Progress 07/15/02 to 07/14/05
Outputs
This project seeks to improve current understanding of air emission factors for agricultural PM and ammonia, and provide tropospheric ozone (tO3) precursor emission factors for use in the California Air Resources Board State Implementation Planning process. The tasks undertaken to meet these objectives were: 1. Compile PM10 and ammonia emission factors for agricultural sources. 2. Measure concentrations of volatile organic compounds (VOC) relevant to tO3 formation upwind and downwind of agricultural sources, specifically dairy lagoons. 3. Compute emission factors for VOC relevant to tO3 formation from dairies. PM10 and precursors: Ammonia and PM10 emission factors for various cropping systems, agricultural industries, and livestock operations have been measured in programs conducted independently in recent years. The efforts of these programs have culminated in five distinct products. Measurements of ammonia emission factors from dairies using the upwind to downwind
method were published as a pair of papers in the Journal of Air and Waste Management. Work has also progressed to develop complementary techniques using isolation flux chambers. Measurements of primary PM10 emission factors for cotton and wheat harvesting and tillage made between 1996 and 2000 were compiled and presented as an on-line published paper; PM10 emission factors for harvest and tillage of row crops and in a poster presentation at EPA Emission Inventories Applying New Technologies conference in San Diego in 2003. This project has been augmented to bring together the measurement, analysis, and computational expertise developed to focus on PM10 emission factors for almond harvesting. In the course of refining that emission factor, the project has produced a detailed description of a measurement and analysis method for PM10 emission factor development for on-field agricultural sources, complete with precision and cost estimates. Finally, investigation into water application as
a PM10 mitigation technique for open lots on dairies involved measurement of both ammonia and PM10 emission rates on a local dairy. Evidence that, while PM10 emission factors are reduced with water application, this strategy initially enhances ammonia emission were presented in the form of a paper in published proceedings; Effects of sprinkling of pens to reduce particulate emissions and subsequent effects on ammonia emissions from open lot dairy facilities and as a poster at the Gaseous and odour emissions from animal production facilities conference in Horsens, Denmark, 1-4 June 2003. Measured concentrations of partial VOC were used to estimate emission factors for those compounds using the Industrial Source Complex (ISCST3) model. This dispersion model uses an estimate of emission rates for the specific region of the dairy effecting the concentration at the measurement location and the meteorological data to compute the air concentration at that location. The estimate of emission
rate can then be refined until the predicted concentration matches the measured concentration. This is repeated for multiple simultaneous measurement locations to build an emission rate for the facility.
Impacts
This project has contributed to the body of PM-10 and PM-10 precursors (ammonia) emission factors currently in use for on-field agriculture in California. The work has produced published documentation of several methods for estimating ammonia emission factors for animal production facilities in the western U.S. The project also describes PM-10 sampling procedures that can be used to produce data for the computation of PM-10 emission rates from operations on orchard crops and provides guidance in the application of publicly available software for same. Investigations into the contribution of agricultural sources to ozone precursors have been initiated through this project.
Publications
- Ammonia flux from open-lot dairies: Development of measurement methodology and emission factors. 2004. Teresa Cassel, Lowell Ashbaugh, Deanne Meyer, Robert Flocchini. J. Air & Waste Manage. Assoc. 55:816-825. Ammonia flux from open-lot dairies: direct measurements and estimation by nitrogen intake. 2004. Teresa Cassel, Deanne Meyer, Lowell Ashbaugh, Robert Flocchini. J. Air & Waste Manage. Assoc. 55:826-833.
