Abstract |
Sampling to determine atmospheric pollution and chemical analysis of the samples requires considerable expenditure of time. Therefore, the problem of the optimum number of sampling points and frequency of sampling is of considerable significance. The task of investigating atmospheric pollution in the vicinity of individual sources is somewhat simpler. Let us deal with it initially, so that we can use this as a basis for moving on to the problem of organizing observations in urban territories with a great many sources emitting pollutants. The problems of organizing the observation of atmospheric pollution around large enterprises have already been discussed in part (8-11). It was noted that the minimum intervals between remote observations have been set at short distances. With increasing distance from the source, the intervals grow longer, so that on the lee side of the enterprise a significant influence is exerted by unorganized emissions and emissions from low stacks whose concentration decreases rapidly. Because of other factors which determine the degree of pollution of a city, it is necessary to conclude that there are changes in the volume of pollution emissions in the atmosphere. The principal influence is the proximity of busy roads and industrial areas. Hence, the density of a network with 3 to 4 km between points may be sufficient to obtain general characteristics of the field of concentration for the territory of the city. In this instance, when the concentration of pollutants is determined primarily by the influence of local sources, it is advantageous to carry out a sampling using automatic devices located at different distances from the center of the emissions. |