I concur in the result announced and all that is said in the opinion of the Acting Presiding Judge. In order to avoid any misunderstanding, however, I desire to emphasize that in order to establish a violation of section 24242(b), the People must establish beyond a reasonable doubt that the defendant discharged into the atmosphere from a single source of emission an air contaminant for a period or periods aggregating more than three minutes in any one hour, which contaminant was of such opacity as to obscure an observer’s view to a degree equal to or greater than does smoke as dark or darker in shade as that designated as No. 2 on the Eingelmann Chart. Implicit in this is the requirement that the People establish beyond a reasonable doubt the degree to which No. 2 Eingelmann smoke obscures the view of an observer, and a defendant charged with a violation of subdivision (b) is entitled, upon timely request, to an instruction to this effect.
"While I cannot escape the feeling that some of the inspectors of the Air Pollution Control District who testified upon behalf of the People were laboring under the erroneous belief that the percentage figures on the Eingelmann Chart expressed degrees of opacity in the sense that smoke of the particular shade obscured the vision of the observer to the *881same degree, expressed in terms of percentage, as the blackness of smoke of the various shades designated thereon, I am in agreement with the conclusion of Judge Bishop that there was competent evidence, if believed by the jury, as it seemingly was, to support their implied finding that the contaminant emitted by the defendant in each case was such as to obscure an observer’s view to a degree equal to or greater than does smoke of a shade as dark or darker than that designated as No. 2 on the Chart.