290 likes | 417 Views
Further Development and Application of the CMAQ Ozone and Particle Precursor Tagging Methodologies (OPTM & PPTM). 7 th Annual CMAS Conference Chapel Hill, NC 6-8 October 2008 Presented by Sharon Douglas ICF International, San Rafael, CA. Co-Authors:. Tom Myers Yihua Wei Jay Haney
E N D
Further Development and Application of the CMAQ Ozone and Particle Precursor Tagging Methodologies (OPTM & PPTM) 7th Annual CMAS Conference Chapel Hill, NC 6-8 October 2008 Presented by Sharon Douglas ICF International, San Rafael, CA
Co-Authors: • Tom Myers • Yihua Wei • Jay Haney • Tom Braverman, ICF EPA OAQPS
Presentation Outline • Overview of CMAQ/OPTM & PPTM source attribution methods • Application of CMAQ/OPTM & CMAQ/PPTM to support ozone & PM2.5 designations (example for Milwaukee) • Application of CMAQ/PPTM to characterize CAAA-related reductions in PM2.5 for cost/benefit analysis • Next steps
OPTM & PPTM: General Concepts • Emissions (or IC/BC) species are tagged in the input files and continuously tracked throughout the simulation • Tags can be applied to source regions, source categories, individual sources, and/or IC/BCs • Tagged species have the same properties and are subjected to the same processes (e.g., advection, chemical transformation, deposition) as the actual species
OPTM & PPTM: General Concepts • OPTM species include ozone, NOx & VOC • PPTM species include PM-related S, N, SOA, POC, EC & other inorganic particulates* • Base simulation results not affected by tagging • OPTM & PPTM quantify the contribution of tagged sources to simulated species concentrations & deposition *PPTM has also been implemented for mercury
Implementation of OPTM for CMAQ (Overview(1)) • Total emissions of both NOx and VOC from the desired sources or source categories are tagged (e.g., NOx_t1, NOx_t2, VOC_t1, VOC_t2) • Oxidant tracers (OXN_t1, OXV_t1, OXN_t2, OXV_t2) correspond to the oxidant produced from NOx & VOC for each tagged category
Implementation of OPTM for CMAQ (Overview(2)) • Advection/Diffusion: • Use standard CMAQ algorithms • Gas Phase Chemistry: • Chemistry step called as usual • Changes in NOx, VOC & oxidant (ΔVOC, ΔNOX & ΔOX) are calculated and apportioned to tags • Deposition: • Calculated for the tags based on fractional change in total NOx, VOC & oxidant due to deposition
Implementation of PPTM for CMAQ (Overview) • Within CMAQ, tagging is accomplished by adding duplicate species (e.g., ANO3_t1, ANO3_t2) • More than 50 (gas & aerosol phase) species per tag required to track total PM2.5 (e.g., for nitrogen: ANH4I, ANH4J, ANO3I, ANO3J, NO, NO2, NO3, N2O5 …) • Key considerations/assumptions: • Linear processes simulated directly • Potentially non-linear processes calculated for total species and apportioned to tags • PPTM can also be used to estimate contributions to N and other forms of deposition
Application of CMAQ/OPTM & PPTM for the Milwaukee Area • Objective: To identify the source regions that potentially contribute to high ozone and high PM2.5 concentrations in the Milwaukee, WI area • Specs: • Regional-scale modeling domain • 2002 base year; limited simulation periods (1 month for ozone; 4 months for PM2.5) • 13 tagged source regions (county level)
Application of CMAQ/OPTM & PPTM for the Milwaukee Area: Domain 12-km resolution
Application of CMAQ/OPTM & PPTM for the Milwaukee Area: Tags T1: Milwaukee Co., WI T2: Washington Co., WI T3: Ozaukee Co., WI T4: Waukesha Co., WI T5: Racine Co., WI T6: Sheboygan & Fond du Lac Co., WI T7: Dodge, Jefferson & Walworth Co., WI T8: Kenosha Co., WI T9: Cook Co., IL T10: Lake, McHenry, Kane, Dupage Co.,IL T11: Will Co., IL & Lake & Porter Co., IN T12: Remainder of 12-km grid T13: IC/BCs
CMAQ/OPTM Results for the Milwaukee Area: NOx Average Contribution to Maximum 8-Hour Ozone Tag 1: Milwaukee Co. Tag 9: Cook Co. Tag 10: 4 Other IL Co.
