Air Quality Modeling for VISTAS

James W. Boylan, Ph.D.Georgia Department of Natural Resources

(VISTAS Technical Lead for Air Quality Modeling)

2005 EPA Region 4 Modelers WorkshopAtlanta, GA

March 10, 2005

Outline

• Background• VISTAS Phase I Modeling

– CMAQ Sensitivity Tests– Emissions Sensitivity Analysis

• VISTAS Phase II Modeling– Annual Simulations

• PM2.5 and Ozone Modeling• VISTAS Web Links

Background

RPOs: created by EPA to initiate and coordinate activities associated with the management of regional haze at federally mandated Class I areas.

VISTAS Organization• John Hornback (SESARM) – Executive

Director• Coordinating Committee

– VISTAS State Air Directors

• Workgroups– Data, Planning, and Technical Analysis Workgroups

• Workgroup Participants– VISTAS State Governments

• AL, GA, MS, FL, NC, SC, TN, KY, VA, WV– Tribal Governments

• Eastern Band of Cherokee Indians– Federal Agencies

•EPA and FLMs– Industry

• Regional haze is the impairment of visibility caused by the presence of particulate matter in the atmosphere that scatter and absorb light

• Visibility is a measure of the clearness of the atmosphere– Light Extinction (bext)

• bext (Mm-1) = 3*f(RH)*[SO4] + 3*f(RH)*[NO3] + 4*[ORG] + 10*[EC] + 1*[Soils] + 0.6*[PMC]

+ brayleigh

• brayleigh= 10 Mm-1

– Deciview• dV=10*ln(bext/brayleigh)

Regional Haze

Regional Haze Rule

• Objectives of Regional Haze Rule– Achieve natural (no man-made

impairment) visibility conditions at federal mandated Class I areas by 2064 for worst 20% visibility days

– No worsening in visibility at Class I areas for best 20% visibility days

• First progress SIP due April 5, 2008 demonstrating progress toward natural conditions between 2000-2004 and 2018

Evaluation of Reasonable Progress

• Reasonable Progress must be demonstrated every 10 years

Natural Background

20% Haziest Days

2000 2018 Year 2064

dV

20% Cleanest Days

http://vista.cira.colostate.edu/views/

bext on 20% Haziest Days (2002)

VISTAS Class I Areas

CM

Soil

Organics

EC

NH4NO3

(NH4)2SO4

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bext on 20% Haziest Days (2000-2002)

Mountain Sites Coastal Sites

VISTAS Modeling Approach• Modeling Systems used by VISTAS

– MM5 for meteorological modeling– SMOKE for emissions modeling– CMAQ for air quality modeling

• Phase I Modeling– Evaluate models for 3 episodes to identify

optimal model configuration for annual modeling

– Preliminary evaluation of emission sensitivities to help develop control strategies

• Phase II Modeling– Perform annual modeling for 2002 and 2018

for use in Regional Haze SIPs

Future year emissions (e.g., 2018)

Compare to Air Quality Goals

Emissions control strategyModeling Complete

Pollutant distributions and sensitivities

Future year (e.g., 2018) emissions with controls

NO YES

Reasonable progress and future year modeling

Air Quality Model Both modeling runs use the same meteorological & air quality inputs

Note:Air Quality Model

Pollutant distribution

Model Performance Evaluation

Base year emissions (e.g., 2002)

Base case modeling

MM5

Meteorological Observations 3-d model predictions Land use, surface elevation, etc

3-D Meteorological Fields (temperature, wind speed, wind direction, humidity, etc)

CMAQ SMOKE

Initial and boundary conditions

Photolysis rates NRM

MOBILE6

TP+

Measured EIEGAS

3-D Pollutant Distributions and 3-D Sensitivities

VISTAS Modeling System

CMAQ is a Grid-Based Model

Si Si

Riui ui

ui

Ki Ki

Ki

iiiii SRcKcut

c

Modeled Mobile NO Emissions

Modeled Wind Vectors

Modeled PM2.5

Phase I CMAQ Sensitivities

Phase I Modeling Overview

• Literature Review• Emissions Modeling for 3 episodes – SMOKE• Air Quality Modeling for 3 episodes – CMAQ

– Perform Model Configuration Sensitivity Tests– Recommend Optimal Model Configuration

• Protocol for Phase II Modeling• Technical Web Site

– http://pah.cert.ucr.edu/vistas/

Phase I Modeling Details• Air Quality Modeling Team

– Environ International Corporation– University of California – Riverside– Alpine Geophysics, LLC

• Modeling Episodes– January 1 ‑ 20, 2002 (20 episode days + ramp‑up

days)– July 13 ‑ 21, 1999 (9 episode days + ramp‑up days) – July 13 ‑ 27, 2001 (15 episode days + ramp‑up

days)

