May 15, 2006

Peter Courtney

Georgia Department of Natural Resources

Environmental Protection Division - Air Protection Branch

4244 International Parkway, Suite 120

Atlanta, Georgia 30354

Re: Protocol for Best Available Retrofit Technology Exemption Modeling: Brunswick Mill

Georgia-Pacific Corporation (GP) is pleased to submit this Protocol for Best Available Retrofit 

Technology (BART) Exemption air modeling for our pulp and paper facility in Brunswick, 

Georgia. BART is required for any eligible source that ‘‘emits any air pollutant which may 

reasonably be anticipated to cause or contribute to any impairment of visibility” in any 

mandatory Class I federal area. 40 CFR Part 51 Appendix Y states, “You can use dispersion 

modeling to determine that an individual source cannot reasonably be anticipated to cause or 

contribute to visibility impairment in a Class I area and thus is not subject to BART.” The 

enclosed protocol describes our proposal for this dispersion modeling. The VISTAS Regional 

Planning Organization (RPO) is providing the technical resources for the analysis through their 

contractor, Earth Tech. While many of the components of a protocol for this analysis are 

thoroughly documented in the VISTAS common protocol, this document provides sourcespecific information.

We look forward to addressing any questions or concerns you have with this protocol. Please 

contact me at (404) 652-4293; FAX (404) 654-4706; mjaguila@gapac.com.

Sincerely,

Mark J. Aguilar P.E.

Senior Environmental Engineer

Georgia-Pacific Corporation

Cc: Jill Holmes, Brunswick Mill
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1.0 INTRODUCTION............................................................................................................. 1

1.1. Overview of the Regional Haze BART Process............................................................... 1

1.2. Organization of the Protocol............................................................................................. 2

2.0 SITE DESCRIPTION....................................................................................................... 2

3.0 VISTAS CONTRIBUTION TO CALPUFF MODELING ........................................... 7

4.0 MODEL DISCUSSION.................................................................................................... 7

4.1 Exemption Procedures.................................................................................................. 7

4.2 CALPUFF Configuration............................................................................................. 8

5.0 RESULTS AND DETERMINATION OF IMPAIRMENT.......................................... 9

5.1 Impact Threshold.......................................................................................................... 9

5.2 Presentation of Modeling Results.............................................................................. 10

6.0 QUALITY ASSURANCE PLAN................................................................................... 12
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1.0 INTRODUCTION

1.1. Overview of the Regional Haze BART Process

Under regional haze regulations, the Environmental Protection Agency (EPA) has issued final

guidelines dated July 6, 2005 for Best Available Retrofit Technology (BART) determinations 

(70 FR 39104-39172). The regional haze rule includes a requirement for BART for certain large 

stationary sources, such as our pulp & paper facility in Brunswick, Georgia. Sources are BARTeligible if they meet three criteria on potential emissions of visibility-impairing pollutants, the 

date when the source was put in place and fall within one of the source categories listed in the

guidance. The guidance requires a BART engineering evaluation using five statutory factors for 

any BART-eligible source that can be reasonably expected to cause or contribute to impairment

of visibility in any Class I areas protected under the regional haze rule. (Note that, depending on 

the five factors, the evaluation may result in no control.) Air quality modeling is an important 

tool available to the States to determine whether a source can be reasonably expected to

contribute to visibility impairment in a Class I area.

The process of establishing BART determination consists of four steps:

1) Identify whether a source is “BART-eligible” based on its source category, when it was 

put in service, and the magnitude of its emissions of one or more “visibility-impairing” air 

pollutants. The BART guidelines list 26 source categories of stationary sources that are

BART-eligible. Sources must have been put in service between August 7, 1962 and

August 7, 1977 in order to be BART-eligible. Finally, a source is eligible for BART if

potential emissions of visibility-impairing air pollutants are greater than 250 tons per year. 

Qualifying pollutants include primary particulate matter (PM10) and gaseous precursors to

secondary fine particulate matter, such as SO2 and NOx. VISTAS has determined that

neither ammonia nor volatile organic compounds (VOCs) should be included as visibilityimpairing pollutants for BART eligibility.

