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Clean Air Interstate Rule (CAIR)

    Photo:  Mountain landscapeEPA’s Clean Air Interstate Rule (CAIR) addressed regional interstate transport of soot (fine particulate matter) and smog (ozone), which are associated with thousands of premature deaths and illnesses each year. CAIR required 28 eastern states to make reductions in sulfur dioxide (SO2) and nitrogen oxides (NOX) emissions that contribute to unhealthy levels of fine particle and ozone pollution in downwind states. CAIR was replaced by the Cross-State Air Pollution Rule, as of January 1, 2015.

Photo:  Leaf

Under CAIR, States must achieve the required emission reductions using one of two compliance options:

  1. Meet the state’s CAIR requirements by requiring power plants to participate in an EPA-administered interstate cap and trade system that caps emissions in two stages, or
  2. Meet an individual state emissions budget through measures of the state’s choosing.

All affected states chose to meet their emission reduction requirements by controlling power plant emissions through three separate interstate cap and trade programs: the CAIR SO2 annual trading program, the CAIR NOX annual trading program, and the CAIR NOX ozone season trading program.

By the year 2015, the Clean Air Interstate Rule will result in:
  • $85 to $100 billion in annual health benefits, annually preventing 17,000 premature deaths, millions of lost work and school days, and tens of thousands of non-fatal heart attacks and hospital admissions.
  • Nearly $2 billion in annual visibility benefits in southeastern national parks, such as Great Smoky and Shenandoah.
  • Significant regional reductions in sulfur and nitrogen deposition, reducing the number of acidic lakes and streams in the eastern U.S.
Charts and Tables – A collection of printable charts, tables, and graphics demonstrating the health and environmental benefits of CAIR.

Where You Live

The final Clean Air Interstate Rule covers 27 eastern states and the District of Columbia. Air emissions in these states contribute to unhealthy levels of ground-level ozone, fine particles or both in downwind states. To learn about the impact of CAIR where you live, please click on your state either on the map or the drop-down list below.

 

Map of the United States Alabama Alaska Arizona Arkansas California Colorado Connecticut Delaware Washington, DC Florida Georgia Hawaii Idaho Illinois Indiana Iowa Kansas Kentucky Louisiana Maine Maryland Massachussets Michigan Minnesota Mississippi Missouri Montana Nebraska Nevada New Hampshire New Jersey New Mexico New York North Carolina North Dakota Ohio Oklahoma Oregon Pennsylvania Rhode Island South Carolina South Dakota Tennessee Texas Utah Vermont Virginia Washington West Virginia Wisconsin Wyoming

Regulatory Actions

You will need Adobe Acrobat Reader, available as a free download, to view some of the files on this page. See EPA's PDF page to learn more about PDF, and for a link to the free Acrobat Reader.

EPA Publishes Final Stay of CAIR and CAIR FIP for Minnesota only
November 3, 2009 - EPA publishes final rule to stay the effectiveness, for Minnesota only, of the Clean Air Interstate Rule (CAIR) and the associated CAIR Federal Implementation Plan (CAIR FIP).

EPA Proposes to Stay CAIR and CAIR FIP for Minnesota only
May 6, 2009 - EPA proposed to stay the effectiveness, for Minnesota only, of the Clean Air Interstate Rule (CAIR) and the associated CAIR Federal Implementation Plan (CAIR FIP).

D.C. Circuit remanded
December 23, 2008 - The D.C. Circuit remanded without vacatur EPA's Clean Air Interstate Rule. Read the court decision (PDF 4pp, 22k)

No public hearing was requested
December 23, 2008 - No public hearing was requested and none will be held for EPA's Rulemaking To Reaffirm the Promulgation of Revisions of the Acid Rain Program Rules.

