Cristina Gonzalez-Maddux
ITEP
MODEL INPUTS AND
FEDERAL GUIDANCE
CRISTINA GONZALEZ-MADDUX
ITEP, 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??
Where are the pollutants headed? How fast? What’s the plume doing?
Coning
Fanning
Looping
Fumigation
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
Lofting
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 plant
Upper right: Eulerian photochemical
model – Boylan et al. 2002, Atmos. Env.
RECEPTORS – REAL WORLD EXAMPLES
RECEPTORS – REAL WORLD EXAMPLES
Photo: Oxbow Coal Mine Somerset, CO
Near-field: < 1 km from mine site
Red Cliff Mine in Mesa and Garfield counties, CO
Resource: Coal
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
AERMOD
 Gaussian plume model
 Steady state model
 Within 50 km
 Preprocessors



AERMET (Met preprocessor)
– Surface and Upper air
data
AERMAP (Terrain processor)
– Terrain files
BPIP (building downwash)
 Input parameters:
o
o
o
o
o
Met data
Buildings
Sources
Receptors
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 data
o Buildings
o Sources
o Receptors
o 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-450/4-87-007
EPA-454/B-08-002
EPA-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
WIN PRIZES!