Air Quality


The Clean Air Act provides the principal framework for national, state, and local efforts to protect air quality. Under the Clean Air Act, the Environmental Protection Agency (EPA) is responsible for setting standards, also known as National Ambient Air Quality Standards (NAAQS), for pollutants which are considered harmful to people and the environment. 

The EPA classifies and monitors these sources of pollutants, as well as national, state and local organizations. As part of the transportation planning process, the OCTC monitors air quality as it relates to mobile sources in Orange County. Specifically, the OCTC must ensure projects and programs conform to the NAAQS as part of the Air Quality/Transportation Conformity process.

Transportation Conformity 

Transportation Conformity is required by the Clean Air Act section 176(c) (42 U.S.C. 7506(c)). The intent of Transportation Conformity is to fully coordinate transportation and air quality planning to ensure that transportation projects, plans and programs will not:

  1. Cause or contribute to any new violation of the National Ambient Air Quality Standards (NAAQS), 
  2. Increase the frequency or severity of any existing NAAQS violations, or 
  3. Delay timely attainment of the NAAQS or any required interim emissions reductions or other milestones in any area.  

The US Environmental Protection Agency (EPA) requires that transportation conformity be demonstrated by metropolitan planning organizations (MPOs) in air quality nonattainment and maintenance areas whenever transportation projects that may significantly impact air quality are planned and programmed.

Air Quality/Transportation Conformity Determinations

Orange County is part of the NY-NJ-CT air quality maintenance area for fine particulate matter (PM2.5) along with New York City, Long Island, Westchester and Rockland Counties. Those areas are part of the New York Metropolitan Transportation Council (NYMTC), which is the MPO for New York City, Long-Island, Westchester, Rockland and Putnam Counties.

Orange County is also part of the Poughkeepsie, NY 1997 ozone nonattainment area comprised of Dutchess, Orange and Putnam Counties. Dutchess County is the planning boundary of the Dutchess County Transportation Council (DCTC), which is the MPO for Dutchess County. 

OCTC Air Quality Conformity Determination & PONA (Resolution) (Adopted December 2023) 

Previous Air Quality/ Transportation Conformity Determinations

Other Air Quality Resources