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Carey Jang, Pat Dolwick, Norm Possiel, Brian Timin, Joe Tikvart U.S. EPA Office of Air Quality Planning and Standards (OAQPS) Research Triangle Park, North Carolina Applications and Evaluation of USEPAs Models-3/CMAQ System: From Regional and Urban Air Pollution to Global Climate Change

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OUTLINE b Overview of USEPAs One-Atmosphere Models-3/CMAQ Modeling System b Applications and Evaluation of Models-3 /CMAQ System b OAQPS Modeling Initiative on Intercontinental Transport and Climatic Effects of Pollutants

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Third-Generation Air Quality Models: U.S.EPAs Models-3/CMAQ System Open-Access Community-Based Models : User-friendly, Modular, Common modeling framework for scientists and policy-makers.User-friendly, Modular, Common modeling framework for scientists and policy-makers. b Advanced Computer Technologies : High performance hardware and software technologies (Cross-platform, GUI, distributed computing, visualization tools, etc.).High performance hardware and software technologies (Cross-platform, GUI, distributed computing, visualization tools, etc.). b One-Atmosphere Modeling : Multi-pollutant (Ozone, PM, visibility, acid deposition, air toxics, etc.), Multi-scale.Multi-pollutant (Ozone, PM, visibility, acid deposition, air toxics, etc.), Multi-scale.

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Air Toxics PM Acid Rain Visibility Ozone One-Atmosphere Management and Modeling MobileSources IndustrialSources AreaSources (Cars, trucks, planes, boats, etc.) (Power plants, refineries/ chemical plants, etc.) (Residential, farming commercial, biogenic, etc.) NOx, VOC, PM, Toxics NOx, VOC, SOx, PM, Toxics NOx, VOC, PM, Toxics Chemistry Meteorology Atmospheric Deposition Climate Change

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Acid Rain (NO 3 - deposition) Water Quality (Nitrogen deposition, Lake Acidification) NO x Visibility (Fine PM) (NOx + VOC + hv) --> Ozone (NO 3 -, NH 4 + ) PM NO x -Related Air Quality Issues

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Acid Rain ( SO 4 2- deposition) SO x (Fine PM) Visibility (SO 4 2-, NH 4 + ) PM SO x -Related Air Quality Issues Water Quality (Lake acidification, Toxics deposition)

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Air Toxics Ozone Acid Rain Visibility PM 2.5 WaterQuality. OH. OH role in pollutants formation : One-Atmosphere NOx + VOC + OH + hv ---> O 3 SOx [or NOx] + NH 3 + OH ---> (NH 4 ) 2 SO 4 [or NH 4 NO 3 ] SO 2 + OH ---> H 2 SO 4 NO 2 + OH ---> HNO 3 VOC + OH ---> Orgainic PM OH Air Toxics (POM, PAH, Hg (II), etc.) Fine PM (Nitrate, Sulfate, Organic PM) NOx + SOx + OH (Lake Acidification, Eutrophication)

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Example of One-Atmosphere Modeling Impact of 50 % NOx Emission Reduction on PM 2.5

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Impact of 50% NOx emission reduction Nitrate PM decrease Sulfate PM decrease

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Impact of 50% NOx emission reduction O 3 decrease HOx decrease

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Formation of Secondary PM : Sulfate PM formation: H 2 SO 4 + 2 NH 3 ---> (NH 4 ) 2 SO 4 (s) Gas Phase: O 2,H 2 O SO 2 + OH ---> H 2 SO 4 Aqueous Phase: H 2 O SO 2 + H 2 O 2 ---> H 2 SO 4 (Dominate over low pH) SO 2 + O 3 ---> H 2 SO 4 Nitrate PM formation: HNO 3 + NH 3 NH 4 NO 3 (aq,s) Gas Phase : (daytime) NO 2 + OH ---> HNO 3 Gas &Aq Phase : (nighttime) N 2 O 5 + H 2 O ---> HNO 3 Oraginc PM formation: Gas Phase : VOC + OH ---> Organic PM (semi- volatile) (Long-chain VOCs, Aromatics, Biogenic VOCs)