2) Determine whether a BART-eligible source can be excluded from BART controls by

demonstrating that the source cannot be reasonably expected to cause or contribute to

visibility impairment in a Class I area. The preferred approach is an assessment with an air 

quality model such as CALPUFF or other appropriate model followed by comparison of

the estimated 24-hr visibility impacts against a threshold above estimated natural

conditions to be determined by the States.1 The threshold to determine whether a single

source “causes” visibility impairment is set at 1.0 deciview (dv) change from natural

conditions over a 24-hour averaging period in the final BART rule (70 FR 39118). The

guidance also states that the proposed threshold at which a source may “contribute” to

visibility impairment should not be higher than 0.5 dv although, depending on factors

affecting a specific Class I area, it may be set lower than 0.5 dv. The test against the

 

1 Guidance to determine the level of the natural conditions baseline for BART modeling purposes is still under 

development by VISTAS members states and EPA Region IV.
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threshold is “driven” by the contribution level, since if a source “causes”, by definition it

“contributes”. 

3) Determine BART controls for the source by considering various control options and

selecting the “best” alternative, taking into consideration:

a) Any pollution control equipment in use at the source (which affects the 

availability of options and their impacts),

b) The costs of compliance with control options,

c) The remaining useful life of the facility, 

d) The energy and non air-quality environmental impacts of compliance, 

and

e) The degree of improvement in visibility that may reasonably be 

anticipated to result from the use of such technology.

Note that if a source agrees to apply the most stringent controls available to BART-eligible 

units, the BART analysis is essentially complete and no further analysis is necessary (70

FR 39165).

4) Incorporate the BART determination into the State Implementation Plan for Regional

Haze, which is due by December 2007.

Step 2 described above reflects 40 CFR Part 51 Appendix Y which states that, “You can use 

dispersion modeling to determine that an individual source cannot reasonably be anticipated to 

cause or contribute to visibility impairment in a Class I area and thus is not subject to BART.” 

(70 FR 39162) This “individual source attribution approach” determines if a BART-eligible 

source (i.e., collection of eligible emission units at a source) is predicted to cause or contribute to 

visibility impairment in a Class I area. As mentioned above, a predicted impact of 1.0 dv change

or more is considered to “cause” visibility impairment, and a predicted impact of 0.5 dv change 

or more is considered to “contribute”. Any source determined to cause or contribute to visibility 

impairment in any Class I area is subject to BART. 

1.2. Organization of the Protocol 

Section 2 presents facility-specific information. Section 3 presents the contribution by VISTAS for 

the BART exemption analyses. Section 4 summarizes the exemption process, modeling approach, 

and model configuration. Section 5 presents the criteria and processing of model results to 

demonstrate what impairment, if any, the facility is predicted to create in the Class I areas. Section 

6 presents the Quality Assurance Plan. 

The exemption modeling is completed in two phases: screening and refined. The sections below 

also identify how values in model input, exemption criteria, and model approach are different in 

these two phases.

2.0 SITE DESCRIPTION
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The Brunswick Mill is located along the Turtle River, approximately 15km upchannel from the 

Atlantic Ocean. The area surrounding the Mill is largely rural or undeveloped to the north and 

west, open water to the south, and generally flat in all directions. Figure A-1 presents a 

topographic map of the G-P Brunswick Mill vicinity.

The Brunswick Mill is a major manufacturer of paper products and fluff pulp. Operations at the 

facility include pulping, steam generation, bleaching, papermaking, and converting. The 

feedstock used by a paper mill can come from a variety of sources, including virgin wood and 

recycled paper (post-manufacturing and post-consumer). The Mill recycles all paper trimmings 

and damaged paper (broke) within the plant. The papermaking operations at the Brunswick Mill 

consist of three paper machines (Nos. 3, 4, and 5). The steam plant at the Mill consists of one 

multi-fuel boiler (No. 4 Power Boiler) which primarily combust bark/wood waste, fuel oil,

natural gas, and two power boilers (Nos. 6 and 7) capable of firing natural gas and No. 6 fuel oil. 

The steam generated in these boilers is sent to a common header for distribution in the Mill.

The only BART-eligible emission units are the No. 5 Recovery Furnace (with 2 stacks), No. 4 

Paper Machine, and No. 5 Smelt Dissolver Tank.

Table 1. Source Parameters, Brunswick Mill BART Eligible Units

Stack ID # R401 R402 MG04 R403

Emissions Unit Name No. 5 

Recovery 

Furnace

No. 5 

Recovery 

Furnace

No. 4 

Paper 

Machine

No. 5 

Smelt 

Dissolver 

Tank

East km 450.275 450.276 450.347 450.275

North km 3448.723 3448.713 3448.460 3448.732

Zone 17 17 17 17

Location 

UTM

Datum NAR-C NAR-C NAR-C NAR-C

Stack Height m 82.9 82.9 19.8 80.5

Base Elevation m 1.5 1.5 1.5 1.5

Diameter m 3.95 3.95 3.66 1.04

Gas Exit Velocity m/s 8.20 8.20 14.33 18.6

Stack Gas Exit 

Temp. K 474 474 339 350
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448000 449000 450000 451000 452000 453000 454000

UTM East (m)

Figure 1. Topographic Map of Brunswick Mill Vicinity

3445000

3446000

3447000

3448000

3449000

3450000

3451000

3452000

U

T

M

N

orth (m)

(Source: USGS)
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Table 2. Maximum 24-hour Actual Emissions, Brunswick Mill BART Eligible Units.

