[en] A pollutant of small particles is emitted by a point source at a height h above ground level in an atmosphere in which a uni-directional wind speed, U, is prevailing. The pollutant is subjected to diffusion in all directions in the presence of advection and settling due to gravity. The equation governing the concentration of the pollutant is studied with the wind speed and the different components of diffusion tensor are proportional to the distance above ground level and the source has a uniform strength. Adopting a Cartesian system of coordinates in which the x-axis lies along the direction of the wind velocity, the z-axis is vertically upwards and the y-axis completes the right-hand triad, the solution for the concentration c(x,y,z) is obtained in closed form. The relative importance of the components of diffusion along the three axes is discussed. It is found that for any plane y=constant (=A), c(x,y,z) is concentrated along a curve of ''extensive pollution''. In the plane A=0, the concentration decreases along the line of extensive pollution as we move away from the source. However, for planes A≅0, the line of extensive pollution possesses a point of accumulation, which lies at a nonzero value of x. As we move away from the plane A=0, the point of accumulation moves laterally away from the plane x=0 and towards the plane z=0. The presence of the point of accumulation is entirely due to the presence of lateral diffusion. (author)

[en] A fixed volume of pollutant of small particles is emitted by a point source at a height h above ground level, at a certain instant of time, in an infinite medium in which wind is blowing horizontally with a uniform speed, U. The pollutant is subject to diffusion in the presence of advection and settling due to gravity. The solution for the concentration is obtained in closed form for subsequent times. It is shown that as time increases the point volume spreads out under the influence of diffusion but the volume of dust always maintains a point of accumulation, where the concentration is a maximum. In the absence of horizontal diffusion, the dust moves as a vertical front with uniform speed U. In both cases the accumulation point moves horizontally with the flow speed but its height is a complicated function of diffusion (both horizontal and vertical) and gravity. The solution is illustrated graphically. (author)

[en] The factor analysis is a modern method of statistical analysis of the experimental data. This method applies in a broad range of sciences like psychology, economy, medicine, electronics, physics and other. This method allows one to extract from a set of experimental data some properties of the studied process (usually called 'hidden') when there is not any theoretical description of studied phenomena. In this study we have done a short presentation of factor analysis followed by some applications as the problem of the boxes (the classical one) and the problem of the polynoms. We apply the factor analysis to an ecological problem using a very simple model of the source of pollution (the gaussian one) by simulating the computer data

[en] In this paper there are presented the main characteristics of the 'new generation' dispersion model which can be used in a real time surveillance system of the pollution level around a major pollution source. There are presented also, the results concerning SO₂ concentration obtained with the described model in the area of power plant sites: Bucharest-South, Craiova-2 and Drobeta Turnu-Severin power plants. Daily mean concentration for June 1993 have been calculated and there are presented plots for the maximum values obtained for all three power plants recorded during this month. Using the predicted concentration values obtained with the dispersion model, decisions can be taken for decreasing the pollutant emission in case that the air quality standards are exceeded in the analyzed area. (authors). 4 figs., 1 tab., 4 refs

[en] The pollutant emission of the thermal power stations may have an important contribution to the local pollution as well as to regional (transfrontier) and global pollution. Due to the impossibility at present of making continuous monitoring of the emission of pollutants it is necessary to use computational models for obtaining inventories of the pollutant sources and for studying their dispersion into atmosphere. The computational code used to simulate the pollutant diffusion in the atmosphere is a climatologic model giving the annual average concentration and the evaluation of the maximum SO₂ concentration. The paper presents the analyses for the case of 14 thermal power stations of Romania

[en] Radiation sources widely used in industry, medicine, agriculture. Research and education are the most dangerous from the viewpoint of their widespread and easy access.The probability that these sources will be stolen and used to assemble a radiological dispersive (RDD) is nor negligible. Such a device can be used by terrorist groups for the purpose of contamination of industrial centers, airports, seaports and residential areas, which can affect a large sector of the economy of a country. Detonation of a RDD can lead to death and exposure of the population to radiation, but, as a whole, the use of the bomb is aimed at creating panic among population, causing economic damage and social shock to the society. In this work, ways to reduce the threat of radiation sources obtained outside and within a country will be discussed

No abstract available

[en] Almost the entire Norwegian population has cell phone. The usefulness of the cell phone is great, but can use a mobile phone to health or discomfort? How can exposure be reduced? NRPA follows research and provides advice on mobile phone use. (AG)

[en] Dispersion modelling is a necessary tool for both qualitative and quantitative estimates of air pollution. There exists a number of models for prediction of the ground-surface air pollutant concentrations resulting from various sources. These models are to be used in a wide variety of applications, such as the installation of new energy-development facilities and other sources of air pollution, regulatory decision making, and environmental planning. In this paper, major types of air pollution models are described along with their applications, advantages, and disadvantages. (author). 19 refs., 2 figs

[en] The paper discusses results from a July 1991 workshop and the progress that has been made in advancing the technology of surface-coating-free materials (SCFMs). The workshop identified opportunities for the development of SCFMs being used by industries and recommended ways for increasing the use of SCFMs by other industries. In addition, the workshop offered the opportunity for the exchange and the development of innovative concepts related to SCFMs. Coating operations release about 15% of stationary area source volatile organic compound (VOC) emissions. Many of these sources cannot be impacted by add-on controls at a reasonable cost due to their small size and/or the difficulty of capturing emissions. In addition, not only do emissions occur during initial coating, they occur each time the surface is recoated. If materials or products could be developed which do not need coating during either manufacture or use (SCFMs), VOC emissions could be reduced significantly. The U.S. ambient air quality standard for ozone (0.12 ppm) is exceeded in over 100 areas in the country. Extensive reduction of VOC emissions is required for attainment. The difficulty of dealing with stationary area sources has been a major obstacle to attaining these reductions. Area sources may contribute as much as 50% of U.S. VOC emissions