“…In winter, the ratio is 0.4 and it increases to 0.5-0.6 in midAugust. (Lewis and Dowding, 1924;Korody, 1938;Camefort, 1956;Anikeeva and Minina, 1959;Fraser, 1966;Schüepp, 1966;Owens and Molder, 1976;Owens et al, 1977; Pillai and Chacko, 1978;Tompsett, 1978;Harrison and Owens, 1983;Skupchenko, 1984;and …”