Document 0gajVGvogo2yDwaexNq0v6mpm

co r/Dar* 8 , A , Xeho3 B r , 0 . g . Kurt Mr* I . J . Gay July 31* 1947 P r . Hoy Gi l b e r t : Co unty o f Los An ge le s Offi c e o f Air P o l l u t i o n Co n tro l iC-is North Sp rin g St r e e t ' Lcs j.n ge le s 1 2 , Ca l i fo r n i a pear o r, Gilb e rts . .. s re pleased te .receive a oopy of the procedure which you Are using for dsteymlnlag aldehydes in the atmosphere. .'Whereas ` we have not had siuoh experience in air s&apling for aldehydes* the method-of assay appears, satisfactory and straightforward. As ;have* however, carried? out considerable research. on the problem of obtaining the sample-- -in this* ease tetraethyllead . ,. and particulate lead from air streams-- -and can endorse-the'-use..'f '. , a midget impinger. The two principal advantages which we have ; found in this cype of sorubberover ths siniered-glass disc typo are lower pressure drop through the system and ease of oleaning. The dimensions were found to be quits critical* and'-1 am enclosing for vour information a Jrswing snowing the scrubber we prefer far air sampling at a rate of 1.0 ou*ft,/min* with 10 ml. of iodine solution. You TMill note that a glass-wool plug is used above the scrubbing solution. This serves the two-fold purpose of-prevent-~ ing ovaporation 'losses.of iodine and entrainsnt of liquid. The firrx nay not- conoern-you,.but entrainsat losses say be important* :e have requested drawings and a description of the son- tinuous automatic apparatus foy determining lead in air which wag .developed at our Baton Rouge Laboratory. When wo have received these* we will- forward them-to you. ' ; ' Ye ry t r u ly yours* BsC En o l. Harold A. Beatty Assistant Director of Chemical Research KB 0004342