1. Technical Review Workshop Report Technical Oversight Committee for the WRAP Board Meeting – July 24, 2002

2. Technical Review Workshop Report Presentation Objectives Organization & content of the workshop Key results Next steps

3. Technical Review Workshop Report Guidelines for §309 Analyses Control strategies already prescribed Technical analyses measure the benefits of these strategies Workshop Statistics Over 100 people in attendance Representatives from 13 western states, plus tribes Members of 3 other Regional Planning Organizations Cross-section of federal and local officials

4. Technical Review Workshop Report Workshop Topics Introduction/review of regional haze & ambient data trends Emission Inventory overview, followed by details of point, area, mobile, and fire Control Strategy Modeling overview, followed by details of modeling process and performance Future work to complete §309 analyses, and list of improvements for §308 work

5. Technical Review Workshop Report Emissions Forum Stationary Point Sources Inventory Area Sources Inventory Mobile Sources Forum On-Road Mobile Sources Inventory (tailpipe, evaporative, tire and brake wear emissions) Off-Road Mobile Sources Inventory (tailpipe and evaporative emissions only) Fire Emissions Joint Forum Wildfire Inventory Prescribed Fire Inventory (Rx) Agricultural Fire Inventory

6. Technical Review Workshop Report Changes in emissions for the WRAP region between 1996 base case & 2018 Annex Milestone inventories: VOCdown 29% NO x down 31% COdown 29% SO 2 down 17% PM 10 up 4% PM 2.5 up 5% NH 3 up 9%

7. Technical Review Workshop Report Modeling analyses: Anticipate planned national/state/local emissions reductions programs Then proceed with evaluation of control strategies Modeling results show visibility improving Annex milestones are better than command & control for 15 of the 16 GCVTC Class I Areas Same or better at all other Class I Areas, with 1 exception, in and around the WRAP region A great deal of modeling and other technical work has been done, particularly in the last year Work is continuing to analyze, understand, and explain results

8. Technical Review Workshop Report Summary of Visibility Benefits of Annex Milestones versus Command & Control with uncertainty Class I areas on Colorado Plateau Best 20% days: The same or better in all 16 GCVTC Class I Areas Worst 20% days: The same or better in 15 of the 16 GCVTC Class I Areas (exception is Petrified Forest) Other Class I Areas in the contiguous WRAP Region Best 20% days: The same or better in all but one Class I Area (exception is Chiricahua Wilderness) Worst 20% days: The same or better in all Class I Areas Class I Areas in AR, MI, MN, MS, OK, and TX The same or better on the Best 20 % and Worst 20% Days

9. Technical Review Workshop Report Preliminary Results for Proposed Mobile Source Significance Threshold Test Initial evaluation involved turning off only on-road emissions for the entire modeling domain Evaluating just on-road emissions, the change in extinction ranges from 3.6% to 8.1% of the Worst Days’ Natural Visibility Condition values at the 16 GCVTC Class I areas on Colorado Plateau Additional mobile source significance tests

10. Technical Review Workshop Report Results for Proposed Road Dust Significance Threshold Test Initial evaluation involved turning off paved and unpaved road dust emissions for the entire modeling domain Evaluating all road dust emissions, the change in extinction ranges from 0.8% to 3.1% of the Worst Days’ Natural Visibility Condition values at the 16 GCVTC Class I areas on Colorado Plateau Regional modeling indicates that road dust emissions are not significant at the initial threshold value

11. Technical Review Workshop Report Next steps for technical work products in the upcoming 6 to 8 months Provide additional mobile on-road significance modeling runs Total mobile (on- & off-road) for the 9 GCVTC states Effect of California mobile emissions Individual urban areas as needed Provide modeling for Fire Management Scenarios 2018 “all control strategies” modeling run Technical Support Document 2/03 Technical Workshop to hand off TSD (4 days)