| Summary: | This paper presents the calculation of harmful substance deposition (air pollution) from the point source (Slanèo, et al., 2001) using equation (1). The point source shall be understood as e.g. chimneys of factory, heat plant, incinerator, boiler plant, local heating plant, etc.The theoretical calculation of concentration (1), or deposition (8) is based on the study of transfer and dispersion of pollution in air (Slanèo, et al., 2000a). The movement of pollution in air consists of a movement of the air itself and a relative movement of pollution particles and air, while the movement of harmful substance in the smoke trail is under the influence of turbulent diffusion, convection and gravitation. Molecular diffusion is not important in this process. When calculating concentrations (1) and deposition (8) of air pollution on a particular place near the source, it is assumed that the air speed is constant, the direction of wind does not change with the height and the source of air pollution is time-constant. The change in the wind speed with the height depends on the stability class of atmosphere (temperature gradient) (Slanèo, et al., 2000a) and it is calculated using equation (10).The theoretical calculation of concentration and or deposition of harmful substance from the point source (1) and (8) shall be applied if the harmful substance particles, which leave the source, have the same density (composition), shape (spherical) and size.The experimental observations of dust deposition showed the significance of 0.1-20 µm particles. The application of equation (1) to calculate the concentration is conditioned, in addition to the recognition of source parameters and meteorological conditions, by the recognition of the particle sedimentation speed, which changes with the size of particle radius (2).For a practical calculation of deposition it is therefore necessary to know the differential distribution function f(r ) of particle radii, which can be made on the basis of the granulometric analysis of particles emitted by the source and to determine the mean sedimentation speed of particles (3), or eventually to use one of the mean particle radius types (4), ( 5), ( 6) in formula (2).If we know the parameters of the harmful substance source and meteorological conditions, then, using equation (8), it is possible to determine the harmful substance deposition using one of equations (3), (4), (5),(6).Equation (8) represents the quantity of substance, which falls down per 1 second on 1 m2 of surface. In practice the deposition is calculated for a period of 30 days. Providing the meteorological conditions (temperature gradient, direction and speed of wind) and source parameters (H,w,d,G), of which the value of uH , or h can be determined, remain unchanged, the deposition will be calculated using equation (8).
|
|---|
