6-1 

### 6.0 NINE-FACTOR ANALYSES OF INDIVIDUAL NONATTAINMENT AREAS Chapter 6 contains the rationale for EPA’s PM2.5 designations sorted by EPA Region. The first section under each Region contains the 9-Factor Analyses for any nonattainment areas that was sent in the 120 day letters from EPA to the states and tribes. These letters, sent on June 28 and 29, 2004 responded to the states and tribes recommendations for areas meeting and not meeting the PM2.5 NAAQS. The second section contains justifications for any modifications made to the intended designations found in the 120 day letters. 

### 6.1 Region 1 Nonattainment Areas 6.1.1 EPA 9-Factor Analyses for Southern New England for the Designation of PM2.5 Nonattainment Areas The following is a 9-factor analysis for New England counties that are candidates for nonattainment status for the PM2.5 air-quality standard. EPA guidance establishes the metropolitan area (i.e., MSA or C/MSA where one exists) as the presumptive boundary for PM2.5 nonattainment areas. (See memo from Jeffrey R. Holmstead to EPA Regional Administrators, April 1, 2003). OMB issued revised urban-area definitions on June 6, 2003. Although states were not asked to use the 2003 urban-area definitions when recommending PM2.5 nonattainment areas to EPA, EPA is using the 2003 definitions in its review of state recommendations. Therefore, this 9-factor analysis considers all counties in New England that are in the 2003 New York-Newark-Bridgeport, NY-NJ-CT CSA, and any counties in New England that are adjacent to this CSA. (A list of the 2003 metropolitan area definitions is available at: www.census.gov/population/www/estimates/metroarea.html). In New England, the New York-Newark-Bridgeport, NY-NJ-CT-PA CSA counties include Fairfield, New Haven, and Litchfield counties in CT. Adjacent counties to the CSA include Middlesex and Hartford counties in CT, and Berkshire and Hampden counties in MA. The only monitor in the New England portion of this CSA that violated the annual PM2.5 standard based on 2001-2003 data is located in New Haven, CT. Additionally, there are no monitors in the adjacent counties that violated the annual PM2.5 standard. However, the absence of a violating monitor does not automatically disqualify a county from a PM2.5 nonattainment designation. Connecticut recommended that the entire state be designated as attainment based on an argument that the violating monitor is a “hot spot” (letter from CT DEP to EPA, February 10, 2004). As an alternative, if EPA does not accept the “hot spot” analysis, CT recommended a nonattainment designation for a limited geographic area, such as the City of New Haven or New Haven County. In addition, CT recommended that all CTcounties should be excluded from the nonattainment area associated with the New YorkNorthern New Jersey-Long Island, NY-NJ-CT-PA CMSA based on an argument that6-347 

### 6.8 Region 8 Nonattainment Areas
6.8.1 EPA 9-Factor Analyses for Montana for the Designation of PM2.5 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 areas to Lincoln County are the Canadian border to the North, Boundary and Bonner County, Idaho to the 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 of the town of Libby due to topographical features and meteorology in the area impacted by emissions. Montana’s recommendation identifying the PM2.5 nonattainment area included part of Lincoln County (the town of Libby 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 intended to 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 of Lincoln County as described further below. The following is a brief summary of the 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 SO2 , NOx, carbon and crustal PM2.5 emissions. A weighted emissions score was applied to Lincoln County and the adjacent counties reflecting the speciation profile of Lincoln County versus the adjacent counties. Counties adjacent to the Lincoln County were assigned an emission score as a way to compare the emissions from those counties against Lincoln County emissions. The following table has the SO 2 , NOx, carbon, and crustal PM2.5 emissions and composite emission scores.6-348 This information is from the 2001 NEI. (The recommended nonattainment area is in bold.)

County SO 2 (tons) NOx (tons) Carbon (tons) Crustal PM2.5 (tons) Composite Emission

Score Lincoln 257 3286 862 275 100
Flathead 1919 6651 1788 1904 257
Bonner 313 5324 1411 730 159.5 Boundary 114 1886 1431 760 134.4
Sanders 328 4543 605 151 88.2
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 7 below) 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

