Section 309 Mobile Source Significance Test Modeling Results

WRAP Regional Modeling Center (RMC)

University of California at Riverside, CE-CERT

ENVIRON International Corporationfor Conference Call with

WRAP Mobile Source Forum

October 18, 2002

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Section 309 SIP Modeling Elements

• Demonstrate that the SO2 Annex Milestone strategy is “better than” Command and Controls with Uncertainty in 2018

• Show visibility progress from 1996 to 2018• Evaluate the “significance” of Mobile Sources

and Road Dust on visibility– Topic of today’s conference call

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Mobile Source Significance Test Metric(Draft Memo from Mobile Source Forum, 06/10/02)• Change in extinction due to Mobile Sources over the

EPA Natural Conditions (Worst 20% Days)– Based on 10/09/02 IOC meeting, added looking at impacts

over the 2018 WRAP Projected Base Case Conditions (Worst 20% Days)

• Applied to 13 urban areas and California to estimate “significance” at 16 Class I Areas on Colorado Plateau

• No On-Road and Off-Road Mobile Source Emissions (“Zero-Out”) modeling priorities:– 9 Grand Canyon (GC) States (Cumulative)– California– Phoenix, Arizona (Maricopa County)– Las Vegas, Nevada (Clark County)

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Estimate 2018 Visibility using Model Scaling of 1996 Observations

• Scale observed 1996 concentrations using Relative Reduction Factors (RRFs) that are ratios of 2018 to 1996 modeling results

• Separate for each Class I Area

• Separate for each species (SO4, NO3, OC, EC, Soil, and CM)

• Calculate based on the mean of the Worst 20% observed visibility days during 1996– e.g., SO42018 = SO4Obs_1996 x (SO4Model _2018/SO4Model_1996)

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Mobile Source Significance Test -- Accounting for Missing Fugitive Dust Emissions

• No Wind Blown Dust in emissions inventory• Model results for Fine Soil and Coarse Matter

(CM) are missing major sources• Cannot use relative changes in modeling results

for Soil and CM• Set RRF(Soil) = RRF(CM) = 1.0

– i.e., 2018 CM&Soil = 1996 CM&Soil

• Not a big issue for Mobile Source Significance Test as Mobile Source Soil and CM are fairly small

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Summary of 2018 Anthropogenic Emissions in 9 Grand Canyon (GC) States

(No Biogenic, Geogenic, Fire, or Wind Blown Dust Emissions)

NOx SO2 NH3 PM2.5(tpy) % (tpy) % (tpy) % (tpy) %

Area 377833 16% 74697 8% 594764 87% 352437 57%Road Dust 0 0% 0 0% 0 0% 66470 11%Point 885720 37% 642133 72% 30218 4% 127374 21%Mobile 407691 17% 5426 1% 57326 8% 12259 2%Non-Road 700271 30% 175343 20% 3398 0% 61131 10%

Total 2371515 100% 897599 100% 685706 100% 619671 100%

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Comments on Emissions in 9 GC States• 47% NOX due to Mobile Sources

– (64% Off-Road vs. 36% On-Road)

• 21% SO2 due to Mobile Sources

– Almost all (97%) due to Off-Road Sources– Off-Road gas engines use low sulfur gasoline– Off-Road Rules for some Off-Road equipment expected

before 2018 that would significantly reduce diesel sulfur content (~4000 ppm to 15 ppm)

• Mobile PM2.5 is 12% of total but consists of EC & OC with high light extinction efficiencies

• New soon to be released EPA NONROAD model results in substantial reductions in emissions

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Mobile Source Draft Significance Thresholds (Draft Memo from Mobile Source Forum, 06/10/02)

• Draft Cumulative Approach due to Mobile Sources in 9 GC States– If < 10%, then individual area significant thresholds of

> 5% shall be used– If >= 10%, then individual area significant thresholds of

> 1% shall be used• Excludes area if it is in lowest 20% of contributions to

the cumulative impact

• Draft Individual Area Approach Significance– Approach#1: > 10%– Approach#2: > 1%

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Cumulative Mobile Source Significance Test9 GC States, EPA Natural Conditions, & 2018 WRAP Base Case

Class I Area on Colorado Plateau

EPA Natural Conditions

(Worst 20%)

