Control strategy optimization for attainment and exposure mitigation: case study for ozone in Macon, Georgia

Area of Science:

• Environmental Science
• Air Quality Management
• Public Health

Background:

• Stringent 8-hour ozone standards designated 474 U.S. counties as nonattainment areas.
• Emission control choices have significant economic and health implications for affected regions.
• Many designated counties had no prior air quality standard violations.

Purpose of the Study:

• To develop and evaluate cost-optimized emission control strategies for ozone nonattainment regions.
• To analyze the effectiveness of different control measures for achieving air quality standards and reducing population exposure.
• To assess the U.S. EPA's photochemical modeling approach for ozone attainment.

Main Methods:

• Case study of Macon, Georgia, a nonattainment region.
• Development of a menu of potential ozone precursor emission controls.
• Linking ozone sensitivities with control menu to identify cost-optimized strategies.
• Analysis of strategies for attainment, spatially averaged, and population-weighted ozone reduction.

Main Results:

• Control menu can reduce 20-35% of ozone precursor emissions, with rapidly increasing marginal costs beyond 15-20%.
• Macon attainment strategies prioritize local nitrogen oxide reductions.
• Atlanta region controls are more effective for reducing statewide population exposure to ozone.
• EPA's attainment demonstration approach is sensitive to baseline period selection.

Conclusions:

• Cost-optimized strategies are essential for achieving ozone attainment and protecting public health.
• Local emission control priorities differ based on regional characteristics and goals.
• Current EPA photochemical modeling approaches may not yield optimal attainment or health protection strategies.