WRAP RMC Phase II Wind Blown Dust Project

ENVIRON International Corporationand

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 StatesDust Yearly Total by State

WRAP States

0

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1996

Annual PM10 for the Western States

Dust Yearly Total by StateWestern States

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scen ascen bscen cscen d1996

Comparison of Monthly Dust Emissions

Monthly Dust Emissions for the Entire Domain

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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. 3Cat. 4Cat. 6Cat. 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