1. Projects:/WRAP RMC/309_SIP/progress_sep02/Annex_MTF_Sep20.ppt Preliminary Mobile Source Significance Test Modeling Results WRAP Regional Modeling Center (RMC) University of California at Riverside, CE-CERT ENVIRON International Corporation Presented at: WRAP Initiatives Oversight Committee (IOC) Meeting October 9, 2002 Tempe Mission Palms Hotel, Arizona

2. Projects:/WRAP RMC/309_SIP/progress_sep02/Annex_MTF_Sep20.ppt Section 309 SIP Modeling Elements Demonstrate that the SO 2 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 presentation

3. Projects:/WRAP RMC/309_SIP/progress_sep02/Annex_MTF_Sep20.ppt Mobile Source Significance Test Metric (Draft Memo from Mobile Source Forum, 06/10/02) Change in extinction due to Mobile Sources over a clean natural background for Worst 20% Observed Visibility Days Applied for 16 Class I Areas on Colorado Plateau No On-Road and Non-Road Mobile Source Emissions (“Zero-Out”) – 9 Grand Canyon (GC) States – California – Phoenix MSA – Las Vegas MSA

4. Projects:/WRAP RMC/309_SIP/progress_sep02/Annex_MTF_Sep20.ppt Estimate 2018 Visibility using Model Scaling of 1996 Observations Scale observed 1996 concentrations using Relative Reduction Factors (RRFs) Separate for each Class I Area Separate for each species (SO 4, NO 3, OC, EC, Soil, and CM) Calculate based on the mean of the Worst 20% observed visibility days during 1996 – e.g., SO4 2018 = SO4 Obs_1996 x (SO4 Model _2018 /SO4 Model_1996 )

5. Projects:/WRAP RMC/309_SIP/progress_sep02/Annex_MTF_Sep20.ppt 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 an issue for Mobile Source Significance Test as Mobile Source Soil and CM insignificant

6. Projects:/WRAP RMC/309_SIP/progress_sep02/Annex_MTF_Sep20.ppt Summary of Anthropogenic Emissions in 9 Grand Canyon (GC) States (No Biogenic, Geogenic, Fire, or Wind Blown Dust Emissions)

7. Projects:/WRAP RMC/309_SIP/progress_sep02/Annex_MTF_Sep20.ppt Comments on Emissions in 9 GC States 47% NO X due to Mobile Sources – (64% Non-Road vs. 36% On-Road) 21% SO 2 due to Mobile Sources – Almost all (97%) due to Non-Road Sources – Non-Road gas engines use low sulfur gasoline – Non-Road Rules for some Non-Road equipment expected before 2018 that would significantly reduce diesel sulfur content (~4000 ppm to 15 ppm) Mobile PM 10 is 6% 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

8. Projects:/WRAP RMC/309_SIP/progress_sep02/Annex_MTF_Sep20.ppt Preliminary Mobile Source Significance Calculation Caveats Still problems with SMOKE emissions processing, emission inputs for scattered days sometimes get corrupted – Screened out known bad days and get qualitatively same result – Results consistent with previous No On-Road Mobile and Bounding Mobile runs – Still problems with No Las Vegas Mobile runs so not presented here Results are preliminary and the final numbers may change slightly, but basic results will remain unchanged

9. Projects:/WRAP RMC/309_SIP/progress_sep02/Annex_MTF_Sep20.ppt 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 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%

10. Projects:/WRAP RMC/309_SIP/progress_sep02/Annex_MTF_Sep20.ppt Cumulative Mobile Source Significance Test

11. Projects:/WRAP RMC/309_SIP/progress_sep02/Annex_MTF_Sep20.ppt Preliminary Individual Area Mobile Significance Test

12. Projects:/WRAP RMC/309_SIP/progress_sep02/Annex_MTF_Sep20.ppt Details Mobile Source Significance Test 9 GC States and Phoenix

13. Projects:/WRAP RMC/309_SIP/progress_sep02/Annex_MTF_Sep20.ppt Comments on Mobile Significance Calculations Effects of High Sulfur Diesel in Non-Road – If Non-Road SO 2 emissions are reduced by 75%, MS 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 – Approximately a factor of 3 reduction – Expect Cumulative < 10%; Individual < 5% Use 2018 Background Visibility instead of 2064 – Reduce impacts by 1/3 to 1/2

14. Projects:/WRAP RMC/309_SIP/progress_sep02/Annex_MTF_Sep20.ppt Road Dust Significance Results Road Dust mainly in Soil and CM components so cannot use scaled modeling results – Currently Road Dust is 20% of PM 10 emissions in 9 GC States (w/o wind blown dust) Use Absolute Modeling Results Results presented at Denver 06/10/02 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%

15. Projects:/WRAP RMC/309_SIP/progress_sep02/Annex_MTF_Sep20.ppt Road Dust Emissions Significance Test Using W20 Absolute Model Results (No RRFs)