Modeling and simulation the environmental protection issues

Andrzej Michalski
The Kazimierz Wielki University,
Bydgoszcz, Pl

Describing the computer-aided teaching strategies, we attach much weight to the so-called simulation strategy. This strategy consists in presentation of a fictitious situation of the real world. It is used in the process of education in order to improve it or shape particular skills.

Therefore, the aim of a computer simulation is to familiarise the learners with the process functioning, to analyse and evaluate the organised whole, process optimalization. The article presents an attempt to use the simulation strategy in the process of teaching technology students, speciality: ecotechnology (environmental protection).

The area of content-related issues covers classes in emission of pollutants from technological processes into the air and their influence upon the condition of air pollution, with special regard to the methodology of emission and imission measurement as well as practical measurements of these parameters in the open air. The possibilities of performing such measurements by students are rather minimal, due to the lack of the expensive specialistic instrumentation and a laboratory base serving as a room for marking pollutants from the air collected by means of an air suction apparatus.

In such a situation there was an attempt to simulate phenomena of the atmosphere with the help of specially-prepared system of computer programs. They seem to be of assistance in familiarising the students with the above mentioned problems.

The comparison of the obtained computer simulation results with the monitoring results will allow to determine the didactic usefulness of the method concerned.

The formulae for the calculation were developed on the basis of the results of the research drawn from the literature on the subject and individual research.

Both theoreticians and practicians generally share the opinion that essential elements of rationally organised education process are teaching aids. Particularly beneficial effects are provided by a complex and integrated application of combined traditional and modern teaching aids.

The postulate of the integrated use of teaching aids, frequently referred to as media in the contemporary literature, is materialised in the idea of multimedia teaching and learning developed on the grounds of education technology. Among the whole group of traditional and modern teaching aids, special hopes are set on computers. These media, being the achievements of the latest technical thought, appeared to be multifunctional means and, therefore, can substitute many other items of educational equipment.

The results of the research into the use of computer techniques in the process of education indicate that educators use computers for designing of graphic teaching materials, production of lesson plans, preparation of demonstration of teaching content (in the form of text and simple drawings) as well as simulation of phenomena and processes occurring in physics, biology, chemistry, and the like.

It is the computer simulation of natural phenomena that interests the authors of this publication. The simulation strategy consists in presentation of fictional situation of the real world. This is used in the process of education in order to improve it or shape particular skills. In general, the simulation strategy is used, first of all, to:

- check theoretical assumptions e.g. in the process of learning by examination,

- facilitate understanding of particular systems, e.g. ecosystem, information, management,

- facilitate making decisions on checking specified sections of the examined system,

- shape the skill of making proper decisions and foreseeing their possible results,

- show phenomena and processes difficult to present e.g. due to possible risk or impossibility of their direct observation.

Therefore, the aim of computer simulation is learning how the particular process functions, analysing and evaluating the organised whole, and process optimising.

The article presents an attempt of using the simulation strategy in the process of teaching students of technology education, major: ecology.

The area of content-related issues covers, among other, classes devoted to emission and diffusion of pollutants introduced into the air from manufacturing processes, with special emphasis being put on methodology of emission and concentration measurement, as well as practical measurements of these parameters in the open air. Possibilities of performing such measurements by students are little because of lack of very expensive specialist appliances and laboratory facilities for determination of pollutants from the air sampled with aspirators.

In this situation, an attempt was made to simulate phenomena occurring in the atmosphere with the help of a specially prepared system of computer programs. It seems they may be of help in introducing the students to the above-mentioned problems.

Comparison of the obtained computer simulation results with the monitoring results will allow to assess the didactic usefulness of the method concerned.

As mentioned above, the functioning of various branches of industry results in emission of different pollutants into the atmosphere, such as gases and solid particles. The highest emission concentrations owe to compounds of sulphur, nitrogen and carbon. When in the atmosphere, these substances undergo diffusion processes. The phenomena of pollutant diffusion can be described by mathematical equations. Based on these equations, a number of different models of pollutants in the atmosphere have been developed1. Such approach to the issue gains more and more importance, since practical measurements of emission concentrations, made by means of installing a monitoring network in the open-air area, are quite an expensive investment in comparison with the mathematical modelling. Besides, results obtained from measuring stations just reflect the phenomenon that has already occurred. In this situation, the convenience of mathematical modelling gives a possibility not only of evaluation of the existing condition of air pollution but also prognostication of results of imminent emission concentration. This is highly advantageous in the process of education.

In our specified case, the values of emission concentration around the emission sources were determined by Pasquill formulae.

The computer simulation was carried out using the data for the city of Bydgoszcz. The town is situated in central Poland. It is a capital of a province, an industrial city, inhabited by more than 400,000 people. The arduousness of the local factories is chiefly determined by pollutants caused by energy combustion of fuels, in particular hard coal. Selected for the analysis were 24 emitters of industrial plants scattered all over the town, emitting sulphur dioxide. The emission was calculated on the basis of the manufacturing process, the indices concerning energy combustion of coal, including, in particular, content of sulphur in the fuel, and the literature on this subject. The obtained results were put in the computer program calculating diffusion of air pollutants. The calculations were made at the level z = 0 m, so at the same level as measurements of concentrations are roughly made with the laboratory method. The results were depicted in the graphic form in the network of receptors x y z. For the article, selected were isolines of the area of presence of just sulphur dioxide (Fig. 1). The reason is that available was only a map of this pollutant concentration made on the basis of the monitoring carried out in 2006. (Fig. 2).

The analysis of both drawings permits us to claim that the concentrations obtained by means of simulation are similar to the measurement values. One concentrated area of isolines is the same, as well as the absolute values of the concentrations. (Area B, Fig. 2). In the other area, the concentration of isolines are situated in the sites with buildings equipped with the so-called house hearths (old districts of Bydgoszcz). These hearths were not taken into account in the computer simulation (Area A, Fig. 2).

Fig. 1. Air pollution with sulphur dioxide in 2006 in Bydgoszcz (based on the computer simulation)

1 – emission concentration – 4 μg/m3

2 – emission concentration – 6 μg/m3

3 – emission concentration – 8 μg/m3

4 – emission concentration – 10 μg/m3

5 – emission concentration – 11 μg/m3

6 – emission concentration – 12 μg/m3

7 – emission concentration – 13 μg/m3

8 – emission concentration – 14 μg/m3

9 – emission concentration – 15 μg/m3

Fig. 2. Air pollution with sulphur dioxide in 2006 in Bydgoszcz (based on the measurements)

Conclusions that arise out of the analysis of the results obtained concern two groups of issues. The first group of conclusions is connected with the assumed methodology and determines the usefulness of the selected method in the didactic process. Another group, on the other hand, is strictly related to practice and contributes remarks and solutions to the

problem in question. Due to the subject matter dealt with in the article, just the former group of conclusions will be presented.

¨ The computer simulation method gives rise to enormous calculation possibilities, approaching the problem on different planes.

This enables:

· evaluation of the existing state of air pollution,

· prognostication of results of imminent emission concentration,

Ø Computer simulation of the phenomena occurring in the air under the influence of emitted pollutants may bring satisfactory didactic results in the question of showing students those processes that are difficult to present in reality. However, it should be added that the strategy in this particular case requires further work and improvement.

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