[Effect of meteorological factors on the 3,4-benzpyrene concentrations in the ground air layer in the region of the city of Sofia]. / Izsledvane vliianieto na meteorologichnite faktori vurkhu kontsentratsiite na 3,4-benzpiren v prizemniia vuzdushen sloi v raiona na gr. Sofiia.

An investigation is performed to determine 3,4-benzpyrene content in the Sofia area (in a single spot), covering a one-year period (1970), on the basis of mean monthly concentrations established through gas chromatography, and compared to some of the averaged meteorologic data. The correlation between 3,4-benzpyrene concentrations and some meteorologic factors found is corroborated by the clearcut seasonal fluctuations of 3,4-benzpyrene concentrations in the atmospheric air. An inversely proportional dependence is established of 3,4-benzpyrene concentration to the summed up radiation, and directly proportional--to the dust amount. A rise of 3,4-benzpyrene concentration under conditions of the various types of temperature inversions, and a complex effect of meteorologic factors have been also noted. Moreover, an attempt is made at establishing the washing effect of rainfalls, and it has been found that up to a certain extent, such an effect really exists. The study performed shows in a clearcut manner that 3,4-benzpyrene content is considerably influenced by a variety of meteorologic factors.