Investigating Stratospheric and Wildfire Impacts on Urban Ozone Using An Automated Screening Tools and a Lagrangian Chemical Transport Model
Abstract
Natural events, such as stratospheric intrusions and wildfires, can have a significant impact on ozone in urban areas. When these natural sources of ozone are added to the anthropogenic ozone production within a city, it can lead to exceedances of air quality standards. US EPA allows for these "exceptional events" to be excluded from regulatory determinations of attainment of air quality standards, but demonstrating that the exceedance would not have happened in the absence of the natural event currently requires detailed photochemical grid modeling and analysis work to be done for each event. We will present results on two recent model developments; a fully automated stratospheric ozone intrusion screening tool and an automated Lagrangian chemical transport model simulating wild fire impacts. In both tools, a back-trajectory component based on the Lagrangian particle dispersion model STILT (Stochastic Time Inverted Lagrangian Transport model) determines the multiple paths that different air masses took to get to the reporting monitor of interest. The stratospheric intrusion screening tool uses STILT to quickly identify days when urban air quality has been impacted by stratospheric ozone intrusions upwind of the monitor, which allows air quality regulators to identify which events should be further investigated for an exceptional event demonstration report. The second component of the screening tool uses satellite observations to confirm the impact of stratospheric intrusions on the air mass. The tool provides qualitative results of the likelihood that an exceptional event has occurred, allowing air quality managers to allocate modeling resources more efficiently and ultimately help in determining the contribution of natural sources to local O3 pollution. We have also developed a fully-automated Lagrangian chemical transport model (STILT-ASP) that determines the contribution of fires to O3 and PM2.5 measured at a monitoring site, and we will present results on using this model to evaluate EPA's screening metrics for the impact of biomass burning on O3. Both models have been developed to run in a containerized format that contains all libraries, executable files, and operating system components needed for the modeling platform, thus allowing a user to run the models on any operating system.
- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2018
- Bibcode:
- 2018AGUFM.A23M3063L
- Keywords:
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- 0305 Aerosols and particles;
- ATMOSPHERIC COMPOSITION AND STRUCTUREDE: 0315 Biosphere/atmosphere interactions;
- ATMOSPHERIC COMPOSITION AND STRUCTUREDE: 0345 Pollution: urban and regional;
- ATMOSPHERIC COMPOSITION AND STRUCTUREDE: 0365 Troposphere: composition and chemistry;
- ATMOSPHERIC COMPOSITION AND STRUCTURE