Document 0gM1kVGNq5mE3BOXJpV3yK7gM

m jr. Kehoe: This letter was written at the specific request of Mr. MacCauley, f t Ethyl Corporation, Ferndale, Detroit, Michigan. November 2b, 195^ AIR MAIL M r . Gordon P . Larson Air Pollution Control District County of Los Angeles Los Angeles, California Dear Mr. Larson: During the "Conference on Vehicle Combustion Products and Other Emissions," held at Pasadena, August 18-21, 195^* I had the pleasure of lunching with you and Dr. McCabe, and discussing some aspects of your air pollution work. One of the matters which was considered was the method of analysis for lead as reported in Tables VIII and IX of the "Second Technical and Administrative Report on Air Pollution Control in Los Angeles County, 1950-1951 " The method of analysis (indicated as by flame spectrophotometry) was questioned as too insensitive for use at the concentrations of lead listed, and you were going to Investigate this statement. Have: you, since that time, checked the statement and can you let; me know what- method of analysis was used? Another !matter of interest to me occurred recently, when I heard that, the concentration of lead in the atmosphere of Los Angeles has, at times, reached or exceeded the threshold limit for industrial atmospheres (150 mlcrograms/M3 a i r ) . Could you tell me where and how this statement originated? Is it based on the work reported in Tables VIII and IX of the 19 5 0 -19 5 1 report, or have you since obtained values of lead greater than the quantity listed in the 1 9 5 0 - 1 9 5 1 report? I am particularly Interested in this information because such concentrations have not heretofore been reported. Thanking you for your co-operation In this matter, I am, Cordially yours, J . Cholak, Associate Professor of Industrial Health N6976 K~ 0004362