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Progress 01/01/04 to 12/31/04
Outputs
Objective 1 activities focus on investigation of a suspected systematic bias in the measurement of PM-10 concentrations and, therefore, PM-10 emissions from agricultural activities of all types. Sampling protocols utilizing two different technologies for isolating PM-10 from total suspended particulate matter (TSP) are in use in the field and in the lab by both the University of California, Davis (UCD) and Texas A&M (TAMU) research groups. In the current reporting period UCD has built TSP samplers and deployed them side-by-side with PM-10 samplers downwind of almond harvesting operations. Analysis of particle size distributions of TSP samples by TAMU researchers has indicated a dependence of the bias in PM-10 measurement on PM plume characteristics influenced by proximity relationships between the harvester, the trees, and the samplers. This phenomenon is being further explored using data collected during the 2004 harvest season in 12 separate testing events conducted
on orchards with each of two tree row arrangements (north-south and east-west). We are also exploring the applicability of dispersion modeling to emission factor development in large area sources with elevated points of emission using orchards as the test case. Sensitivity analysis of the model applications are progressing with respect to sampler and meteorological instruments placement, sampling duration, and row configuration. Agreement between model results for samples collected at different locations downwind of the operation as well as a consistent ability to quantify differences in PM-10 emissions produced by changes in harvest implement are two end-points being used to assess model sufficiency. Data collected in 2004 indicate sensitivity of the model to placement of meteorological equipment. Preliminary analysis shows consistent quantification of both absolute values and relative differences of PM-10 emission factors for two types of almond wind-row conditioners working on the
same orchard. These efforts will result in the development of an industry specific procedure for measurement of PM-10 emission rates to help almond growers assess PM-10 mitigation techniques. Work on Objectives 2 and 3 has been incorporated into the subsequently funded project; proposal number 2003-06124.
Impacts
This project assesses the impact of sampler design on PM-10 emission factors currently in use for on-field agriculture in California. If PM-10 concentrations are found to have been over-estimated relative to other sources in the PM-10 emission inventory, current emission factors may require revision. The project also describes PM-10 sampling procedures that can be used to produce data for the computation of PM-10 emission rates from operations on orchard crops and provides guidance in the application of publicly available software for same.
Publications
- No publications reported this period
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Progress 01/01/03 to 12/31/03
Outputs
Objective 1 activities focus on investigation of a suspected systematic bias in the measurement of PM-10 concentrations and, therefore, PM-10 emissions from agricultural activities of all types. Sampling protocols utilizing two different technologies for isolating PM-10 from total suspended particulate matter (TSP) are in use in the field and in the lab by both the University of California, Davis (UCD) and Texas A&M (TAMU) research groups. A field study employing both sampling protocols in several almond orchards in California demonstrated a dependence of the bias in measurement on soil textural properties of the field site. The two groups are also exploring the applicability of dispersion modeling to emission factor development in large area sources with elevated points of emission using orchards as the test case. These efforts will result in the development of an industry specific procedure for measurement of PM-10 emission rates to help almond growers assess PM-10
mitigation techniques. Work on Objectives 2 and 3 is progressing on three fronts; measurement of carbonyl concentrations, measurement of Total Non-Methane Non-Ethane Organic Carbon (TNMNEOC) concentrations, and development of methods for the measurement of Reactive Organic Gases (ROG). Two field trials have been conducted in collaboration with CSU Fresno on commercials dairies in the San Joaquin Valley. Side-by-side sampling was conducted using conventional evacuated canisters, evacuated canisters with an ice water trap for the condensation of compounds not recoverable from the canisters, and adsorbent-based traps for the collection of a specific group of constituents (carbonyls) which are not quantifiable via the canister method. Analysis by liquid chromatography-mass spectrometry (LC-MS) of the carbonyl traps show increases in carbonyl concentrations downwind of dairy corrals, relative to upwind, but did not show similar consistent increases downwind of the dairy manure water
storage pond. Analysis of TNMNEOC concentrations show a more consistent increase downwind of both regions of the dairy as compared with upwind. The emission of TNMNEOC relative to methane, however, appears to be fundamentally different for the different source areas such that net methane concentrations are larger relative to TNMNEOC downwind of the manure water storage pond than downwind of animal housing areas. Quantification of specific ROG compounds has been attempted by CSU Fresno with the goal of discovering the percentage of TNMNEOC that can be accounted for in conventional (cryo-focused GC-MS) analysis from canisters. Current work is focused on supplementing this field-based comparison with laboratory experiments to identify an ROG compound list which will account for a majority of the TNMNEOC and indicate a defensible ROG sampling technique. Having established conditions under which positive net concentrations of the tropospheric ozone (tO3) precursors of interest can be
measured, computation of emission factors will follow via application of dispersion modeling in collaboration with TAMU-trained staff currently at CSU Fresno.
