SIP Status Reports

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Status of Montana Designated Areas

Montana Areas by NAAQS
As of 09/22/2020

Jump to Montana section for: CO (1971) Lead (1978) Lead (2008) NO2 (1971) Ozone-1Hr (1979) Ozone-8Hr (1997) Ozone-8Hr (2008) Ozone-8Hr (2015) PM-10 (1987) PM-2.5 (1997) PM-2.5 (2006) PM-2.5 (2012) SO2 (1971) SO2 (2010)


Montana CO (1971) Areas    Return to map
 
Click on the Area name
to view SIP Required Elements


Area
Status Designation
Date
Classification 2010
Population
(state portion)
Meets NAAQS
Basis
Design Value
Annual
(ppm)
(entire area)
Meets
NAAQS
SIP
Requirements
Original/
Approved
Clean Air
Determination
Citation
Effective Date
Click to view
FR notice
Redesignation
Request Date
Redesignation
Citation
Effective Date
Click to view
FR notice
Billings Area Maintenance 11/15/1990 Not Classified 104,360 2019   No Data 1 / 1  
 
02/09/2001 04/22/2002
67 FR 7966
Great Falls Area Maintenance 11/15/1990 Not Classified 57,573 2019   No Data 1 / 1  
 
02/09/2001 07/08/2002
67 FR 31143
Missoula Area Maintenance 11/15/1990 Moderate <= 12.7ppm 59,733 2019   No Data 4 / 4  
 
05/27/2005 09/17/2007
72 FR 46158

Montana Lead (1978) Areas    Return to map     Top of page

Click on the Area name
to view SIP Required Elements


Area
Status Designation
Date
Classification 2010
Population
(state portion)
Meets NAAQS
Basis
Design Value
Annual
(µg/m3)
(entire area)
Meets
NAAQS
SIP
Requirements
Original/
Approved
Clean Air
Determination
Citation
Effective Date
Click to view
FR notice
Redesignation
Request Date
Redesignation
Citation
Effective Date
Click to view
FR notice
Lewis & Clark County (part); City of East Helena and vicinity Maintenance 01/06/1992   2,669 2009-2010   No Data 2 / 2  
 
10/28/2018 10/11/2019
84 FR 47895

Montana Lead (2008) Areas     Return to map Top of page

No designated areas for this pollutant.

Montana NO2 (1971) Areas     Return to map Top of page

No designated areas for this pollutant.

Montana Ozone-1Hr (1979) Areas     Return to map Top of page

No designated areas for this pollutant.

Montana Ozone-8Hr (1997) Areas     Return to map Top of page

No designated areas for this pollutant.

Montana Ozone-8Hr (2008) Areas     Return to map Top of page

No designated areas for this pollutant.

Montana Ozone-8Hr (2015) Areas     Return to map Top of page

No designated areas for this pollutant.

Montana PM-10 (1987) Areas    Return to map     Top of page

Click on the Area name
to view SIP Required Elements


Area
Status Designation
Date
Classification 2010
Population
(state portion)
Meets NAAQS
Basis
Average
Estimated
Exceedances
(est. exc.)
(entire area)
Meets
NAAQS
SIP
Requirements
Original/
Approved
Clean Air
Determination
Citation
Effective Date
Click to view
FR notice
Redesignation
Request Date
Redesignation
Citation
Effective Date
Click to view
FR notice
Flathead County; Columbia Falls and vicinity Maintenance 11/15/1990 Moderate 4,610 2017-2019 0.0 Yes 3 / 3 04/01/2011
76 FR 5280
  07/27/2020
85 FR 38327
Flathead County; Kalispell and vicinity Maintenance 11/15/1990 Moderate 18,422 2017-2019 0.0 Yes 3 / 3  
 
  07/27/2020
85 FR 38327
Flathead County; Whitefish and vicinity Nonattainment 11/18/1993 Moderate 6,138 2017-2019 0.3 Yes 3 / 3  
 
   
Lake County; Polson Nonattainment 11/15/1990 Moderate 4,099 2017-2019   No Data 3 / 0  
 
