FIELD TESTING AND EVALUATION OF DUST DEPOSITION AND ...

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Figure 5-8. Concentration profiles measured at the three towers downwind of an unpaved road and concentration profiles predicted by the ADE model for equivalent downwind distances a. for 32 passes with u * between 0.15 and 0.25 m/s and b. for 15 passes with u * between 0.45 and 0.55 m/s. Tower distances from edge of road: T1 - 7 m, T2 – 50 m, T3 – 100 m. Modeled profiles are based on neutral atmospheric conditions. Both measured and modeled concentration have been normalized to the concentration at 1.26 m.......................................................................................... 5-13 Figure 5-9. Normalized measured and modeled gaussian concentration profiles at a. Tower 2, 50 meters downwind of unpaved road and b. Tower 3, 100 meters downwind............................................................................................................... 5-14 Figure 5-10. Comparison of ISC3 gaussian concentration profile and profile from numerical solution of Atmospheric Diffusion Equation at multiple downwind distances. Solutions for the ADE are for neutral conditions................................. 5-15 Figure 5-11. Particle removal rates measured at Ft. Bliss at tower 100 m downwind of an unpaved road. a. Comparison of horizontal flux among the three downwind towers. Data are averages over 27 individual passes when the wind direction was within 15 degrees of perpendicular to the road. Concentrations measured with DustTrak monitors with PM 10 inlets. Fluxes calculated according to Equation 5-1 and normalized to value at Tower 1. Vertical bars indicate standard errors; b. Comparison of particle size distributions at Towers 1 and 3 measured by GRIMM 1.108 OPC with model predictions. Data are averages over 137 individual passes. X- axis shows particle aerodynamic diameter calculated by assuming a density of 2.6 g/cm 3 and geometric mean diameter representing each size bin. Particle concentrations at Towers 1 and 3 were each normalized by concentration of 3.9 micron particles. Y-axis represents ratios of normalized concentrations. ............ 5-16 Figure 5-12. Example of emission factor dependence on vehicle speed. The vertical bars are the standard deviations among the three downwind towers. ........................... 5-18 Figure 5-13. The ratio of emission factors calculated according to AP-42 (USEPA, 1999) and those measured at Ft. Bliss. The upper line is the ratio based on a 7% silt content, while the lower line assumes 4% silt content. The top panel shows the ratios when all the vehicles in Table 5-2 are considered. The bottom panel shows the same data, but only for the passenger vehicles. .............................................................. 5-20 Figure 5-14. Turbulence generated vs. height above ground for three vehicle types. The x-axis represents the difference between the vertical component of turbulence generated by the passing of the vehicle and the background fluctuations in vertical velocity normalized by the speed of the vehicle. The horizontal lines represent the background turbulence standard deviation. The dotted lines represent hand drawn curves to fit the data. The dotted line corresponding to the compact car was drawn based on the assumption that the height of the wake plume is proportional to the height of the vehicle (see Figure 5-15). ................................................................. 5-21 Figure 5-15. Estimate of turbulent wake height vs. physical vehicle height. The dotted line represents a zero-intercept regression on the data from the Cargo Van and the Moving Truck. The hollow circle is an estimate of the wake height for the Compact Car based on the regression. .................................................................................. 5-21 xiv
Figure 5-16. Comparison of fraction of particles removed according to the ISC3 model for various values of the injection height under a. moderately unstable conditions; b. neutral conditions; c. very stable conditions; and d. same as c. but x-axis extends to 10 km. The injection height is manifested in the model by setting the initial value of σ z to 0.5×IH. .......................................................................................................... 5-23 Figure 6-1. Plan view of the MUST site showing the array of shipping containers representing buildings and the location of the measurements. (1) 2-D sonic anemometers at 4, 8, 16 m; (2) DustTraks at 0.9, 1.7, and 3.7 m; (3) 3-D sonic anemometer at 1.6 m; (4) DustTraks at 1.8, 4.6, 9.1, and 18.3 m and 2-D sonic anemometers at 4, 8, 16, 32 m. ................................................................................ 6-1 Figure 6-2. Wind Equation Fit. Both the logarithmic (dashed line) and power law (solid line) equations give a reasonable fit to the 15-minute average wind speed measurements (circles)............................................................................................. 