# Section 6.8.1, EPA 9-Factor Analyses for the Designation of PM2.5 Montana Nonattainment Areas (pages 6-347 through 6-352)

### Technical Support ( 

### Fine Particle 

### (PM2.5) Designations 

## I US 

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You are here: EPA Home A.ir & Radiation Six Common Air Pollut&s Particulate Matter PMx Designations Techrl~cal Support 

# Technical Support Here you can find links to various technical resources related to the You will need Adobe PM2.5 designations process. Reader to view some ofthe files on this page. See EPA's * Responsa-to

- Com~wnts on PM,. designations (PDF) (258 pp., PDF pag-e to learn 3.9 MB) more. * Technical support document for December 17, 2004 designations * Table of Contents (wit-hAcr0ny.m~) (PDF) (3 pp, 56KBj * Chapter 1: 1ntrodu.ction (withcover paqe) (PDF) (3pp, 64KB) * Chapter 2: EPAPM2.5 Ivonattainment Desiqnations (PDF) (24 pp., 148KB) * Chapter 3: Urban Excess Methodology (PDF) (9 pp, 1.8MB) * Chaper 4: Constructing the Weighted Emissions S~re Metric (PDF) (3pp, 64~~) * Chapters: An Explanation of EPA's Nine-Factor Analysis (3 pp, 76KB) * Chapter 6: Nine Factor Analyses of Individual Nonattainment Areas [PDF) (434 pp, 17.2MB) Chapter7;Su~porting Maps a.nd~-_FiquresSPDFI (49 pp, 95.9MB) Append-lA: Partial County Boundaries (PDF) (8 pp, 44KB) Technology Transfer Network PM2.5 Desiqnations Implementationlechnicg! Information * Technical support document for April 5, 2005 supplemental notice (PDFJ (75 pp, 4.1MB)

## Technical Support for State and Tribal Air Quality Fine Particle 

## (PM2.5) Designations
December 2004



## U.S. Environmental Protection Agency 

## Office ofAir Quality Planning and Standards Integrated Policy and Strategies Group Research Triangle Park, NC 277 11

For information on this document, please contact Mr. Larry Wallace at (919) 541-0906

### 1.0 

### INTRODUCTION This document contains factual and technical data in support ofthe U.S. Environmental Protection Agency's (EPA) designations ofthe fineparticle nonattainment areas. Fine

. particles are those less than 2.5 micrometers in aerodynamic diameter and are also referred to as "PM2.5." Additional supportinginformation is contained in the EPA June 28 and June 29,2004 response letters to the states and tribes. TheJune letters address where EPA agreed with the submitted recommendations and the cases where EPA made modificationstothe states' and tribes' recommendations as authorized under the Clean Air Act (CAA). This chapter presents an overview ofthe PM2.5 designationsprocess. Chapter 2 contains two tables ofEPA's nonattainment designations for PM2.5. Section 2.1 contains a table with nonattainment counties arranged alphabetically by state and then area name. Section 2.2 contains nonattainment counties arranged alphabetically by Region, state, and area name. Chapter 3 discussesthe results and methodology for the urban excess calculation. Chapter 4 discusses weighted emissions scoresmethodology and results. Chapter 5 contains information on the nine-factor analysis methodology. Chapter 6 contains the results of the nine-factor analyses for individual nonattainment areas sorted by EPA Region and state. Chapter 7 contains maps, wind roses, and other documentation to support EPA's designations. 

