treasure valley road dust study: final report - ResearchGate

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3.4.2 Flux Calculation from Meteorological and Particulate Concentrations Horizontal flux emissions were calculated from the 1-second DustTrak data and the vertical wind profiles measured on the towers. Figure 3-17 shows typical time series of the PM 10 concentrations measured by the DustTraks at each tower. The concentration spikes in the figure represent individual vehicle passes. The time series are labeled based on the position of the sampler. DW1_2 is the second from the bottom DustTrak on downwind tower 1 (See Figure 3-18 for DustTrak heights). The results of the close downwind tower 1 are shown in the upper panel of the figure while the results from the farther downwind tower 2 are shown in the lower panel. The figure shows that the concentrations at the close downwind tower typically decrease with height. At the far downwind tower, the second highest sampler typically measures the highest concentrations. More over, the duration of the plume impact on the close tower is approximately 3-7 seconds while the duration at the far tower is 10-15 seconds. These results indicate that the road dust emissions plume is dispersing both vertically and horizontally as the plume moves downwind of the road. Figure 3-18 shows the vertical distribution of the plume at 9 m and 50 m downwindof the road. Concentrations have been normalized so that they sum to unity. The profile at the far downwind tower clearly shows that the plume is dispersing vertically. Analysis of the DustTrak data from the three towers indicated that baseline drift over the course of a day did not affect all instruments equally. In order to calculate emissions fluxes from the PM 10 concentrations, a baseline for each instrument was determined from the peaks shown in Figure 3-17. This baseline concentration was subtracted from the PM 10 time series so that the resulting concentration time series was due only to the emissions of the vehicle passing the tower. PM 10 emissions fluxes were calculated using the assumption that each DustTrak monitor represented a uniform concentration over an interval half way between the monitor and the neighboring monitor on the tower. For example, the lowest monitor on downwind tower 1 (DW1_1) was representative of the PM 10 concentration from the ground to 1.83 m above ground level (AGL). The second monitor represented the PM 10 concentrations from 1.83 m AGL to 3.56 m AGL, and so on. The flux of particles at each tower was calculated using the following equation: ? 4 EF ? cos( ? ) u C ? z ? t ( 3 ) i? 1 i where EF is the emissions factor of PM 10 in grams per vehicle kilometer traveled, ? is the angle between the wind direction and a line perpendicular to the road, i is one of the four positions of the monitors on the tower, u i is the average wind speed in m/s over the interval represented by the i th monitor, C i is the average PM 10 concentration in mg/m 3 as measured by the i th monitor over the interval ? t, ? z in m is the vertical distance represented by the th i monitor, and ? t is the duration that the plume impacts the tower in seconds. A database of the emissions factors was assembled for the parameters: vehicle speed, vehicle type (i.e. Ford Ranger, Chevy Van, HumVee), date, and road orientation (i.e. East-West or North-South). The database is presented in Table 3-3. i i 3-18
30 25 Downwind Tower #1 (9 m from Road) DW1_1 DW1_2 DW1_3 DW1_4 20 DustTrak PM 10 (mg/m 3 ) 15 10 5 0 16:50:53 16:51:36 16:52:19 16:53:02 16:53:46 16:54:29 16:55:12 Time 30 25 Downwind Tower #2 (50 m from Road) DW2_1 DW2_2 DW2_3 DW2_4 20 DustTrak PM 10 (mg/m 3 ) 15 10 5 0 16:50:53 16:51:36 16:52:19 16:53:02 16:53:46 16:54:29 16:55:12 Time Figure 3-17. Time series plots of concentrations measured on downwind tower #1 (9 m from unpaved road) and downwind tower #2 (50 m from unpaved road). 3-19
Page 1: TREASURE VALLEY ROAD DUST STUDY: FI
Page 5 and 6: EXECUTIVE SUMMARY The Idaho Departm
Page 7 and 8: TABLE OF CONTENTS 1. INTRODUCTION..
Page 9: 6.3 DISCUSSION ....................
