MDEQ Air Quality Division Updates two key Policy and Procedure Documents

UPDATE: AQD-022 and AQD-023

The Air Quality Division has recently updated two Policy and Procedure Documents that are used internally and externally. The two updated documents are AQD-022: Dispersion Modeling Guidance for Federally Regulated Pollutants and AQD-023: Replacement of Engines, Compressors, or Turbines as Part of a Normal Maintenance Program at Landfill Gas-To-Energy Facilities.

AQD-022: Dispersion Modeling Guidance for Federally Regulated Pollutants – This Policy and Procedure is a guideline to use when federally regulated pollutant emissions must be modeled in comparison to the National Ambient Air Quality Standards (NAAQS) and Prevention of Significant Deterioration (PSD) Increment to demonstrate compliance with those standards.  This document was updated recently to provide clarification based on comments received from both internal and external stakeholders.

Some key updates and changes in this document:

• A flow chart was added to guide the user
• More explanation was added to each category covered in the document
• Table 3 – The “natural gas” category was removed from this table
• Qualitative Assessment section was expanded to clarify the analysis required
• Appendix B – “Modeling Scenario Examples” was updated to include an introduction as well as sections for the analysis required.

AQD-023: Replacement of Engines, Compressors, or Turbines as Part of a Normal Maintenance Program at Landfill Gas-To-Energy Facilities – This Policy and Procedure lays out guidelines for replacement of combustion equipment at landfill gas to energy facilities and includes suggestions on information to keep on site.

Some key changes in this document:

• Was made “External/Interpretative”
• Added language clarifying what “catastrophic” means
• Added language to the recordkeeping at the end of the Policy and Procedure

The final revised documents can be found on our website.

If you have any questions regarding these Policy and Procedure documents, or how they apply to your facility, please contact Annette Switzer, Permit Section Manager, 517-284-6803 or switzera2@michigan.gov.