POINT SOURCES (POLLUTION) – clearly defined locations for pollutants entering the environment, for example, sewage (drain pipes), fumes (chimneys), etc. Contrary to non-point sources.Point sources are emissions of pollutants in one narrowly concentrated place, which has comparable in length and width. To this type include, for example, the emissions of pipes, shaft and ventilation shafts. The harmful substances released from point sources should not be superimposed on the other in the distance of two heights of the building (on the windward side). Sources of environmental pollution are divided into concentrated (point) and dispersed.
To the point smoke and ventilation pipes, shafts, etc., to dispersed – the ventilation lights of the workshops (several of them), rows of closely located pipes, open warehouses, etc. Sources of pollution can also be continuous and periodic action. Linear sources of emissions have a significant length in the direction perpendicular to the wind and are located in the windward circulation zone. Linear refers to point sources for which the areas of impurity distribution are within the adjacent half of the winded circulation zone (open window openings, technological lines and equipment, etc.)As in the case of point sources, the predicted values of concentrations from linear sources can be determined from the expected values of wind speed and atmospheric stability, and also from the value of the ejection using the above formulas.
By location, sources of emissions should be divided into high and low. To high include point sources – pipes, the height of more than 3.5 Yaed (NZA – the height of buildings near the pipe). According to experiments at such source heights, it is possible to neglect the influence on the propagation of impurities of the deformation of the wind flow caused by structures. The distribution of harmful substances also has little effect on the turbulence of the flow, formed during detachments at the sharp edges of the building, and the turbulence of the atmosphere itself is the determining factor. The degree of pollution of the atmosphere depends on the amount of emission of harmful substances and their chemical composition, but also largely on the characteristics of the emission source – the source height above ground level, speed, volume and temperature of the gas ejection from the mouth of the tube, unorganized source size at the plant site location of the source etc. In accordance with this, the sources of air pollution differ in the power of the outburst (powerful, large, small), the height of the ejecta (low, medium and high), the temperature exiting gas (hot and cold).
There are also mobile and stationary, organized and unorganized, point and area sources of pollution. The peculiarity of the enterprise as an object of nature protection measures is the heterogeneity and dispersal of emission sourcesThe main difference between a point source and a linear one is that the first one is characterized by the maximum impurity concentration at the source axis, for example, a torch, whereas for the second one there is a constant concentration of pollutants at any point of the surface layer of industrial sites.