### 1.1 Background The CAA establishes a process for air quality management through the national ambient air quality standards (NAAQS). Area designations arerequired after promulgation of a new or revised NAAQS. After evaluating numerous health studies and conducting an extensive peer review process, on July 18, 1997, EPA promulgated a PM2.5 standard of 15micrograms per cubic meter, based on the 3-year average ofannual mean PM2.5 concentrations. The 24-hour standard for PM2.5 is 65 micrograms per cubic meter, determined by the 3-year average ofthe annual 98th percentile concentrations. The CAA and the Transportation Equity Act for the 2 1 st Century (TEA-21) required EPA to designate all PM2.5 nonattainment areas by July 2000. However, a number ofevents delayed the implementation ofthe PM2.5 standard. TEA-21 revised the deadlineto publish nonattainment designations in order to provide additional time to collect three years of air quality monitoring data. Additionally, the 1977NAAQS rule was challenged by the American Trucking Association, the U.S. Chamber of Commerce and other state and business groups. SeeAmerican Trucking Assoc. v. EPA, 175F.3d 1027, 1047-48, on rehearing 195 F.3d 4 (D.C. Cir. 1999). In February 2001, the Supreme Court upheld EPA's authority under the CAA to set NAAQS that protect the American public from harmful effects of air pollution. The Supreme Court remanded the case to the D.C. Court of Appeals for disposition of issues the Court did not address in its initial decision. See Whitman v. American Trucking Assoc., 121 S.Ct. 903, 91 1-914'916-919 (2001) (Whitman). In March 2002, the D.C. Circuit rejected all remaining legal challenges to the PM2.5 standard. SeeAmerican Trucking Assoc. v. EPA, 283 F.3d 355 (D.C. Cir. 2002) ATA 111).

### 1.2 Correspondence with States and Tribes Section 107(d)ofthe CAA defines a nonattainment area as "any areathat does not meet (or that contributes to ambient air quality in a nearby areathat does not meet) thenational primary or secondary ambient air quality standard for the pollutant." In February and April 2003, EPA provided guidelines to states and tribes for recommending nonattainment area boundaries forthe PM2.5 standard. Theguidance instructed states and tribes to begin their analysis of attainment and nonattainment area boundaries based on the boundaries of metropolitan areas.The guidance also instructed statesto include in the nonattainment areas any nearby counties contributing to fine particle pollution in those metropolitan areas. EPA alsorecommended that states and tribes use common boundaries for areas to be designated asnonattainment for both PM2.5 and the 8-hour ozone standardsin order to facilitate future planning and implementation activities. EPA listed nine factors for states and tribes to consider asthey developed their boundary recommendations. Chapter 5 contains a detailed discussion ofthese factors and the analysis methodology. States and tribes madetheir initial recommendation of nonattainment area designations toEPA in February 2004. As stated above, in accordance with the CAA, EPA carefully reviewed the state and tribal recommended designations and accompanying documentation todetermine where modifications needed to be made as deemed necessary in light ofthe CAA definition of nonattainment. On June 28 and 29, 2004 EPA responded to the states' and thetribes' recommendations by notifying them regarding where EPA agreed or disagreed with their recommendations. Following the June letters, some states and tribes submitted follow-up data to supporttheir original recommendations. EPA has carefully reviewed all ofthe requests and the data submitted throughout the designations process. Thisdocument contains the technical information and rationale supporting EPA decisionsto designate and classify areas for the PM2.5 NAAQS.

### TABLE OF CONTENTS Chapter Page Abbreviations and Acronyms iii 

### 1.0 Introduction


### ..................................................................................................... 1-1



### .............................................................................................. 

### . 1 1Background 1-1



## ................................................... 1.2 Correspondence with States and Tribes 1-2



## ........................................................ 2.0 EPA PM2.5 Nonattainment Designations 2-1



### .................... 2.1 PM2.5 Nonattainment Designations by State and Area Name 2-1



## .......................... 2.2 PM2.5 Nonattainment Designationsby EPA Region 2-12



### ............................................................................. 3.0 Urban Excess Methodology 3-1



### .................................................................................................... 3.1 Concept 3-1 3.2 Derivation ofUrban Excess


### ...................................................................... 3-3 3.3 Resolution ofUncertainties


### ...................................................................... 3-4



### ............................................................................................ 3.4 Site Selection 3-8



### ......................................... 4.0 Constructing the Weighted Emissions Score Metric 4-1



### ........................................................................ 4.1 Basis and Assumptions 4-1



### ........................................... 4.2 Calculatingthe Weighted Emission Scores 4-2



### .................... 4.3 Comparing Weighted Emissions Scores Among Counties 4-3



## ............................................... 5.0 An Explanation ofEPA's Nine-Factor Analysis 5-1 Factor 1:

### Emissions in Areas Potentially Included Versus Excluded from theNonattainment Area


### .......................................... 5-1 Factor 2: 

### Air Quality in Potentially Included Versus Excluded



### .................................................................................................. Areas 5-2 Factor 3: Population Density and Degree ofUrbanization Including