• Modeling Domain– 36 km grid resolution (149 x 113)– 12 km grid resolution (169 x 178)– 19 vertical layers (collapsed from 34 MM5 layers)

VISTAS 36 km Grid

VISTAS 12 km Grid

Model Performance Evaluation

• Evaluate for each major component of PM– Sulfate (SO4) Nitrate (NO3)– Elemental Carbon (EC) Organic Carbon (OC)– Soil (Other PM2.5) Coarse Mass (CM)

• Evaluate separately across each network– IMPROVE (24-hr speciated PM and PM mass)– CASTNet (Weekly speciated PM, some gas)– STN (24-hr speciated PM)– SEARCH (24-hr and hourly speciated PM/gas)– AQS (Hourly gaseous species: O3, NO2, SO2, CO)– NADP (Weekly wet deposition: SO4, NO3, NH4)

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SEARCH

STN

NADP

AQS

Monitoring Networks

Summary of Model Performance

• January 2002 Episode– Sulfate, Elemental Carbon, Organic Carbon, and

Coarse Mass in the “Ball Park”– Large Nitrate Overestimation

• Ammonia Emissions (Magnitude and Temporal Distribution)?

• Dry Deposition? Chemistry? Nighttime Mixing? Others?

– Large Soil Overestimation• Emissions (Magnitude and Speciation)? • Mixing (PBL Heights)? Others?

• July 1999 and July 2001 Episodes– Sulfate, Elemental Carbon, Organic Carbon, and

Coarse Mass in the “Ball Park”– Nitrate Underestimation– Soil Overestimation

1) Fugitive Dust Transport Factor• FDTF=1.0 vs. FDTF=0.25 vs. FDTF=0.05

2) Number of Vertical Layers• NLAYS=34 vs. NLAYS=19

3) Vertical Diffusivity - Minimum Kz • Kz_min=1.0 vs. Kz_min=0.1

4) Ammonia Emissions (Winter Episode)• 0% Reduction vs. 50% Reduction• Standard Diurnal Pattern vs. Revised Diurnal Pattern

5) Mexican/Canadian Emissions • MX/CAN Emissions vs. No MX/CAN Emissions

6) Boundary Conditions• EPA Default vs. GEOS-CHEM

7) Boundary Layer Heights – Minimum PBLs• Standard PBL Code vs. Revised PBL Code

CMAQ Sensitivity Tests

8. Alternative MM5 Configuration• Pleim-Xiu vs. NOAH-ETA-MY

9. Aerosol Mass Conservation• No Patch vs. GT Patch

10.Alternative Chemical Mechanisms• CB-IV vs CB4-2002 vs. SAPRC-99

11.Alternative Aerosol Module• AE3/ISORROPIA vs. CMAQ–AIM

12.Grid Resolution• 36 km vs. 12 km

13. Alternative Air Quality Model• CMAQ vs. CAMx

CMAQ Sensitivity Tests (cont.)

Phase I Emission Sensitivities

Approach• Georgia Tech performed emission sensitivities

using CMAQ on the VISTAS 12 km modeling domain

• Model simulations for two episodes– July 13-27, 2001 and January 1-20, 2002– 2018 OTB and 2018 OTW (next slide)

• Brute-force sensitivities performed by reducing specific emissions by 30%

• Modeling results used in a relative fashion rather than absolute fashion

• Goal is to perform a PRELIMINARY evaluation of the reasonable progress goals at each Class I area and evaluate the relative importance of various emission reductions

Emission Projection Scenarios• On-the-Books (OTB) - Promulgated as of July 1, 2004

– Atlanta / Northern Kentucky / Birmingham 1-hr SIPs– Combustion Turbine MACT– Gulf Power SCR application– Heavy Duty Diesel (2007) Engine Standard– Industrial Boiler/Process Heater/RICE MACT– Large Spark Ignition and Recreational Vehicle Rule– Nonroad Diesel Rule– North Carolina Clean Smokestacks Act– NOx RACT in 1-hr NAA SIPs– NOx SIP Call (Phase I)– Petroleum Refinery Initiative – RFP 3% Plans where in place for one hour plans– TECO & VEPCO Consent Agreements– Tier 2 Tailpipe– Title IV for Phase I and II EGUs– VOC 2-, 4-, 7-, and 10-year MACT Standards

• On-the-Way (OTW) – OTB Assumptions plus:– Clean Air Interstate Rule (CAIR) – NOx SIP Call (Phase II) – 8-hr attainment plans (e.g., NOx RACT)

Mammoth Cave

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MACA Reasonable Progress Goal

