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UF ENV 6146 - Atmospheric Modeling

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Slide 1Slide 2Slide 3Slide 4Air Quality ModelsSlide 6Slide 7Regulatory Application of ModelsGuideline on Air Quality ModelsSuitability of ModelsTopographyLevels of Sophistication of ModelsScreening ModelsSlide 14Slide 15Preferred/Recommended ModelsSlide 17Slide 18Slide 19Slide 20Slide 21Alternative ModelsAvailable Alternative ModelsSlide 24Slide 25Slide 26Slide 27Slide 28Slide 29Photochemical ModelingSlide 31Receptor ModelsSlide 33Models for O3, PM, CO, NO2 & PbSlide 35Summary01/14/2019Aerosol & Particulate Research Lab1ENV 6146/6932/4932 Atmospheric Modeling01/14/2019Aerosol & Particulate Research Lab2Q: What is the level of my exposure to these emissions? Is my family safe? Where is safe? How about the adverse impact on the environment (plants, animals, buildings)?Q: Any other real examples?01/14/2019Aerosol & Particulate Research Lab3Newberry/Suwannee Cement PlantPb concentration along highwayVisibilityLandfill gasChemical SpillMilitary OperationBP Oil Rig Explosion01/14/2019Aerosol & Particulate Research Lab4Q: What are the factors that affect the exposure to the emissions?•Temporal and spatial emission rates•Terrain•Chemical transformation•Equilibrium between particles and gases •Pollutant transport•Vertical Mixing01/14/2019Aerosol & Particulate Research Lab5SourceDispersion ModelReceptorModelEmissionModelMeteorologicalModelChemicalModelTemporal and spatial emission ratesTopographyChemical TransformationPollutant TransportEquilibrium between Particles and gasesVertical MixingAir Quality Models01/14/2019Aerosol & Particulate Research Lab6•Emission Model–Estimates temporal and spatial emission rates based on activity level, emission rate per unit of activity and meteorology•Meteorological Model–Describes transport, dispersion, vertical mixing and moisture in time and space•Chemical Model–Describes transformation of directly emitted particles and gases to secondary particles and gases; also estimates the equilibrium between gas and particles for volatile species01/14/2019Aerosol & Particulate Research Lab7•Source Dispersion Model–Uses the outputs from the previous models to estimate concentrations measured at receptors; includes mathematical simulations of transport, dispersion, vertical mixing, deposition and chemical models to represent transformation. Gaussian Plume, Puff and Grid Models.•Receptor Model–Infers contributions from different primary source emissions or precursors from multivariate measurements taken at one ore more receptor sites. Chemical Mass Balance (CMB), Time Series, Neural NetworksQ: When are model applications required for regulatory purposes?01/14/2019Aerosol & Particulate Research Lab8Regulatory Application of Models•PSD: Prevention of Significant Deterioration of Air Quality in relatively clean areas (e.g. National parks)•SIP: State Implementation Plan revisions for existing sources and for New Source Reviews (NSR)Q: Which type of model is better? Which one should I use?01/14/2019 Aerosol & Particulate Research Lab 9Guideline on Air Quality Models•Revised 40 CFR Pt 51, App. W. – effective 11/9/2005 (http://www.epa.gov/scram001/guidance/guide/appw_05.pdf)–Overview of Model Use–Recommended Air Quality Models – Preferred and Alternative–Traditional Stationary Source Models–Model use in Complex Terrain–Models for O3, PM, CO and NO2 –Other Model Requirements–General Modeling Considerations–Model Input Data–Accuracy and Uncertainty of Models–Regulatory Application of Models01/14/2019 Aerosol & Particulate Research Lab 10•The meteorological and topographical complexities of the area•The level of detail and accuracy need for the analysis•The technical competence of those undertaking such simulation modeling•The resources available•The detail and accuracy of the data base; i.e. emission inventory, meteorological data and air quality dataSuitability of Models01/14/2019 Aerosol & Particulate Research Lab 11TopographySimple Terrain•Terrain features are all lower in elevation than the top of the stack of the source•Criteria pollutants•Average time of concentration estimates ranges from 1 hour to annual averageComplex Terrain•Terrain exceeding the height of the stack•SO2 and PM from stationary sourcehttp://www.fire.nist.gov/fire/aloft/01/14/2019 Aerosol & Particulate Research Lab 12•Screening: simple estimation techniques use preset, worst-case meteorological conditions to provide conservative estimates. Purpose?•Refined: Analytical techniques that provide more detailed treatment of physical and chemical atmospheric processes, require more detailed and precise input data and provide more specialized concentration estimates. So what?Levels of Sophistication of Models01/14/2019 Aerosol & Particulate Research Lab 13•Available at http://www.epa.gov/ttn/scram/dispersion_screening.htm •AERSCREEN: a screening model based on AERMOD. The model will produce estimates of "worst-case" 1-hour concentrations for a single source, without the need for hourly meteorological data, and also includes conversion factors to estimate "worst-case" 3-hour, 8-hour, 24-hour, and annual concentrations. •RTDM3.2 (Rough Terrain Diffusion Model): a sequential Gaussian plume model designed to estimate ground-level concentrations in rough (or flat) terrain in the vicinity of one or more co-located point sources. Screening Models01/14/2019 Aerosol & Particulate Research Lab 14•CTSCREEN (Complex Terrain Screening model): a Gaussian plume dispersion model designed as a screening technique for regulatory application to plume impaction assessments in complex terrain. •SCREEN3: a single source Gaussian plume model which provides maximum ground-level concentrations for point, area, flare, and volume sources, as well as concentrations in the cavity zone, and concentrations due to inversion break-up and shoreline fumigation. •TSCREEN: (Toxics Screening) a Gaussian model that implements the procedures to correctly analyze toxic emissions and their subsequent dispersion from one of many different types of possible releases for superfund sites. It contains 3 models within it, SCREEN3, PUFF, and RVD (Relief Valve Discharge).01/14/2019 Aerosol & Particulate Research Lab 15•VISCREEN: calculates the potential impact of a plume of specified emissions for specific transport and dispersion conditions. •VALLEY: a steady-state, complex terrain, univariate Gaussian plume dispersion algorithm designed


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