Guidance - Air Quality


The Air Quality Guidebook describes ADOT processes used for air quality, transportation conformity and CMAQ projects. The “Guidebook” is updated as new information becomes available or when new emissions models or regulations are implemented. Any additional updates or supplements to this guide are provided below.

Project-Level Conformity Determinations

Project-Level conformity determinations for Environmental Assessments (EA) or Environmental Impact Statements (EIS) will be posted to Projects and/or be available from ADOT NEPA staff.  Project-Level conformity determinations for Categorical Exclusion (CE) classified projects will be posted to Transportation Conformity for projects approve after January 3, 2018.

Any non-Exempt Federal Projects in PM10, PM2.5 or CO maintenance and/or nonattainment areas are required to complete the following documents, as applicable,  and submit to ADOT Air Quality Staff for further action and Interagency Consultation.

  • Project Level CO Questionnaire - Document to be used in CO Maintenance Areas
  • Project Level PM Project of Air Quality Concern Questionnaire - Document to be used in PM10 and/or PM2.5 Nonattainment or Maintenance Areas

For Project-Level Conformity Hot-Spot Analysis:  Any new PM hot-spots needed after January 1, 2020, will be required to use the latest version of AERMOD, refer to the Training section of the “Project Development” tab.  The modeling and planning assumptions used for transportation conformity project level hot-spots require interagency consultation, ADOT utilizes the following documents for consultation:

  • Project Level CO Hot-Spot Analysis - Consultation Document - to be used in CO Maintenance areas
  • Project Level PM Quantitative Hot-Spot Analysis - Consultation Document - to be used in PM10 and/or PM2.5 Nonattainment or Maintenance Areas