Almond harvest accounts for substantial particulate matter less than 10 m in aerodynamic diameter (PM 10 ) emissions in California each harvest season. This paper addresses the reduction of harvester ground speed from a standard 8 km/hr (5 mph) to 4 km/hr (2.5 mph) as a possible mitigation measure for reducing PM 10 emissions. Ambient total suspended particulate (TSP) and PM 10 sampling was conducted during harvest with alternating control (8 km/hr [5 mph]) and experimental (4 km/hr [2.5 mph]) treatments. On-site meteorological data were used in conjunction with both Industrial Source ComplexShort Term version 3 (ISCST3) and the American Meteorological Society/U.S. Environmental Protection Agency Regulatory Model (AERMOD) dispersion models to backcalculate emission rates from the measured concentrations. Baseline annual emission factors for nut pickup of 381 Ϯ 122 and 361 Ϯ 123 kg PM 10 /km 2 ⅐yr were determined using ISCST3 and AERMOD, respectively. Both of these values are substantially lower than the current PM 10 emission factor for almond pickup of 4120 kg PM 10 / km 2 ⅐yr. The particulate matter less than 2.5 m in aerodynamic diameter (PM 2.5 ) emission factors for nut pickup developed from this study were 25 Ϯ 8 kg PM 2.5 /km 2 ⅐yr and 24 Ϯ 8 kg PM 10 /km 2 ⅐yr were determined using ISCST3 and AERMOD, respectively. Reducing harvester speed resulted in an emissions reduction of 42% for TSP, but no differences were detected in emissions of PM 10 and PM 2.5 . Differences detected in the emission factors developed using ISCST3 and AERMOD were not statistically significant, indicating that almond harvest emission factors previously developed using ISCST3 may be applied appropriately in AERMOD.

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A survey of 14 dairies in Texas and California was conducted to determine their total energy use on an annual basis. The goal of the survey was to evaluate the effect of production and management processes on energy consumption. The total energy used on facilities varied widely with the type of operation; e.g., pasture, open lot, or hybrid (a combination of open-lots and free-stall) systems, as well as with the relative age of the facility. The on-farm energy supply sources included electricity, gasoline, diesel, propane, and natural gas. Total energy usage ranged from as low as 464 kWh per year per animal (kWh/yr·a) for a pasture dairy in Northeast Texas, to as high as 1,637 kWh/yr·a for a hybrid facility in Central Texas. The electricity usage at the dairies was allocated to four main energy sinks, the milking parlor, the animal housing areas, feeding, and waste management, where possible. Generally, milking and housing components dominated the electrical usage for hybrid dairies with the milking parlor being the primary consumer of energy for the openlot facilities.

The Federal Reference Method (FRM) ambient PM 10 sampler does not always measure the true PM 10 concentration. There are inherent sampling errors associated with the PM 10 samplers due to the interaction of particle size distribution (PSD) and sampler performance characteristics. These sampling errors, which are the relative differences between theoretical estimation of the sampler concentration and the true concentration, should be corrected for equal regulation between industries. An alternative method to determine true PM 10 concentration is to use the total suspended particulate (TSP) concentration and PM 10 fraction of the PSD in question. This article reports a new theoretical method to correct PM 10 sampling errors for a true PM 10 /TSP ratio. The new method uses co-located PM 10 /TSP samplers' measurements to derive the mass median diameter (MMD) of PSD and true PM 10 /TSP ratio. Correction equations and charts have been developed for the PMs with GSDs of 1.2, 1.3, ..., 2.1, respectively, and the PM 10 sampler with a cutpoint of 10 mm and slope of 1.5. These equations and charts can be used to obtain a corrected PM 10 /TSP ratio for the given GSD and sampler characteristics. The corrected PM 10 /TSP ratio will be treated as the true PM 10 /TSP ratio for PM 10 concentration calculations. This theoretical process to obtain a corrected PM 10 /TSP ratio will minimize the inherent PM 10 sampler errors and will provide more accurate PM 10 measurement for the given conditions.

The authors are solely responsible for the content of this technical presentation. The technical presentation does not necessarily reflect the official position of the American Society of Agricultural and Biological Engineers (ASABE), and its printing and distribution does not constitute an endorsement of views which may be expressed. Technical presentations are not subject to the formal peer review process by ASABE editorial committees; therefore, they are not to be presented as refereed publications.

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