## ............ Commercial Development in Included Versus Excluded Areas 5-2



### ............................................ Factor 4: Traffic and Commuting Patterns 5-2



### .................................................................... Factor 5: Expected Growth 5-2 Factor 6: 

### Meteorology


### .......................................................................... 5-2 Factor 7: GeographyITopography


### ......................................................... 5-3 Factor 8: 

### Jurisdictional Boundaries


### ...................................................... 5-3



### ................................... Factor 9: 

### Level ofControl ofEmission Sources 5-3TABLE OF CONTENTS CONTINUED Chapter Page 

### 6.0 Nine Factor Analyses of Individual Nonattainment Areas

## ...........................

## .....6-1 7.0 Supporting Maps and Figures 

## ...................................................................... 7-1

### Abbreviations and Acronyms CAA- Clean Air Act CBSA- CoreBased Statistical Area CM- Crustal matter CNSA-Consolidated Metropolitan Statistical Area CSA- Combined Statistical Area EC- Elemental carbon EPA- United States Environmental Protection Agency FIPS- Federal Information Processing Standards FTIR -

### Fourier Transform Infrared IMPROVE- Interagency Monitoring of Protected Visual Environments MDL- Minimum detection limit MOBILE6- Mobile Source Emission Factor Model version 6 NA- Nonattainment NAAQS- National Ambient Air Quality Standards NA-P- Part ofthe county was designated nonattainment NEI- National Emissions Inventory NOx- Nitrogen Oxides OC- Organic carbon OMC- Organic mass by carbon OP-Pyrolized organics PIXE- Particle Included X-Ray Emission PM -

### Particulate Matter PM2.5

## -Particulate Matter with aerodynamic diameter less than 2.5 microns SASS- Source Assessment Sampling System SIP- State lmplementation Plan STN- Speciation Trends Network TEA-21-

### Transportation Equity Act for the 2

### IS' Century (TEA-2 1) 

### TCM- Total carbon mass TOR -Thermal Optical Reflectance TOT-Thermal Optical Transmittance 

### U- Unclassifiable UE- Urban Excess 

### VMT- Vehicle Miles Traveled VOC- Volatile Organic Compound WES- Weighted Emission Score

### 6.8 Region 8 

### Nonattainment Areas 6.8.1 

### EPA 9-Factor Analyses for Montana for the Designation ofPM2.5 Nonattainment Areas Based on air quality data for 2001-2003, the PM2.5 monitor at the Libby Courthouse Annex is violating the annual PM2.5 standard. EPA utilized the 9 factors identified in the April 

### 1,2003 "Designations for the Fine Particle National Ambient Air Quality Standards" guidance to evaluate whether the surrounding rural counties around Lincoln, MT should be included as part of the nonattainment area. However, due to the topographical features and local meteorology within Lincoln County and more specifically around the Libby, Montana vicinity, several of the 

### 9 factors were not significant for this particular nonattainment area when looking at adjacent counties to Lincoln County, MT. Lincoln County is considered a rural county, according to EPA's April 1,2003 "Designations for the Fine Particle National Ambient Air Quality Standards" which defines a rural area as counties or areas not included in or adjacent to urban areas (metropolitan statistical areas (MSA). The adjacent areasto Lincoln County arethe Canadian border to the North, Boundary and Bonner County, Idahotothe West, Sanders County, MT to the South, and Flathead County, MT to the East. Lincoln County contains a violating monitor located in the town of Libby. The Lincoln County PM2.5 nonattainment issue is unique in that the area of impact is localized within and around the vicinity ofthe town ofLibby due to topographical features and meteorology in the area impactedby emissions. Montana's recommendation identifying the PM2.5 nonattainment area included part of Lincoln County (thetown ofLibby and vicinity). EPA initially responded to Montana's recommendation stating that EPA agreed with Montana's recommended nonattainment designation for Lincoln County but that EPA intendedto modify Montana's recommended boundary for the nonattainment area to cover all of Lincoln County. However, based upon supplemental information provided by Montana, EPA is identifying the boundary of this PM2.5 nonattainment area to include a part ofLincoln County as described further below. The following is a brief summary ofthe 9 factor criteria for the Lincoln County, MT area and surrounding counties. These analyses were based on existing available data. The counties recommended as nonattainment are in bold. 

