Cr i s t ina Gonza lez -MadduxITEPMODEL INPUTS AND

FEDERAL GUIDANCECRISTINA GONZALEZ-MADDUXITEP, RESEARCH SPECIALIST

WHAT ARE OUR INPUTS?

• Fundamental inputs: source data (EI) and met data

What is being emitted and in what quantities??

Are these “named” pollutants according to the CAA??

Clockwise from upper left hand corner: Coning plume, Fanning plume, Fumigation, Lofting plume, Looping plume

Source: US EPA, APTI Lesson 4 – Vertical Motion and Atmospheric Stability

Coning Fanning

Fumigation

Lofting

Looping

Where are the pollutants headed? How fast? What’s the plume doing?

MODEL INPUTS AND CONSIDERATIONS

• Meteorological data• RECALL: Wind speed and direction; Ambient temperature,

Differential temperature; Atmospheric stability class (A-G); Mixing height; Surface roughness

• Receptor Coordinates (x, y, z)

• Options: Grid (C/P), Discrete receptors (C/P), Plant boundary (C/P), Fenceline grids, Multi-tier grids

POLLUTANT RECEPTORS

Above: Chemical manufacturing plantUpper right: Eulerian photochemical model – Boylan et al. 2002, Atmos. Env.

RECEPTORS – REAL WORLD EXAMPLES

RECEPTORS – REAL WORLD EXAMPLES

Near-field: < 1 km from mine siteRed Cliff Mine in Mesa and Garfield counties, COResource: Coal

Photo: Oxbow Coal Mine Somerset, CO

MODEL INPUTS

• Source type• Point• Square, rectangular,

circular, polygon area• Volume• Open pit• Line• Flare

MODEL INPUTS

• Site Data• Geographic location• i.e. Proximity to coast

• Topography – simple v. complex

• Source - Stack data• Diameter• Exit temperature (Ts) and velocity (Vs)

• Pollutant emission rate (Q)• Stack height• Stack diameter

OTHER FACTORS INFLUENCING MODEL SELECTION AND OUTPUT

• Temporal and spatial scales • seconds or hours; 10 km or 1000 km

• Pollutant transport (mobile or stationary; fixed or moving frame)

• Atmospheric turbulence• Met conditions (quiescent v.

turbulent)• Topography• Pollutant type (i.e. stable or

reactive)• Source types (line, area, volume)

Modified from APTI 410

AERMOD PRE-PROCESSORS

CALPUFF PRE-PROCESSORS

AERMODGaussian plume modelSteady state modelWithin 50 km Preprocessors

AERMET (Met preprocessor) – Surface and Upper air data

AERMAP (Terrain processor) – Terrain files

BPIP (building downwash)

Input parameters:o Met datao Buildings o Sourceso Receptorso Averaging periods

CALPUFF• Gaussian puff model• Non-steady state model• > 50 km• Preprocessors▫ CALMET▫ Geophysical preprocessors▫ Met preprocessor▫ CALPUFF (dispersion

model)▫ CALPOST (post-processor)

Input parameters:o Met datao Buildings o Sourceso Receptorso Averaging periods

WHAT IS THE END RESULT?

• Representative model?• Concentrations @ (x, y, z)• Data requirements • Must be representative!• Instrument siting • Data completeness• Analyze and evaluate

What is our ideal model? → one that “most accurately estimates concentrations in the area of interest”US EPA, Appendix W

FEDERAL GUIDANCE ON AQ MODELS

Guideline on Air Quality Models (‘‘Guideline’’)• 40 CFR Ch. I (7–1–99 Edition), APPENDIX W TO PART

51—GUIDELINE ON AIR QUALITY MODELS• What is the Guideline?• “The Guideline recommends air quality modeling techniques

that should be applied to State Implementation Plan (SIP) revisions for existing sources and to new source reviews, including prevention of significant deterioration (PSD).”

• Newest Edition: August 1, 1999• First Published: 1978 (recall CAA enacted in 1977)• Congress “mandated consistency & encouraged

standardization of model applications”• Regulatory app of AQ models – Criteria pollutants under the

CAA

CAA – APPENDIX W

• “Provides a common basis for estimating the air quality concentrations used in assessing control strategies and developing emission limits.”• Regularly updated:• EPA workshops• EPA cooperative agreement with the American Met

Society (representing the scientific community)• Solicitation & review of new models (privately developed

– procedure developed and published in 1980)• Ongoing research in AQ and met modeling

CAA – APPENDIX W

• Guideline provides recommendations on: • air quality models• databases• requirements for concentration estimates • the use of measured data in lieu of model estimates, and • model evaluation procedures

• “…intended for use by EPA Regional Offices in judging the adequacy of modeling analyses performed by EPA, State and local agencies and by industry.”

SAMPLE REFERENCE DOCUMENTS

• Quality Assurance Handbook for Air Pollution Measurement Systems (Vol. IV Meteorological Measurements)• Ambient Monitoring Guidelines for PSD• Meteorological Monitoring Guidance for Regulatory

Modeling Applications

EPA-454/B-08-002

EPA-450/4-87-007EPA-454/R-99-005

SAMPLE REFERENCE DOCUMENTS

• Model-specific guidance documents• δύσκολο να κατανοήσουμε!

FEDERAL LAND MANAGERS

• NEPA Guidance: BLM, USFS, USDOT, FTA, state DOTs, regional transportation districts, municipalities • i.e. USFS guidance docs for smoke, oil and gas,

ski areas, planning “The Clean Air Act and subsequent amendments give Federal land managers an ‘affirmative responsibility’ to protect Air Quality Related Values in Class 1 areas and to protect human health and basic resource values in all areas.” - USFS

US EPA - TTN SCRAM SITE

Technology transfer network - Support Center for Regulatory Atmospheric Modeling• Modeling Guidance and Support• Permit Modeling• SIP Attainment Demonstrations• Toxics Guidance

TTN SCRAM site BINGO GAME

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