1. 1997 Southern California Ozone- NARSTO Study: Preparation of the 1997 Gridded Emission Inventory Dale Shimp SCOS97-NARSTO Conference Presentation February 14, 2001

2. INTRODUCTION qComprehensive emission inventory for the entire SCOS97 domain qLarge study domain with multiple agencies qInventory to be used for both SCOS97 study and Southern California air quality plans qNeed for hourly, daily emission inventory data qBuilt upon lessons learned from past studies

3. LESSIONS FROM EARLIER STUDIES q Need for day-specific traffic data to answer hour-of-day/day-of-week activity issues o Improved information on off-road mobile sources especially ships and aircraft o Improved biogenic emission inventory

4. LESSIONS FROM EARLIER STUDIES Development of updated and improved spatial allocation factors Stack and locational information often incomplete or missing

5. ORGANIZING THE PROCESS sIdentify responsible agencies and contractors s Emission Inventory Working Group (EIWG) s Identify annual average and day-specific data needs

6. EIWG Members m California Air Resources Board m Local Air Pollution Control Agencies m United States EPA m United States Navy

7. ROLE OF EIWG vEmission Inventory Collection and Reporting v Define Inventory Needs vTechnical Support Group v Quality Assurance v Keep Project on Schedule

8. DAY-SPECIFIC INFORMATION G Stationary Sources G On-Road Mobile Sources G Off-Road Mobile Sources G Non-Anthropogenic Sources

9. ROLES & RESPONSIBILITIES

10. DAY-SPECIFIC INFORMATION COLLECTION m Collect hourly, day-specific emission data from stationary sources m Collect hourly motor vehicle traffic count information on major state highways m Collect hourly aircraft activity data

11. DAY-SPECIFIC INFORMATION COLLECTION (continued) m Collect hourly ship activity data at ports m Collect daily wildfire information m Develop a comprehensive biogenic inventory for the entire SCOS97 study domain

12. Adopted a two-tier approach to the development of the modeling emission inventory s First Tier - will provide modelers with a “fast- track” inventory based on annual average data s Second Tier - will provide modelers with a “final” inventory with all day-specific data MODELING EMISSION INVENTORY DEVELOPMENT

13. FAST-TRACK EMISSION INVENTORY p Preliminary Domain-Wide Modeling Inventory p 1996 Annual Average Emission Inventory p Day-Specific Wildfire Information p Used to Test Model Performance

14. FINAL EMISSION INVENTORY p Integration of Day-Specific Information p Application of 1997 Spatial Surrogates p Weekend Inventories p Future Year Inventories

15. SUMMARY P Key to success was hard work and interagency cooperation P Regular EIWG meetings minimized problems and misunderstandings and helped maintain schedule P Proactive problem solving approach by focusing on inventory deficiencies from earlier studies PAdopted a two-tier approach for developing a modeling emission inventory