ATMOSPHERIC POLLUTION — FRENKIEL 



283 



their geographic distribution in the area, we have used the same 

 distribution as we did for the motorcar traffic, which is approximately 

 comparable to the distribution of population. We have further 

 assumed that the incinerators are operated between 6 and 10 a. m. 

 with an hourly variation presenting a maximum at 8 a. m. Finally, 

 we have considered the case when the relative amounts of pollutants 

 emitted in our mathematical model during a period of 48 hours by 

 the four sources — motorcars, oil and gas heating, incinerators, and 

 industry — are 52, 6, 16, and 26 percent, respectively. These percent- 

 ages were derived from data referring to the emission of "important" 



0.028 



0.024 - 



0.020- 



0.016 



0.012 



0.008 



0.004 



10 12 14 16 

 HOUR OF DAY 



18 20 22 24 



Figure 11. — Relative contributions of the selected four principal sources to the mean 

 concentration at the California Institute of Technology. The data refer to a mathe- 

 matical model of Los Angeles County in which the topographic features and inversion 

 are taken into account. For this hypothetical model the relative proportion of the 

 "important" pollutants (including acids, organics, and nitrogen dioxide) emitted by the 

 four principal sources are based on the 1954 data for Los Angeles County [7]. The 

 meteorological conditions are based in large part on data for the month of September [5]. 



