40 CFR 81.327: Montana.

Montana—1971 Sulfur Dioxide NAAQS

[Primary and Secondary]

Designated area Does not meet primary standards Does not meet secondary standards Cannot be classified Better than national standards

Laurel Area X

East Helena Area X

Anaconda Area X

Rest of State X

Montana—2010 Sulfur Dioxide NAAQS

[Primary]

Designated area 1 Designation

Date 2 Type

Yellowstone County (part) 5/10/2016 Attainment.

The area originates at the point defined as the southwest corner of Section 11, Township 1S, Range 26E. From that point the boundary proceeds north along the western section line of Section 11 to the point of intersection with the midline of Interstate Highway 90. From that point the boundary follows the midline of Interstate Highway 90, across the Yellowstone River, to the point where the highway midline intersects the northern boundary of Section 35, Township 1N, Range 26E. From that point the boundary proceeds east along the northern section line of Sections 35 and 36 to the point where Old US 87/Hardin Road leaves the section line and turns southeast. The boundary follows the midline of Old US 87/Hardin Road southeast to the point where the road intersects the western boundary of the SE 1⁄4 of the SE 1⁄4 of Section 31, Township 1N, Range 27E. From that point the boundary proceeds south along the 1⁄4 section line to the southern boundary of Township 1N, then east to the northeast corner of Section 5, Township 1S, Range 27E. The boundary then proceeds south along the eastern section line of sections 5 and 8 to the southeast corner of Section 8, Township 1S, Range 27E, where it turns west and follows the south section line of Sections 8 and 7, Township 1S, Range 27E; and Sections 12 and 11, Township 1S, Range 26E, back to the point of origin

Beaverhead County Attainment/Unclassifiable.

Big Horn County Attainment/Unclassifiable.

Blaine County Attainment/Unclassifiable.

Broadwater County Attainment/Unclassifiable.

Carbon County Attainment/Unclassifiable.

Carter County Attainment/Unclassifiable.

Cascade County Attainment/Unclassifiable.

Chouteau County Attainment/Unclassifiable.

Custer County Attainment/Unclassifiable.

Daniels County Attainment/Unclassifiable.

Dawson County Attainment/Unclassifiable.

Deer Lodge County Attainment/Unclassifiable.

Fallon County Attainment/Unclassifiable.

Fergus County Attainment/Unclassifiable.

Flathead County Attainment/Unclassifiable.

Gallatin County Attainment/Unclassifiable.

Garfield County Attainment/Unclassifiable.

Glacier County Attainment/Unclassifiable.

Golden Valley County Attainment/Unclassifiable.

Granite County Attainment/Unclassifiable.

Hill County Attainment/Unclassifiable.

Jefferson County Attainment/Unclassifiable.

Judith Basin County Attainment/Unclassifiable.

Lake County Attainment/Unclassifiable.

Lewis and Clark County Attainment/Unclassifiable.

Liberty County Attainment/Unclassifiable.

Lincoln County Attainment/Unclassifiable.

McCone County Attainment/Unclassifiable.

Madison County Attainment/Unclassifiable.

Meagher County Attainment/Unclassifiable.

Mineral County Attainment/Unclassifiable.

Missoula County Attainment/Unclassifiable.

Musselshell County Attainment/Unclassifiable.

Park County Attainment/Unclassifiable.

Petroleum County Attainment/Unclassifiable.

Phillips County Attainment/Unclassifiable.

Pondera County Attainment/Unclassifiable.

Powder River County Attainment/Unclassifiable.

Powell County Attainment/Unclassifiable.

Prairie County Attainment/Unclassifiable.

Ravalli County Attainment/Unclassifiable.

Richland County Attainment/Unclassifiable.

Roosevelt County Attainment/Unclassifiable.

Rosebud County Attainment/Unclassifiable.

Sanders County Attainment/Unclassifiable.

Sheridan County Attainment/Unclassifiable.

Silver Bow County Attainment/Unclassifiable.

Stillwater County Attainment/Unclassifiable.

Sweet Grass County Attainment/Unclassifiable.

Teton County Attainment/Unclassifiable.

Toole County Attainment/Unclassifiable.

Treasure County Attainment/Unclassifiable.

Valley County Attainment/Unclassifiable.

Wheatland County Attainment/Unclassifiable.

Wibaux County Attainment/Unclassifiable.

Yellowstone County (part) (remainder) Attainment/Unclassifiable.

1 Includes any Indian country in each county or area, unless otherwise specified. EPA is not determining the boundaries of any area of Indian country in this table, including any area of Indian country located in the larger designation area. The inclusion of any Indian country in the designation area is not a determination that the state has regulatory authority under the Clean Air Act for such Indian country.

