Air Resources and Publications

Opportunity for public comments.

Guidance Documents

• Licensing Acronyms (.docx) - A list of acronyms/abbreviations that may be used in processing Air Emissions Licenses.
• NESCAUM BACT Guidance (pdf, offsite) - Guidance for determining BACT from the Northeast States for Coordinated Air Use Management (NESCAUM)
• State of Maine BACT Guidance (.docx) - Summary of general requirements when preparing a BACT analysis for the Maine DEP
• Construction Guidance (.docx) – Information on what construction activities may take place prior to issuance of an air emission license.
• Reminder to Obtain an Air Emission License Prior to Beginning Construction of a New or Modified Source (.pdf) – Memo dated July 29, 2024
• NMMPP FAQ (pdf) - Frequently Asked Questions about Nonmetallic Mineral Processing Plants (Rock Crushers)
• Temporary Insignificant Activities (.docx) - Guidance on what equipment is eligible to be considered a temporary insignificant activity and the process for requesting approval
• Clean Air Act Section 176A Petition (.docx) – Frequently Asked Questions about implementation of Maine’s approved Clean Air Act Section 176A Petition
• Chapter 138, NOx RACT – Frequently Asked Questions about implementation of revisions to this rule effective May 7, 2025

Guidance Specific to Engines

See Stationary Reciprocating Internal Combustion Engines for guidance documents and other information specific to stationary engines.

Reports

• Air Emissions Inventory Data - Maine DEP provides summaries of criteria air pollutant and greenhouse gas emissions inventories, as well as other inventory products, through its FTP site. Please view the readme.txt file for a full description of available information.
• Annual Air Monitoring Plan
• Five Year Assessment of Ambient Air Monitoring Network (pdf)
• Department Reports