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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)


Revised draft section 4 (03/16/2021) New! 


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


Draft section 4 (01/25/2021)


Draft section 4 table of issues and recommendations (02/01/2021)



Please submit questions or comments on the amendment of section 4 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 March 17, 2021