2 This date is April 9, 2018, unless otherwise noted.

Montana—Carbon Monoxide

Designated Area Designation Classification

Date 1 Type Date 1 Type

Billings Area

Yellowstone County (part):

The following areas of Yellowstone Co. (Range and Township) sections: R25E T1N—Sections 24 through 27 and 34 through 36; R25E T1S—Sections 1, 2, and 12; R26E T1N Sections 19 through 22 and 27 through 34; R26E T1S Sections 2 through 11 and 15 through 18. April 22, 2002. Attainment

Great Falls Area July 8, 2002 Attainment

Cascade County (part)

Great Falls designated area: North boundary—9th Avenue South or its straight line extension; East boundary—54th Street South or its straight line extension; South boundary—11th Avenue South or its straight line extension; West boundary—2nd Street South or its straight line extension

Missoula Area:

Missoula County (part) September 17, 2007 Attainment

Missoula and vicinity including the following (Range and Township) sections: R19W T14N—sections: 29 and 32; R19W T13N—sections 2, 5, 7, 8, 11, 14 through 24, and 26 through 34; R19W T12N—sections: 4 through 7; R20W T13N—sections: 23 through 26, 35 and 36

Beaverhead County Unclassifiable/Attainment

Big Horn County (part) excluding Crow, Northern Cheyenne Indian Reservations Unclassifiable/Attainment

Blaine County (part) excluding Fort Belknap Indian Reservation Unclassifiable/Attainment

Broadwater County Unclassifiable/Attainment

Carbon County Unclassifiable/Attainment

Carter County Unclassifiable/Attainment

Cascade County (part)

Remainder of Cascade County Unclassifiable/Attainment

Chouteau County (part) excluding Rocky Boy Indian Reservation Unclassifiable/Attainment

Custer County Unclassifiable/Attainment

Daniels County (part) excluding Fort Peck Indian Reservation Unclassifiable/Attainment

Dawson County Unclassifiable/Attainment

Deer Lodge County Unclassifiable/Attainment

Fallon County Unclassifiable/Attainment

Fergus County Unclassifiable/Attainment

Flathead County (part) excluding Flathead Indian Resevation Unclassifiable/Attainment

Gallatin County Unclassifiable/Attainment

Garfield County Unclassifiable/Attainment

Glacier County (part) excluding Blackfeet Indian Reservation Unclassifiable/Attainment

Golden Valley County Unclassifiable/Attainment

Granite County Unclassifiable/Attainment

Hill County (part) excluding Rocky Boy Indian Reservation Unclassifiable/Attainment

Jefferson County Unclassifiable/Attainment

Judith Basin County Unclassifiable/Attainment

Lake County (part) excluding Flathead Indian Reservation Unclassifiable/Attainment

Lewis and Clark County Unclassifiable/Attainment

Liberty County Unclassifiable/Attainment

Lincoln County Unclassifiable/Attainment

Madison County Unclassifiable/Attainment

McCone County Unclassifiable/Attainment

Meagher County Unclassifiable/Attainment

Mineral County Unclassifiable/Attainment

Missoula County (part)

Remainder of Missoula County Unclassifiable/Attainment

Musselshell County Unclassifiable/Attainment

Park County Unclassifiable/Attainment

Petroleum County Unclassifiable/Attainment

Phillips County (part) excluding Fort Belknap Indian Reservation Unclassifiable/Attainment

Pondera County (part) excluding Blackfeet Indian Reservation Unclassifiable/Attainment

Powder River County Unclassifiable/Attainment

Powell County Unclassifiable/Attainment

Prairie County Unclassifiable/Attainment

Ravalli County Unclassifiable/Attainment

Richland County Unclassifiable/Attainment

Roosevelt County (part) excluding Fort Peck Indian Reservation Unclassifiable/Attainment

Rosebud County (part) excluding Northern Cheyenne Indian Reservation Unclassifiable/Attainment

Sanders County (part) excluding Flathead Indian Reservation Unclassifiable/Attainment

Sheridan County (part) excluding Fort Peck Indian Reservation Unclassifiable/Attainment

Silver Bow County Unclassifiable/Attainment

Stillwater County Unclassifiable/Attainment

Sweet Grass County Unclassifiable/Attainment

Teton County Unclassifiable/Attainment

Toole County Unclassifiable/Attainment

Treasure County Unclassifiable/Attainment

Valley County (part) excluding Fort Peck Indian Reservation Unclassifiable/Attainment

Wheatland County Unclassifiable/Attainment

Wibaux County Unclassifiable/Attainment

Yellowstone County (part)

Remainder of Yellowstone County Unclassifiable/Attainment

Yellowstone National Park Unclassifiable/Attainment

Blackfeet Indian Reservation Unclassifiable/Attainment

Glacier County (part)

area inside Blackfeet Reservation

Pondera County (part)

area inside Blackfeet Reservation

Crow Indian Reservation Unclassifiable/Attainment

Bighorn County (part)

area inside Crow Reservation

Yellowstone (part)

area inside Crow Reservation

Flathead Indian Reservation Unclassifiable/Attainment

Flathead County (part)

area inside Flathead Reservation

Lake County (part)

area inside Flathead Reservation

Missoula County (part)

area inside Flathead Reservation

Sanders County (part)

area inside Flathead Reservation

Fort Belknap Indian Reservation Unclassifiable/Attainment

Blaine County (part)

area inside Fort Belknap Reservation

Phillips County (part)

area inside Fort Belknap Reservation

Fort Peck Indian Reservation Unclassifiable/Attainment

Daniels County (part)

area inside Fort Peck Reservation

Roosevelt County (part)

area inside Fort Peck Reservation

Sheridan County (part)

area inside Fort Peck Reservation

Valley County (part)

area inside Fort Peck Reservation

Northern Cheyenne Indian Reservation Unclassifiable/Attainment

Bighorn County (part)

area inside Northern Cheyenne Reservation

Rosebud County (part)

area inside Northern Cheyenne Reservation

Rocky Boy Indian Reservation Unclassifiable/Attainment

Chouteau County (part)

area inside Rocky Boy Reservation

Hill County (part)

area inside Rocky Boy Reservation

1 This date is November 15, 1990, unless otherwise noted.

Montana—1978 Lead NAAQS

Designated Area Designation Classification

Date Type Date Type

Lewis & Clark County (part)

City of East Helena and vicinity October 11, 2019 Attainment.

