Air Quality Planning

Hartford Clean Air Logo EPA establishes air quality standards, protective of public health and welfare for various pollutants. Connecticut DEEP prepares plans to attain and maintain compliance with these standards. These State Implementation Plans (SIPS) include regulations to prevent, reduce and control air pollution. These SIPs are developed through a planning process that combines technical information and air quality policy.
Large data sets defining the emissions sources (such as mobile and stationary) and meteorological data are analyzed and combined in mathematical models to inform the choice of regulatory options.  These data-driven options inform decisions about air quality plan development, regulatory development and program implementation.  Programs and regulations are routinely evaluated and updated with respect to changes in environmental conditions, health impact data and federal laws.  In carrying out its air quality planning, DEEP takes into account a wide range of stakeholder concerns.  

Air Quality Plans

State Implementation Plan (SIP) Revisions The Connecticut State Implementation Plan (SIP) for air quality is a collective of historical plans and regulations, which were approved by EPA as meeting certain requirements of the Clean Air Act.  EPA has the authority to enforce the Connecticut air quality regulations incorporated into the SIP.  EPA’s record of the SIP-incorporated regulations is set out in 40 CFR Part 52 Subpart H.

Ozone Planning Efforts All of Connecticut is currently classified as nonattainment. 

PM2.5 Planning Efforts All of Connecticut is currently classified as unclassifiable/attainment.

PM10 Planning Efforts All of Connecticut is currently classified as unclassifiable/attainment.  

SO2 Planning Efforts All of Connecticut is currently classified as unclassifiable/attainment.

NO2 Planning Efforts All of Connecticut is currently classified as unclassifiable/attainment.

Lead Planning Efforts All of Connecticut is currently classified as unclassifiable/attainment.  

Regional Haze Planning Efforts

EPA requires states to submit regional haze SIPs that describe the states’ measures for meeting the national goal of a return to natural visibility conditions at Class I areas (national parks and wilderness areas) by 2064. 

Regulation Development

Comments on Federal Rulemaking

Federal regulations are enforceable laws authorized by legislation enacted by Congress. Agencies, such as EPA are empowered to create and enforce regulations.  These federal regulations are created according to the Uniform Administrative Procedures Act (APA).  Connecticut comments on proposed federal regulations that would have an effect on the State's air quality.

State Rulemaking

The Connecticut eRegulations System is the official site for public access to regulation development records. Once a DEEP regulatory action is proposed, you can follow its activity through the Connecticut eRegulations System. Prior to publication of the notice of intent for a regulatory action, the Air Bureau’s regulatory development materials may be available below.

Amendment of section 22a-174-4 of the Regulations of Connecticut State Agencies (section 4)

The proposal was approved with technical corrections during the October 25th Legislative Regulation Review Committee (LRRC) meeting. The revisions recommended by the Legislative Commissioner’s Office have been incorporated into the regulation and the proposal was submitted to the Secretary of the State (SOTS). Approval from the SOTS was received on October 28th, and the new regulation is effective as of that day. The final, approved copy of the amendment and all the documents produced during this rulemaking are available here. A copy of the final approved RCSA section 22a-174-4a will be available in the eRegulations System soon (10/28/2022) New!

The proposal was rejected without prejudice during the July 26th Legislative Regulation Review Committee (LRRC) meeting. The revisions recommended by the Legislative Commissioner’s Office have been incorporated into the draft and the proposal has been resubmitted to the office of the Attorney General (AG). Approval from the AG’s office was received on August 24th. Resubmission to the LRRC is anticipated before the October 4th deadline for consideration during the October 25th Committee meeting. The revised proposal and other related materials can be found here (08/31/2022)

A response-to-comments document has been posted to the eRegulations website and the proposal has been submitted to the office of the Attorney General. A copy of the response-to-comments document, the revised proposal and other related materials can be found here (05/11/2022) 


The notice of intent has been published in eRegulations and the formal comment period was open through 5 pm on Friday, December 17, 2021. You can view the notice of intent and all related materials here (11/02/2021)


Response to informal comments from stakeholders (03/16/2021) 


Please submit questions or comments on this rulemaking to Paula Gomez (



Mobile Source Planning

Mobile sources includes a variety of vehicles, engines and equipment. Sources like these account for the largest sector of man-made air pollution in Connecticut and throughout the Northeast. As such, Connecticut employs several strategies to address these emissions. Strategies include inspection and maintenance programs, diesel emissions reduction initiatives, incentive programs and more. Find the relevant information here.

Content Last Updated on November 1, 2022