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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 SO2, NOx, carbon, and crustal PM2.5 emissions and composite emission scores. 
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This information is from the 2001 NEI. (The recommended nonattainment area is in 

bold.) 

County 

SO2

(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. 
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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: 12 
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 - 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 higher 
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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, 
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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, MT 
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- 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.1

 In 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: 

 

1

 EPA’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.” 
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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.