Northern boundary - horizontal universal transverse mercatur(UTM) 5,162,000 mN; eastern boundary - vertical UTM 432,500 mE; southern boundary - horizontal UTM 5,158,000 mN; western boundary - vertical UTM 427,000 mE

Rest of State Not Designated

Montana—Ozone (1-Hour Standard)2

Designated area Designation Classification

Date 1 Type Date 1 Type

Beaverhead County Unclassifiable/Attainment

Big Horn County (part) excluding Crow, Northern Cheyenne Indian Reservations Unclassifiable/Attainment

Blaine County (part) excluding Fort Belknap Indian Reservation

Broadwater County Unclassifiable/Attainment

Carbon County Unclassifiable/Attainment

Carter County Unclassifiable/Attainment

Cascade County Unclassifiable/Attainment

Chouteau County (part) excluding Rocky Boy Indian Reservation Unclassifiable/Attainment

Custer County Unclassifiable/Attainment

Daniels County (part) excluding Fort Peck Indian Reservation Unclassifiable/Attainment

Dawson County Unclassifiable/Attainment

Deer Lodge County Unclassifiable/Attainment

Fallon County Unclassifiable/Attainment

Fergus County Unclassifiable/Attainment

Flathead County (part) excluding Flathead Indian Reservation Unclassifiable/Attainment

Gallatin County Unclassifiable/Attainment

Garfield County Unclassifiable/Attainment

Glacier County (part) excluding Blackfeet Indian Reservation Unclassifiable/Attainment

Golden Valley County Unclassifiable/Attainment

Granite County Unclassifiable/Attainment

Hill County (part) excluding Rocky Boy Indian Reservation Unclassifiable/Attainment

Jefferson County Unclassifiable/Attainment

Judith Basin County Unclassifiable/Attainment

Lake County (part) excluding Flathead Indian Reservation Unclassifiable/Attainment

Lewis and Clark County Unclassifiable/Attainment

Liberty County Unclassifiable/Attainment

Lincoln County Unclassifiable/Attainment

Madison County Unclassifiable/Attainment

McCone County Unclassifiable/Attainment

Meagher County Unclassifiable/Attainment

Mineral County Unclassifiable/Attainment

Missoula County (part) excluding Flathead Indian Reservation Unclassifiable/Attainment

Musselshell County Unclassifiable/Attainment

Park County Unclassifiable/Attainment

Petroleum County Unclassifiable/Attainment

Phillips County (part) excluding Fort Belknap Indian Reservation Unclassifiable/Attainment

Pondera County (part) excluding Blackfeet Indian Reservation Unclassifiable/Attainment

Powder River County Unclassifiable/Attainment

Powell County Unclassifiable/Attainment

Prairie County Unclassifiable/Attainment

Ravalli County Unclassifiable/Attainment

Richland County Unclassifiable/Attainment

Roosevelt County (part) excluding Fort Peck Indian Reservation Unclassifiable/Attainment

Rosebud County (part) excluding Northern Cheyenne Indian Reservation Unclassifiable/Attainment

Sanders County (part) excluding Flathead Indian Reservation Unclassifiable/Attainment

Sheridan County (part) excluding Fort Peck Indian Reservation Unclassifiable/Attainment

Silver Bow County Unclassifiable/Attainment

Stillwater County Unclassifiable/Attainment

Sweet Grass County Unclassifiable/Attainment

Teton County Unclassifiable/Attainment

Toole County Unclassifiable/Attainment

Treasure County Unclassifiable/Attainment

Valley County (part) excluding Fort Peck Indian Reservation Unclassifiable/Attainment

Wheatland County Unclassifiable/Attainment

Wibaux County Unclassifiable/Attainment

Yellowstone County (part) excluding Crow Indian Reservation Unclassifiable/Attainment

Yellowstone Natl Park Unclassifiable/Attainment

Blackfeet Indian Reservation Unclassifiable/Attainment

Glacier County (part) area inside Blackfeet Reservation

Pondera County (part) area inside Blackfeet Reservation

Crow Indian Reservation Unclassifiable/Attainment

Bighorn County (part) area inside Crow Reservation

Yellowstone (part) area inside Crow Reservation

Flathead Indian Reservation Unclassifiable/Attainment

Flathead County (part) area inside Flathead Reservation

Lake County (part) area inside Flathead Reservation

Missoula County (part) area inside Flathead Reservation

Sanders County (part) area inside Flathead Reservation

Fort Belknap Indian Reservation Unclassifiable/Attainment

Blaine County (part) area inside Fort Belknap Reservation

Phillips County (part) area inside Fort Belknap Reservation

Fort Peck Indian Reservation Unclassifiable/Attainment

Daniels County (part) area inside Fort Peck Reservation

Roosevelt County (part) area inside Fort Peck Reservation

Sheridan County (part) area inside Fort Peck Reservation

Valley County (part) area inside Fort Peck Reservation

Northern Cheyenne Indian Reservation Unclassifiable/Attainment

Bighorn County (part) area inside Northern Cheyenne Reservation

Rosebud County (part) area inside Northern Cheyenne Reservation

Rocky Boy Indian Reservation Unclassifiable/Attainment

Chouteau County (part) area inside Rocky Boy Reservation

Hill County (part) area inside Rocky Boy Reservation

1 This date is October 18, 2000, unless otherwise noted.

2 The 1-hour ozone standard is revoked effective June 15, 2005 for all areas in Montana.

Montana—PM-10

Designated Area Designation Classification

Date Type Date Type

Cascade County, Great Falls area 11/15/1990 Unclassifiable

Flathead County:

The area bounded by lines from Universal Transmercator (UTM) coordinate 700000mE, 5347000mN, east to 704000mE, 5347000mN, south to 704000mE, 5341000mN, west to 703000mE, 5341000mN, south to 703000mE, 5340000mN, west to 702000mE, 5340000mN, south to 702000mE, 5339000mN, east to 703000mE, 5339000mN, south to 703000mE, 5338000mN, east to 704000mE, 5338000mN, south to 704000mE, 5336000mN, west to 702000mE, 5336000mN, south to 702000mE, 5335000mN, west to 700000mE, 5335000mN, north to 700000mE, 5340000mN, west to 695000mE, 5340000mN, north to 695000mE, 5345000mN, east to 700000mE, 5345000mN, north to 700000mE, 5347000mN 7/27/2020 Attainment

Columbia Falls and vicinity 11/15/1990 Nonattainment 11/15/1990 Moderate.

Township T30N, R20W—Sections 7, 8, 9, 16, 17, and 18

The City of Whitefish and surrounding vicinity bounded by lines from Universal Transmercator (UTM) coordinates 695000 mE, 5370000 mN, east to 699000 mE, 5370000 mN, south to 699000 mE, 5361000 mN, west to 695000 mN, 5361000 mN, and north to 695000 mE, 5370000 mN 7/8/2022 Attainment

Lake County, Ronan, Polson 11/15/1990 Nonattainment 11/15/1990 Moderate.

Lincoln County, Libby and vicinity 11/15/1990 Nonattainment 11/15/1990 Moderate.

T30N, R31W—Sections 2, 3, 4, 5, 9, 10, 11, 14, 15, 23, 26, 35, and west 1⁄2 of Section 24, west 1⁄2 of Section 25, and west 1⁄2 of Section 36; plus T31N, R31W—Sections 26, 27, 29, 32, 33, 34, 35 and the east 1⁄2 of Section 30.

Lewis and Clark County, East Helena area 11/15/1990 Unclassifiable

Missoula County, Missoula and vicinity including the following sections: 6/24/2019 Attainment

T13N, R19W—2, 8, 11, 14, 15, 16, 17, 19, 20, 21, 22, 23, 24, 27, 28, 29, 30, 31, 32, 33, and 34; T12N, R19W—Sections 4, 5, 6, 7; T13N, R20W—Sections 23, 24, 25, 26, 35, and 36.

Rosebud County:

Lame Deer 11/15/1990 Nonattainment 11/15/1990 Moderate.

Colstrip area 11/15/1990 Unclassifiable

Sanders County (part) 7/8/2022 Attainment

Thompson Falls and vicinity: Including the following Sections: R29W, T21N—Sections 5, 6, 7, 8, 9, 10, 15, and 16

Silver Bow County, Butte 7/26/2021 Attainment.

The following area of Butte-Silver Bow excluding the territorial limits of the City of Walkerville: Beginning at the Northwest corner of Section 2, T.3N., R.8W., thence Easterly to Northeast corner Section 5, T.3N., R.7W.; then Southerly to Northwest corner Section 9, T.3N., R.7W.; thence Easterly to Northeast corner Section 10, T.3N., R.7W.; thence Southerly to Southeast corner Section 22, T.2N., R.7W.; thence Westerly to Southwest corner Section 19, T.2N., R.7W.; thence Northerly to Northwest corner Section 19, T.2N., R.7W.; thence Westerly to Southwest corner Section 14, T.2N., R.8W.; thence Northerly to Southwest corner Section 35, T.3N., R.8W.; thence Westerly to Southwest corner Section 34, T.3N., R.8W.; thence Northerly to Northwest corner Section 27, T.3N., R.8W.; thence Westerly to Southwest corner Section 20, T.3N., R.8W.; thence Northerly to Northwest corner Section 17, T.3N., R.8W.; thence Easterly to Northwest corner Section 14, T.3N., R.8W.; thence Northerly to the point of beginning.

Yellowstone County, Billings area 11/15/1990 Unclassifiable

Rest of State1 11/15/1990 Unclassifiable

1 Denotes a single area designation for PSD baseline area purposes.

Montana—1997 Annual PM2.5 NAAQS

[Primary and Secondary]

Designated area Designation a Classification

Date 1 Type Date 2 Type

Libby, MT:

Lincoln County (part) 8/23/2023 Attainment

The area bounded by lines from Universal Transverse Mercador Zone 11 (North American Datum 1983) coordinates beginning at 600,000mE, 5,370,000mN east to 620,000mE, 5370,000mN south to 620,000mE, 5340,000mN west to 600,000mE, 5,340,000mN north to 600,000mE, 5,370,000mN

Rest of State:

Beaverhead County Unclassifiable/Attainment.

Big Horn County Unclassifiable/Attainment.

Blaine County Unclassifiable/Attainment.

