Emission tests shall be undertaken by generally recognized standards or methods of measurement.  Methods found in the A.S.M.E Test Code for Determining Dust Concentrations in Gas Streams P.T.C. 27-1957, the Los Angeles County Source Testing Manual or recommended procedures of the National Air Pollution Administration shall be used but these may be modified or adjusted by the Commissioner of Air Pollution Control to suit specific sampling conditions or needs based upon good practice, judgment and experience.  Updating of these standards and modifications thereof shall be published in rules and regulations of the Commissioner of Air Pollution Control.  (Ord. 1970-69.  Passed 7-28-70.)