On-Farm Measurements of Methane and Select Carbonyl Emission Factors for Dairy Cattle Teresa Cassel, Robert Flocchini, Peter Green, Richard Higashi University of California, Davis with Barry Goodrich, Matt Beene, Charlie Krauter California State University, Fresno
Purpose • Violation of NAAQS for ozone in CA Ø Permitting of Ag based on VOC emission ØNeed for better VOC emission factors • Multiple aspects to achieving goal • Emission rate modeling • Consideration of biogenic source variability • Quantification of VOC as defined by EPA
Volatile Organic Compounds “…any compound of carbon, excluding CO, CO 2, CO 3 H 2, metallic carbides or carbonates, and NH 4+CO 3 -, which participates in atmospheric photochemical reactions. This includes. [all]… other than the following, which have … negligible photochemical reactivity: ” Jenkin and Hayman, 1999. (40 CFR Part 51 Section 51. 100 (s)) U. S. EPA definition of VOC
VOC Collection and Recovery Strategies Increasing MIR TO-15, etc. SCAQMD 25. 3 DNPH Speciation TOC in water Limited speciation in can only Speciation OCls, esters, & alkanes phenols alcohols ethers aldehydes & ketones benzenes alkenes & alkynes acids nitrogenous
Carbonyl Speciation DNPH OCls, esters, alkanes aldehydes & ketones OFF-THE-SHELF: inexpensive, long shelf life, well defined for ambient air measurement. OPTIMIZATION: experience interpreting published methods and miniaturizing applicable.
Carbonyl Speciation DNPH STANDARD • • Acetaldehyde Acetone Acrolein Benzaldehyde Butyraldehyde Crotonaldehyde Dimethylaldehyde • • Formaldehyde Hexaldehyde Isovaleraldehyde Propionaldehyde o-Tolualdehyde m-Tolualdehyde p-Tolualdehyde Valeraldehyde
Total Organic Carbon – SC 25. 3 Methane Ethane Non-Methane, Non. Ethane Organic Carbon CONTEXT: Developed for natural gas (clean) burning sources so impact of more labile constituents unknown. EXTERNAL ANALYSIS: No in-house control of analytical error. CARBON COUNTING: Requires estimate of molecular weight to compute air concentration.
Calibration Standards Sample Injection Loop Initially Forward Through Column Speciation Column Sample Then Back-Flushed Through Column Non-Methane Organics CO, CH 4, CO 2 Oxidation Catalyst H 2 Reduction Catalyst H 2 Flame Ionization Detector Combustion Air
Units Translation • Using data produced by “established” analytical lab, reverse engineer “correction factor”.
Lab Recovery experiment 5 min. and 1 hour samples from standard C 4 mixture diluted w/ N 2.
Predominant Wind Direction Sampling locations Free stall + Open lot Lagoon
Methane Emission Factors Study type Emission factor Authors Physiological 209 lbs head-1 yr-1 Crutzen et al. , 1986 Respiration chamber 207 lbs LU-1 yr-1 Kirchgessner et al. , 1991 Natural vent. , tracer gas 215 -314 lbs LU-1 yr-1 Seipelt et al. , 1999 Natural vent. , tracer gas 161 -201 lbs LU-1 yr-1 Jungbluth et al. , 2001 Nutrient Cycling in Agroecosystems 60: 133 -145, 2001 lbs head-1 yr-1 Corrals Lagoon 9/15/03 9/16/03 4/22/04 108 237 151 247 358 206 191 182
Carbonyl Emission Factors
Carbonyl Emission Factors
Upwind corrected Carbonyl concentrations
Upwind corrected Carbonyl concentrations
TNMHC Emission Factors
Conclusions • Modeling assumptions validated by CH 4 • Emission factors (per head) of monitored compounds lower for lagoons than corrals – All seasons, sites, and sampling methods – Should be summed to get facility-wide EFs • Monitored compounds not direct measure of ROG, as defined • Source specific compound list still needed
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