Broadwater County Unclassifiable/Attainment.

Carbon County Unclassifiable/Attainment.

Carter County Unclassifiable/Attainment.

Cascade County Unclassifiable/Attainment.

Chouteau County Unclassifiable/Attainment.

Custer County Unclassifiable/Attainment.

Daniels County Unclassifiable/Attainment.

Dawson County Unclassifiable/Attainment.

Deer Lodge County Unclassifiable/Attainment.

Fallon County Unclassifiable/Attainment.

Fergus County Unclassifiable/Attainment.

Flathead County Unclassifiable/Attainment.

Gallatin County Unclassifiable/Attainment.

Garfield County Unclassifiable/Attainment.

Glacier County Unclassifiable/Attainment.

Golden Valley County Unclassifiable/Attainment.

Granite County Unclassifiable/Attainment.

Hill County Unclassifiable/Attainment.

Jefferson County Unclassifiable/Attainment.

Judith Basin County Unclassifiable/Attainment.

Lake County Unclassifiable/Attainment.

Lewis and Clark County Unclassifiable/Attainment.

Liberty County Unclassifiable/Attainment.

Lincoln County (remainder) Unclassifiable/Attainment.

McCone County Unclassifiable/Attainment.

Madison County Unclassifiable/Attainment.

Meagher County Unclassifiable/Attainment.

Mineral County Unclassifiable/Attainment.

Missoula County Unclassifiable/Attainment.

Musselshell County Unclassifiable/Attainment.

Park County Unclassifiable/Attainment.

Petroleum County Unclassifiable/Attainment.

Phillips County Unclassifiable/Attainment.

Pondera County Unclassifiable/Attainment.

Powder River County Unclassifiable/Attainment.

Powell County Unclassifiable/Attainment.

Prairie County Unclassifiable/Attainment.

Ravalli County Unclassifiable/Attainment.

Richland County Unclassifiable/Attainment.

Roosevelt County Unclassifiable/Attainment.

Rosebud County Unclassifiable/Attainment.

Sanders County Unclassifiable/Attainment.

Sheridan County Unclassifiable/Attainment.

Silver Bow County Unclassifiable/Attainment.

Stillwater County Unclassifiable/Attainment.

Sweet Grass County Unclassifiable/Attainment.

Teton County Unclassifiable/Attainment.

Toole County Unclassifiable/Attainment.

Treasure County Unclassifiable/Attainment.

Valley County Unclassifiable/Attainment.

Wheatland County Unclassifiable/Attainment.

Wibaux County Unclassifiable/Attainment.

Yellowstone County Unclassifiable/Attainment.

a Includes Indian Country located in each county or area, except as otherwise specified.

1 This date is 90 days after January 5, 2005, unless otherwise noted.

2 This date is July 2, 2014, unless otherwise noted.

Montana—2012 Annual PM2.5 NAAQS

[Primary]

Designated area 1 Designation Classification

Date 2 Type Date 2 Type

Statewide:

Beaverhead County Unclassifiable/Attainment

Big Horn County Unclassifiable/Attainment

Blaine County Unclassifiable/Attainment

Broadwater County Unclassifiable/Attainment

Carbon County Unclassifiable/Attainment

Carter County Unclassifiable/Attainment

Cascade County Unclassifiable/Attainment

Chouteau County Unclassifiable/Attainment

Custer County Unclassifiable/Attainment

Daniels County Unclassifiable/Attainment

Dawson County Unclassifiable/Attainment

Deer Lodge County Unclassifiable/Attainment

Fallon County Unclassifiable/Attainment

Fergus County Unclassifiable/Attainment

Flathead County Unclassifiable/Attainment

Gallatin County Unclassifiable/Attainment

Garfield County Unclassifiable/Attainment

Glacier County Unclassifiable/Attainment

Golden Valley County Unclassifiable/Attainment

Granite County Unclassifiable/Attainment

Hill County Unclassifiable/Attainment

Jefferson County Unclassifiable/Attainment

Judith Basin County Unclassifiable/Attainment

Lake County Unclassifiable/Attainment

Lewis and Clark County Unclassifiable/Attainment

Liberty County Unclassifiable/Attainment

Lincoln County Unclassifiable/Attainment

McCone County Unclassifiable/Attainment

Madison County Unclassifiable/Attainment

Meagher County Unclassifiable/Attainment

Mineral County Unclassifiable/Attainment

Missoula County Unclassifiable/Attainment

Musselshell County Unclassifiable/Attainment

Park County Unclassifiable/Attainment

Petroleum County Unclassifiable/Attainment

Phillips County Unclassifiable/Attainment

Pondera County Unclassifiable/Attainment

Powder River County Unclassifiable/Attainment

Powell County Unclassifiable/Attainment

Prairie County Unclassifiable/Attainment

Ravalli County Unclassifiable/Attainment

Richland County Unclassifiable/Attainment

Roosevelt County Unclassifiable/Attainment

Rosebud County Unclassifiable/Attainment

Sanders County Unclassifiable/Attainment

Sheridan County Unclassifiable/Attainment

Silver Bow County Unclassifiable/Attainment

Stillwater County Unclassifiable/Attainment

Sweet Grass County Unclassifiable/Attainment

Teton County Unclassifiable/Attainment

Toole County Unclassifiable/Attainment

Treasure County Unclassifiable/Attainment

Valley County Unclassifiable/Attainment

Wheatland County Unclassifiable/Attainment

Wibaux County Unclassifiable/Attainment

Yellowstone County Unclassifiable/Attainment

1 Includes areas of Indian country located in each county or area, except as otherwise specified.

2 This date is April 15, 2015, unless otherwise noted.

Montana—1997 24-Hour PM2.5 NAAQS

[Primary and Secondary]

Designated area Designation a Classification

Date 1 Type Date Type

Statewide:

Beaverhead County Unclassifiable/Attainment.