2018 WRAP Base Case

(Worst 20%) Arches NP 21.78% 11.95% Black Canyon NP 19.58% 11.55% Bryce Canyon NP 12.02% 8.07% Canyonlands NP 18.63% 10.86% Capitol Reef NP 25.62% 13.50% Flat Tops Wilderness 19.37% 11.38% Grand Canyon NP 25.01% 14.07% Maroon Bells Wilderness 24.19% 12.97% Mesa Verde NP 10.51% 6.11% Mount Baldy Wilderness 19.10% 7.86% Petrified Forest NP 22.49% 11.89% San Pedro Parks WA 8.74% 4.91% Sycamore Canyon WA 28.38% 13.53% West Elk Wilderness 20.99% 11.86% Weminuche Wilderness 16.19% 9.35% Zion NP 16.97% 11.38%

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Individual Area Mobile Significance TestEPA Natural Conditions (Worst 20% Days)

Class I Area (EPA Natural Conditions)

9 GC States

CA Phoenix Las Vegas

Arches NP 21.78% 0.64% 0.24% 0.59% Black Canyon NP 19.58% 1.62% 0.48% 0.24% Bryce Canyon NP 12.02% 4.21% 0.31% 0.98% Canyonlands NP 18.63% 0.92% 0.35% 0.58% Capitol Reef NP 25.62% 5.04% 0.22% 2.37% Flat Tops Wilderness 19.37% 2.21% -0.06% 0.31% Grand Canyon NP 25.01% 16.16% 1.41% 0.90% Maroon Bells Wilderness 24.19% 1.96% 0.12% 0.25% Mesa Verde NP 10.51% 1.43% 1.25% -0.19% Mount Baldy Wilderness 19.10% 1.70% 5.74% 0.21% Petrified Forest NP 22.49% 1.68% 7.17% 0.25% San Pedro Parks WA 8.74% 1.31% 1.23% 0.00% Sycamore Canyon WA 28.38% 14.52% 4.01% 0.48% West Elk Wilderness 20.99% 1.59% 0.44% 0.11% Weminuche Wilderness 16.19% 0.76% 0.77% -0.03% Zion NP 16.97% 4.25% 0.30% 1.69%

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Individual Area Mobile Significance Test2018 WRAP Base Case Visibility for Worst 20% Days

Class I Area (2018 WRAP Base Case)

9 GC States

CA Phoenix Las Vegas

Arches NP 11.95% 0.35% 0.13% 0.32% Black Canyon NP 11.55% 0.95% 0.29% 0.14% Bryce Canyon NP 8.07% 2.83% 0.21% 0.65% Canyonlands NP 10.86% 0.54% 0.21% 0.34% Capitol Reef NP 13.50% 2.65% 0.11% 1.25% Flat Tops Wilderness 11.38% 1.30% -0.04% 0.18% Grand Canyon NP 14.07% 9.10% 0.80% 0.51% Maroon Bells Wilderness 12.97% 1.05% 0.07% 0.13% Mesa Verde NP 6.11% 0.83% 0.73% -0.11% Mount Baldy Wilderness 7.86% 0.70% 2.36% 0.08% Petrified Forest NP 11.89% 0.89% 3.79% 0.13% San Pedro Parks WA 4.91% 0.74% 0.69% 0.00% Sycamore Canyon WA 13.53% 6.92% 1.91% 0.23% West Elk Wilderness 11.86% 0.90% 0.25% 0.06% Weminuche Wilderness 9.35% 0.44% 0.44% -0.02% Zion NP 11.38% 2.85% 0.20% 1.13% 11

Details Mobile Source Significance Test9 GC States, Phoenix, and Las Vegas (EPA Natural Conditions)

Class I Area EPA Nat.

Conditions 2018 Base

2018 NoGC

2018 No Phx

2018 No Vgs

%Chng No GC

%Chng No Phx

%Chng No Vgs

Arches NP 20.12 36.65 32.27 36.60 36.53 21.78% 0.24% 0.59% Black Canyon NP 20.26 34.34 30.37 34.24 34.29 19.58% 0.48% 0.24% Bryce Canyon NP 20.12 29.96 27.54 29.89 29.76 12.02% 0.31% 0.98%

Canyonlands NP 20.08 34.44 30.70 34.37 34.32 18.63% 0.35% 0.58% Capitol Reef NP 20.18 38.30 33.13 38.26 37.82 25.62% 0.22% 2.37%

Flat Tops Wilderness 20.28 34.50 30.57 34.51 34.44 19.37% -0.06% 0.31% Grand Canyon NP 20.08 35.68 30.66 35.40 35.50 25.01% 1.41% 0.90% Maroon Bells WA 20.30 37.84 32.93 37.81 37.79 24.19% 0.12% 0.25%