6-6 Figure 6-3. Dust concentration versus time as measured by DustTraks. Vehicle passes generated well-defined spikes at 3 m horizontal and 1 m vertical from the road (bottom). The spikes were broader but still well defined 95 m downwind and 4.6 m above grade (middle). Most vehicle trips did not cause a noticeable spike at 95 m downwind and 18.3 m above grade (top). Note that full scale for the top graph and middle graph are 1/1000 and 1/50 of full scale for the near road measurements respectively. ............................................................................................................. 6-7 Figure 6-4 Collocated DustTraks. Five collocated DustTraks showed large differences in individual readings but little difference between the instruments when averaged over the entire experiment. Left: Histogram of maximum minus minimum divided by the average for sets of five coincident readings. Middle: outlier box plot of the same data. Right: a typical time trend showing poor correlation between individual readings.................................................................................................................... 6-8 Figure 6-5. Comparison of fraction of PM 10 particles remaining in suspension 95 m downwind of an unpaved road during a nighttime test on Dugway Proving Grounds, UT. The white circles represent the fraction of PM 10 associated with each size bin. Mass fractions associated with each size bin were estimated from Ft. Bliss data from a different experiment. The gray circle is the fraction remaining in suspension according to the methods described in the previous section. The black squares and triangles correspond to modeled removal rates under very stable conditions. ...... 6-10 xv
Page 1: FIELD TESTING AND EVALUATION OF DUS
Page 5 and 6: EXECUTIVE SUMMARY The Western State
Page 7 and 8: models. Countess (2001) summarized
Page 9 and 10: TABLE OF CONTENTS 1. INTRODUCTION 1
Page 11 and 12: TABLE OF FIGURES Figure 2-1. Develo
Page 13: Figure 4-6. The fraction of particl
Page 17 and 18: LIST OF TABLES Table 2-1. Parameter
Page 19 and 20: 1. INTRODUCTION 1.1 Background The
Page 21 and 22: 2.BACKGROUND Fugitive dust is emitt
Page 23 and 24: Planetary Boundary Layer (PBL) F =
Page 25 and 26: C D u* = ur The overall drag c
Page 27 and 28: St a vg u g = cA L * Equation 2
Page 29 and 30: Table 2-1. Parameters used in the S
Page 31 and 32: 1E+01 1E+00 z0 = 4.4 cm z0 = 6.4 cm
Page 33 and 34: pathway for deposition for particle
Page 35 and 36: An alternative method for modeling
Page 37 and 38: 3. MEASUREMENT OF DEPOSTION VELOCIT
Page 39 and 40: Department at the University of Uta
Page 41 and 42: In the laboratory, the deposited ma
Page 43 and 44: Table 3-2. Log of all flat substrat
Page 45 and 46: 16 Normalized Deposition Velocity 1
Page 47 and 48: 1.E+05 Deposition Velocity - cm/s 1
Page 49 and 50: are deposition from a horizontally
Page 51 and 52: single element that is intended to
Page 53 and 54: 4. MODELS USED TO STUDY PARTICLE RE
Page 55 and 56: κu ( ) * z 8 fz K zz = exp −
Page 57 and 58: C = −6 ( 1× 10 ) QV 2π u s σ
Page 59 and 60: oad. M is the mass of particles in
Page 61 and 62: By making the approximation that dm
Page 63 and 64: diameters less than 10 microns. Dis
Page 65 and 66:
of such a height is somewhat arbitr
Page 67 and 68:
1 0.9 0.8 1 0.9 0.8 Fraction remain
Page 69 and 70:
Fraction of Particles Remaining in
Page 71 and 72:
gravitational settling. Stable cond
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though it is expected to improve at
Page 75 and 76:
5. DETERMINATION OF PARTICLE REMOVA
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PM 10 measured by the DustTrak must
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100% 90% 80% Relative Frequency (pr
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average wind speed measured at 12 m
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where the subscript i indicates tha
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k C int = peakend k C peeakstart d
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Height z (m) 14 12 10 8 6 T1_data T
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Horizontal fluxes of PM 10 measured
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Table 5-2 enumerates the speed-depe
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6 Ratio of AP-42 Emission Factor to
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to the ground) giving an approximat
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models analyzed in this study is su
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Table 6-1. Screen analysis of test
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value which was used up to the midp
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measured at 3,1. Downwind the dust
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trips, the average readings for the
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Fraction of particles of stated siz
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the ground, where particles have a
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particles through the top of the bo
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deposition. Much of the decrease in
Page 116 and 117:
7-8
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Gifford, F.A. (1961). Use of Routin
Page 120:
Venkatram, A. (1993). The Parametri
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FIELD TESTING AND EVALUATION OF DUST DEPOSITION AND ...

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