Petition for rehearing in the Clean Air Interstate Rule
November 17, 2008 - The United States filed a reply in support of its petition for rehearing in the Clean Air Interstate Rule case. Read the Reply (PDF 10pp, 390k) | Attachment 1 (PDF 23pp, 137k) | Attachment 2 (PDF 12pp, 165k)

Petition for rehearing
September 24, 2008 - The United States filed a petition for rehearing in the Clean Air Interstate Rule case. Read the Petition (PDF 23pp, 1058k) | Declarations by Brian McLean and William Harnett (PDF 11pp, 454k)

Quick Fix Changes
August 23, 2008 - Analysis of Potential Quick Fix Legislative Changes to Address Court Decision (PPT 12pp, 985k)

Brian Mclean's Testimony
July 29, 2008 - Brian Mclean's Testimony for the Senate Committee on Environment and Public Works: EPA's preliminary assessment of the potential affect of the recent DC Circuit Court Decision on CAIR and EPA's programs (PDF, 15 pp. 57 KB) | Supplemental Attachments (PDF, 5 pp. 877 KB)

D.C. Circuit vacated EPA's Clean Air Interstate Rule
July 11, 2008 - The D.C. Circuit vacated EPA's Clean Air Interstate Rule. EPA is reviewing the Court's decision and evaluating its impacts. Read the Court's Opinion (PDF) (60pp, 221k)

Automatic FIP Withdrawal Rule
October 17, 2007 - EPA amended the Federal Implementation Plans (FIPs) for the Clean Air Interstate Rule (CAIR) to provide for automatic withdrawal of the CAIR FIPs in a state once EPA has approved a full CAIR State Implementation Plan (SIP) meeting the CAIR requirements. EPA promulgated the CAIR FIPs on April 28, 2006, to implement CAIR in each CAIR state until a state has an EPA-approved SIP in place to achieve the required reductions.

Final Cogeneration Unit Definition Change
October 11, 2007 - EPA finalized a change to the thermal efficiency calculation in the cogeneration unit definition in the Clean Air Interstate Rule (CAIR), CAIR Federal Implementation Plans, and the Clean Air Mercury Rule (CAMR) for boilers co-firing biomass that will likely make it possible for some additional units to qualify for the cogeneration unit exemption in these rules. EPA also made minor technical corrections to CAIR, the CAIR FIPs, CAMR, and the Acid Rain Program rules. This rule becomes effective on November 19, 2007, 30 days from publication in the Federal Register.

Corrections to the Clean Air Interstate Rule and the CAIR Federal Implementation Plan
September 25, 2007 - EPA is making a minor correction to the Clean Air Interstate Rule (CAIR) to restore a phrase of regulatory text related to state annual emissions reporting requirements that was inadvertently deleted when the rule was amended in 2006.

Notice of Denial of Petitions for Reconsideration of CAIR FIPs and Response to NC 126 Petition
June 22, 2007 - Following its publication, EPA received four separate petitions for reconsideration of the Federal Implementation Plans for the Clean Air Interstate Rule and Final Response to North Carolina's Section 126 Petition. After considering the petitions, EPA sent letters to the petitioners denying their requests to reconsider certain aspects of the rule. EPA concluded that reconsideration of the issues was not warranted under the Clean Air Act.

Petitioners

Petitions

EPA Response Letters

ARRIPA

Cover Letter for Petition (PDF) (1pg, 39k)
Petition for Reconsideration (PDF) (17pp, 3.3 MB)

Response (PDF) (3pp, 226k)

Colver Power Project

Petition for Reconsideration (PDF) (36pp, 2.0 MB)

Response (PDF) (3pp, 229k)

State of North Carolina

Cover Letter for Petition (PDF) (1pg, 145k)
Petition for Reconsideration (PDF) (36pp, 360k)

Response (PDF) (4pp, 339k)

Southern Environmental Law Center, Sierra Club, Environment North Carolina

Petition for Reconsideration (PDF) (46pp, 1.8 MB)

Response (PDF) (3pp, 196k)

 

Proposed Cogeneration Unit Definition Change
April 16, 2007 - EPA proposed a change to the thermal efficiency calculation in the cogeneration unit definition in the Clean Air Interstate Rule (CAIR) model cap-and-trade rules, the CAIR FIP, the Clean Air Mercury Rule (CAMR) and the proposed CAMR Federal Plan for units burning biomass. EPA also proposed minor technical corrections to CAIR and the Acid Rain Program rules, and minor revisions to National Emission Standards for Hazardous Air Pollutants for Industrial, Commercial, and Institutional Boilers and Process Heaters. Comments on this proposal are due to EPA by 45 days after publication in the Federal Register.

