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Support Center for Regulatory Atmospheric Modeling (SCRAM)

Sulfur Dioxide (SO2) Designations and Implementation Modeling Guidance and Assistance

The information and links provided below are intended to help inform and assist Regional, State, Local, and Tribal modelers with respect to designation and implementation modeling for the 1-hour sulfur dioxide (SO2) National Ambient Air Quality Standard that became effective on June 2, 2010. Examples of State and local SO2modeling protocols, requests for information (source characterization and emissions data), and modeling input data are provided for illustrative purposes and will be updated as additional information becomes available to the EPA. Please note that consultation with the appropriate EPA Regional Office must be sought before implementing any of the information contained in the State and local examples that are provided below.



Sulfur Dioxide (SO2) National Ambient Air Quality Standard:

General Information
Final Revision to Primary NAAQS - June, 2, 2010

Appendix W (40 CFR Part 51) - 1-Hour SO2 Policy Relevant Guidance:

Applicability of Appendix W Modeling Guidance for the 1-hour SO2 NAAQS (PDF - 396 KB)
Additional Clarification Regarding Applicability of Appendix W Modeling Guidance for the 1-hour NO2 NAAQS (Applicable for the 1-hour SO2 NAAQS) (PDF - 538 KB)

SO2 Designations Modeling Guidance:

Summary of Modeling Guidance for SO2 Designations - One Pager (PDF - 240 KB)
Area Designations for the 2010 Revised Primary Sulfur Dioxide National Ambient Air Quality Standards Memorandum (PDF - 12.0 MB)

SO2 Implementation Modeling Guidance:

Summary of Modeling Guidance for SO2 Implementation - One Pager (PDF - 296 KB)
Draft Primary Sulfur Dioxide National Ambient Air Quality Standards Implementation Guidance (PDF - 1.1 MB)
Webinar Presentation - Draft Modeling Guidance for SO2 Implementation (PDF - 840 KB)

2011 Regional, State, and Local Modelers' Workshop - SO2 Related Presentations:

2011 RSL Modelers' Workshop Website and Agenda Exit EPA disclaimer
     SO2 Designation Modeling (PDF - 775 KB) Exit EPA disclaimer
     SO2 Implementation Modeling (PDF - 526 KB) Exit EPA disclaimer
     1-hour SO2 Modeling Examples (PDF - 221 KB) Exit EPA disclaimer
     LADCO SO2 Modeling Protocol (PDF - 3.7 MB) Exit EPA disclaimer

State and Local SO2 Modeling Protocol Examples:

LADCO SO2 Modeling Protocol (PDF - 878 KB) Exit EPA disclaimer

State and Local Requests for Information (Source Characterization and Emissions Data) Examples:

Illinois Environmental Protection Agency - Template Document (PDF - 16 KB)
Indiana Department of Environmental Management - Template Document (PDF - 38 KB) & Template Spreadsheet (XLS - 39 KB)
Oklahoma Department of Environmental Quality - Template Document (PDF - 12 KB)
Texas Commission on Environmental Quality - Special Inventory Request Presentation (PDF - 172 KB)

SO2 Modeling Input Data:

Meteorological Data - Surface and Upper Air Databases
Monitored SO2 Ambient Concentrations - EPA Air Quality System (AQS)
Source Emissions - EPA National Emission Inventory (NEI) Database

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