### Factor 1: Emissions in areas potentially included versus excluded from the nonattainment area For this factor, EPA looked at S02,NOx, carbon and crustal PM2.5 emissions. A weighted emissions score was applied toLincoln County and the adjacent counties reflecting the speciation profile ofLincoln County versus the adjacent counties. Counties adjacent to the Lincoln County were assigned an emission score as a way to comparethe emissions from those counties against Lincoln County emissions. The following table has the SO2,NOx, carbon, and crustal PM2.5 emissions and composite emission scores.This information is from the 2001 NEI. (The recommended nonattainment area is in bold.)

Since Lincoln County is considered to be a rural county as defined in EPA's April 

### 1, 2003 PM2.5 Designations Guidance and not a metropolitan statistical area, this factor did not play a significant role in the decision making process. Also, due to the topographical features and meteorology in Lincoln County (see factors 6 and 

### 7below) and more specifically surrounding Libby, MT where the PM2.5 problem is, EPA feels the surrounding counties emissions are not impacting the PM2.5 monitor located at the Libby Courthouse Annex. Factor 2: Air quality in potentially included versus excluded areas 

# I PM2.5 2001-2003 County design value

Flathead 9.1

I

I1 I J



### * Lincoln County PM2.5 monitor is located at the Libby Courthouse Annex, Libby, MT. Bonner I

All adjacent counties to Lincoln, MT are attaining the PM2.5 standard. This factor played a significant role in the decision making process. 8.0 Boundary 8.2

### Factor 3: 

### Population density and degree of urbanization including commercial development in included versus excluded areas The following table has the population and population density for Lincoln County and the adjacent counties. County 2002 Population 

## 1 2002 Population Density (pop. Lincoln 

# 1Flathead I I 18,66S4 77,240 I I



### * Town of Libby, MT population: 2,626; 

### ** Town ofLibby, MTpopulation density: 2,020 personslsquare mile per square mile) 5** 15 Bonner Boundary Sanders

The town ofLibby, where the PM2.5 problem is located has a much higher population density than the remainder ofLincoln County or any of the surrounding counties. Also, due to the commutingpatterns, topographical features and meteorology in Lincoln County (see factors 4, 6 and 

### 7 below), EPA feels the adjacent county populations donot impactthe PM2.5 monitor located at the Libby Courthouse Annex. This factor played a significant role in the decision makingprocess. 

### Factor 4: Traffic and commuting patterns 38,205 10,085 10,367

Commuting Information: 22 8 4

Lincoln County, the design value county, has a total of 6,721 commuters. 

### - Commuterswho remain in Lincoln County: 6,177 Flathead County, an adjacent county, has a total of 34,035 commuters. 

### - Commuters from Flathead County toLincoln County: 85 

### - Commutersthat remain in Flathead County: 32,956 Bonner County, an adjacent county, has a total of 15,570commuters. - Commuters from Bonner County to Lincoln County: 0 

### - Commuters that remain in Bonner County: 12,968 Boundary County, an adjacent county, has a total of 3,830 commuters. 

### - Commuters from Boundary County to Lincoln County: 10 

### - Commutersthat remain in Boundary County: 3,310 Sanders County, an adjacent county, has a total of 3,903 commuters. 

### - Commuters from Sanders County to Lincoln County: 12- Commuters that remain in Sanders County: 3,337 The following table has the vehicle miles traveled (thousand miles) for Lincoln County and the adjacent counties.

Based on the analysis forthis factor there are no adjacent counties impactingthe 

### PM2.5 monitor located atthe Libby Courthouse Annex. This factor played a significant role in the decision making process. Factor 

### 5: Expected growth The following table has the population and population growth figures for Lincoln County and the adjacent counties. (Nonattainment counties are in bold.)

