Final Report by - Department of Mechanical and Aerospace ...

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Abstract Factors leading to high PM 10 emissions fluxes at Owens Dry Lake, an EPA Superfund Site for particulate matter, were investigated using an environmental laboratory wind tunnel. Four soils believed to be causal in fugitive dust events at Owens Lake were transported back to the University of California at Davis and tested under varying conditions in the Saltation Wind Tunnel (SWT), an environmental laboratory wind tunnel. The variable conditions tested include increasing the wind shear velocity and turbulence, enhancing saltation, varying moisture content, changing the surface condtions, and simulating atmospheric instabilities by heating the tunnel floor. A control volume approach in the tunnel was used to establish rates of entrainment of PM 10 and PM 2.5 for the soils under these variable conditions. The measurements necessary for the control volume approach were obtained with two aerosol monitors using a light scattering photometer technique to measure concentrations. Also used were two pressure transducers to obtain wind velocities for inlet and outlet flows. All data was collected in real time with an acquisition system in order to obtain mass fluxes from which the emission rates were calculated. The highest emission rates produced were for a loose soil from the northern end of Owens Lake with saltation at the estimated equivalent 10 m wind velocity of 21 m/s (North Sheet Simulation). The before mentioned case corresponds to a Northerly blowing wind at Owens Lake. The emission rate for this soil under these conditions was found to be 27,600 µg/m 2 s for PM 10 with about 30% of these emissions being PM 2.5. Moisture content played a significant role in reducing the emission rates; a 10% increase in moisture content in the air-dried soils can reduce the emissions by an order of ii
magnitude. Loose soil surfaces with and without saltation had the highest calculated emission rates. A hard crust surface without saltation had the lowest emission rates. The results from the Saltation Wind Tunnel testing suggest that knowing and predicting trends are imperative in successfully modeling dust emissions from Owens Lake. The wind tunnel is thus one tool which can establish baseline quantities for expected emission rates at Owens Lake for variable conditions; however, it can not be expected to reproduce exact meteorological conditions. The usefulness of the wind tunnel is thus in quantifying the expected behavior of the near surface where dust emissions begin in order to develop control strategies. iii
Page 1 and 2: Final Report Simulation and Analysi
Page 3: Executive Summary of Report • Fou
Page 7 and 8: Table of Contents v Page 2.8.5. Fet
Page 9 and 10: List of Tables Table Page 1. GPS lo
Page 11 and 12: List of Figures Figure Page 12. TSI
Page 13 and 14: List of Figures Figure Page 35. The
Page 19 and 20: List of Figures Figure Page 81. Con
Page 21 and 22: 1. Introduction 1.1. Background The
Page 23 and 24: a) b) d) Figure 1. Owens Lake histo
Page 25 and 26: 1.2. Project Objectives and Applica
Page 27 and 28: Section 2. Experimental Techniques
Page 29 and 30: valley surface winds; and in the su
Page 31 and 32: a) b) Radiative Arctic/Pacific Air
Page 33 and 34: Figure 6. The process of formation
Page 35 and 36: soil in these locations appeared qu
Page 37 and 38: Lone Pine “North Sheet Simulation
Page 39 and 40: 2.3. Soil Properties Properties of
Page 41 and 42: 2.4. Wind Tunnel Quantification of
Page 43 and 44: 2.5. Measurement Instrumentation Th
Page 45 and 46: concentration limit. For the DustTr
Page 47 and 48: height of oil in a U-tube. The pres
Page 49 and 50: a) b) Figure 12. TSI DustTrak used
Page 51 and 52: ∆P, (Pa) 800 600 400 200 0 Pressu
Page 53 and 54: 2.6. Measurements 2.6.1. Threshold
Page 55 and 56:
four different soils and variations
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was repeated for up to five velocit
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coarse Owens Lake sand (Soil #2 and
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The procedure of crust formation is
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a minimum temperature difference be
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Figure 16. Schematic of the believe
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Figure 18. Bagnold (1941) experimen
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a) b) Figure 20. The above figure i
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me Control Volume l, length Figure
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0.30 m Soil being Tested 5.0 m Wind
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a) b) Figure 26. Photographs of the
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Figure 28. Photograph showing the i
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0.30 m Hard Soil Crust Wind Directi
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Section 3. Results Summary • Soil
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extract. The arsenic soil concentra
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that crust development is most like
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3.2. Threshold Studies The threshol
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Voltage (V) 7 6 5 4 3 2 1 0 -1 Nort
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Voltage (V) 6 5 4 3 2 1 0 -1 UCD Fe
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tube. The corresponding plots of th
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z (m) 10 0 10 -1 10 -2 10 -3 10 -4
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z (m) 10 0 10 -1 10 -2 10 -3 10 -4
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z (m) 10 0 10 -1 10 -2 10 -3 10 -4
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u * (m/s) 1.0 0.8 0.6 0.4 0.2 0.0 N
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u * (m/s) 1.0 0.8 0.6 0.4 0.2 0.0 U
