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ANNUAL REPORT SMITHSONIAN INSTITUTION, 1956 



In a study of various pollution control methods, it is important to 

 determine if their effects are sufficiently significant to justify their 

 expenses and inconveniences. Let us, for instance, consider the meth- 

 ods which consist in a reduction of the quantity of pollutants emitted at 

 the sources. Our mathematical model can be helpful in such an esti- 

 mate. Referring to the contribution of the industry to ozone concen- 

 tration, we have already determined the contamination level when all 

 industrial sources are eliminated from our mathematical model (see 

 fig. 15b). Such an elimination would either require a complete stop 

 to all industrial operations or complicated and expensive equipment 

 to avoid production or emission of ozone- forming pollutants. It is 

 doubtful that such extreme solutions would be practical and it is 

 difficult to imagine a situation in which they might be necessary, al- 



0.00016 



0O00I2 - 



000008 



000004 - 



10 12 14 



HOUR OF DAY 



Figure 16. — Effects of general improvements of industry operation on the ozone pollution. 



though during an emergency, an industrial area not prepared to con- 

 trol air pollution by more reasonable methods may be forced to stop 

 the operation of all its industrial sources. Such a situation should be 

 avoided by studying in advance the effects of a partial reduction of the 

 quantity of pollutants emitted into the atmosphere. In the ozone for- 

 mation of our mathematical model, nitrogen dioxide and hydrocar- 

 bons both play an important role. Figure 16 illustrates the effects 

 of each of these pollutants on the ozone concentration. It appears 

 that the elimination of nitrogen dioxide from industrial pollutants 

 would have a much larger effect than the elimination of hydrocarbons. 

 This conclusion refers, of course, to the location of the California In- 

 stitute of Technology and the result may be different for another loca- 

 tion. If we can evaluate the expenses in investment and operation 