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Impact of 50% NOx emission reduction O 3 decrease HOx decrease

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Impact of 50% NOx emission reduction Nitrate PM decrease Sulfate PM decrease

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Third-Generation Air Quality Models: U.S.EPAs Models-3/CMAQ Open-Access Community-Based Models : User-friendly, Modular, Common modeling framework for scientists and policy-makers.User-friendly, Modular, Common modeling framework for scientists and policy-makers. b Advanced Computer Technologies : High performance hardware and software technologies (Cross-platform, GUI, distributed computing, visualization tools, etc.).High performance hardware and software technologies (Cross-platform, GUI, distributed computing, visualization tools, etc.). b One-Atmosphere Modeling : Multi-pollutant (Ozone, PM, visibility, acid deposition, air toxics, etc.), Multi-scale.Multi-pollutant (Ozone, PM, visibility, acid deposition, air toxics, etc.), Multi-scale.

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Models-3/CMAQ System Framework Meteorology Processor Emission Processor Air Quality Model SMOKE or RAMS or PAVE

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Domain : Eastern U.S.A. Grid Resolution : 36-km/12-km/4-km (Nested Modeling) Episode : July 6 - 16, 1995 Models-3/CMAQ Demo & Evaluation: USEPA/ORD

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O 3 Episode in the Northeast U.S. (7/12-15, 1995) Nested 4 km grid domain (144 x 147 cells)

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Measurement Sites and Terrain Features (Courtesy of USEPA/ORD, Daewon Byun)

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Model Predictions vs. Observations

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Models-3/CMAQ Applications at EPA/OAQPS b Western U.S. Application Episodic O 3, July 96, 36/12 km, Evaluation completed b Annual Nationwide U.S. Application 1-atmosphere, annual 1996, 36-km, evaluation & diagnostics, on-going annual 2000 b Eastern U.S. Application 1-atmosphere, July 95, urban applications, 36/12/4-km, emissions control & growth b Intercontinental Transport/Air Quality & Climate Change Intercontinental transport and climatic effects of air pollutants

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12 km western US ozone domain 36 km western US ozone domain 36 km eastern US domain Models-3/CMAQ Modeling: Domain Maps 36 km Annual National US domain 12 km domain 4 km domain

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Western U.S. Application b Objectives : New M3/CMAQ Domain New Episode (July 1996) b Model Setup : Episodic O 3 modeling Meteorology : MM5 Emissions : Tier-2 regridded 36km/12km, 12 layers Compared against UAM-V 177 153

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ModeledObserved

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Chem Diffusion O 3 Conc. dO 3 /dt Process Contribution to O 3 (ppm / hr) O 3 Conc. and Trend ( ppm & ppm / hr) Time Step (7/19 - 7/31/96) Process Analysis : (Los Angeles grid)

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Western U.S. CMAQ Ozone Modeling

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BEIS3 Sensitivity Testing -- Western U.S.

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Annual Nationwide U.S. Application b Features : Annual CMAQ Run Nationwide CMAQ Domain b Model Setup : Annual PM and O 3 (1996) 36-km, 8 vertical layers Meteorology : MM5 Emissions Processing: SMOKE Model Evaluation: Compared against observed data (IMPROVE & CASTNET) & REMSAD

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July 1, 1996 NOx EmissionsSO 2 Emissions

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Models-3/CMAQ Simulation: Annual Average PM 2.5Sulfate PM Organic PM Nitrate PM

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Models-3/CMAQ : Monthly Average (July) PM 2.5 Sulfate PM Organic PM Nitrate PM

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Models-3/CMAQ : Monthly Average (January) PM 2.5 Sulfate PM Organic PM Nitrate PM

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National 1996 CMAQ Modeling: CB4 vs. RADM2 Nitrate PM (Jan. 1996)

