30 



of these reactions is not well known, and even the nature of the spe- 

 cies undergoing oxidation has not been clearly established (Cadle, 

 1975; Gaspar, 1975). 



On a global scale, natural sources of S emissions are estimated 

 to be greater than anthropogenic sources (Junge and Werby, 1958: 

 Robinson and Robbins , 1972; Terman, 1978). Kellogg et al . (1972) esti- 

 mated that man is contributing about half as much atmospheric S now as 

 is nature. However, recent studies in Florida indicate that man-made 

 sources of atmospheric S account for more than 85% of the total S in 

 the air over Florida (E. S. Edgerton, personal communication). The 

 burning of fossil fuels accounts for most of this S. World-wide, 

 about 70% of this S is from the burning of coal, 16% from petroleum 

 combustion, 4% from petroleum refining, and 10% from the smelting of 

 ores (Gaspar, 1975; Terman, 1978). A quantification of the sources 

 and sinks of S compounds present in the biosphere is shown in Fig. 2 

 (Cadle, 1975). 

 1.2.2.1 Anthropogenic sources 



In Florida, most of the anthropogenic S comes from 36 electric 

 power plants (most of which are oil burning) , eight pulp and paper 

 mills in the northern portion of the state, the phosphate industry in 

 west-central Florida, sugar refineries around Lake Okeechobee, various 

 oil companies, cement plants, and chemical companies, and automobile 

 emissions (Urone, 19 75). Many of the power plants which are presently 

 burning low-S oil may have to convert to high-S coal because of the 

 cost of imported oil and the availability of coal. This conversion 

 uld increase the output of S0 ? into the environment. Burning of wood 



wo 