Technical Corrections
December 7, 2006 - EPA is making minor corrections to the Clean Air Interstate Rule (CAIR) and the Federal Implementation Plans (FIPs) for the CAIR to clarify text that may potentially be misleading.

EPA announced the following CAIR-related actions on March 15, 2006:

1. Federal Implementation Plan for Clean Air Interstate Rule and Final Response to North Carolina's Section 126 Petition
To ensure that the emissions reductions required by the CAIR are achieved on schedule, EPA promulgated Federal Implementation Plans, or FIPs, for power plants. In the same action, EPA also denied a petition submitted by North Carolina under section 126 of the Clean Air Act. The CAIR FIPs will eliminate significant contribution from the states now linked to North Carolina nonattainment.

2. Inclusion of Delaware and New Jersey in Clean Air Interstate Rule
In a second CAIR related action, EPA issued a final rule to include Delaware and New Jersey in the CAIR for fine particle pollution.

3. Reconsideration of the Clean Air Interstate Rule
Following its publication, EPA received twelve separate petitions for reconsideration of the CAIR. In response, EPA made final its decisions on five issues reopened for public comment in response to petitioners. EPA has determined that its decisions in the final CAIR were reasonable and should not be changed.

To complete the reconsideration process, EPA sent letters to nine petitioners denying their requests to reconsider certain aspects of the final Clean Air Interstate Rule (CAIR). EPA concluded that reconsideration of these issues was not warranted under the Clean Air Act.

Petitioner Petitions and Attachments EPA Response Letter
Connecticut Business and Industry Association (CBIA) Petition for Reconsideration (PDF) (1pg, 21k) Response (PDF) (3pp, 46k)
City of Amarillo, El Paso Electric, Occidental Permian, Southwestern Public Service Co, d/b/a Xcel Energy Petition for Reconsideration (PDF) (15pp, 972k)
Attachment 2 (PDF) (2pp, 414 k)
Attachment 3 (PDF) (20pp, 2.2 MB)
Attachment 4 (PDF) (38pp, 5.6 MB)
Response (PDF) (4pp, 59k)
State of Connecticut Department of Environmental Protection (CT DEP) Petition for Reconsideration (PDF) (5pp, 318k) Response (PDF) (4pp, 45k)
Florida Association of Electric Utilities (FAEU)

Petition for Reconsideration (PDF) (20pp, 702k)
Supplement (PDF) (3pp, 198k)
Second Supplement (PDF) (5pp, 284k)

Response (PDF) (7pp, 111k)
FPL Group (parent of Florida Power and Light) Petition for Reconsideration (PDF) (21pp, 934k)
Supplement (PDF) (8pp, 200k)
Second Supplement (PDF) (6pp, 147k)
Response (PDF) (5pp, 73k)
Minnesota Power (Div. of Allete) Petition for Reconsideration (PDF) (15pp, 685k) Response (PDF) (6pp, 89k)
State of North Carolina Petition for Reconsideration (PDF) (25pp, 1.0 MB) Response (PDF) (6pp, 89k)
Northern Indiana Public Service Company (NIPSCO) Petition for Reconsideration (PDF) (50pp, 1.5 MB)
Supplement (PDF) (11pp, 352k)
Response (PDF) (6pp, 97k)
Texas Commission on Environmental Quality Petition for Reconsideration (PDF) (47pp, 1.4 MB) Response (PDF) (3pp, 31k)

EPA to Reconsider an Additional Aspect of the Clean Air Interstate Rule
December 22, 2005 - EPA has decided to grant an industry petition asking EPA to reconsider and provide an opportunity for public comment on an additional issue related to the Clean Air Interstate Rule. The petition asks EPA to examine the impact of a recent D.C. Circuit Court decision, New York v. EPA, 413 F.3d 3 (D.C. Cir. 2005), on analyses used in developing CAIR. This decision vacated the pollution control project (PCP) exclusion in the New Source Review (NSR) regulations. The exclusion allowed for certain environmentally beneficial PCPs to be excluded from certain NSR requirements. EPA's analysis shows that the court decision does not impact the CAIR analyses. EPA is providing an opportunity for public comment on the issue and is not proposing any changes to CAIR at this time.