CMAQ/OPTM Results for the Milwaukee Area: VOC Average Contribution to Maximum 8-Hour Ozone Tag 1: Milwaukee Co. Tag 9: Cook Co. Tag 10: 4 Other IL Co.
CMAQ/OPTM Results for a Monitoring Site: NOx & VOC Average Contribution to Maximum 8-Hour Ozone IC/BCs Milwaukee Co. 12-km grid Milwaukee Bayside
Summary CMAQ/OPTM Results for All Monitoring Sites: NOx & VOC
CMAQ/PPTM Results for a Monitoring Site 12-km grid IC/BCs Milwaukee Co. Milwaukee Virginia Fire Station
CMAQ/PPTM Results for a Monitoring Site 12-km grid IC/BCs Waukesha Co. Milwaukee Co. Waukesha
Summary for Milwaukee • OPTM & PPTM can be used to quantify • the contribution of emissions (by species) from specified source regions to CMAQ-derived concentrations • the potential for sources/source regions to contribute to nonattainment in a given area • Contributions vary by location and are different for the different species (NOx, VOC and PM species) • Ozone & PM2.5 nonattainment issues in the Milwaukee area are the combined result of local emissions as well as intra- & inter-state transport
Application of CMAQ/PPTM to Support the §812 Cost/Benefit Analysis • Objectives: • Quality assurance • To quantify and compare the source category contributions to PM2.5 both with and without the Clean Air Act Amendments (CAAA) • Specs: • National-scale modeling domain • Annual simulation period; two scenarios (2010 without CAAA and 2010 with CAAA) • 7 tagged source categories
Application of CMAQ/PPTM for the §812 Modeling Analysis: Domains 36-km resolution for PM2.5
Application of CMAQ/PPTM for the §812 Modeling Analysis: Tags • T1: EGU sources (U.S.) • T2: Non-EGU point sources (U.S.) • T3: On-road mobile sources (U.S.) • T4: Non-road mobile sources (U.S.) • T5: Area (non-point, non-mobile) sources (U.S.) • T6: Initial and boundary conditions (IC/BCs) • T7: All other sources (natural emissions, offshore sources, and non-U.S. sources)
CMAQ/PPTM Results: Contribution from EGU Sources (Tag 1) Annual Average PM2.5 2010 without CAAA 2010 with CAAA
CMAQ/PPTM Results: Contribution from Non-EGU Point Sources (Tag 2) Annual Average PM2.5 2010 without CAAA 2010 with CAAA
CMAQ/PPTM Results: Contribution from On-Road Sources (Tag 3) Annual Average PM2.5 2010 without CAAA 2010 with CAAA
CMAQ/PPTM Results for a Monitoring Site Philadelphia
Summary of PPTM Results for the §812 Modeling Analysis • PPTM used as a probing tool to attribute the overall reductions in PM2.5 (due to the CAAA measures) to specific source categories • Total simulated PM2.5 concentration is lower under the CAAA scenario, primarily due to reductions in area- & point-source (EGU & non-EGU) emissions (relative importance varies by region and by location) • Health benefits can be similarly attributed to source categories, sources, or specific measures
Next Steps • Incorporate OPTM & PPTM (for ozone and PM2.5) into CMAQv4.7 • Incorporate PPTM (for mercury and 10 additional toxic pollutants) into CMAQv4.7 • Distribute OPTM & PPTM codes through CMAS