Air Quality

In response to the Clean Air Act, the US Environmental Protection Agency has established health-based National Ambient Air Quality Standards (NAAQS) for 6 air pollutants:

Carbon monoxide (CO)
Lead
Nitrogen dioxide
Ozone
Particulate matter (PM10 (coarse) and PM2.5 (fine))
Sulfur dioxide

Areas that fail to meet the NAAQS are designated “non-attainment” and are required to develop plans to come into compliance with the standards.

Transportation Conformity

Transportation conformity is a way to ensure that Federal funding goes to those transportation activities that are consistent with the NAAQS. Conformity applies to transportation plans, transportation improvement programs (TIPs) and projects funded or approved by the Federal Highway Administration (FHwA) or the Federal Transit Administration (FTA) in areas that do not meet or previously have not met air quality standards for various pollutants. A conformity determination is a finding that the projects in a plan or program do not adversely impact air quality.

In 2014, the Eugene-Springfield region completed the 20 year maintenance period for the pollutant carbon monoxide (CO). This means that the air quality standards for CO have now been met for at least 20 years. No further assessment for CO thus needs to be done under the Clean Air Act regulations when reviewing transportation projects. The State will continue to monitor conditions and will be alert for any backsliding. In 2010, levels of CO had reached a maximum of 1.6 ppm, well below the NAAQS of 9 ppm.

Coarse Particulate Matter

In our area, the only other air pollutant that is required to be assessed under the Clean Air Act when transportation projects are being considered is that of coarse particulate matter (PM10). On June 10, 2013, Eugene-Springfield was redesignated by USEPA to attainment for PM10 with an approved 10 year maintenance plan. This action was based on the measurements that indicate that the region has not exceeded the air quality standards for this pollutant since 1987. The maintenance plan, prepared by Lane Regional Air Protection Agency (LRAPA) lays out the approach for ensuring that this area will continue to meet the Clean Air Act standard for this pollutant. Within this plan, an inventory of sources established that emissions from motor vehicles were less than 15% of the total PM10 emissions, and that growth in vehicle emissions was unlikely to cause a future violation. Because of this, no regional conformity analysis is required for PM10 for plans or projects within the Eugene-Springfield urban growth boundaries. Implementation by LRAPA of home wood heating rules continues to be required.

In 2013, the level of PM10 fell to 42 ug/m3, well below the NAAQS level of 150 ug/m3. Trends over time can be seen here.

Project Level Conformity

This is a process whereby each project is reviewed for its localized impact (such as at intersections or terminals) once the design has been determined and construction phases are pending. Many projects are exempt from this requirement due to their negligible effect on PM10 emissions. However, major projects that impact auto and truck volumes must be reviewed and, in some cases, must undertake a "hot spot analysis" for PM10, as well as fulfill other requirements for project conformity including public involvement opportunities.

Note also, that within Lane County, LRAPA requires an indirect source permit for new construction or modifications of certain road, airport and parking facilities for certain projects.

Central Lane MPO's transportation plans or programs include a list of all projects that must be examined for conformity with an annotation as to whether each project is exempt or not.

Conformity Determination Documents

Conformity Determination for FFY24-27 Metropolitan Transportation Improvement Program (MTIP) approved by MPO Policy Committee on May 4, 2023
- Complete Document (pdf)
Conformity Determination for the 2045 Regional Transportation Plan
- Approved Air Quality Conformity Determination for the 2045 Regional Transportation Plan

Conformity Determination for FFY21-24 Metropolitan Transportation Improvement Program (MTIP) approved by MPO Policy Committee on May 7, 2020
- Complete document with maps and appendices (pdf)
Conformity Determination for 2040 Regional Transportation Plan and FFY18-21 Metropolitan Transportation Improvement Program (approved by MPO Policy Board on May 4, 2017 and pending approval by USDOT and USEPA).
- Complete Document with maps and appendices (PDF)