## Local air modeling (GPM tool)

This excel spreadsheet calculates the concentration of a compound in the air at different distances from the stack where it is emitted. It might be important to know the concentration of a certain compound in air because of its impact on human health. Default calculations can be done by EUSES but the results are based on very conservative non-adjustable parameters. The “GPM tool” allows entering stack specific parameters which impact the distribution of a compound in the air and thus give more realistic predictions. The calculations are based on Gaussian Plume Models (GPM). These Lagrangian models describe the dispersion in the direct vicinity of a source, and are thus local models (no regional component). Assuming that turbulence is a random process, it is expected that the mean concentration of material emitted from a point source will have a two-dimensional Gaussian distribution perpendicular to the mean wind direction.

The **input parameters** required for the calculation of a compound at a specific location in the “GPM tool” models are the following:

- stack height (m)
- stack diameter (m)
- emission rate (g/s)
- gas exit velocity (m/s)
- gas exit temperature (°C)
- ambient temperature (°C)

* The excel version can be freely downloaded below by our clients and DU and governmental organizations*:

Any feedback is highly appreciated and can be sent to Maxime Eliat at maxime.eliat@arche-consulting.be.