Introduction to AERMOD

'AERMOD' (American Meteorological Society/Environmental Protection Agency Regulatory Model) is an atmospheric dispersion model developed by the U.S. EPA (Environmental Protection Agency) in collaboration with the American Meteorological Society (AMS). It is designed to assess air quality by estimating pollutant concentrations emitted from industrial and other stationary sources.

AERMOD is used for:

• Assessing environmental impacts from atmospheric emissions;
• Checking compliance with air quality standards;
• Supporting environmental permitting processes;
• Simulating pollutant dispersion under different meteorological conditions.

AERMOD simulates the transport and dispersion of pollutants in the atmosphere based on local meteorological conditions, terrain features, and emission source characteristics. The model requires preprocessed input data from auxiliary tools, including:

• 'AERMET' — processes surface and upper air meteorological data (e.g., from radiosondes);
• 'AERMAP' — determines terrain characteristics for each receptor location;
• 'AERSURFACE' — calculates land use parameters such as surface roughness, albedo, and Bowen ratio;
• 'AERMINUTE' — refines hourly wind data based on 1-minute METAR/ASOS observations.

Using these inputs, AERMOD calculates hourly pollutant concentrations at specific receptor locations, accounting for:

• Horizontal and vertical dispersion;
• Atmospheric stability effects;
• Terrain elevation influences;
• Different source types (point, area, volume, and line sources).

AERMOD output includes:

• Hourly, daily, monthly, or annual pollutant concentrations;
• Statistics for comparison with legal thresholds (e.g., percentiles);
• Pollution plume maps (when used with external visualization tools).

• Chemical and petrochemical industries;
• Thermoelectric power plants;
• Landfills and incineration facilities;
• Environmental licensing studies;
• Emergency atmospheric release modeling.

'AERPLOT' is a graphical utility used alongside AERMOD to generate visual representations of modeled results, improving spatial interpretation of pollutant concentrations.

Its main functions include:

• Generating dispersion plume maps;
• Visualizing source and receptor locations within the modeling domain;
• Displaying maximum concentrations per time period (e.g., hour, day, year);
• Exporting graphics for reports and documentation.

AERPLOT does not perform additional calculations. It reads AERMOD output files (such as `.plt`, `.con`, `.exc`, etc.) to generate visual summaries of dispersion data.

It is an essential tool for environmental analysts, helping communicate potential air quality impacts clearly and effectively.

AERMOD is recognized as a regulatory model by the U.S. EPA and is widely adopted internationally — including in Brazil — for environmental impact studies involving atmospheric emissions.