Transportation conformity is a mechanism to ensure that federal funding and approval are given to those transportation activities that are consistent with air quality goals as contained in the State Implementation Plans (SIPs). Once an area reaches attainment, the SIPs are amended to include a 10-year maintenance plan. OKI is the metropolitan planning organization (MPO) for the Greater Cincinnati/Northern Kentucky area responsible for transportation planning and air quality conformity. The latest regional emissions and air quality conformity analysis was completed in June 2012 with the adoption of OKI’s 2040 Regional Transportation Plan and amended FY 2012-FY 2015 Transportation Improvement Program.
Pursuant to provisions of the CAAA of 1990, U.S. EPA designated a nine county area in the Cincinnati area as a marginal nonattainment area for ozone under the 2008 ozone standard in May 2012. The Cincinnati nonattainment area includes Lawrenceburg Township in Dearborn County Indiana, portions of the Kentucky counties of Boone, Campbell and Kenton, and the Ohio counties of Butler, Clermont, Clinton, Hamilton and Warren. The OKI Regional Council of Governments, as the Metropolitan Planning Organization (MPO), consists of Dearborn, Boone, Campbell, Kenton, Butler, Clermont, Hamilton and Warren counties and is responsible for the air quality conformity determination for the region’s Transportation Plan and Transportation Improvement Program. Clinton County is outside of the OKI region, but is part of the nonattainment area. The Ohio Department of Transportation (ODOT) is the lead planning agency for Clinton County.
In 2011, U.S. EPA approved requests to redesignate the region to attainment of the annual fine particulate (PM2.5) standard. The PM2.5 maintenance area is identical except for the exclusion of Clinton County.