4. AERMAP

AERMAP is a topographic preprocessor developed by the EPA (Environmental Protection Agency) to support the atmospheric dispersion model AERMOD. It processes terrain elevation data, generating essential information about the relief that influences pollutant dispersion.

Primary Objective:

• Process topographic data to characterize the terrain in the study area.
• Generate elevation parameters used by AERMOD, such as terrain heights at each receptor/source, slopes, and obstacle effects.

Why is AERMAP important?

• Accuracy: Ensures AERMOD correctly accounts for terrain impact on pollutants.
• Efficiency: Automates complex elevation calculations for multiple points.
• Compatibility: Uses global topographic data standards (e.g., USGS).

See Figure 1:

First, download the AERMAP executable from EPA AERMAP and extract the file to the folder C:\Users\Cliente\Desktop\AermodTutorial\4.AERMAP.

Next, visit: National Map to acquire elevation data for AERMAP. Follow the steps below, as shown in Figure 2:

1. Click the search bar and type Bloomigton, then select Bloomington, Illinois;
2. Adjust the zoom as shown in the figure and click Extent;
3. Select the region of interest by left-clicking to draw the area;
4. Check Elevation Products (3D Elevation Program Products and Services) under Data;
5. Check Select All under Subcategories;
6. Click “Search Products”.

Now locate the data USGS 1 Arc Second n41w089 20240104 and USGS 1 Arc Second n41w090 20240104 and click their respective Download links, as shown in Figure 3:

Save the files to C:\Users\Cliente\Desktop\AermodTutorial\4.AERMAP and rename them to n41w089 and n41w090.

Create a subfolder named Seamless_dem within AERMAP and move the files n41w089 and n41w090 there. Next, download a .Tif image converter to make these files compatible with the subprocessor (native .tif files are compressed). Click conversao and extract it to the AERMAP folder. Open CMD and enter:

gdal_translate -of GTiff -co COMPRESS=NONE “C:\Users\Cliente\Desktop\AermodTutorial\4.AERMAP\Seamless_dem\n41w089.tif” “C:\Users\Cliente\Desktop\AermodTutorial\4.AERMAP\Seamless_dem\a1.tif”

Press Enter. Repeat for the other image:

gdal_translate -of GTiff -co COMPRESS=NONE “C:\Users\Cliente\Desktop\AermodTutorial\4.AERMAP\Seamless_dem\n41w090.tif” “C:\Users\Cliente\Desktop\AermodTutorial\4.AERMAP\Seamless_dem\a2.tif”

A discrete receptor grid is available here. Extract it to C:\Users\Cliente\Desktop\AermodTutorial\4.AERMAP.

With all inputs ready, configure AERMAP. Create a text file named aermap with the following content:

CO STARTING
   TITLEONE  UFSC/ TraPoDisO
   TITLETWO  Bloomington, IL, 2024 NED Data File
   DATATYPE  NED  FILLGAPS 
   DATAFILE  .\Seamless_dem\a1.tif
   DATAFILE  .\Seamless_dem\a2.tif
   DOMAINXY  300000  4470000 16    355784  4499506  16
   ANCHORXY  333420  4482400       333420  4482400  16  4
   RUNORNOT  RUN
CO FINISHED

SO STARTING
   LOCATION    STACK1  POINT  333415  4482405 
SO FINISHED

RE STARTING
   INCLUDED receptores_bloomington.dat
RE FINISHED

OU STARTING
   RECEPTOR  Bloomington.rec
   SOURCLOC  Bloomington.src
OU FINISHED

Below is a description of each line:

With aermap.txt ready, open CMD and navigate to C:\Users\Cliente\Desktop\AermodTutorial\4.AERMAP. Type aermap aermap.txt and press Enter to generate AERMAP outputs. This may take time due to the high number of receptors per project.

Wait for the process to complete, and in the end, we will have the last two files required for the final execution of AERMOD: - Bloomington.rec - Bloomington.src

Now we are almost finished; the only step left is to integrate all the data previously generated by AERMET and AERMAP in order to run them in AERMOD and obtain the output data we need

Here you can download the folder I used to create this document. It is important that you use it only for comparison purposes or in case you are unable to make progress on the project. Attached: download.rar