Long-Term Trends in Tropospheric Ozone and Ozone Chemistry in the Baltimore-Washington Region
Abstract
Over the past four decades, policy-led reductions in anthropogenic emissions have led to dramatic improvements in air quality over the Baltimore-Washington region (BWR). However, due to the nonlinear chemistry behind ozone production, most of the improvement in meetings the ozone air quality metric (NAAQS) did not occur until the early 2000s despite large reductions in ozone precursors (NOx, CO, and volatile organic compounds) in the prior decades. We use observations of ozone and ozone precursors from satellites, ground-based sites, and the 2011 DISCOVER-AQ aircraft campaign in Maryland to present a comprehensive analysis on how ozone chemistry in the BWR has evolved between 1972-2017. We use ground-based data in conjunction with a box model to determine when the BWR transitioned to the NOx-limited regime and to quantify how the reductions in each ozone precursor impacted the change in ozone production rates. Long-term trends in ozone chemistry over the BWR are inferred from satellite observations of the tropospheric column HCHO/NO2 ratio using a re-evaluated chemical transition regime definition derived from DISCOVER-AQ data. One salient result is that the benefit per unit mass NOx control has improved recently. This multi-faceted analysis combining airborne, satellite, and ground-based observations with a conceptual box model provides context for past and future regulatory efforts.
- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2018
- Bibcode:
- 2018AGUFM.A41H3051R
- Keywords:
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- 0305 Aerosols and particles;
- ATMOSPHERIC COMPOSITION AND STRUCTUREDE: 0345 Pollution: urban and regional;
- ATMOSPHERIC COMPOSITION AND STRUCTUREDE: 0365 Troposphere: composition and chemistry;
- ATMOSPHERIC COMPOSITION AND STRUCTUREDE: 0368 Troposphere: constituent transport and chemistry;
- ATMOSPHERIC COMPOSITION AND STRUCTURE