Preferred / Recommended Air Quality Models

Contact: Robert Irvine, 517-648-7367
Agency: Environment, Great Lakes, and Energy


The American Meteorological Society / Environmental Protection Agency Regulatory Model (AERMOD) is a steady-state plume model and is EPA's preferred/recommended regulatory dispersion model. The AERMOD model has two input data processors that are regulatory components of the model: AERMET and AERMAP.

  • AERMET is a meteorological (met) data pre-processor that creates two files: surface data and profile data. The AQD has created a met database containing canned met data for 29 one-minute and 72 hourly met stations. This met data was processed with AERMET and is ready for use with AERMOD. The data can be found on our meteorological data web site.
  • AERMAP is a terrain data pre-processor that incorporates complex terrain using USGS digital elevation data. AERMAP produces terrain base elevations for each receptor and source and a hill height scale value for each receptor.
  • LEADPOST is a post-processing tool that can be used to calculate design values from monthly AERMOD output. This tool calculates and outputs the cumulative rolling three-month average concentration at each modeled receptor. Currently, AERMOD does not calculate design values for the lead NAAQS (rolling three-month averages).

The AERMOD, AERMET, AERMAP, and LEADPOST user guides, support documentation, and executable files are available for download via the EPA's Support Center for Regulatory Air Models (SCRAM) web site.


CALPUFF is a non-steady-state puff dispersion model that simulates the effects of time- and space-varying met conditions on pollution transport, transformation, and removal. CALPUFF can be applied for long-range transport.

The CALPUFF executables/source code, preprocessors, associated utilities, test cases, and met data sets are available from EPA's SCRAM web site.


AERSCREEN is EPA's recommended screening model based on AERMOD and is intended to produce results equal to or greater than those produced by AERMOD. The AERSCREEN model will produce estimated "worst case" 1-hour concentrations for a single source, without the need for hourly met data. It also includes conversion factors to estimate "worst case" 3-hour, 8-hour, 24-hour, and annual concentrations.

The AERSCREEN user's guide, support documents, and executable file is available for download from EPA's SCRAM web site.