ATMOSPHERIC POLLUTION — FRENKIEL 



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Figure 14. — Relative contributions of various pollution sources to the mean concentration 

 of ozone at the California Institute of Technology. These results refer to a hypothetical 

 model of atmospheric pollution in Los Angeles County. 



A comparison of the results which the mathematical model yields 

 for cars and industry is given in figure 15. In this figure we have com- 

 bined the contributions of the petroleum industry with the other in- 

 dustries. Figure 15a shows the ozone concentration for the case when 

 only the industrial sources are in operation, while figure 15b refers 

 to the case when all the sources except the industry are in operation. 

 These two figures show how difficult it may sometimes be to assign 

 relative responsibilities to the various pollution sources for their 

 contamination. Let us consider, for instance, the concentration values 

 at noon. Figure 15a indicates that if only the industry is in opera- 

 tion, the 12 M. concentration is about 9 percent of the value obtained 

 when all the sources are combined (dash-line curve) . However, figure 

 15b shows that all of the other sources except the industry will produce 

 a concentration of about 44 percent of the value for the combined 



