WRAP RMC Phase II Wind Blown Dust Project

ENVIRON International Corporation

and

University of California, Riverside

August 24, 2004

Phase I Project Summary• Objectives

– Develop general methodology based on ‘MacDougall Method’ – Develop 1996 gridded PM inventory of WB Dust for the

Western States

• Limitations– Threshold surface friction velocities– Emission factors– Vacant land stability– Dust reservoirs– Rain events– Vegetation density

Phase II Project Background

• Develop improved general methodology based on Phase I recommendations and recent literature review

• Update gridded PM inventory of WB Dust for 2002 using the Inter-RPO regional modeling domain

• Develop of surface friction velocities and threshold friction velocities

• Develop improved emission flux relationships

• Improve vacant land characterization– Disturbance– Land use type– Reservoirs

• Conduct model performance evaluation

Revised methodology to consider:

• Threshold velocities• Emission factors• LULC and Soil characteristics• Reservoir characteristics• Agricultural adjustments

• Full presentation from DEJF Meeting in Reno at http://64.27.97.126/forums/dejf/meetings.html

Dust Category 3 4 6 7

Land use Ag. Grass Shrubs Barren

Surface roughness (cm) 0.031 0.1 0.05 0.002

Threshold friction Velocity (mile/h) 8.33 13.81 9.62 6.81

Threshold wind velocity at 38m height (mile/h) 29.50 44.25 32.75 28.50

Characteristics of Dust Categories

Model Sensitivity Simulations

• Run a :

– No limitation on dust event duration

– All soils considered loose undisturbed

• Run b :

– Dust events limited to 10 hrs/day

– All soils considered loose undisturbed

Model Sensitivity Simulations

• Run c :

– No limitation on dust event duration – Assume 10% of barren, grass & shrublands area is disturbed– Threshold velocity for grass & shrublands = 0.5 * undisturbed value– Threshold velocity for barren lands = .27 * undisturbed value

• Run d :– Dust events limited to 10 hrs/day for undisturbed soils– Assume 10% of barren, grass & shrublands area is disturbed– Threshold velocity for grass & shrublands = 0.5 * undisturbed value– Threshold velocity for barren lands = .27 * undisturbed value

Model ResultsScenario a: no limit on duration; all soils loose, undisturbed

Dust emissions, Scenario a

62.50%

17.24%

19.38%

0.88%

Dust code 3

Dust code 4

Dust code 6

Dust code 7

Model ResultsScenario b: event duration <=10 hrs/day; all soils loose, undisturbed

Dust emissions, Scenario b

63.83%

15.32%

19.92%

0.93%

Dust code 3

Dust code 4

Dust code 6

Dust code 7

Model ResultsScenario c: no limit on duration; assume 10% disturbed area for grass,

shrub, barren lands

Dust emissions, Scenario c

50.29%

24.82%

22.95%

1.94%Dust code 3

Dust code 4

Dust code 6

Dust code 7

Model ResultsScenario d: event duration <= 10hrs/day for disturbed soils; assume 10%

disturbed area for grass, shrub, barren lands

Dust emissions, Scenario d

44.35%

27.75%

25.33%

2.58%

Dust code 3

Dust code 4

Dust code 6

Dust code 7

Dust Totals for WRAP Statestons/year

Scenario WRAP States Domain Total (US only)

a 2,222,219   9,451,368

b 1,310,120  5,228,818

c 3,077,196 11,098,731

d 2,165,096 6,876,180

1996 Results 2,240,288 4,366,907

Annual PM10 for WRAP States

Dust Yearly Total by StateWRAP States

0

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1996

Annual PM10 for the Western States

Dust Yearly Total by StateWestern States

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CO ID IA KS

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OK

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TX UT

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I

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scen b

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1996

Comparison of Monthly Dust Emissions

Monthly Dust Emissions for the Entire Domain

0.0

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Dust from Category 3 (Ag land)PM10 Yearly Total

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Annual PM10 from Ag Land for WRAP States

Dust from Category 4 (Grass land)PM10 Yearly Total

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Annual PM10 from Grass Land for WRAP States

Dust from Category 6 (Shrub land)PM10 Yearly Total

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Annual PM10 from Shrub Land for WRAP States

Dust from Category 7 (Barren land)PM10 Yearly Total

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Annual PM10 from Barren Land for WRAP States

Dust from all Categories for Scenario dPM10 Yearly Total

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Cat. 3

Cat. 4

Cat. 6

Cat. 7

Scenario d Annual PM10 from All Dust Categories for WRAP States

2002 Annual PMC Scenario a: no limit on duration; all soils loose, undisturbed

2002 Annual PMC Scenario b: event duration <=10 hrs/day; all soils loose, undisturbed

2002 Annual PMC Scenario c: no limit on duration; assume 10% disturbed area for grass,

shrub, barren lands

2002 Annual PMC Scenario d: event duration <=10 hrs/day; assume 10% disturbed area for

grass, shrub, barren lands

Model Performance Evaluation• Evaluate model results for reasonableness and accuracy

• Compare predicted WB dust emissions near IMPROVE monitors with measured IMPROVE dust extinction (Bdust)

• Enhancements to CMAQ to track WB and other dust

• Evaluate model CMAQ model performance with and with out WB dust emissions

• Refined model performance evaluation using results of Etyemezian, et al.

• For events characterized as wind blown dust events, determine whether dust model predicts impacts

Model Performance EvaluationSchedule

• Initial Model Performance Evaluation Report:

August 31, 2004

• Refined Model Performance Evaluation Report:

October 31, 2004