Previous PreviousNext Next

EPA Home > Region 5 > Air > Correspondence


March 24, 2000

Thomas V. Skinner, Director
Illinois Environmental Protection Agency
1021 North Grand Avenue East
Post Office Box 19276
Springfield, Illinois  62794-9276

Dear Mr. Skinner:

Pursuant to Section 93.118(e)(4) of the Transportation Conformity Rule (40 CFR Part 93, Subpart A), the United States Environmental Protection Agency (USEPA) has reviewed the Chicago ozone attainment demonstration, and supplemental information, submitted on April 30, 1998, December 17, 1999, January 14, 2000, and January 21, 2000.

The conformity rule identifies limited technical and administrative criteria that must be used in determining adequacy of submitted State Implementation Plan (SIP) budgets for transportation conformity purposes.  We have determined that the Chicago ozone attainment demonstration contains adequate mobile source emission budgets for volatile organic compounds (VOC) and oxides of nitrogen (NOx) for the 2007 attainment year.

This adequacy finding means that the submitted 2007 motor vehicle emissions budgets for VOC and NOx for Chicago meet the standard requirements that any budget must meet before it can be used to determine conformity for a transportation improvement program or long range plan.  This adequacy finding does not relate to the merits of the SIP submittal nor does it indicate whether the submittal meets the USEPA’s requirements for approval of an attainment demonstration.

The USEPA opened a comment period on the SIP’s adequacy by posting it to our web site on January 7, 2000.  The web address is GOTOBUTTON BM_1_ The comment period closed on February 7, 2000, and no comments were received. In addition, the USEPA reviewed the comments made to the Illinois
Environmental Protection Agency on the Chicago ozone attainment demonstration. One negative comment was received on the adequacy of the attainment demonstration budgets.  The USEPA has reviewed the responsiveness summary of the Illinois Environmental Protection Agency to the comments and found the response adequate.

The USEPA acknowledges that the Chicago ozone attainment demonstration is undergoing refined urban air shed modeling and will be updated with the new modeling information.  Illinois has made a commitment to submit the new modeling and any necessary updated control strategy information by December of 2000.

In summary, the USEPA finds that the budgets submitted in the documentation for the Chicago ozone attainment demonstration have met the limited technical and administrative requirements of the transportation conformity adequacy criteria.  The USEPA also acknowledges that further modeling and refinement of the attainment demonstration is necessary.  Illinois has committed to submit these materials by December 2000.  In the December submittal, Illinois may refine the transportation conformity budgets in the attainment demonstration to be consistent with the new submittal.  If Illinois submits new transportation conformity budgets based on the updated modeling and attainment information, the submitted budgets will be subject to posting on the website, public comment and review of adequacy.

More information on SIPs and adequacy reviews is also available on the USEPA web site.  The USEPA will soon publish a notice in the Federal Register announcing this adequacy finding.  If you have questions, please feel free to call me or Patricia Morris, of my staff, at (312) 353-8656.
Sincerely yours,

Cheryl Newton, Associate Director
Air and Radiation Division

cc: Dennis Lawler
    Bureau of Air
    Illinois Environmental Protection Agency

    Eugene Ryan
    Chicago Area Transportation Study

For further information, contact:
This Information Last Modified On: 09/18/2008 04:03 PM