Air Modeling for Air Permitting

The Division of Air Resource Management’s Office of Permitting and Compliance manages DEP's Prevention of Significant Deterioration (PSD) air permitting program. When a major stationary source of emissions is constructed or modified and it is projected to emit more than a certain amount of air pollutants, the facility must perform an air quality impact analysis to ensure that the project’s future emissions will not cause or contribute to an exceedance of an established air quality standard.

Air modeling is used as a part of this analysis to predict the ambient concentrations of air pollutants for comparison to the National Ambient Air Quality Standards (NAAQS) and PSD increments and to evaluate certain Air Quality Related Values (AQRVs) such as deposition and visibility degradation in protected areas known as Federal Class I areas.

The Air Modeling and Data Analysis Group reviews these analyses to determine if the applicant has provided reasonable assurances that the facility will not cause or contribute to an exceedance of an established air quality standard.

DEP is reviewing the U.S. Environmental Protection Agency change to the National Ambient Air Quality Standards for PM2.5's impact on the information in the PSD Air Quality Modeling Best Practices document. The document was written to assist applicants in preparing a PSD air quality impact analysis as part of a PSD permit application in Florida. It is highly recommended that applicants consult early and often with the Air Modeling Group and follow this document and to ensure a smooth application process.

Additional Information and Links

• DEP is reviewing the PSD Air Quality Modeling Best Practices.
• PSD Air Quality Impacts Analysis Modeling Guide.
• Appendix W to Part 51 of Title 40 of the Code of Federal Regulations: Guideline on Air Quality Models – Governing document for all regulatory Clean Air Act Modeling.
• Support Center for Regulatory Atmospheric Modeling (SCRAM) - The U.S. Environmental Protection Agency (EPA) has published a plethora of modeling guidance and resources.
• AMS/EPA Regulatory Model (AERMOD) – Modeling system developed and managed by EPA that is used for most regulatory modeling.
• AERMET – AERMOD meteorological data pre-processing program. DEP has compiled 32 AERMOD-ready meteorological datasets that can be used for regulatory modeling.

Download AERMET Datasets - This interactive map shows the locations of the 32 AERMOD-ready meteorological datasets that DEP has compiled for regulatory modeling. Links to download the data are included in the map.

• Emissions inventory data may be requested directly from the Air Modeling Group.

Active Permitted Facilities Map - This interactive map shows all active permitted facilities in Florida.

• The pre-construction monitoring requirement for PSD can usually be satisfied using data from one of Florida’s 102 air monitors.

Florida Air Quality System (FLAQS) - FLAQS allows the user to visualize and download a variety of monitored ambient air data.

• Federal Land Managers’ Air Quality Related Values Work Group: Phase I Report – This is the official Class I analysis guidance document.
• All areas in Florida are located within 250 kilometers of a Federal Class I area. As such, DEP generally requires that all applicants perform a class I analysis.
  • Class I Area Map - This interactive map allows the user to locate the nearest Class I areas to any location. 
  • Class I Modeling Receptors - The National Park Service has created a set of modeling receptors for every Class I area.