Effects of Emission Adjustments on Peak GroundLevel Ozone Concentration in Southeast Texas

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
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
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
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 O3 levels compared to field observations
  made by TCEQ.
• Sensitivity simulations based on same input
  meteorology but varied emission adjustments.

5
Base-case Simulation (8/25/2000)
6
Statistics for Data Analysis
7
Base-case Verification
8
Scatter Plots August 25, 2000
Houston-Galveston
Beaumont-Port Arthur
17 monitoring stations 4 monitoring stations
9
Sensitivity Cases
10
Impact on Peak O3
11
Ozone Difference for Cases 1 4
12
Ozone Difference for Cases 5 6
13
Ozone Difference for Cases 7 12
14
Summary

• Removing point source emissions (VOC or NOX)
  leads to the greatest reduction in peak O3
  concentration.
• The impact of point source emissions on O3
  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 O3 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 O3 levels.

15
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