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Division of Planning
Office of Environmental Services
Environmental Policy

Air Quality

Projects listed on the Statewide Transportation Improvement Program (STIP) and/or Transportation Improvement Program (TIP) are required to have Mobile Source Air Toxics (MSAT), Particulate Matter (PM2.5), Ozone (O3), and Carbon Monoxide (CO) addressed under NEPA. The OES-Noise and Air Quality Unit provides guidance that is necessary to ensure that transportation projects are in compliance with NEPA relative to air quality issues. All required air quality analyses must be conducted and coordinated, as necesssary, prior to approval of the NEPA document. All air quality analyses are submitted to the OES-Noise and Air Quality Unit for review and coordination. The OES-Noise and Air Quality Unit provides assistance in determining what level of air quality analysis is required on a project and, in some cases, prepares the required air quality analysis on specific projects when workload permits.

The OES-Noise and Air Quality Unit is also responsible for coordinating air quality analyses with the FHWA, OEPA and USEPA. The OES-Noise and Air Quality Unit also advises local transportation project sponsors of the air quality analysis requirements of their projects. Local project sponsors are then required to conduct the required air quality analyses prior to NEPA approval.

One copy of an air quality analysis report is required for OES-Noise and Air Quality Unit review. Once accepted, 2-4 copies are required (1 copy each for OES, FHWA, OEPA, and/or USEPA).

Guidance on Project-Level Air Quality Analysis Requirements

An MSAT analysis is required for any project that has sensitive land uses within 500' of the project area and the project involves adding capacity, adding a new interchange, constructing a new road on new alignment, or expanding an intermodal center.

Relative to a Particulate Matter (PM2.5) analysis, if a project is not in a PM2.5 nonattainment or maintenance area, no further PM2.5 analysis is required. A PM2.5 Hotspot Analysis is required if a non-exempt project is located in a PM2.5 nonattainment or maintenance area and the project's design year Average Daily Traffic (ADT) > 125,000 and the design year diesel truck volume > 10,000. If a project is in a PM2.5 nonattainment or maintenance area but a PM2.5 Hotspot Analysis is not required based on ADT and diesel truck volume, then the project is either exempt from air quality conformity for PM2.5 per 40CFR93.126 or the project will require a conformity determination approval letter from FHWA prior to NEPA approval. The OES-Noise and Air Quality Unit is responsible for obtaining the conformity determination approval letter from FHWA by project batch approval or project specific approval.

Relative to Ozone, if a project is listed in the STIP/TIP, then ozone has been addressed. However, it must be confirmed that the project description in the NEPA document is the same as what is in the STIP/TIP.

Relative to Carbon Monoxide (CO), if the constructed project will not result in an increase in the ADT of more than 10,000 vehicles within 10 years of project completion date or the project does not involve a new road on new right-of-way that will have an ADT increase of more than 20,000 vehicles within 10 years of construction, the project is exempt from project level conformity analysis for CO per the ODOT/OEPA Air Quality Agreement. Otherwise, a Quantitative CO analysis will be required.

Legislation Section 1796 of The National Clean Air Act is part of a Federal Law that requires NEPA integration. When a proposed Federal Action (i.e. New or Expanded Roadway, Interchange , etc.) could potentially interfere with Clean Air Standards under The Clean Air Act, ODOT with the assistance of the local MPO is required to conduct a special Air Quality analysis to determine the likehood and extent of such interference. This analysis is known as a "Conformity Analysis" and must adhere to specific evaluation protocols established by the Ohio EPA and USEPA. The Federal Highway Administration will not support or fund any highway project that doesn't conform to an approved State Implementation Plan (SIP). No local Metropolitan Planning Organization (MPO) may approve any Transportation project that doesn't conform to an approved SIP. Furthermore, no MPO may adopt or approve a Transportation Improvement Program (TIP) that does not follow the requirements of the 1990 Clean Air Act amendments.

Windmills in an Ohio cornfield

 Guidelines & Documents

Clean Air ActWeb
PM2.5 Technical Guidance for Qualitative Hot SpotPDF
Electronic Code of Federal Regulations - Title 40 Protection of Environmental Air ProgramsWeb
PM2.5 Conformity Process Flowchart REVISEDPDF
EPA Transportation Conformity Guidance for Qualitative Hot-Spot Analyses in PM2.5 and PM10 Non-attainment and Maintenance AreasPDF
MSAT Analysis FlowchartPDF
Ozone Process FlowchartPDF
Technical Guidance for Analysis of Mobile Source Air ToxicsPDF
Ozone Maintenance Areas in OhioWeb
Interim Guidance Update on MSATs in NEPA Documents, Sept. 30, 2009Web
Interim Guidance Update on MSATs in NEPA Documents, December 6, 2012Web

 Related Links

Ozone Non-Attainment Areas in OhioWeb
National Ambient Air Quality StandardsWeb
PM2.5 FAQsWeb
PM2.5 Basic InformationWeb
PM2.5 Non-Attainment Areas in OhioWeb
The Bridge to Cleaner Air: Transportation ConformityPDF