Mesa Verde NP 20.18 34.69 32.57 34.43 34.72 10.51% 1.25% -0.19% Mount Baldy WA 20.04 48.67 44.84 47.52 48.63 19.10% 5.74% 0.21%

Petrified Forest NP 20.08 37.98 33.46 36.54 37.93 22.49% 7.17% 0.25% San Pedro Parks WA 20.18 35.88 34.12 35.63 35.88 8.74% 1.23% 0.00%

Sycamore Canyon WA 20.34 42.65 36.88 41.84 42.56 28.38% 4.01% 0.48% West Elk Wilderness 20.26 35.86 31.61 35.77 35.83 20.99% 0.44% 0.11%

Weminuche WA 20.20 34.97 31.70 34.81 34.98 16.19% 0.77% -0.03% Zion NP 20.06 29.92 26.52 29.86 29.58 16.97% 0.30% 1.69%

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Estimate On-Road & Off-Road Contributions9 GC States for Petrified Forest, Capitol Reef, and Grand Canyon

Visibility Impacts bySpecies

Mobile EmissionsFraction

PEFO CARE GRCA On-Road Off-RoadSulfate 21% 25% 19% 3% 97%Nitrate 34% 33% 46% 37% 63%PM 45% 42% 35% 17% 83% % Change MS 22.5% 25.6% 25.0% % On-Road 4.7% 5.1% 5.9% % Off-Road 17.8% 20.5% 19.1%

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Comments on Mobile Significance Calculations• Effects of High Sulfur Diesel in Off-Road

– If eliminate SO2 effects, Mobile Source significance reduced but still > 10%/1%

• Effects of New NONROAD Model– Substantially lower, no numbers available

• If Applied Sig Test to On-Road Mobile Only– Estimate a factor of 3-5 reduction (20% in examples)– WRAP July Workshop presented On-Road Mobile

Significance Test for entire domain (WUSA) of 3-8 percent

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Postprocessing of Modeling Results

• If perform either a 9 GC States On-Road only or Off-Road only run then obtain separate Mobile Source contributions and can postprocess modeling results to estimate effects of:– Use of lower sulfur diesel in off-road engines– Effects of EPA’s new NONROAD model– Effects of potential new off-road engine

standards/fuels

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Road Dust Significance Results

• Road Dust mainly in Soil and CM components so cannot use scaled modeling results– Currently Road Dust is 20% of PM10 emissions in 9

GC States (w/o wind blown dust)

• Use Absolute Modeling Results• Results presented at Denver 07/10/02 WRAP

Workshop No Road Dust in the Entire Domain– Will be conservative (overestimate) of Road Dust

emission impacts for 9 GC States

• Cumulative impact from 0.80% to 3.13%16

Road Dust Emissions Significance TestUsing W20 Absolute Model Results (No RRFs)

16 Class I Areas Colorado Plateau

2018 Base Case

(Mm-1)

2018 No Road

Dust (Mm-1)

EPA Nat. Conditions

W20% Days (Mm-1)

Bext change No Road Dust

(Mm-1)

Bext change No Road Dust

(%)

dv Change No Road Dust (dv)

Arches NP 25.91 25.63 20.12 0.29 1.42 0.14 Black Canyon of Gunnison NP

32.84 32.20 20.26 0.63 3.13 0.31

Bryce Canyon NP 24.24 23.99 20.12 0.25 1.24 0.12 Canyonlands NP 23.89 23.71 20.08 0.18 0.89 0.09 Capitol Reef NP 25.56 25.30 20.18 0.26 1.29 0.13 Flat Tops Wilderness 28.55 28.37 20.28 0.19 0.92 0.09 Grand Canyon NP 27.78 27.53 20.08 0.25 1.22 0.12 Maroon Bells-Snowmass WA

31.78 31.46 20.30 0.32 1.57 0.16

Mesa Verde NP 34.47 34.21 20.18 0.26 1.30 0.13 Mount Baldy Wilderness 41.63 41.26 20.04 0.37 1.87 0.19 Petrified Forest NP 32.46 32.22 20.08 0.24 1.20 0.12 San Pedro Parks Wilderness 28.90 28.65 20.18 0.24 1.21 0.12 Sycamore Canyon Wilderness

35.34 34.95 20.34 0.39 1.92 0.19

West Elk Wilderness 31.15 30.85 20.26 0.30 1.47 0.15 Weminuche Wilderness 29.93 29.77 20.20 0.16 0.80 0.08 Zion NP 25.57 24.95 20.06 0.61 3.05 0.30

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