[An attempt at the dynamic classification of population centers in Bulgaria in relation to atmospheric pollution].

A method for evaluation, comparison and classification of the settlements is proposed according to the rate of pollution of the atmospheric air by a given component. For basis is accepted the sigma method. Three normative categories for classification are used. It is proceeded from the standardized towards MAC concentrations. In this case the average annual are applied. The method permits an objective comparison and classification in accordance with the rate of pollution of the settlements and their survey in dynamics. The approbation is made on the basis of the data from 1981 and 1985 for the settlements with 5 pollutants. It is established that the basic group of settlements do not change their category during the 5-year plan, while the changes of the groups are smooth in the neighbouring categories. The method gives adequate results and could serve the evaluation of the state of the atmospheric air in this country and the effectiveness of the air protective measurements.