treasure valley road dust study: final report - ResearchGate

More documents

Recommendations

Info

Figure 3-6 shows the TRAKER coefficient of variation for the left and right PM 10 DustTrak signals as a function of the vehicle speed. The coefficient of variation is a measure of the relative precision and is equal to the standard deviation of the measurement divided by the average of the measurement. In the Figure, the measurement corresponds to multiple passes on the same 1-mile stretch of road in the Treasure Valley. The Figure clearly shows that the precision of the measurement improves with increasing vehicle speed. The precision is 84% at 5 mps, 30% at 9 mps, and approximately 10% above 14 mps. Note that most TRAKER measurements occur at speeds greater than 9 mps (approximately 20 mph). The poor precision at low speeds is probably due to the influence of fluctuating ambient winds on the flow regime behind the front tires. As the vehicle speed increases, such fluctuations become less important compared to the speed of the vehicle (see section 3.3.4 for discussion of the relationship between the TRAKER signal and vehicle speed). The equivalent information for PM 2.5 DustTraks is shown in Figure 3-7. Note that for PM 2.5 , DustTrak data at speeds less than 50 km/hr are below the detection limits of the instruments. The trend of improved precision with higher speeds is similar to the PM 10 case. 3.3.1.1 Inferring PM 10 from PM 2.5 Unpaved roads are by nature much dustier than paved roads. A dilution system was designed for the TRAKER in order to reduce the particle concentration in the TRAKER inlets and allow the DustTrak measurements to remain within the manufacturer’s specified operating range. In some cases, the PM 10 DustTrak upper limit (150 mg/m 3 ) was exceeded even with the dilution system in operation. For both the Treasure Valley Road Dust Study, and the calibration tests at Ft. Bliss (described in detail in section 3.4) PM 2.5 DustTraks were collocated with PM 10 DustTraks in the sampling plena within the TRAKER. Figure 3-8 shows the relationship between collocated PM 2.5 and PM 10 DustTraks. Based on the correlation shown in the figure, when the PM 10 DustTrak was out of range, the PM 2.5 value was divided by 0.39 in order to estimate the PM 10 value. Note that while useful for correcting out of range data, the DustTrak is calibrated for PM 10 and measurements with a 2.5 ?m inlet only give a nominal value for PM 2.5 . For a few cases, both the PM 10 and PM 2.5 DustTraks were out of range. Under such circumstances, default values of 770 and 280 mg/m 3 were assumed for PM 10 and PM 2.5 , respectively. This occurrence is rare and applies to less than 0.5% of the unpaved road data. 3.3.1.2 TRAKER Validity Criteria A TRAKER data point is only considered valid if it meets all of the criteria outlined in Table 3-1. Criteria are applied to the speed, acceleration, deceleration, and the wheel angle of the TRAKER vehicle. If a data point does not meet any one of the criteria, then that data point is flagged as “Invalid” and is not used in any subsequent data processing activities. Note that the TRAKER measurement uses the difference between the particle concentration measured behind the front tire and the concentration measured through the front bumper (see equation 1 in section 3.3.4). Under certain conditions, the concentration at the front bumper may be higher than it is behind the front tire resulting in a negative measurement. Negative values are NOT considered invalid and are retained in the database. It is important to retain negative values so that a systematic bias is not introduced into the dataset. 3-8
100 90 80 Coefficeient of Variation % 70 60 50 40 30 20 10 0 0 5 10 15 20 25 30 Vehicle Speed (mps) Figure 3-6. TRAKER coefficient of variation expressed as a percentage for left and right PM 10 DustTrak signals as a function of speed. The data represent left and right PM 10 DustTrak signals averaged over a 1-mile stretch of road in the Treasure Valley. The coefficient of variation provides an estimate of the precision and is equal to the standard deviation of a measurement divided by the average. 100 90 80 Coefficeient of Variation % 70 60 50 40 30 20 10 0 0 5 10 15 20 25 30 Vehicle Speed (mps) Figure 3-7 TRAKER coefficient of variation expressed as a percentage for left and right PM 2.5 DustTrak signals as a function of speed. The data represent left and right PM 2.5 DustTrak signals averaged over a 1- mile stretch of road in the Treasure Valley. The coefficient of variation provides an estimate of the precision and is equal to the standard deviation of a measurement divided by the average. Note that data for speeds less than 50 km/hr are below detection limits for the PM 2.5 DustTraks. 3-9
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 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 52 and 53: 3.4.2 Flux Calculation from Meteoro
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
Page 103 and 104:
complete link-level emissions inven
Page 105 and 106:
Table 5-14. Distributions of averag
Page 107:
Taken on an average annual basis, T
Page 110 and 111:
Z n , K zn , ? c/ ? z n Z 3 , K z3
Page 112 and 113:
Table 6-1. Aerodynamic particle siz
Page 114 and 115:
14 m 0 s 15 s 30 s 60 s 120 s 240 s
Page 116 and 117:
Furthermore, the vertical profile o
Page 118 and 119:
?? Sieving each sample to obtain a
Page 120 and 121:
7-4 Table 7-1. Source Profile Key M
Page 122 and 123:
Table 6-1 (continued). Table of geo
Page 124 and 125:
Treasure Valley Road Dust Winter Pa
Page 127 and 128:
7.3 Source Profile Summary This a p
Page 129 and 130:
Table 7-4. Source profiles of Summe
Page 131:
Table 7-6. Source profiles of Winte
Page 134 and 135:
Bliss experiments were significant
Page 136 and 137:
section was swept with a vacuum swe
Page 138 and 139:
8.3 Differences Between Emissions M
Page 140 and 141:
determine at this time what fractio
Page 142 and 143:
sweepers to reduce PM 10 emissions
Page 144 and 145:
McMahon T.A., and P.J. Denison (197
Page 146 and 147:
Figure A-1. Map of Sample Collectio
Page 148 and 149:
Table A-2. Summer 2001 Silt Samplin
Page 150 and 151:
Table A-3. Laboratory Silt Analysis
Page 152 and 153:
Figure A-3. Map of Silt Loading Loc
Page 154 and 155:
Page 156 and 157:
Page 158 and 159:
Page 160 and 161:
Table A-10. Laboratory Silt Analysi
Page 162 and 163:
Page 164 and 165:
Page 166 and 167:
Page 168 and 169:
Page 170 and 171:
Page 172 and 173:
Page 174 and 175:
Page 176 and 177:
Figure A-11. Sampling locations of
Page 178 and 179:
Page 180 and 181:
Page 182 and 183:
Page 184 and 185:
Page 186 and 187:
Page 189 and 190:
APPENDIX B. BOISE PRECIPITATION AND
Page 191 and 192:
Pecentile among days with precipita
Page 193 and 194:
A.1 Wind speed The cumulative frequ
Page 195 and 196:
APPENDIX C : EMISSIONS INVENTORIES:
Page 197 and 198:
C.1.1.2a Field List for worksheets
Page 199 and 200:
values specified by AP-42 and do no
show all

treasure valley road dust study: final report - ResearchGate

You also want an ePaper? Increase the reach of your titles

Delete template?

Save as template?