Modelling the impact on the environment is a general term, implying the mathematical modelling and computer simulation of pollutant dispersion in the air and waters, and also can give an assessment of the expected environmental impacts as a result of large industrial accidents that may occur.
To assess the environmental impacts, Sokolovski’s Environment uses as approved by MEW methodologies and software packages (PLUME and TRAFFIC ORACLE), as well as other software packages for computer simulation (PHOENICS and ALOHA).
Approved by MEW methodology for assessing the spread of pollutants from point sources is a software package PLUME. It is based on the application of the Gaussian model, which is associated with certain restrictions, the most important of which are:
Emission parameters - the flow, the composition, and the temperature are constant;
Wind speed is constant in time;
The model does not account for wind speed at height;
Wind speed cannot be 0 m/s (calm weather);
The polluter is not falling apart, does not participate in chemical reactions and cannot be postponed on the ground;
Surroundings source can be assumed to be flat and open;
Cursory analysis of the above requirements, immediately leads to the conclusion that in practice the model is always used in violation of one or more of them. Therefore, relatively large amount of errors may occur in predicting the distribution of the concentration of the contaminant.
One of the computer packages that can be successfully applied to simulate the spread of pollutants in the air in complex terrain and in all weather conditions is the package PHOENICS.
It is a powerful computer code applicable to simulate:
Single-and two-phase fluid flows;
And related processes;
PHOENICS maintains and offers users a huge range of world-recognized analytical and experimental-mathematical analyst relationships to calculate the parameters characterizing the various phenomena and processes. It has a flexible structure and allows the user to construct and implement the most appropriate in each case mathematical model. With these characteristics, the package is suitable for simulating the behaviour of the emitted into the atmosphere, water or soil contaminants, which is a prerequisite for assessing the impact and significance of the environmental pollution sources.
TRAFFIC ORACLE methodology is used to determine the content of harmful substances in exhaust gases (emissions) from internal combustion engines of motor vehicles, and in determining scattering (expected concentrations) of these substances in the surface layer of the atmosphere.
Emission and dispersion of harmful substances (pollutants) from motor vehicle in traffic on highways, roads, streets and concrete complex street network are approximated as linear or area sources.
The methodology consists of two main software modules: EMISSIONS (performed first for the calculation of emissions) and DIFFUSION (used second to determine the standard estimates of the expected concentrations).