Parameter

No. 5 

Recovery 

Furnace

(N Stack)

No. 5 

Recovery 

Furnace

(S Stack)

No. 4 

Paper 

Machine

No. 5 

Smelt 

Dissolver 

Tank

Fuels

Black 

Liquor

Black 

Liquor None None

Existing Control 

Equipment ESP ESP None

Scrubber/

Demister

SO2 Emissions gram/sec 3.88(a) 3.88(a) 0 0.16

H2SO4 Emissions gram/sec 0.225 0.225 0 0

NOx Emissions gram/sec 10.4 10.4 0 0.35

PM10 Emissions gram/sec 2.61(b) 2.61(b) 0.111 2.1

PM2.5 Emissions gram/sec 1.6 1.6 0.111 1.9

PM Speciated Emissions % filterable % 88 88 No data 84

condensable% 12 12 No data 16

Notes:

(a) Maximum short term emissions reflect 100% Black Liquor firing at a rate of 4 millions lbs BLS/day. The Mill has 

tested emission for this source to determine that maximum actual emissions are less than 260 tpy of SO2.

(b) Reflects MACT limit of 0.021 grains/dry standard cfm corrected to 8% oxygen

BUILDING DOWNWASH 

As presented below, the Brunswick Mill is within approximately 26 km of the Wolf Island Class 

I Area. For air permit applications, GP has evaluated the effect of building downwash on 

predicted air quality concentration levels in the modeling analysis. For this analysis, GP 

proposes to use the US EPA-developed Building Profile Input Program-PRIME to determine the 

appropriate direction-specific building dimensions for all modeled sources at the Mill for the 

Wolf Island receptors only. GP has submitted the model-ready downwash input text in its 

January 2006 PSD permit application for Mill Optimization (currently under review at GDNR). 

As all other Class I areas are greater than 100 km from the Mill, GP proposes not to include the 

downwash information for those receptors.

Figure 2 presents a regional map showing the Brunswick Mill and all PSD Class I Areas within

300 km. 
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200 250 300 350 400 450 500 550 600 650

UTM East (km)

Figure 2. Class I Area Receptors within 300km of GP Brunswick

3200

3250

3300

3350

3400

3450

3500

3550

3600

3650

GP

Okefenokee

Wolf Island

Cape Romain

Chassahowitzka

St. Marks
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3.0 VISTAS CONTRIBUTION TO CALPUFF MODELING

For this application of BART Exemption Modeling, VISTAS is providing the technical analysis 

through its contractor, Earth Tech. Earth Tech will apply its compiled data for the 12-km 

datasets.

VISTAS will provide updates and supporting information concerning the VISTAS Common 

Modeling Protocol on the VISTAS website. In addition, VISTAS will make publicly available 

the following data bases developed by Earth Tech:

• VISTAS version of the CALPUFF modeling system, maintained on the Earth Tech 

website. And will not be updated further unless errors are found in the code.

• 12-km CALMET output files for 2001, 2002, and 2003 produced as described in 

previous sections. Further detail on model configuration and settings will be 

provided with the output files and will be made available on the CALPUFF website.

• CALMET will include a software modification to allow the meteorological data 

inputs into CALMET to be used to generate finer grid CALMET files without having 

to go back to the original MM5 output files

• Five 4-km CALMET subdomains for 2001, 2002, and 2003, produced as described in 

previous sections. Further detail on model configuration and settings will be 

provided with the output files and will be made available on the website.

• File with CALPUFF model configuration and settings sufficient to replicate 

CALPUFF modeling done for VISTAS using 12 km CALMET, including

o Ozone data used to run CALPUFF

o Ammonia data used to run CALPUFF and to partition NO3 in POSTUTIL.

o Background concentrations files for use in POSTUTIL 

o All other set up files used in VISTAS 12-km CALPUFF run

4.0 MODEL DISCUSSION

4.1 Exemption Procedures

For determining if a BART-eligible source is subject to a full BART engineering analysis,

GDNR is using a two-tier approach. For the initial exemption modeling use CALPUFF with 12-

km grid CALMET. For finer resolution of meteorological fields, use CALPUFF with CALMET 

of 4-km or smaller grid size. For sources with Q/d less than or equal to 10 (such as the

Brunswick Mill), VISTAS is funding Earth Tech to assist States with the initial CALPUFF
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exemption modeling. Each State will prioritize which sources will be offered modeling by

VISTAS. Modeling of these sources will be conducted in priority order to first accommodate

States with nearer term timing constraints in their SIP development process.