Big Horn County Unclassifiable/Attainment.

Blaine County Unclassifiable/Attainment.

Broadwater County Unclassifiable/Attainment.

Carbon County Unclassifiable/Attainment.

Carter County Unclassifiable/Attainment.

Cascade County Unclassifiable/Attainment.

Chouteau County Unclassifiable/Attainment.

Custer County Unclassifiable/Attainment.

Daniels County Unclassifiable/Attainment.

Dawson County Unclassifiable/Attainment.

Deer Lodge County Unclassifiable/Attainment.

Fallon County Unclassifiable/Attainment.

Fergus County Unclassifiable/Attainment.

Flathead County Unclassifiable/Attainment.

Gallatin County Unclassifiable/Attainment.

Garfield County Unclassifiable/Attainment.

Glacier County Unclassifiable/Attainment.

Golden Valley County Unclassifiable/Attainment.

Granite County Unclassifiable/Attainment.

Hill County Unclassifiable/Attainment.

Jefferson County Unclassifiable/Attainment.

Judith Basin County Unclassifiable/Attainment.

Lake County Unclassifiable/Attainment.

Lewis and Clark County Unclassifiable/Attainment.

Liberty County Unclassifiable/Attainment.

Lincoln County Unclassifiable/Attainment.

McCone County Unclassifiable/Attainment.

Madison County Unclassifiable/Attainment.

Meagher County Unclassifiable/Attainment.

Mineral County Unclassifiable/Attainment.

Missoula County Unclassifiable/Attainment.

Musselshell County Unclassifiable/Attainment.

Park County Unclassifiable/Attainment.

Petroleum County Unclassifiable/Attainment.

Phillips County Unclassifiable/Attainment.

Pondera County Unclassifiable/Attainment.

Powder River County Unclassifiable/Attainment.

Powell County Unclassifiable/Attainment.

Prairie County Unclassifiable/Attainment.

Ravalli County Unclassifiable/Attainment.

Richland County Unclassifiable/Attainment.

Roosevelt County Unclassifiable/Attainment.

Rosebud County Unclassifiable/Attainment.

Sanders County Unclassifiable/Attainment.

Sheridan County Unclassifiable/Attainment.

Silver Bow County Unclassifiable/Attainment.

Stillwater County Unclassifiable/Attainment.

Sweet Grass County Unclassifiable/Attainment.

Teton County Unclassifiable/Attainment.

Toole County Unclassifiable/Attainment.

Treasure County Unclassifiable/Attainment.

Valley County Unclassifiable/Attainment.

Wheatland County Unclassifiable/Attainment.

Wibaux County Unclassifiable/Attainment.

Yellowstone County Unclassifiable/Attainment.

a Includes Indian Country located in each county or area, except as otherwise specified.

1 This date is 90 days after January 5, 2005, unless otherwise noted.

Montana—2006 24-Hour PM2.5 NAAQS

[Primary and Secondary]

Designated area Designation a Classification

Date 1 Type Date Type

Statewide:

Beaverhead County Unclassifiable/Attainment.

Big Horn County Unclassifiable/Attainment.

Blaine County Unclassifiable/Attainment.

Broadwater County Unclassifiable/Attainment.

Carbon County Unclassifiable/Attainment.

Carter County Unclassifiable/Attainment.

Cascade County Unclassifiable/Attainment.

Chouteau County Unclassifiable/Attainment.

Custer County Unclassifiable/Attainment.

Daniels County Unclassifiable/Attainment.

Dawson County Unclassifiable/Attainment.

Deer Lodge County Unclassifiable/Attainment.

Fallon County Unclassifiable/Attainment.

Fergus County Unclassifiable/Attainment.

Flathead County Unclassifiable/Attainment.

Gallatin County Unclassifiable/Attainment.

Garfield County Unclassifiable/Attainment.

Glacier County Unclassifiable/Attainment.

Golden Valley County Unclassifiable/Attainment.

Granite County Unclassifiable/Attainment.

Hill County Unclassifiable/Attainment.

Jefferson County Unclassifiable/Attainment.

Judith Basin County Unclassifiable/Attainment.

Lake County Unclassifiable/Attainment.

Lewis and Clark County Unclassifiable/Attainment.

Liberty County Unclassifiable/Attainment.

Lincoln County Unclassifiable/Attainment.

McCone County Unclassifiable/Attainment.

Madison County Unclassifiable/Attainment.

Meagher County Unclassifiable/Attainment.

Mineral County Unclassifiable/Attainment.

Missoula County Unclassifiable/Attainment.

Musselshell County Unclassifiable/Attainment.

Park County Unclassifiable/Attainment.

Petroleum County Unclassifiable/Attainment.

Phillips County Unclassifiable/Attainment.

Pondera County Unclassifiable/Attainment.

Powder River County Unclassifiable/Attainment.

Powell County Unclassifiable/Attainment.