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3.4. PM10 Loose Soil Emission Rates
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source of emissions and dust storms
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z (m) 10 0 10 -1 10 -2 10 -3 10 -4
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z (m) 10 0 10 -1 10 -2 10 -3 10 -4
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z (m) UCD Fence Soil (Soil #4), ure
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Table 5. Emission Rates for enhance
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z (m) South Saltation Simulation, u
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PM 10 Emission Rate (µg/m 2 s) Sou
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z (m) 10 0 10 -1 10 -2 North Sand (
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North Sand Sheet (Soil #2 over Soil
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Q, Sand Flux (kg/m*s) 0.35 0.30 0.2
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Q, Sand Flux (kg/m*s) 0.08 0.06 0.0
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3.7. Fetch Studies In studying the
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similar amounts of PM 10; however,
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z (m) 10 0 10 -1 10 -2 UCD Fence So
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Emission Rate (mg/m*s) 15 10 Dirty
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Emission Rate (mg/m*s) 8 6 4 2 0 No
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Emission Rate (mg/m*s) North Sand S
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3.8. Moisture Content Studies The m
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z (m) 10 0 10 -1 10 -2 10 -3 10 -4
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Emission Rate (g/m 2 s) PM 10 Emiss
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%(PM 2.5 /PM 10 ) 40 30 20 10 Pipe
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3.10. Crust Studies Experimentally,
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sand abrasion, broken apart by expa
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z (m) 10 0 10 -1 10 -2 10 -3 10 -4
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Emission Rate (mg/m 2 s) 4 3 2 1 0
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Figure 84. The hard crust was broke
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PM 10 Concentration (mg/m 3 ) 0.8 0
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• The major results are re-summar
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enhancing the emissions. Moisture c
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developed allow comparisons of the
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Gillette, D.A., and Passi, R., 1988
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White, B.R., 1979. Soil Transport b
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Appendix A: Loose Soil Emissions Co
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z (m) 1.00 0.10 0.01 Old Pipe Line
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z (m) 1.00 0.10 0.01 Old Pipe Line
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z (m) 1.00 0.10 0.01 North Sand (So
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z (m) 1.00 0.10 0.01 North Sand (So
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z (m) 1.00 0.10 0.01 North Sand (So
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Dirty Socks Dune Sand (Soil #3), ur
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Dirty Socks Dune Sand (Soil #3), ur
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z (m) 1.00 0.10 0.01 UCD Fence Soil
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Page 191 and 192:
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Appendix B: Enhanced Saltation Emis
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z (m) 1.00 0.10 0.01 North Saltatio
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z (m) North Saltation Simulation, u
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z (m) 10 0 10 -1 10 -2 10 -3 10 -4
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South Sand Saltation Simulation, ur
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z (m) South Saltation Simulation, u
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z (m) 10 0 10 -1 10 -2 10 -3 10 -4
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Appendix C: Fetch Study Concentrati
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z (m) Dirty Socks Sand Fetch Study,
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Dirty Socks Sand Fetch Study, uref
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z (m) 10 0 10 -1 10 -2 10 -3 10 -4
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z (m) UCD Fence Soil Fetch Study, u
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z (m) 10 0 10 -1 10 -2 10 -3 10 -4
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z (m) 10 0 10 -1 10 -2 10 -3 10 -4
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z (m) 1.00 0.10 0.01 Old Pipe Line
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z (m) 1.00 0.10 0.01 Old Pipe Line
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Page 235 and 236:
Page 237 and 238:
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Appendix E: PM2.5 Study Concentrati
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z (m) 1.00 0.10 0.01 Old Pipe Line
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z (m) 1.00 0.10 0.01 Old Pipe Line
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Appendix F: Wallace Laboratories Ch
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234
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236
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Appendix H: Individual Soil Gradati
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%Passing 100 80 60 40 20 0 North Sa
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%Passing 100 80 60 40 20 0 UCD Fenc
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