Based on the analysis for this factor, there is no significant growth, on either an absolute or a percentage basis, to indicate a contribution to the air quality in Lincoln County. This factor did not play a significant role in the decision making process. Factor 6: Meteorology Libby Montana is located in the northwestern part ofthe state in a narrow north-south oriented valley. The ridgetops surrounding Libby are approximately 4,000 feethigherthan the town. There are no other towns or large emissions sources immediately upwind, sotransport ofhigh background concentrations into Libby is considered unlikely. The highest PM2.5 concentrations in Libby generally occur duringthe months ofNovember through February. During the summer months concentrationstypically average lessthan half the level ofthe annual PM2.5 NAAQS, while winter concentrations may double the NAAQS. The much higher concentrationsin winter are related to stagnant weather conditions dominated by lightwinds and strong temperature inversions. These meteorological conditions may trap emissions within the valley for many days. Norecent meteorological data is available for Libby, however, data from Kalispell, MT show calm wind conditions occur 35 percent of thetime in the winter months and only 15percent of thetime in the spring and summer. Vertical temperature soundings at Great Falls in Western MTalso show a very high frequency of surface temperature inversions in the winter. Due to the meteorology conditions in the town and surrounding vicinity ofLibby and due to thetopographical featureswithin Lincoln County and more specifically around Libby (seefactor 

### 7below), that create stagnant weather conditions,

### EPA feelsthe adjacent counties do not impact the PM2.5 monitor located at the Libby Courthouse Annex and that the nonattainment problem is a localized PM2.5 problem.

This factor played a significant role in the decision making process. Factor 7: Geographyttopography Lincoln County, MT Lincoln County has a land area of 3,675 square miles. The area ofconcern showinghigh PM2.5 concentrations is located within and around the Libby, Montana vicinity. Lincoln County has numerous geographical ortopographical boundaries limiting its airshed to a very narrow valley including the surroundingvicinity ofLibby. Thetown ofLibby has a total area of 1.3 miles. As ofthe 2000 census, there are 2,626 people, 1,132 households, and 669 families residing in the city. The elevation for the town ofLibby is2,601 feet. The ridgetops surrounding Libby are approximately 4,000 feet higher than the town. The town sits in a narrow valley that runs in a north-south direction (4S023'17"North,115O33'13"West). The Kootenai River runs adjacent to the town in an east-west direction. The Kootenai Basin is largely mountainous and dominated by three major ranges. The Rocky Mountain Range and the Flathead Range constitute the eastern boundary; the Purcell Range roughly bisects it from north to south.The Selkirk and Cabinet Ranges mark the western boundary. Elevationsreach a maximum of about 12,000 feet with most summit elevationsbetween 6,000 and 7,500 feet. Except for a few areas, the entire watershed is heavily forested (practically all ofLincoln County and a large portion ofthe surrounding counties consists ofNational Forest land). TheKootenai River has its origins in British Columbia's Kootenay National Park in Canada. From there it flows 485 miles into northwest Montana and through the towns of Libby and Troy. From there it flows into northern Idaho, then back into Canada and Kootenay Lake. Ultimately itjoins with the Columbia River. Sixteen miles north ofLibby, the river is held back by Libby Dam, creating a 90-mile long reservoir that reaches into Canada. Theriver drops less than 1,000 feet (305 meters) in elevation fi-omCanal Flats to Kootenay Lake, a distance of over 300 miles (480 

### krn). However, even along the river's slow meandering course, valley-bottom widths are generally less than two miles and are characterized by tree-covered rolling hills with few grassland openings. Due to the topographical features and meteorological data (see factor 6 above) within and surroundingthe vicinity ofLibby resulting in stagnant weather conditions trapping emissions in the valley, EPA feelsthe adjacent counties donot impact the PM2.5 monitor located at the Libby Courthouse Annex. Emissions from adjacent counties would haveto traverse one or more major mountain ranges, in some cases against the prevailing wind direction, in order to impact the town of Libby. This factor played a significant role in the decision making process. Factor 8: Jurisdictional boundaries No areas in Montana or ldaho were designated nonattainment for the 8-hour ozone standard on April 15,2004. The town ofLibby and vicinity within Lincoln County are designated nonattainment for PM 10. Due to the fact that thetown and surroundingvicinity ofLibby, Montana was designated nonattainment for PMlO and did not include the surrounding counties around Lincoln, MT, EPA believes this factorplays a significant role in the decision making process. Factor 9: Level ofcontrol ofemission sources The followingare sources located in Lincoln County, MTbut arenot considered major PSD sources.

- Plum Creek Northwest Lumber, Inc. (Ksandka Sawmill), Fortine, MT 

### - Eureka Pellet Mills, Eureka, MT