SIP Status Reports

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Status of Colorado Designated Areas

Colorado Areas by NAAQS
NOTE: As of 03/12/2021, these reports are no longer being updated. For the latest information, see the SIP Status Tools.

Jump to Colorado 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)


Colorado 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
Colorado Springs Area Maintenance 11/15/1990 Moderate <= 12.7ppm 555,742 2019 1.6 Yes 4 / 4  
 
08/19/1998 10/25/1999
64 FR 46279
Denver-Boulder Area Maintenance 11/15/1990 Serious 2,610,637 2019 2.9 Yes 7 / 7  
 
05/10/2000 01/14/2002
66 FR 64751
Fort Collins Area Maintenance 11/15/1990 Moderate <= 12.7ppm 170,639 2019 1.6 Yes 4 / 4  
 
08/09/2002 09/22/2003
68 FR 43316
Greeley Area Maintenance 11/15/1990 Not Classified 138,101 2019 0.9 Yes 1 / 1  
 
09/22/1997 05/10/1999
64 FR 11775
Longmont Area Maintenance 11/15/1990 Moderate <= 12.7ppm 86,558 2019   No Data 5 / 5  
 
08/19/1998 11/23/1999
64 FR 51694

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

No designated areas for this pollutant.

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

No designated areas for this pollutant.

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

No designated areas for this pollutant.

Colorado Ozone-1Hr (1979) 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
(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
Denver-Boulder Area Maintenance (NAAQS revoked) 11/15/1990 Transitional 2,770,524 2017-2019 0.101 Yes 2 / 2  
 
08/12/1996 10/11/2001
66 FR 47086

Colorado Ozone-8Hr (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
(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
Denver-Boulder-Greeley-Ft. Collins-Loveland Nonattainment (NAAQS revoked) 11/20/2007 Subpart 2/Marginal 3,330,139 2017-2019 0.078 Yes 3 / 1  
 
   

Colorado Ozone-8Hr (2008) 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
(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
Denver-Boulder-Greeley-Ft. Collins-Loveland Nonattainment 07/20/2012 Serious 3,330,139 2017-2019 0.078 No 59 / 47  
 
   

Colorado Ozone-8Hr (2015) 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
(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
Denver Metro/North Front Range Nonattainment 08/03/2018 Marginal 3,329,773 2017-2019 0.078 No 3 / 0  
 
   

Colorado 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
Adams, Denver, and Boulder Counties; Denver Metropolitan area Maintenance 11/15/1990 Moderate 2,770,524 2017-2019 0.3 Yes 3 / 3  
 
07/30/2001 10/16/2002
67 FR 58335
Archuleta County; Pagosa Springs Maintenance 11/15/1990 Moderate 2,261 2017-2019 0.0 Yes 3 / 3  
 
05/10/2000 08/14/2001
66 FR 32556
Fremont County; Canon City Area Maintenance 11/15/1990 Moderate 18,860 2017-2019   Insufficient Data 3 / 3  
 
09/22/1997 07/31/2000
65 FR 34399
Pitkin County; Aspen Maintenance 11/15/1990 Moderate 6,772 2017-2019 0.0 Yes 3 / 3  
 
11/09/2001 07/14/2003
68 FR 26212
Prowers County; Lamar Maintenance 11/15/1990 Moderate 7,523 2017-2019 0.3 Yes 3 / 3  
 
07/31/2002 11/25/2005
70 FR 61563
Routt County (part); Steamboat Springs Maintenance 01/20/1994 Moderate 12,088 2017-2019 0.3 Yes 3 / 3  
 
07/31/2002 11/24/2004
69 FR 62210
San Miguel County; Telluride Maintenance 11/15/1990 Moderate 2,014 2017-2019 0.0 Yes 3 / 3  
 
05/10/2000 08/14/2001
66 FR 32556

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

No designated areas for this pollutant.

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

No designated areas for this pollutant.

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

No designated areas for this pollutant.

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

No designated areas for this pollutant.

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

No designated areas for this pollutant.
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.