For the 12-km initial modeling exemption test, compare the highest single 24-hour average value 

across all receptors in the Class I area to the threshold value of 0.5 dv. If the highest 24-hr 

average value is below 0.5 dv at all Class I areas, then the source is not subject to BART. If the 

highest 24-hr average value is greater than 0.5 dv, then the source may choose to perform finer

grid modeling for exemption purposes or may accept determination that the source is subject to

BART and proceed to establish visibility impacts prior to and after BART controls. If using the 

single highest 24-hr average value proves, after initial 12-km grid CALPUFF modeling, to be too 

conservative a screening level, VISTAS may allow some exceedances of the threshold value for

exemption purposes, up to no more than the 98th percentile value. 

The 12-km modeling results can be used to focus finer grid modeling for exemption purposes on 

only those Class I areas where impacts greater than 0.5 dv were projected in the 12-km 

modeling.

For finer grid (4 km or less) analyses, use the 98th percentile impact value for the 24-hr average. 

Use either the 8th highest day in each year or the 22nd highest day in the 3-year period,

whichever is more conservative, for comparison to the exemption threshold.

The analysis uses the same model assumptions for pre-BART visibility impact and for BART

control options modeling: establish baseline visibility from the pre-BART run; change one

control at a time; and evaluate the change in visibility impact, i.e. the delta-deciview. Note that 

“no control” may constitute BART.

The VISTAS Common Modeling Protocol consistently recommends conservative assumptions. 

Individual States ultimately have responsibility to determine which, if any, BART controls are

recommended in their State Implementation Plans (SIPs). The VISTAS protocol presents

additional detailed information on the meteorological fields, and specific settings for CALPUFF

and CALPOST (see section 4.33 of the VISTAS Common Modeling Protocol).

4.2 CALPUFF Configuration

Source emissions should be defined using the maximum 24-hour actual emission rate during

normal operation for the most recent 3 or 5 years. If maximum 24-hr actual emissions are not

available, continuous emissions data, permit allowable emissions, potential emissions, and

emissions factors from AP-42 source profiles may be used as available. Specific configuration

settings presented in the VISTAS Common Modeling Protocol are listed below:
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• Use CMAQ modeling data from 2001-2003 to determine background concentrations of

SO4 and total NO3 (HNO3 + NO3). CMAQ data in CALPUFF-ready format will be

provided for each Class I area by VISTAS. After running CALPUFF for an individual

facility, repartition NO3 in POSTUTIL using the CMAQ background data, including that

for NH3.

• Use ozone data from non-urban monitors as the background ozone input. 

• Use the Pasquill-Gifford dispersion method 

• In CALPOST, use Method 6 with monthly average RH for calculating extinction, as

recommended by the EPA. 

• Use EPA default calculations of light extinction under current and natural background

conditions.

The major features and options of the meteorological and dispersion model are summarized and

discussed in the VISTAS Common Modeling Protocol.

As also discussed in the VISTAS Common Modeling Protocol, CALPUFF is currently not

recommended for addressing visibility impacts from VOC because its capability to simulate

secondary organic aerosol formation from VOC emissions is not adequately tested, especially for 

anthropogenic emissions. (Separately, condensable organic carbon can be calculated from

PM10.) 

EPA has given states the option to address ammonia (NH3) emissions from BART-eligible 

sources. VISTAS has also contracted with Georgia Tech to perform emissions sensitivities using 

CMAQ v 4.4 with a refined SOA module and the Jun-Jul and Nov-Dec periods in 2002. At the

time of this protocol, GDNR is not requesting the objective treatment of ammonia emissions

from the source.

5.0 RESULTS AND DETERMINATION OF IMPAIRMENT

5.1 Impact Threshold

The final BART guidance recommends that the threshold value to define whether a source

“contributes” to visibility impairment is 0.5 dv change from natural conditions (although states

may set a lower threshold). The 98th percentile (8th highest annual) 24-hr average predicted

impact at the Class I area, as calculated using CALPOST Method 6 (monthly average relative

humidity values), is to be compared to this contribution threshold value. For this comparison, the 

predicted impact at the Class I area on any day is taken to be the highest 24-hr average impact at 

any receptor in the Class I area on that day. (Note that the receptor where the highest impact

occurs can change from day to day.) According to clarification of the BART guidance received
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from EPA, for a three-year simulation the modeling values to be compared with the threshold are 

the greatest of the three annual 8

th highest values or the 22nd highest value over all three years

combined, whichever is greater. 