   
Lake County; Ronan Nonattainment 11/15/1990 Moderate 2,734 2017-2019   No Data 3 / 0  
 
   
Lincoln County; Libby and vicinity Maintenance 11/15/1990 Moderate 3,378 2017-2019 0.0 Yes 3 / 3 04/01/2011
76 FR 5280
  07/27/2020
85 FR 38327
Missoula county; Missoula and vicinity Maintenance 11/15/1990 Moderate 59,733 2017-2019 0.0 Yes 3 / 3  
 
08/03/2016 06/24/2019
84 FR 24037
Rosebud County; Lame Deer Nonattainment 11/15/1990 Moderate 527 2017-2019   No Data 3 / 0  
 
   
Sanders County (part); Thompson Falls and vicinity Nonattainment 01/20/1994 Moderate 1,317 2017-2019 0.4 Yes 3 / 3  
 
   
Silver Bow County; Butte Nonattainment 11/15/1990 Moderate 34,201 2017-2019 0.0 Yes 3 / 3  
 
   

Montana PM-2.5 (1997) Areas    Return to map     Top of page

Click on the Area name
to view SIP Required Elements


Area
Status Designation
Date
Classification 2010
Population
(state portion)
Meets NAAQS
Basis
Design Value
Annual
(µg/m3)
(entire area)
Meets
NAAQS
SIP
Requirements
Original/
Approved
Clean Air
Determination
Citation
Effective Date
Click to view
FR notice
Redesignation
Request Date
Redesignation
Citation
Effective Date
Click to view
FR notice
Libby Nonattainment 04/05/2005 Moderate 9,429 2017-2019 13.4 Yes 8 / 4 08/13/2015
80 FR 40911
   

Montana PM-2.5 (2006) Areas     Return to map Top of page

No designated areas for this pollutant.

Montana PM-2.5 (2012) Areas     Return to map Top of page

No designated areas for this pollutant.

Montana SO2 (1971) Areas    Return to map     Top of page

Click on the Area name
to view SIP Required Elements


Area
Status Designation
Date
Classification 2010
Population
(state portion)
Meets NAAQS
Basis
Design Value
Annual/24-Hr
(ppb)
(entire area)
Meets
NAAQS
SIP
Requirements
Original/
Approved
Clean Air
Determination
Citation
Effective Date
Click to view
FR notice
Redesignation
Request Date
Redesignation
Citation
Effective Date
Click to view
FR notice
East Helena Area Maintenance 11/15/1990   2,669     /     2 / 2  
 
10/26/2019 10/11/2019
84 FR 47897
Laurel Area Nonattainment 11/15/1990   6,525     /     1 / 1  
 
   

Montana SO2 (2010) Areas    Return to map     Top of page

Click on the Area name
to view SIP Required Elements


Area
Status Designation
Date
Classification 2010
Population
(state portion)
Meets NAAQS
Basis
3 Year
1-⁠Hour
Design Value
(ppb)
(entire area)
Meets
NAAQS
SIP
Requirements
Original/
Approved
Clean Air
Determination
Citation
Effective Date
Click to view
FR notice
Redesignation
Request Date
Redesignation
Citation
Effective Date
Click to view
FR notice
Billings Maintenance 10/04/2013   2,621 2017-2019 24 Yes 6 / 5 06/09/2016
81 FR 28718
12/14/2015 06/09/2016
81 FR 28718
We have made our best effort to ensure that the data contained in these reports is accurate. We note that there may be brief delays in updating the reports as we receive new state submissions and we take rulemaking action on plans. In order to assist us in providing accurate information, we request that you contact us by clicking on the "Contact Us" link near the top of this page with any comments regarding or corrections to the posted information, including concerns about whether the entries reflect the most recent status.

Current and historical design value data can be found on the EPA Air Quality Design Values website and the EPA Green Book contains comprehensive nonattainment area, designation status, and historical information.

The level of the 1-hour NAAQS for sulfur dioxide is 75 parts per billion (ppb) calculated as the 3-year average of the 99th percentile of the annual distribution of daily maximum 1-hour average concentrations.