Particulate Matter Emissions from Reduced-Pass Almond Sweeping

Journal of the Air & Waste Management Association

Goodrich²,

Botlaguduru

et al. 2009

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.

Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

See 1 more Smart Citation

Particulate Matter Emission Factors for Almond Harvest as a Function of Harvester Speed

Journal of the Air & Waste Management Association

Goodrich²,

Botlaguduru

et al. 2009

“…The PSD (described by a log-normal mass distribution) of each sample was determined and characterized by a mass median diameter (MMD) and geometric standard deviation (GSD). 12 The MMDs were converted from equivalent spherical diameter (ESD) to aerodynamic equivalent diameter (AED) using a particle density ( p ) of 2.6 g/cm 3 (on the basis of soil particle samples taken from each orchard and analyzed using a pycnometer [AccuPyc 1330, Micrometrics]) and a shape factor of 1.05 (eq 1). This shape factor was a departure from earlier work described by Faulkner et al.…”

Section: Sweeping Trialsmentioning

confidence: 99%

“…2 For the past several years, the Almond Board of California has been investigating abatement strategies to reduce PM emissions from almond harvest operations. Goodrich et al 3 compared conventional almond sweeping (using three blower-passes per harvested row) and reduced-pass almond sweeping (using one blower-pass per harvested row). The authors reported that reducing the number of blower-passes from three to one lowered the average PM 10 emissions by 49%.…”

Section: Introductionmentioning

confidence: 99%

Evaluation of Particulate Matter Abatement Strategies for Almond Harvest

Journal of the Air & Waste Management Association

Downey

Giles

et al. 2011

Almond harvest accounts for substantial PM 10 (particulate matter [PM] Յ10 m in nominal aerodynamic diameter) emissions in California each harvest season. This paper evaluates the effects of using reduced-pass sweepers and lower harvester separation fan speeds (930 rpm) on lowering PM emissions from almond harvesting operations. In-canopy measurements of PM concentrations were collected along with PM concentration measurements at the orchard boundary; these were used in conjunction with on-site meteorological data and inverse dispersion modeling to back-calculate emission rates from the measured concentrations. The harvester discharge plume was measured as a function of visible plume opacity during conditioning operations. Reduced-pass sweeping showed the potential for reducing PM emissions, but results were confounded because of differences in orchard maturity and irrigation methods. Fuel consumption and sweeping time per unit area were reduced when comparing a reduced-pass sweeper to a conventional sweeper. Reducing the separation fan speed from 1080 to 930 rpm led to reductions in PM emissions. In general, foreign matter levels within harvested product were nominally affected by separation fan speed in the south (less mature) orchard; however, in samples conditioned using the lower fan speed from the north (more mature) orchard, these levels were unacceptable.

Harvesting equipment to reduce particulate matter emissions from almond harvest

Journal of the Air & Waste Management Association

2012

Almond harvest accounts for an estimated 12 Gg of PM 10 emissions in California each harvest season. Emissions from three new, "low-dust" almond harvesters (Exact Harvest Systems E4000; Flory Industries 8550; Weiss-McNair 9800 California Special) and one exhaust abatement device (Joe DiAnna, Clean Air Concept) were compared to those from a conventional harvester operating in the same orchard. Emissions of TSP and PM 10 trended lower for all new harvesters and were significantly lower for most harvesters (a < 0.10). Significant reductions in PM 2.5 emissions were observed from two harvesters as well. Fractionation analysis was not conducted on nut samples collected in the second year of the project, but differences observed in the composition of material that would be delivered to the huller between the Exact E4000 and conventional harvesters were functionally insignificant. The results of these tests imply that new harvest technologies are able to reduce PM 10 emissions from one of the largest sources in the San Joaquin Valley (SJV) of California without affecting product quality. As such, use of these new harvesters should be considered a conservation measure that would help the SJV Air Pollution Control District (SJVAPCD) meet the requirements of their PM 10 maintenance plan.Implications: The results of this research indicate that new harvesting technologies have the potential to substantially reduce PM emissions from almond harvest operations over traditional harvester designs without negatively affecting product quality. As such, use of these new harvesters could aid the SJVAPCD in maintaining its attainment status for PM 10 and should be considered as candidate conservation management practices for producers.