The 2.5 version of GasSim is available as a free download on our software library. Our built-in antivirus checked this download and rated it as virus free. The actual developer of the program is Golder Associates. The program lies within Education Tools, more precisely Science Tools. The latest installer occupies 22.2 MB on disk.
From the developer:
GasSim simulates the fate of landfill gas arising from managed or unmanaged landfill sites. The model uses information on waste composition and quantity, landfill engineering, and landfill gas management techniques to enable assessment of the best combination of control measures for a particular design and rate of filling.
You may want to check out more software, such as GasSimLite, which might be related to GasSim.