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### BRANCH OfficeofAirQualityPlanningandStandards 

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" I..J -J EPA-RJ.I:CH01v1.V ATLANi'Jl,GA. (CO) Technical Support Documents (TSD's) for Redesignation Ozone and Carbon Monoxide Nonattainment Areas



# . /-yv--- G. T. Helms, Ch1ef /Iti ozone/Carbon Monoxide Programs Branch (MD-15) FROM: SUBJECT:

TO: Air Branch Chief, Regions I-X

The purpose of this memorandum is to request your help in trying to upgrade the TSD's prepared by the Regional Offices which support Federal Register notices of proposed and final rUlemaking actions on ozone and CO redesignations. To make the review process flow more efficiently as we reduce Headquarters review time and move state implementation plan (SIP) actions from Table 1 to Table 2, it is important for Headquarters to quickly process redesignation packages. To do this, we will rely heavily on the Regional Offices to review the State submittals and present the results of their reviews in the TSD.1 Therefore, it is important that the Regional Offices present documentation in the TSD to support the Environmental Protection Agency's (EPA's) evaluation of the submittals along with the complete technical basis for EPA's rulemaking action. For redesignations, the TSD should answer basic questions such as: -What years are the supporting air quality data covering? Where are the monitors located? What are the relevant concentrations?

- For what years were emissions inventories prepared and how were they developed? In the interim, what are the total

{:**l~** ::**~~** INote that a TSDshouldbepreparedfortheproposedrulemaking action or a direct final action. If EPA's position changes prior to final rulemaking, the reasons for the changes are normally addressed in the notice of final rulemaking rather than redrafting the TSD. General information onTSD's is in the document entitled, "Processing Procedures For SIP Revisions For Part 52, Part 62 111(d) Plans," and Part 81 Redesignations."

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### season-day and/or annual emissions by pollutant for point, area, and mobile sources for the attainment and maintenance years?

- What transportation, emission, and/or dispersion models were used? What were the significant inputparameters, including air quality data and assumptions used in the demonstration? What are the model results?

- What are the maintenance plan triggers, commitments, and contingency measures? What is the process for tracking the plan and reporting results to EPA? What are the adoption and implementation schedules for the contingency measures? How is maintenance demonstrated in the interimyears? Are additional controls to be adopted and implemented in the future to offset emission increases, and what is the impact of these controls on emissions inventory planning cap(s)? - Whenwas the public hearing and what are the results of any comments received by the state? What is the status of an outstanding SIP call or findings letter, ifany?

- What is EPA's evaluation ofthe State's supporting materials that accompanied the submittal, such as the technical data and commitment letters, and how do these materials conformto EPA policy, guidance, and the Clean Air Act? Hopefully, you are checking the emissions inventories submitted for redesignations and they are ofthe same quality as those submitted to meet nonattainment area requirements. Ifthis is not the case, you should start transitioning to better inventories. You may use the relevant portions ofthe document entitled, "Quality Review Guidelines For Base Year 1990 Emission Inventories," as a guide to summarizing the inventories in the TSD. 

### Ifyou have any questions, please contact Sharon Reinders at (919) 541-5284.