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Formation of Secondary PM : Sulfate PM formation: H 2 SO 4 + 2 NH 3 ---> (NH 4 ) 2 SO 4 (s) Gas Phase: O 2,H 2 O SO 2 + OH ---> H 2 SO 4 Aqueous Phase: H 2 O SO 2 + H 2 O 2 ---> H 2 SO 4 (Dominate over low pH) SO 2 + O 3 ---> H 2 SO 4 Nitrate PM formation: HNO 3 + NH 3 NH 4 NO 3 (aq,s) Gas Phase : (daytime) NO 2 + OH ---> HNO 3 Gas &Aq Phase : (nighttime) N 2 O 5 + H 2 O ---> HNO 3 Oraginc PM formation: Gas Phase : VOC + OH ---> Organic PM (semi- volatile) (Long-chain VOCs, Aromatics, Biogenic VOCs)

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NH 3 Sensitivity Modeling Nitrate PM : (January Avg.) Nitrate PM : (January Avg.) Base 50% NH 3 reduction Base 50% NH 3 reduction 1.16 0.62 1.24 0.53 0.70 0.08 1.69 0.09

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144 127 194 132 126 119 134 13976 56 107 113 149 62 137 215 131 99 National 1996 CMAQ Modeling: O 3 (July Max in ppb)

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26 19 26 24 24 22 16 22 24 26 14 14 10 15 18 9 16 9 23 11 12 National 1996 CMAQ Modeling: Visibility (January Average in Deciview)

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National 1996 CMAQ Modeling (January average) Sulfur Wet Deposition Nitrogen Wet Deposition

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OAQPS Modeling Initiative on Intercontinental Transport and Climatic Effects of Air Pollution

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Background : b O 3 and PM are not only key air pollutants, but also major climate- forcing substances; b Reduction of non-CO 2 substances (e.g., O 3 and PM, especially black carbon) could be a viable alternative to CO 2 reduction to curb global warming. A key strategy suggested was to focus on air pollution to benefit regional and local air quality and global climate simultaneously (Hansen et al., PNAS, 2000); b Black carbon could be the second largest heating component after CO 2 contributing to global warming; Control of fossil-fuel black carbon could be the most effective method of slowing glabal warming (Jacobson, Nature, 2001); Air Pollution/Climate Change Modeling Initiative

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(Hansen et al., PNAS, 2001) Climatic Effects of Air Pollution O 3 (0.3+0.1) Black (0.8) Carbon

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Background (continued): b There is also mounting evidence that criteria pollutants originating from some developing countries, especially those in Asia such as China and India, could impact U.S. domestic air quality as well as contribute to the global background of climate-forcing substances. This intercontinental transport issue is expected to worsen with the rapid growth in emissions in these regions. b For example, recent modeling studies showed that by 2020 Asian emissions could contribute as much as 2 ~ 6 ppb of O 3 in the western U.S., offsetting the Clean Air Act efforts up to 25% in that region (Jacob et al., Geophys. Res. Letts., 1999) and increase global mean O 3 level up to 10% (Collins et al., Atmos. Env., 2000); Asian and Sahara dust could contribute a significant amount of PM in the western and southeastern U.S. (Husar, http://capita.wustl.edu/CAPITA/).http://capita.wustl.edu/CAPITA/ ! Air Pollution/Climate Change Modeling Initiative

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(4/7) Asian Dust Storm Event: April 2001 (NASA/TOMS) (4/9) (4/11)(4/12) (4/13)(4/14)

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(Byun and Uno, 2000) Transport of CO : March 2000 (NASA/MOPITT) (3/10) (3/12) (3/13) (3/15)

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Objectives : b To assess available approaches for evaluating the linkage of air pollution to climate change and enhancing modeling capacity within EPA to address these linkage issues. b To explore the impacts of intercontinental transport of O 3 and PM as well as their implications for US domestic and regional air quality and global climate change b To design integrated emissions control strategies to benefit global climate and regional and local air quality simultaneously Air Pollution/Climate Change Modeling Initiative

