1. Effects of Emission Adjustments on Peak Ground-Level Ozone Concentration in Southeast Texas Jerry Lin, Thomas Ho, Hsing-wei Chu, Heng Yang, Santosh Chandru, Nagesh Krishnarajanagar, Paul Chiou, and Jack R. Hopper Lamar University 2003 CMAQ Users’ Workshop October 28, 2003

2. Lamar University Motivation Air quality in southeast Texas metroplex among the worst in the nation Ongoing debates on the contribution to air quality problems from various emission sources To investigate the impact of emission adjustments on peak ground-level ozone levels in Houston-Galveston and Beaumont- Port Arthur airshed

3. Lamar University Models & Inputs Emission Inventory: NEI99 Final Version 2 pasted with Texas EI by Texas Commission on Environmental Quality. Meteorological Fields: TexAQS 2000 MM5 meteorology (TCEQ/TAMU) – August 22 to September 2, 2000. Emission Model: SMOKE 1.5  with MIMS spatial surrogate for gridded emission processing. Chemical Mechanism: SAPRC99 mechanism. Chemical Transport Model: CMAQ June 2002 Release on Linux platform. Data Analysis & Visualization: PAVE and Matlab with netCDF/statistics toolboxes.

4. Lamar University Domain and Approach 87  87 Lambert Conformal grids. 12-km grid resolution. Period: August 22-26, 2000. Texas point source VOC scaled up for base case simulation. Modeled O 3 levels compared to field observations made by TCEQ. Sensitivity simulations based on same input meteorology but varied emission adjustments. Beaumont Galveston Houston

5. Lamar University Base-case Simulation (8/25/2000)

6. Lamar University Statistics for Data Analysis

7. Lamar University Base-case Verification

8. Lamar University Scatter Plots – August 25, 2000 Houston-GalvestonBeaumont-Port Arthur 17 monitoring stations 4 monitoring stations

9. Lamar University Sensitivity Cases

10. Lamar University Impact on Peak O 3

11. Lamar University Ozone Difference for Cases 1 & 4

12. Lamar University Ozone Difference for Cases 5 & 6

13. Lamar University Ozone Difference for Cases 7 & 12

14. Lamar University Summary Removing point source emissions (VOC or NOX) leads to the greatest reduction in peak O 3 concentration. The impact of point source emissions on O 3 concentration only affect a small urban area for a relatively short period of time. Removing area, mobile or biogenic source emission (VOC or NOx) causes O 3 reduction in a larger area. However, the magnitude of reduction is less than that of point sources. Transport from adjacent states may contribute significantly to the BPA O 3 levels.

15. Lamar University Acknowledgement Texas Commission on Environmental Quality (Work Order #48561-03) Texas Air Research Center Prof. Daewon Byun at University of Houston Alison Eyth at Carolina Environmental Program