Prairie County Unclassifiable/Attainment.

Ravalli County Unclassifiable/Attainment.

Richland County Unclassifiable/Attainment.

Roosevelt County Unclassifiable/Attainment.

Rosebud County Unclassifiable/Attainment.

Sanders County Unclassifiable/Attainment.

Sheridan County Unclassifiable/Attainment.

Silver Bow County Unclassifiable/Attainment.

Stillwater County Unclassifiable/Attainment.

Sweet Grass County Unclassifiable/Attainment.

Teton County Unclassifiable/Attainment.

Toole County Unclassifiable/Attainment.

Treasure County Unclassifiable/Attainment.

Valley County Unclassifiable/Attainment.

Wheatland County Unclassifiable/Attainment.

Wibaux County Unclassifiable/Attainment.

Yellowstone County Unclassifiable/Attainment.

a Includes Indian Country located in each county or area, except as otherwise specified.

1 This date is 30 days after November 13, 2009, unless otherwise noted.

Montana—NO2 (1971 Annual Standard)

Designated area Does not meet primary standards Cannot be classified or better than national standards

Entire State X

Montana—NO2 (2010 1-Hour Standard)

Designated area Designation a

Date 1 Type

Beaverhead County Unclassifiable/Attainment.

Big Horn County Unclassifiable/Attainment.

Blaine County Unclassifiable/Attainment.

Broadwater County Unclassifiable/Attainment.

Carbon County Unclassifiable/Attainment.

Carter County Unclassifiable/Attainment.

Cascade County Unclassifiable/Attainment.

Chouteau County Unclassifiable/Attainment.

Custer County Unclassifiable/Attainment.

Daniels County Unclassifiable/Attainment.

Dawson County Unclassifiable/Attainment.

Deer Lodge County Unclassifiable/Attainment.

Fallon County Unclassifiable/Attainment.

Fergus County Unclassifiable/Attainment.

Flathead County Unclassifiable/Attainment.

Gallatin County Unclassifiable/Attainment.

Garfield County Unclassifiable/Attainment.

Glacier County Unclassifiable/Attainment.

Golden Valley County Unclassifiable/Attainment.

Granite County Unclassifiable/Attainment.

Hill County Unclassifiable/Attainment.

Jefferson County Unclassifiable/Attainment.

Judith Basin County Unclassifiable/Attainment.

Lake County Unclassifiable/Attainment.

Lewis and Clark County Unclassifiable/Attainment.

Liberty County Unclassifiable/Attainment.

Lincoln County Unclassifiable/Attainment.

McCone County Unclassifiable/Attainment.

Madison County Unclassifiable/Attainment.

Meagher County Unclassifiable/Attainment.

Mineral County Unclassifiable/Attainment.

Missoula County Unclassifiable/Attainment.

Musselshell County Unclassifiable/Attainment.

Park County Unclassifiable/Attainment.

Petroleum County Unclassifiable/Attainment.

Phillips County Unclassifiable/Attainment.

Pondera County Unclassifiable/Attainment.

Powder River County Unclassifiable/Attainment.

Powell County Unclassifiable/Attainment.

Prairie County Unclassifiable/Attainment.

Ravalli County Unclassifiable/Attainment.

Richland County Unclassifiable/Attainment.

Roosevelt County Unclassifiable/Attainment.

Rosebud County Unclassifiable/Attainment.

Sanders County Unclassifiable/Attainment.

Sheridan County Unclassifiable/Attainment.

Silver Bow County Unclassifiable/Attainment.

Stillwater County Unclassifiable/Attainment.

Sweet Grass County Unclassifiable/Attainment.

Teton County Unclassifiable/Attainment.

Toole County Unclassifiable/Attainment.

Treasure County Unclassifiable/Attainment.

Valley County Unclassifiable/Attainment.

Wheatland County Unclassifiable/Attainment.

Wibaux County Unclassifiable/Attainment.

Yellowstone County Unclassifiable/Attainment.

a Includes Indian Country located in each county or area, except as otherwise specified.

1 This date is 90 days after October 31, 2011, unless otherwise noted.

Montana—1997 8-Hour Ozone NAAQS

[Primary and Secondary]

Designated area Designation a Category/classification

Date 1 Type Date 1 Type

Statewide:

Beaverhead County Unclassifiable/Attainment

Big Horn County Unclassifiable/Attainment

Blaine County Unclassifiable/Attainment

Broadwater County Unclassifiable/Attainment

Carbon County Unclassifiable/Attainment

Carter County Unclassifiable/Attainment

Cascade County Unclassifiable/Attainment

Chouteau County Unclassifiable/Attainment

Custer County Unclassifiable/Attainment

Daniels County Unclassifiable/Attainment

Dawson County Unclassifiable/Attainment

Deer Lodge County Unclassifiable/Attainment

Fallon County Unclassifiable/Attainment

Fergus County Unclassifiable/Attainment

Flathead County Unclassifiable/Attainment

Gallatin County Unclassifiable/Attainment

Garfield County Unclassifiable/Attainment

Glacier County Unclassifiable/Attainment

Golden Valley County Unclassifiable/Attainment

Granite County. Unclassifiable/Attainment

Hill County Unclassifiable/Attainment

Jefferson County Unclassifiable/Attainment

Judith Basin County Unclassifiable/Attainment

Lake County Unclassifiable/Attainment

Lewis and Clark County Unclassifiable/Attainment

Liberty County Unclassifiable/Attainment

Lincoln County Unclassifiable/Attainment

Madison County Unclassifiable/Attainment

McCone County Unclassifiable/Attainment

Meagher County Unclassifiable/Attainment

Mineral County Unclassifiable/Attainment

Missoula County Unclassifiable/Attainment

Musselshell County Unclassifiable/Attainment

Park County Unclassifiable/Attainment

Petroleum County Unclassifiable/Attainment

Phillips County Unclassifiable/Attainment

Pondera County Unclassifiable/Attainment

Powder River County Unclassifiable/Attainment

Powell County Unclassifiable/Attainment

Prairie County Unclassifiable/Attainment

Ravalli County Unclassifiable/Attainment

Richland County Unclassifiable/Attainment

Roosevelt County Unclassifiable/Attainment

Rosebud County Unclassifiable/Attainment

Sanders County Unclassifiable/Attainment

Sheridan County Unclassifiable/Attainment

Silver Bow County Unclassifiable/Attainment

Stillwater County Unclassifiable/Attainment

Sweet Grass County Unclassifiable/Attainment

Teton County Unclassifiable/Attainment

Toole County Unclassifiable/Attainment

Treasure County Unclassifiable/Attainment

Valley County Unclassifiable/Attainment

Wheatland County Unclassifiable/Attainment

Wibaux County Unclassifiable/Attainment

Yellowstone County Unclassifiable/Attainment

Yellowstone Natl Park Unclassifiable/Attainment

a Includes Indian Country located in each county or area, except as otherwise specified.

1 This date is June 15, 2004, unless otherwise noted.

Montana—2008 8-Hour Ozone NAAQS

[Primary and Secondary]

Designated area Designation Classification

Date 1 Type Date 1 Type

Statewide and Any Areas of Indian Country Unclassifiable/Attainment

1 This date is July 20, 2012, unless otherwise noted.

Montana—2015 8-Hour Ozone NAAQS

[Primary and Secondary]

Designated area 1 Designation Classification

Date 2 Type Date Type

Beaverhead County Attainment/Unclassifiable.

Big Horn County Attainment/Unclassifiable.

Blaine County Attainment/Unclassifiable.

Broadwater County Attainment/Unclassifiable.

Carbon County Attainment/Unclassifiable.

Carter County Attainment/Unclassifiable.

Cascade County Attainment/Unclassifiable.

Chouteau County Attainment/Unclassifiable.

Custer County Attainment/Unclassifiable.

Daniels County Attainment/Unclassifiable.

Dawson County Attainment/Unclassifiable.

Deer Lodge County Attainment/Unclassifiable.

Fallon County Attainment/Unclassifiable.

Fergus County Attainment/Unclassifiable.

Flathead County Attainment/Unclassifiable.

Gallatin County Attainment/Unclassifiable.

Garfield County Attainment/Unclassifiable.

Glacier County Attainment/Unclassifiable.

Golden Valley County Attainment/Unclassifiable.

Granite County Attainment/Unclassifiable.

Hill County Attainment/Unclassifiable.

Jefferson County Attainment/Unclassifiable.

Judith Basin County Attainment/Unclassifiable.

Lake County Attainment/Unclassifiable.

Lewis and Clark County Attainment/Unclassifiable.

Liberty County Attainment/Unclassifiable.

Lincoln County Attainment/Unclassifiable.

McCone County Attainment/Unclassifiable.

Madison County Attainment/Unclassifiable.

Meagher County Attainment/Unclassifiable.

Mineral County Attainment/Unclassifiable.

Missoula County Attainment/Unclassifiable.

Musselshell County Attainment/Unclassifiable.

Park County Attainment/Unclassifiable.

Petroleum County Attainment/Unclassifiable.

Phillips County Attainment/Unclassifiable.

Pondera County Attainment/Unclassifiable.

Powder River County Attainment/Unclassifiable.

Powell County Attainment/Unclassifiable.

Prairie County Attainment/Unclassifiable.

Ravalli County Attainment/Unclassifiable.

Richland County Attainment/Unclassifiable.

Roosevelt County Attainment/Unclassifiable.

Rosebud County Attainment/Unclassifiable.

Sanders County Attainment/Unclassifiable.

Sheridan County Attainment/Unclassifiable.

Silver Bow County Attainment/Unclassifiable.

Stillwater County Attainment/Unclassifiable.

Sweet Grass County Attainment/Unclassifiable.

Teton County Attainment/Unclassifiable.

Toole County Attainment/Unclassifiable.

Treasure County Attainment/Unclassifiable.

Valley County Attainment/Unclassifiable.

Wheatland County Attainment/Unclassifiable.

Wibaux County Attainment/Unclassifiable.

Yellowstone County Attainment/Unclassifiable.

1 Includes any Indian country in each county or area, unless otherwise specified. EPA is not determining the boundaries of any area of Indian country in this table, including any area of Indian country located in the larger designation area. The inclusion of any Indian country in the designation area is not a determination that the state has regulatory authority under the Clean Air Act for such Indian country.

2 This date is January 16, 2018, unless otherwise noted.

Montana—2008 Lead NAAQS

Designated area Designation for the 2008 NAAQS a

Date 1 Type

Whole State Unclassifiable/Attainment.

a Includes Indian Country located in each county or area, except as otherwise specified.

1 December 31, 2011 unless otherwise noted.