30.3 dV = 206.97 Mm-1

25.44 dV = 127.28 Mm-1

MACA Required Reductions

bext2002 – bext2018 = 206.97 Mm-1 – 127.28 Mm-1

= 79.69 Mm-1

On the Books Regulations reduces extinction by 18.47 Mm-1

Need an additional reduction of: 79.69 Mm-1 - 18.47 Mm-1 = 61.23

Mm-1

Level 1 Sensitivity Acronyms

• OTB-TYP 2018 OTB – 2002 Typical• OTW-OTB 2018 OTW – 2018 OTB• ASO2 30% reduction in all SO2 domain-wide

• ANOX 30% reduction in all NOX domain-wide • ANH3 30% reduction in all NH3 domain-wide

• ASO2NOXNH3 30% reduction in all SO2/NOX/NH3 domain-wide

• AMVOC 30% reduction in all Anthropogenic VOCs domain-wide

• ABVOC 30% reduction in all Biogenic VOCs domain-wide • APRIC 30% reduction in all Primary Carbon domain-wide

Mammoth Cave (KY)Weighted Bext Response at Site to Reductions in

OTB Emissions: Worst 20%

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ASO2NOXNH3

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ABVOC

APRIC

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ext (

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SOIL

EC

OC

NO3

NH4*

SO4

Red line indicates the additional reductions in light extinction beyond 2018 OTB required to reach the Reasonable Progress Goals (Goal – OTB)

Required reductions from 2002 79.7 Mm-1

Level 2&3 Sensitivity Acronyms

• GSO2ALL 30% reduction in all ground SO2 domain-wide

• ESO2ALL 30% reduction in all point SO2 domain-wide

• ESO2VCPP (CPP) 30% reduction in all VISTAS point coal-fired power plant SO2

• ESO2VNPP (NPP) 30% reduction in all VISTAS point non power plant SO2

• ESO2VOPP (OPP) 30% reduction in all VISTAS point non coal-fired power plant SO2

• ESO2nonV 30% reduction in all non VISTAS point SO2

• BCSO2 30% reduction in all SO2 boundary conditions

• BCSO4 30% reduction in all SO4 boundary conditions

Mammoth Cave (KY)Weighted Bext Response at Site to Reductions in

OTB Emissions: Worst 20%

-100.0

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ESO2nonV

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Red line indicates the additional reductions in light extinction beyond 2018 OTB required to reach the Reasonable Progress Goals (Goal – OTB)

Required reductions from 2002 79.7 Mm-1

Reasonable Progress for 2018 OTW?

YesNoMaybeUndetermined

Preliminary Results

Phase II Annual CMAQ Modeling

Phase II Modeling Approach• Annual (12 month) CMAQ simulations to support

regional haze SIP development– Will be modeling entire year of 2002

• Emissions and Air Quality Modeling– Initial (completed) and Final (May 2005) AQ Modeling with

“Actual” Baseyear Emissions • Model Performance Evaluation

– AQ Modeling with “Typical” Baseyear Emissions (April 2005)• Same assumptions for Seasonal Distributions as Projected Future Year

Emissions (Point Sources, Fires, etc.) RRFs for SIP– AQ Modeling with Future Year (2018) Emissions (April 2005)

• On-the-Books (OTB) and On-the-Way (OTW)– AQ Modeling with Future Year (2018) Control Strategies (July

2005)– AQ Modeling with Future Year (2009) Emissions (May 2005)– AQ Modeling with Future Year (2009) Control Strategies (Aug.

2005)

• Final Report (delivery date December 2005)

Annual CMAQ Simulations• Need to solve the Atmospheric Diffusion

Equation for each species in each grid cell for each time step– (200 * 100 horizontal grid cells) x (19 vertical

layers) x (100 species) x (4 time step/hour) x (24 hours/day) x (365 days/year)

• IN AN ANNUAL SIMULATION, NEED TO SOLVE OVER 1,330,000,000,000 PARTIAL DIFFERENTIAL EQUATIONS!!!!– Unix or Linux workstations (3.2 GHz )– CPU time ~ 4 months/simulation– CMAQ Inputs 3.0 TB– CMAQ Outputs 1.2 TB/simulation

Sulfate: 12 Months (2002)

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IMPROVE

STN

SEARCH

CASTNET

(+) Goal

(-) Goal

(+) Criteria

(-) Criteria

Modeled Sulfate Bias

Nitrate: 12 Months (2002)

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IMPROVE

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CASTNET

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Modeled Nitrate Bias

Organics: 12 Months (2002)

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CASTNET

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Modeled Organics Bias

Elem. Carbon: 12 Months (2002)

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CASTNET

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Modeled Elemental Carbon Bias

Soils: 12 Months (2002)

