Centre for Environmental Modelling and Chemistry

A Level I simulation is of the equilibrium distribution of a fixed quantity of conserved (ie. non-reacting) chemical, in a closed environment at equilibrium, with no degrading reactions, no advective processes, and no intermedia transport processes (eg. no wet deposition, or sedimentation). The medium receiving the emission is unimportant because the chemical is assumed to become instantaneously distributed to an equilibrium condition.

Physical-chemical properties are used to quantify a chemical's behaviour in an evaluative environment. Three types of chemicals are treated in this model: chemicals that partition into all media (Type 1), involatile chemicals (Type 2), and chemicals with zero, or near-zero, solubility (Type 3). The Level I Program assumes a simple, evaluative, closed environment with user-defined volumes and densities for the following homogeneous environmental media (or compartments): air, water, soil, sediment, suspended sediment, fish and aerosols.

This model is useful for establishing the general features of a new or existing chemical's behaviour. A Level I calculation gives the general impression of the likely media into which a chemical will tend to partition and an indication of relative concentrations in each medium. The results of changes in chemical and environmental properties may be explored.

Features of the Level I Program:
Provides a database of chemicals and chemical properties.
Permits temporary additions/changes of chemicals and their properties to a simulation.
Permits permanent additions, changes and deletions of chemicals and their properties to the chemical database.
Supplies default values for all input fields which may be easily changed. These values are regarded as typical, as discussed in the text referred to below.
Provides context-sensitive Help.
Displays and prints the Level I model calculations, as performed by the program.
Allows the printing of simulation tables and the summary diagram.
Allows the program results to be saved as an ASCII text file.

This program was based on the following publication:

Mackay, Donald (1991) "Multimedia Environmental Models: The Fugacity Approach" Lewis Publ., CRC Press, Boca Raton, FL.

The required input data are:
Chemical Properties:

Environmental Properties:

Emissions:

Model Output:

This program is only available in compiled form. A "readme.txt" file with more detailed technical information is included in the zipped file.

The 32-bit version requires at least a Pentium-75MHz with 8 Mb of RAM running Windows 95. The monitor should be set to SVGA (800 x 600) resolution. The zipped file is 3.30 MB and requires about 12.5 MB of hard disk space to install.

The 16-bit version (2.1 of September 1998) requires at least a 486DX-50MHz with 8 Mb of RAM running MS Windows 3.x. The monitor should be set to standard VGA (640 x 480) resolution. The zipped file is 3.29 MB and requires about 11.5 MB of hard disk space to install.

For non-Windows users the BASIC, evaluative, Level I, II and III fugacity models are available.

Please read the LEVEL I SOFTWARE LICENSE before downloading the software. Use of the software constitutes your agreement to abide by the terms and conditions set out in the license agreement.