Reconsideration of Certain Aspects of the Clean Air Interstate Rule
November 22, 2005 - Following promulgation of the final rule in March 2005, the EPA Administrator received eleven petitions for reconsideration. While the Agency does not believe that its final decision was in error, it is granting reconsideration and providing an additional opportunity for public comment on the following issues related to the final rule:

  1. Claims that inequities result from applying the sulfur dioxide (SO2) allocation methodology that states choosing to participate in the CAIR SO2 trading program would use to allocate SO2 emissions allowances to sources;
  2. EPA’s use of fuel adjustment factors (1.0 for coal, 0.6 for oil, and 0.4 for gas) in establishing state nitrogen oxides (NOx) budgets;
  3. Certain inputs to the fine particle (PM2.5) modeling used to determine Minnesota's inclusion in the CAIR region for PM2.5; and
  4. EPA’s determination that Florida should be included in the CAIR region.

EPA has agreed to reconsider certain aspects of its Clean Air Interstate Rule (CAIR). EPA issued the final CAIR on March 10, 2005.

Proposed Federal Implementation Plan for Clean Air Interstate Rule and Proposed Response to North Carolina's Section 126 Petition
August 1, 2005 - To ensure emissions reductions required under CAIR are achieved, EPA proposed a Federal Implementation Plan (FIP) to require power plants in CAIR states to participate in one or more of three separate cap and trade programs. EPA also proposed a response to a North Carolina petition that requested the Agency to require emission reductions in several upwind states.

Notice of Data Availability
June 21, 2005 - In support of its proposal to include New Jersey and Delaware in the CAIR region for purposes of controlling fine particle pollution in downwind states, EPA is issuing a notice announcing the availability of modelling data. In this notice, EPA also is extending the comment period for the NJ and DE proposal so that it aligns with the comment period for this new data.

Final Clean Air Interstate Rule
March 10, 2005 - EPA finalized the Clean Air Interstate Rule (CAIR), a rule that will achieve the largest reduction in air pollution in more than a decade. This action, called the Interstate Air Quality Rule when it was proposed in January 2004, offers steep and sustained reductions in air pollution as well as dramatic health benefits at more than 25 times greater than the cost by 2015.

Proposal to include NJ and DE in the CAIR Region
March 10, 2005 - EPA proposed to include New Jersey and Delaware in the CAIR region for purposes of controlling fine particle pollution in downwind states. Delaware and New Jersey are already subject to the ozone-related provisions of CAIR but not to the provisions that relate to fine particles.

Finding that States have Failed to Submit Plans to Address Interstate Transport of Pollutants that form Ozone and Particle Pollution
March 10, 2005 - EPA officially notified states that they have failed to submit plans, known as State Implementation Plans or SIPs, addressing the transport of pollutants that form ozone and particle pollution in downwind states.

Notice of Data Availability
July 30, 2004 - EPA is providing notice that it has placed in the docket for the CAIR (Docket no. OAR-2003-0053) additional information relevant to the rulemaking, including, among other things, a new modeling platform that EPA proposes to use to support the proposed rule. This new modeling platform consists of new meteorological data, updated emissions data, an updated air quality model, and revised procedures for projecting future air quality concentrations. The additional information also includes revised state NOx budgets. EPA may place additional documents in the docket. If it does so, EPA will announce their availability by posting a notice on the CAIR website.

Information Collection Request
July 13, 2004 - EPA has proposed a Rule to Reduce Interstate Transport of Fine Particulate Matter and Ozone (Clean Air Interstate Rule, or CAIR) that includes new reporting requirements and combines these new requirements with existing requirements from the Consolidated Emissions Reporting Rule (CERR), the Emission Reporting Requirements for Ozone State Implementation Plan (SIP) Revisions Relating to Statewide Budgets for NOx Emissions to Reduce Regional Transport of Ozone (NOx SIP Call), and the Acid Rain Program under Title IV of the CAA Amendments of 1990. An Information Collection Request (below) has been submitted to the Office of Management and Budget (OMB) for review and approval in accord with the requirements of the Paperwork Reduction Act.

Supplemental Proposal
May 18, 2004 - This supplemental proposal provides additional details and rule language for implementing the Clean Air Interstate Rule (CAIR). These details include specifics on EPA’s proposed model cap and trade program for power plants, as well as details on proposed integration of the CAIR with existing Clean Air Act requirements. The supplemental proposal does not alter any of the emission reduction requirements proposed in January.

