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ANNUAL REPORT SMITHSONIAN INSTITUTION, 1956 







5 00 p.m. 



awurt 







Figure 8. — Isoconcentration curves at 2 p. m , 5 p. m., and 8 p. m. for a single point source 

 continuously emitting particles at a constant rate located at Long Beach-Wilmington. 

 (Effects of topographic features and temperature inversion not included in this mathe- 

 matical model.) 



point at successive times, one can find the mean concentration pattern 

 produced by a continuous point source. 



Such a study has been made for Los Angeles County. The main 

 difficulty in the analysis was the lack of appropriate micrometeoro- 

 logical measurements for the Los Angeles Basin. Although some 

 very valuable data on hourly flow patterns are available [5], data 

 on turbulent fluctuations are not sufficient. It was therefore necessary 

 tc make several assumptions concerning the characteristics of turbu- 

 lence. Figure 8 represents some results of this analysis. The point 

 source is located in the Long Beach-Wilmington area ; it is assumed 

 that it emits pollutants at a constant rate. The mean concentration 

 distributions at 2, 5, and 8 p. m. have been determined, and the cor- 

 responding isoconcentration curves are traced on the figure. The 