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CASTNET

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Modeled Soils Bias

Coarse Mass: 12 Months (2002)

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CASTNET

(+) Goal

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Modeled Coarse Mass Bias

Performance Summary• Sulfate and Elemental Carbon

– Very good performance for all months

• Nitrate– Large over-predictions in winter– Updated ammonia monthly emission profiles (CMU

model)• Resulted in lower NH3 emissions in winter (~60%) and

much better nitrate performance

• Organics– Large under-predictions in summer– Updated CMAQ to include secondary organic aerosol

(SOA) formation due to sesquiterpenes and polymerization (neither process currently accounted for in model)

• Resulted in much better organics performance

• Soils and Coarse Mass– Small contribution to light extinction due to small

extinction coefficients

PM2.5 and Ozone

PM2.5 Modeling

• PM2.5 NAAQS– 15 g/m3 (annual average over 3 years)– 65 g/m3 (24-hour average)

• Most states will use VISTAS modeling as starting point for PM2.5 modeling– Annual modeling for 2002, 2009, and 2014 (?)

• PM2.5 modeling collaboration between VISTAS states (e.g., AL and GA)

VISTAS 12 km

ALGA 12 km

8-Hour Ozone Modeling• 8-Hour Ozone NAAQS

– Each monitor in an area must show the three year average of the fourth highest daily 8-hour ozone concentration to be 0.08 ppm or below

– Average of three Design Values (2001, 2002, 2003)

• Some states will use VISTAS modeling as starting point for 8-hr ozone modeling

• Atlanta 8-hour ozone modeling – Will use ALGA 12 km modeling as starting point– Created new 4 km modeling domain – Modeling entire ozone season (05/20/02 –

09/20/02)– Modeling 2009 for attainment demonstration

VISTAS 12 km

ALGA 12 km

GA 4 km

GA Regional Sensitivities• Sensitivity of ozone (ppb/tpd) and PM2.5 (g/m3/tpd)

• 1 Winter and 1 Summer Episode ( 1 week)– Prefer 4 seasonal episodes with high summer ozone

• 10% Emission Reductions– NOx, VOCs, SO2, NH3, and primary PM2.5

• ALGA 12-km domain– 4-km for summertime VOCs (?)

• Emission Regions– Atlanta, Macon, Columbus, Chattanooga, Floyd

County

• 5 species * 4 episodes * 7 days/episode * 5 regions 700 modeled days

GA Point Source Sensitivities

• Sensitivity of ozone (ppb/tpd) and PM2.5 (g/m3/tpd)

• 1 Winter and 1 Summer Episode ( 1 week)– Prefer 4 seasonal episodes with high ozone summer

• SCR (NOx) and Scrubber (SO2) Reductions

– Discrete amounts (> 80%)

• ALGA 12-km domain– 4-km preferred to capture plume structure

• Emission Locations– Bowen (SO2), Scherer (NOx,SO2), Branch (NOx, SO2), Yates

(NOx, SO2), Wansley (SO2), McDonough (NOx,SO2), others (?)

• 10 scenarios * 4 episodes * 7 days/episode 280 modeled days

VISTAS Web Links• UCR's website containing presentations, documents,

and protocol associated with VISTAS Phase I emissions and air quality modeling (episodic simulations):– http://pah.cert.ucr.edu/vistas/docs.shtml

• UCR's website containing modeling results associated with VISTAS Phase I emissions and air quality modeling (episodic simulations):– http://pah.cert.ucr.edu/vistas/results.shtml

• UCR's website containing presentations, documents, and workplan associated with VISTAS Phase II emissions and air quality modeling (annual simulations):– http://pah.cert.ucr.edu/vistas/vistas2/docs.shtml

• UCR's website containing modeling results associated with VISTAS Phase II emissions and air quality modeling (annual simulations):– http://pah.cert.ucr.edu/vistas/vistas2/results.shtml

VISTAS Web Links (cont.)• VISTAS website containing presentations and

documents associated with VISTAS Workgroups (Data, Planning, and Technical Analysis):– http://www.vistas-sesarm.org/documents/index.asp

• BAMS website containing presentations and documents associated with episodic and annual MM5 meteorological modeling:– http://www.baronams.com/projects/VISTAS/

• Georgia Tech's website containing presentations and documents associated with VISTAS emission sensitivities:– http://www.ce.gatech.edu/research/vistas/

documents.htm

• Georgia Tech's website containing model results associated with VISTAS emission sensitivities:– http://www.ce.gatech.edu/research/vistas/products.htm

Jim BoylanGeorgia Dept. of Natural

Resources4244 International Parkway,

Suite 120Atlanta, GA 30354

james_boylan@dnr.state.ga.us 404-362-4851

Contact Information

Questions?