Impacts
This project will measure the rates of emission of Reactive Organic Gases from dairies in the San Joaquin Valley (SJV) in California. These data are critical to determining the source of tropospheric ozone in this district where national standards for ozone have not been attainable in the last decade. If dairies are found to be a significant source of ozone precursor organic gases, the results of this research will aid in identifying strategies to reduce ozone concentrations in the SJV.
Publications
- No publications have been issued as a result of this work within the reporting period 2003.
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Progress 01/01/02 to 12/31/02
Outputs
Objective 1 activities include the identification of two major data gaps in PM10 and ammonia emission factors for agricultural sources. Errors in the measured PM10 emission factors for dairies, including inappropriate site selection criteria and incorrect data averaging techniques, were documented through team efforts. Subsequent field measurements of PM10 emission factors at a dairy by the Texas A&M (TAMU) researchers produced a more accurate emission factor for use by local agencies in both states. A systematic bias in the measurement of PM10 concentrations and, therefore, PM10 emissions from agricultural activities of all types is also being explored by the research team. Sampling protocols utilizing two different technologies for isolating PM10 from total suspended particulate matter (TSP) are in use in the field and in the lab by both UCD and TAMU research groups. A field study employing both sampling protocols at an almond orchard in California demonstrated the
same bias in measurement as a lab study using three synthetic dust sources. A second field study of the protocols is currently under way at a beef feed yard in Texas. Progress on Objectives 2 and 3 is also the result of work in the field and in the laboratory. One field trial has been conducted in collaboration with CSU Fresno on a commercial dairy in Hanford. Cryotraps were designed, built, and deployed in the field side-by-side with more conventional evacuated canister samplers and an adsorbent-based trap for the collection of a specific group of constituents (carbonyls) which are not quantifiable via the canister method. The performance of the adsorbent traps was tested in the lab by introduction of formaldehyde under field sampling conditions where recovery of 88% was achieved over the entire experimental procedure including sample collection, elution, and analysis by liquid chromatography-mass spectrometry (LC-MS). Differences between upwind and downwind concentrations of the
three compounds identified in the field samples (formaldehyde, acetaldehyde, and acetone) did not identify the dairy as a source. The new gas chromatograph-mass spectrometer (GC-MS) funded by this project was not yet installed when this experiment was conducted, so a less sensitive GC-MS was used to analyze the contents of the cryotraps. While many aspects of the field deployment and analytical handling of the cryotraps were evaluated during this pilot study, the lack of analytical sensitivity prevented a useful assessment of this technique as a whole. The canister samples collected by the CSU Fresno researchers and analyzed by contract through their funding produced considerable data to indicate that upwind/downwind sampling of ROG from AFO is feasible. Tests of vertical and horizontal dispersion of methane and ROG indicate that decreases in concentration of many constituents can be measured with height and used to estimate flux. As of this writing, the capital equipment (GC-MS)
funded in the current project has been delivered to UC Davis. Key personnel have received training in the use of the new GC-MS and installation is proceeding.
Impacts
This project will measure the rates of emission of Reactive Organic Gases from dairies in the San Joaquin Valley (SJV) in California. These data are critical to determining the source of tropospheric ozone in this district where national standards for ozone have not been attainable in the last decade. If dairies are found to be a significant source of ozone precursor organic gases, the results of this research will aid in identifying strategies to reduce ozone concentrations in the SJV.
Publications
- No publications reported this period
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