What is Air Dispersion Modeling?

Air dispersion modeling provides a visual mathematical simulation of how air pollutants disperse in the ambient atmosphere. Based on emissions source and meteorological data as well as topography information, a dispersion model calculates an estimate of the downwind concentration of pollutants as they travel away from emissions sources.

How are dispersion models used?

Dispersion models can be used to determine whether a new source will adversely impact an area or to predict whether the control of an individual source will have a beneficial effect. For example, these models are used to determine compliance with National Ambient Air Quality Standards (NAAQS) and other regulatory requirements, such as New Source Review (NSR) and Prevention of Significant Deterioration (PSD) regulations.

ADEQ Modeling Guidance for Permits 

ADEQ has developed a guidance document to help applicants understand air quality modeling procedures with regard to Air Quality Permit applications for sources located in Arizona under ADEQ jurisdiction | See Guidance >

ADEQ Modeling Checklist for Minor NSR Permits

This checklist provides assistance to the Permittee required to perform modeling analyses for a minor NSR permit. It is recommended but not required that the Permittee attaches a completed modeling checklist to a modeling report when submitting a permit application | See Checklist >

ADEQ AERMET Pre-processed Meteorological Data 

ADEQ processed the meteorological data using AERMET version 23132 and AERMINUTE version 15272 and AERSURFACE version 20060.  Data are available for the five-year period of 2017 to 2021 for 11 stations across Arizona and one station in California.  The ADJ_U* option was used to process all meteorological data | View Data > 

EPA's 2013 - 2015 Prognostic Meteorological Data

The EPA has generated a nationwide prognostic meteorological dataset for 2013 – 2015 (12km WRF simulations for CONUS and MMIF processed data for each 12km grid cell). The dataset has approximately 2,000 data points (a point is the center of a grid cell) within the State of Arizona. A full listing of these points is shown in the following KMZ file. The Permittee may open the KMZ file in Google Earth and find the points of interest for a particular project. To request the meteorological data for specific points, please email ADEQ | Email > | View Google Earth Map for Locations of Data Points >