County PM2.5 2001-2003 design value Lincoln 16.2*
Flathead 9.1
Bonner 8.0 Boundary 8.2
Sanders 6.2 * Lincoln County PM2.5 monitor is located at the Libby Courthouse Annex, Libby, MT. All adjacent counties to Lincoln, MT are attaining the PM2.5 standard. This factor played a significant role in the decision making process.6-349 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 2002 Population Density (pop. per square mile) Lincoln 18,665* 5** Flathead 77,240 15 Bonner 38,205 22 Boundary 10,085 8 Sanders 10,367 4 * Town of Libby, MT population: 2,626; ** Town of Libby, MT population density: 2,020 persons/square mile The town of Libby, where the PM2.5 problem is located has a much higher population density than the remainder of Lincoln County or any of the surrounding counties. Also, due to the commuting patterns, topographical features and meteorology in Lincoln County (see factors 4, 6 and 7 below), EPA feels the adjacent county populations do not impact the PM2.5 monitor located at the Libby Courthouse Annex. This factor played a significant role in the decision making process. Factor 4: Traffic and commuting patterns Commuting Information: Lincoln County, the design value county, has a total of 6,721 commuters. - Commuters who remain in Lincoln County: 6,177 Flathead County, an adjacent county, has a total of 34,035 commuters. - Commuters from Flathead County to Lincoln County: 85 - Commuters that remain in Flathead County: 32,956 Bonner County, an adjacent county, has a total of 15,570 commuters. - 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 - Commuters that 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: 126-350 - 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.

County VMT Lincoln 231
Flathead 756
Bonner 442 Boundary 139
Sanders 93
Based on the analysis for this factor there are no adjacent counties impacting the PM2.5 monitor located at the 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.)

County 2002 Population Population Density Area (sq. mile) Growth (90-00) % Change (90-00)

Lincoln 18665 5 3613 1356 8
Flathead 77240 15 5099 15253 26
Bonner 38205 22 1738 10213 38 Boundary 10085 8 1269 1539 18
Sanders 10367 4 2762 1558 18
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 of the state in a narrow north-south oriented valley. The ridgetops surrounding Libby are approximately 4,000 feet higher6-351 than the town. There are no other towns or large emissions sources immediately upwind, so transport of high background concentrations into Libby is considered unlikely. The highest PM2.5 concentrations in Libby generally occur during the months of November through February. During the summer months concentrations typically average less than half the level of the annual PM2.5 NAAQS, while winter concentrations may double the NAAQS. The much higher concentrations in winter are related to stagnant weather conditions dominated by light winds and strong temperature inversions. These meteorological conditions may trap emissions within the valley for many days. No recent meteorological data is available for Libby, however, data from Kalispell, MT show calm wind conditions occur 35 percent of the time in the winter months and only 15 percent of the time in the spring and summer. Vertical temperature soundings at Great Falls in Western MT also show a very high frequency of surface temperature inversions in the winter. Due to the meteorology conditions in the town and surrounding vicinity of Libby and due to the topographical features within Lincoln County and more specifically around Libby (see factor 7 below), that create stagnant weather conditions, EPA feels the 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.
Prevailing Wind Directions (%) County NW SW SE NE Lincoln 14 37 22 26 Flathead 21 34 22 24
Bonner 14 42 20 24 Boundary 12 40 22 27
Sanders 26 28 24 22
This factor played a significant role in the decision making process. Factor 7: Geography/topography Lincoln County, MT Lincoln County has a land area of 3,675 square miles. The area of concern showing high PM2.5 concentrations is located within and around the Libby, Montana vicinity. Lincoln County has numerous geographical or topographical boundaries limiting its airshed to a very narrow valley including the surrounding vicinity of Libby. The town of Libby has a total area of 1.3 miles. As of the 2000 census, there are 2,626 people, 1,132 households, and 669 families residing in the city. The elevation for the town of Libby is 2,601 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 (48°23'17" North,6-352 115°33'13" 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. Elevations reach a maximum of about 12,000 feet with most summit elevations between 6,000 and 7,500 feet. Except for a few areas, the entire watershed is heavily forested (practically all of Lincoln County and a large portion of the surrounding counties consists of National Forest land). The Kootenai 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 it joins with the Columbia River. Sixteen miles north of Libby, the river is held back by Libby Dam, creating a 90-mile long reservoir that reaches into Canada. The river drops less than 1,000 feet (305 meters) in elevation from Canal Flats to Kootenay Lake, a distance of over 300 miles (480 km). 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 surrounding the vicinity of Libby resulting in stagnant weather conditions trapping emissions in the valley, EPA feels the adjacent counties do not impact the PM2.5 monitor located at the Libby Courthouse Annex. Emissions from adjacent counties would have to 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 Idaho were designated nonattainment for the 8-hour ozone standard on April 15, 2004. The town of Libby and vicinity within Lincoln County are designated nonattainment for PM10. Due to the fact that the town and surrounding vicinity of Libby, Montana was designated nonattainment for PM10 and did not include the surrounding counties around Lincoln, MT, EPA believes this factor plays a significant role in the decision making process.
Factor 9: Level of control of emission sources The following are sources located in Lincoln County, MT but are not considered major PSD sources. - Plum Creek Northwest Lumber, Inc. (Ksandka Sawmill), Fortine, MT - Eureka Pellet Mills, Eureka, MT6-353 - Genesis Inc. (Troy Mine), Troy, MT - Lone Pine Timber Industries, Eureka, MT - Stimson Lumber Mill, Libby, MT (closed - Spring, 2003) Due to the topographical features and meteorology in Lincoln County (see factors 6 and 7 below) and more specifically surrounding Libby, MT where the PM2.5 problem is located, EPA believes this factor does not play a significant role in the decision making process. 