Page 12 and 13: are strongly correlated and that on
Page 14 and 15: Figure 4-17. Map of street sweeper
Page 16 and 17: xvi
Page 18 and 19: Table 5-3. Speeds and VKT by county
Page 20 and 21: Table A-28. Laboratory Silt Analysi
Page 22 and 23: ?? To assess the impact of winterti
Page 25 and 26: 2. SILT MEASUREMENTS For this study
Page 27 and 28: vehicle tires. The lengths of the s
Page 29 and 30: Figure 2-1. Map of Sample Collectio
Page 31 and 32: Table 2-5 Silt Content and Silt Loa
Page 33: collectors. In contrast, summer sil
Page 36 and 37: 3.2 TRAKER Measurements For the TVR
Page 38 and 39: introduced by the carbon vanes insi
Page 40 and 41: 3.2.4.1 Data Acquisition The TRAKER
Page 42 and 43: Figure 3-6 shows the TRAKER coeffic
Page 44 and 45: 250 200 PM2.5 signal (mg/m 3 ) 150
Page 46 and 47: Line losses associated with the Dus
Page 48 and 49: 1.2 1 Left Diluted Right Diluted Pr
Page 50 and 51: Table 3-2. Regression exponents for
Page 54 and 55: 12.2 m 0.16 9.0 m 0.05 5.7 m 0.22 4
Page 56 and 57: 400 Ford Ranger on NS Road by DW1 4
Page 58 and 59: ceiling can be further stretched to
Page 60 and 61: 100 sL = 2.5717(T*) 0.4741 R 2 = 0.
Page 62 and 63: 4.1.1 Converting TRAKER Data Into E
Page 64 and 65: Table 4-1. (cont) GIS coverages use
Page 66 and 67: Table 4-1. (cont) GIS coverages use
Page 68 and 69: a. b. Figure 4-1. Map of TRAKER Str
Page 70 and 71: egressions, R 2 and P-values are al
Page 72 and 73: Summer - Ada - Rural Summer - Ada -
Page 74 and 75: The average emissions factor is 6.7
Page 76 and 77: Figure 4-5. TRAKER Loop 4.3.1 Tempo
Page 78 and 79: weeks prior to being swept. While t
Page 80 and 81: 4.3.2 Meteorological Effects on Unp
Page 82 and 83: Section 1 Section 2 Section 3 Figur
Page 84 and 85: Figure 4-13. Johnston HSD mechanica
Page 86 and 87: Approximately 8 hours after the ini
Page 88 and 89: One-second emissions potentials (i.
Page 91 and 92: 5. EMISSIONS INVENTORIES FOR THE TR
Page 93 and 94: where E i.10 is the emissions in gr
Page 95 and 96: County Setting Road Class Speed (m/
Page 97 and 98: January, February, and March were u
Page 99 and 100: 5.1.3.2a January 1 - 9, 2000, 2010,
Page 101 and 102: Table 5-9 Precipitation and snow co
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complete link-level emissions inven
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Table 5-14. Distributions of averag
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Taken on an average annual basis, T
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Z n , K zn , ? c/ ? z n Z 3 , K z3
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Table 6-1. Aerodynamic particle siz
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14 m 0 s 15 s 30 s 60 s 120 s 240 s
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Furthermore, the vertical profile o
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?? Sieving each sample to obtain a
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7-4 Table 7-1. Source Profile Key M
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Table 6-1 (continued). Table of geo
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Treasure Valley Road Dust Winter Pa
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7.3 Source Profile Summary This a p
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Table 7-4. Source profiles of Summe
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Table 7-6. Source profiles of Winte
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Bliss experiments were significant
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section was swept with a vacuum swe
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8.3 Differences Between Emissions M
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determine at this time what fractio
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sweepers to reduce PM 10 emissions
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McMahon T.A., and P.J. Denison (197
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Figure A-1. Map of Sample Collectio
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Table A-2. Summer 2001 Silt Samplin
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Table A-3. Laboratory Silt Analysis
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Figure A-3. Map of Silt Loading Loc
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Table A-10. Laboratory Silt Analysi
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Figure A-11. Sampling locations of
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APPENDIX B. BOISE PRECIPITATION AND
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Pecentile among days with precipita
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A.1 Wind speed The cumulative frequ
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APPENDIX C : EMISSIONS INVENTORIES:
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C.1.1.2a Field List for worksheets
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values specified by AP-42 and do no
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