For the purposes of the initial analysis, however, the highest value over the three-year period (not 

the 98th percentile value) is to be compared to the contribution threshold. This ensures a

significant measure of conservatism in the initial approach. VISTAS will evaluate the initial

CALPUFF results to determine if using the single highest value provides too conservative a

screen for exemption purposes. If so, VISTAS may increase the number of exceedances of the

contribution threshold that would be allowed and still qualify to exempt a source. 

5.2 Presentation of Modeling Results 

The CALPOST processing computes the daily maximum change in deciviews. A sample of the

summary table produced by CALPOST is shown in Table 3. For evaluating compliance with the 

VISTAS screening threshold, the highest change in extinction value, located at the bottom of the 

CALPOST list file is compared to the threshold value (e.g., 0.5 dv). For example, in the sample 

shown in Table 3, the summary at the bottom shows that the highest visibility impact is 1.219 dv, 

with 9 days over the year showing values greater than 0.5 dv. Therefore this source would not

pass the initial analysis, and finer grid modeling would be required.

In addition to the highest change in deciview value on each day over all the receptors in a

particular Class I area, the CALPOST summary table in Table 3 contains the coordinates of the

receptor, receptor type (D indicates discrete receptors), the total haze level (background + source, 

in dv), the background haze in deciviews, the change in haziness (delta dv), the humidity term

applied to hygroscopic aerosols (F(RH)), and the contribution of each species to light extinction

(in percent of the total source contribution) for SO4, NO3, organics, elemental carbon, coarse

and fine particulate matter.

If the maximum predicted impact is above 0.5 dv, then these results will also be presented:

• Number of receptors within a single Class I area with impact > 0.5 dv

• Number of days at all receptors in the Class I area with impact > 0.5 dv

• Number of Class I areas with impacts > 0.5 dv

Section 4 of the VISTAS Common Modeling Protocol present sample tables for these results.
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Table 3. Example of CALPOST Output, Showing Maximum Daily Impacts of Source and Locations of Those Impacts.

YEAR DAY HR RECEPTOR COORDINATES (km) TYPE DV(Total) DV(BKG) DELTA DV F(RH) %_SO4 %_NO3 %_OC %_EC %_PMC %_PMF 

2001 2 0 3 20.540 79.782 D 5.397 5.358 0.039 4.314 44.33 47.22 3.07 1.07 0.00 4.30 

2001 3 0 9 31.680 79.822 D 4.566 4.421 0.145 1.767 40.75 33.89 9.19 3.24 0.00 12.94 

2001 4 0 1 24.723 77.951 D 4.540 4.540 0.000 2.076 0.00 0.00 0.00 0.00 0.00 0.00 

2001 5 0 77 30.228 94.571 D 4.950 4.939 0.011 3.144 43.13 44.74 4.64 1.45 0.00 6.05 

2001 6 0 1 24.723 77.951 D 5.181 5.166 0.015 3.772 38.58 56.05 1.90 0.70 0.00 2.76 

2001 7 0 3 20.540 79.782 D 6.366 5.745 0.620 5.439 44.98 44.99 3.69 1.26 0.00 5.08 

 .

 .

 .

2001 363 0 113 27.414 103.782 D 5.725 5.652 0.073 5.164 53.49 35.51 4.03 1.39 0.00 5.58 

2001 364 0 113 27.414 103.782 D 6.554 6.521 0.033 7.826 48.12 47.09 1.67 0.64 0.00 2.48 

2001 365 0 1 24.723 77.951 D 6.499 6.499 0.000 7.757 0.00 0.00 0.00 0.00 0.00 0.00 

--- Number of days with Delta-Deciview => 0.50: 9

--- Number of days with Delta-Deciview => 1.00: 2

--- Largest Delta-Deciview = 1.219
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6.0 QUALITY ASSURANCE PLAN 

Air quality modeling covered under this protocol is an important tool for use in

determining whether a BART-eligible source can be reasonable expected to cause or

contribute to visibility impairment in a Class I area, and therefore whether this source

should be subject to BART controls, and if so, to determine the relative benefits of

various BART controls. The purpose of the quality assurance (QA) program is to

establish procedures for ensuring that products produced by the application of the

modeling techniques for BART studies satisfy the regulatory objectives of the BART

program. Section 6 of the VISTAS Common Modeling Protocol presents additional

detailed information on the QA plan.