### 6.8.2 Justifications for Changes to EPA Recommendations Contained in the June 29, 2004 Letters to States Background:In a letter dated February 25, 2004, the Governor of Montana submitted to EPA a letter recommending that the PM2.5 nonattainment boundary for Lincoln County, MT be designated as a partial county. The Governor’s letter did not provide a specific justification for a partial county recommendation or identify what the partial county boundaries would be for Lincoln County. On June 29, 2004, EPA responded to Montana’s recommendation stating that EPA agreed with Montana’s recommended nonattainment designation for Lincoln County but that EPA intended to modify Montana’s recommended boundary for the nonattainment area and designate the entire Lincoln County area as nonattainment for the PM2.5 national ambient air quality standards. 1In two follow-up letters from Montana dated June 25, 2004 and September 7, 2004, Montana identified specific PM2.5 nonattainment boundaries for Libby, MT along with a technical justification for the less-than-county request. EPA’s Recommended Change:Based upon EPA’s review of Montana’s letters dated June 25, 2004 and September 7, 2004 and subsequent discussions EPA has had with the Montana Department of Environmental Quality (MT DEQ), EPA is modifying our original recommendation and identifying the PM2.5 nonattainment boundary area as follows: 600,000mE, 5,370,000mN east to 620,000mE, 5,370,000mN south to 620,000mE, 5,340,000mN west to 600,000mE, 5,340,000mN north to 600,000mE, 5,370,000mN as identified in Montana’s September 7, 2004 letter. EPA believes these boundaries are reasonable for the following reasons:

1EPA’s April 1, 2003 “Designations for the Fine Particle National Ambient Air Quality Standards” which states: “When a rural monitor violates the standard, EPA intends to apply a presumption that the nonattainment area shall include the full county in which the monitor is located. EPA will consider recommendations to adjust rural area nonattainment boundaries based on the same factors as it applies to urban areas, as discussed in question 5 above. Using these factors, a State or Tribe that recommends that a smaller area should be designated nonattainment should provide convincing evidence that the monitor is not representative of the full county, that the excluded portions of the county are not source areas contributing to the nonattainment, and that the excluded portions of the county are meeting the standard. Similarly, a State or Tribe may recommend that a larger area be designated nonattainment based on technical information relevant to these factors. Nevertheless, as discussed above, if nonattainment is demonstrably very localized and is attributable to localized sources, EPA intends to establish nonattainment area boundaries based on a case-specific evaluation of the nature and extent of the problem.”6-354 1. As stated under factors 6 and 7 of EPA’s factor analysis for Lincoln County, meteorology and geographical/topographical features within and surrounding the town of Libby played a significant role in the decision making process and in EPA’s consideration to modify the nonattainment boundary to only include the town of Libby and surrounding vicinity. (See Factors 6 and 7 for more details.)
2. The MT DEQ conducted a winter monitoring study in the Libby, Montana area from November 2003 through March 2004. This information was submitted to EPA in MT DEQ’s June 25, 2004 PM2.5 nonattainment boundary area recommendation for the town of Libby. The monitoring study showed that within the “T” shape basin where Libby Creek flows into the Kootenai River, significant drops in PM2.5 occur along the northwestern edge of the Libby valley as well as the northeastern edge of the valley. Wind speed results showed that there is very little wind in the Libby area during winter confirming that much higher concentrations in winter are related to stagnant weather conditions dominated by light winds and strong temperature inversions. As a result, meteorological conditions may trap emissions within the valley for many days. In MT DEQ’s June 25, 2004 recommendation, MT DEQ acknowledged in the boundary analysis that while monitoring was not conducted further south than 3 miles from the town’s center, MT DEQ was confident that the boundary that they recommended in their June 25 letter adequately surrounds the source area for the Libby PM2.5 nonattainment area. EPA disagreed with MT DEQ’s southern boundary recommendation and in further discussions with MT DEQ, came to an agreement to extend the southern boundary area to include an additional 20,000 meter UTM Grids beyond what was recommended in MT DEQ’s June 25, 2004 recommendation. This new boundary agreement is reflected in MT DEQ’s letter dated September 7, 2004. Due to the geographical/topographical features and meteorological data within and surrounding the vicinity of Libby and the study performed by MT DEQ, EPA feels the surrounding Lincoln County area outside the recommended boundary area does not impact the PM2.5 monitor located at the Libby Courthouse Annex. Emissions from the surrounding area within Lincoln County would have to traverse one or more major mountain ranges, in some cases against the prevailing wind direction, in order to impact the town of Libby.