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Work Plan : Phase I : Short-Term (~6 months) b Establish a better scientific foundation to address the issues related to intercontinental transport and climatic effects of air pollutants by leveraging current studies 1. Global Modeling of O 3 and PM 2. Global Radiative Forcing of Aerosols 3. Emission Inventories for Climate-Forcing Pollutants b Hold a Workshop on Air Quality and Climate Change and establish an expert advisory panel to provide guidance in developing a conceptual model and modeling protocol for Phase II work. Air Pollution/Climate Change Modeling Initiative

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Work Plan : Phase II - Long-Term (~2 years) Based on Phase I effort, a series of activities will be conducted. These efforts may include, but not limited to: 1. Support continued development of global and regional modeling capabilities for studying policy-relevant climatic effects of air pollution and the impacts of intercontinental transport 2. Improve global and regional emission inventories for global and regional modeling of O 3 and PM 3. Develop nesting capability between global chemistry/climate models and regional air quality models 4. Simulate hemispheric or regional air quality under a variety of current and future global and regional emission scenarios 5. Evaluate global and regional air quality models using a diverse set of observational data sets, including data from satellites, surface networks, intensive field studies, etc 6. Assessment of the potential radiative forcing and climate benefits resulting from planned and alternative non-CO2 control strategies Air Pollution/Climate Change Modeling Initiative

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(Byun and Uno, 2000) (MCNC, 2000) 3D Tracer from Gobi DesertTrans-Pacific O 3 simulation Air Pollution/Climate Change Modeling Initiative

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1. Support continued development of global and regional modeling capabilities for studying policy-relevant climatic effects of air pollution and the impacts of intercontinental transport Are there existing global/regional models that can be practically used for the assessment of these two issues simultaneously? If not, which models are better for addressing the climatic effects of air pollution (global climate/chemistry model)? Which are better for addressing the impacts of intercontinental transport (global chemistry/regional air quality models)? 2. Improve global and regional emission inventories for global and regional modeling of O 3 and PM Are current global and regional EI sufficient for O 3 and PM modeling? If not, what are the weaknesses of exising regional/global EI? O 3 and PM precursors (NOx, SOx, VOC, NH 3, etc.), black carbon? Geographic distribution (Asia, America, Europe?) and resolution (global, regional, and urban)? Source categories (biomass burning, biogenic emissions, domestic, mobile/point/area sources, etc.)? EI modeling tools to convert EI to data needed for modeling? Charge Questions

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3. Develop nesting capability between global chemistry/climate models and regional air quality models Are the chemical boundary conditions sufficiently represented in regional air quality models? Do global models have sufficient resolution to address regional impacts? Is grid-nesting between global and regional models a good approach to bridge these gaps? 4. Simulate hemispheric or regional air quality under a variety of current and future global and regional emission scenarios What current and future scenarios are to be simulated? Emissions sensitivity scenarios (NOx, SOx, VOC, BC, CH 4, etc.)? Source categories sensitivity scenarios (fossil fuel, transportation, biomass burning, etc.)? IPCC & LRTAP emission scenarios? Climate change scenarios? Energy use scenarios? Charge Questions

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5. Evaluate global and regional air quality models using a diverse set of observational data sets What data sets are available for evaluating the model results? Satellite and spacecraft? Surface network? Remote/Sentinel monitoring stations? Special field studies? How to effectively use the observed data to evaluate against the model results? 6. Assessment of the potential radiative forcing and climate benefits resulting from planned and alternative non-CO2 control strategies Can global climate models be used to estimate the climate-forcing effects of air pollutants? How to account for the photochemistry of O 3 and PM? Can regional air quality models be used to estimate the climate- forcing effects How to translate changes in pollutant concentrations to climatic- forcing? Can we assume changes in pollutant concentration is linear to changes in radiative properties? How to extrapolate from regional-/hemispheric-scale modeling results to global-scale climate change? Charge Questions