest relative abundances of organic acids were observed in the DenverJulesburg Basin and are likely due to primary emissions from concentrated animal feeding operations and not photochemistry (Eilerman et al, 2016;Yuan et al, 2017). Figure 4 compares the distribution of oxygenates to that measured during the Uintah Basin Winter Ozone Study (UB-WOS) 2013 campaign (Utah Division of Air Quality, 2014), the SENEX and CalNex flights, and the CalNex ground site in Los Angeles (Veres et al, 2011;Warneke et al, 2013).…”