Proposed Rule
December 17, 2003 - EPA proposes Rule to Reduce Interstate Transport of Fine Particulate Matter and Ozone (Interstate Air Quality Rule). The proposed rule would cut emissions of SO2 and NOx in the eastern U.S., and is an important component of EPA's efforts to implement the new national air quality standards for fine particle pollution and 8-hour ozone.

Technical Info

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Additional Information Supporting the Clean Air Interstate Rule – Notice of Data Availability (NODA)

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Technical Support Documents for Proposed Revisions to Cogeneration Definition in CAIR, CAIR FIP, CAMR, and Proposed CAMR Federal Plan

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Technical Support Documents for Clean Air Interstate Rule FIP

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Technical Support Documents for Notice of Final Action on Reconsideration of the Clean Air Interstate Rule

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Technical Support Documents for Notice of Reconsideration of the Clean Air Interstate Rule

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Technical Support Documents for the Final Clean Air Interstate Rule

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Technical Support Documents for the Supplemental Proposal of the Clean Air Interstate Rule

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Response to Comments for the Clean Air Interstate Rule

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Technical Support Documents for Proposed Interstate Air Quality Rule (IAQR)
These items are also available in the Docket Center which can be accessed at www.epa.gov/dockets.

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Additional Information Supporting the Clean Air Interstate Rule - Notice of Data Availability (NODA)

EPA may place additional supporting documents in the docket in the future, and if EPA does so, EPA will announce their availability by posting a notice on this website.

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Other Technical Information

Applicability Determinations

You will need Adobe Acrobat Reader to view some of the files on this page. See EPA's About PDF page to learn more about PDF, and a link to the free Adobe Acrobat Reader.


Roy S. Nelson Station, Nelson Industrial Steam Company (NISCO) (PDF, 7 pp. 26 KB - 10/22/2007)
Two boilers that serve 130 MWe generators producing electricity, some of which is sold, and steam but that do not meet the efficiency requirement for qualification as cogeneration units.

Custer Energy Center Simple-Cycle Combustion Turbine (PDF, 4 pp. 31 KB - 2/19/2008)
A simple cycle combustion turbine originally with a nameplate capacity of 23.7 MWe that was reconstructed and refurbished.

ISG Sparrows Point Penwood Boilers 1-4 (PDF, 6 pp. 34 KB - 3/20/2008)
Four boilers that serve three 42 MWe generators and one 28 MWe generator producing electricity, a small amount of which went onto the grid but for which no payment was received, and steam but that do not meet the efficiency standard required for qualification as cogeneration units

Horsehead (PDF, 5 pp. 107 KB - 4/6/2009)
Two boilers that each serve a 60 MWe generator producing electricity, some of which is sold.

Roy S. Nelson Station, Nelson Industrial Steam Company (NISCO) (PDF, 2 pp. 215 KB - 7/6/2009)
Affirmation of the October 22, 2007 Applicability Determination .

Wheelabrator Ridge Energy (PDF, 14 pp. 5.07 MB - 9/9/2009)
A boiler combusting wood, yard waste, and tires, plus, in the past, propane and, currently. landfill gas and serving a generator with a nameplate capacity of 50 MWe that produces electricity for sale.

Exeter Energy Facility (PDF, 11 pp. 14.7 MB - 8/31/2010)
Two boilers combusting tires and propane and serving a generator with a nameplate capacity of 31.3 MWe that produces electricity for sale.

FPL Energy Marcus Hook MH50 Cogeneration Unit (PDF, 7 pp. 9.7 MB - 10/20/2010) A combustion turbine with a nameplate capacity of 66 MWe that produces electricity for sale and qualifies for the cogeneration unit exemption.

Georgia Pacific Broadway Mill facility (PDF, 9 pp. 55 KB - 5/25/2011)
A boiler serving a common header that is incapable of providing enough steam to a steam turbine/generator combination to generate at least 25 MWe without additional steam from some other unit or source.

Veolia Energy Edison Street facility (PDF, 9 pp. 55 KB - 1/4/2012)
Four boilers that have never served electrical generators.

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