Document ZnojLQ0ydbBpxaBypbXYQaRMp

ETHYL CORPORATION APPROVAL OF TECHNICAL PUBLICATION \ To: Members of the Technical Publications Committee E. Bartholomew H. R. Berg J. E. Boudreau J. J. Frey (2) W. T. Hack J. B. Macauley M. Morgana R. K. Scales J. H. Schaefer B. B. Turner R. B. Weston Attached is an:____outline; tion by: .. X .abstract;!;-- final draft of a technical paper recommended for publica- 'Orrf'BinfJ yS-'fL Associate Director Date DDi^reector Date Title: Particulate Lead Compounds in Automobile Exhaust Gas Authors: D. A. Hirschler, L. F. Gilbert, F. W. Lamb, and L. M. Niebylski Presentation Before what group: Petroleum Division, ACS Date: September, 1956 Place: Atlantic City, N. J. Will copies be available (preprints . X ... or reprints,_______ ): . Publication Journal: Industrial and Engineering Chemistry Explanatory Comments To what extent does this paper present new data or conclusions? Which items may raise questions of public relations policy? What objective is to be achieved by presentation and publication of this paper? No data have been published on the nature of exhausted lead compounds since the 1926-1930 reports of the U.S. Bureau of Mines, Public Health Service, and British Ministry of Health. This paper is the first work' in which the amounts, particle sizes and composition of exhausted lead have been determined. This publication will surely raise questions as to the effects of TEL on atmospheric pollution, smog, and public health However, Dr. Kehoe feels that these questions will arise anyway, and that we should present actual data before they do. The data will help to obtain approval for 1; ml TEL (and credit us with this effort), since they show that only pari of the lead burned is exhausted in airborne size ranges, particularly in metropolitan driving, and that an increase from 3 to i* ml would increase lead emission by only l/3 from present low levels* This publication is contingent on obtaining prior direct data, from studies in progress at Midwest Research Institute, to show that TEL has no harmful effect on smog formation* Please Indicate: Approve D Disapprove Wish to see final draft Do not wish to see final draft No opinion . Comments Signature Date Please return to J. R. Howard, Secretary, by ____ N15310 C0KFID2KTL:L Particulate Lead Comnoimds in Autcenobilo Exhaust Go Preface Since this report has been prepared for potential release outside of the Company, codes have been used to designate tho cars and phosphorus fuel additives uhich t'ere used* These are as follows: Engine D Car 3 Car K Phosphorus Additive Phosohorus Additive A 3 195*0 Chevrolet 19$k Ford Wo,392 1953 Cadillac 62, Ko. 385 ICC TCP 4. Kf 001300; Draft No 1 Confidential D 0 A, Hirschler & L* F. Gilbert 12/9/55 (Proposed Research Memorandum for Release to Customer Companies) Particulate Lead Compounds in Automobile Exhaust Gas CD Oo U Summary Studies to determine the amount, composition, and particle size distribution of the lead compounds present in engine exhaust gases have been made with laboratory engines and with two conventional cars operated on fuels containing tetraethyllead No studies were made of the exhausted carbon and organic particulate matter Approximately 20 to 30 percent of the lead burned in the fuel was retained in passenger car exhaust system deposits and lubricating oil, leaving ?0 to 80 ' 'VVJOULpercent of the lead to be exhausted over a 20,000 to 30,000/Nperiod of city and country driving Lead mission was increased by speed The lead recovered from the exhaust gas under city-type driving conditions, which included idling, acceleration, deceleration and cruise conditions, normally ranged from 20 per cent of the lead burned when the exhaust system was comparatively clean, to as \ high as 60 percent when the exhaust system was heavily deposited after extensive light-duty service However, under sustained high-speed driving conditions or during high-speed full-throttle accelerations, the amount of exhausted lead initially was several times greater than the amount burned but diminished in quantity as the exhaust system became cleaner with continued severe service The exhausted particles ranged in size from 0 o00!? micron to several milli meters in diameter Particles smaller than one micron were by far the most numerous, but accounted for less than 5 weight percent of the exhausted lead Heavy particles 5 microns and larger, which might be expected to settle rapidly, represented about 25 percent of the exhausted lead under city-typo driving but k0increased to about percent under accelerating conditions {3The lead was exhausted principally as mixtures of FbCl^Br, < and forms of NHliCX02PbGlBr5 and 2NHitGl',Fb01oBrg together with small amounts of FoSQJJj and was exhausted as 3Fb3(PO|i)gFbGlf'Br.5 The amount of lead exhausted was proportional to the concentration of TEL in gasoline* but particle size distribution and composition were independent of this variableo Neither phosphorus^containing gasoline additives nor changes in fuel sulfur concentration introduced definite changes in the amount and size of the exhausted lead compounds, and only phosphorus altered their composition The quantity of load exhausted in size ranges which might remain suspended to the atmosphere appears to be reduced by conditions which produce low gas velo cities and low temperatures in exhaust systems0 These would include design factors such as multiple exhaust systems as well as operating factors0 Since lower^speed driving conditions as are encountered to congested areas tend to minimize lead emissions this fact probably explains why the reported analyses of urban air show lead concentrations which are lew in respect to hygienic standards*, and in respect to the amount of lead burned, 0013 \ KE Introduction The current interest in the contribution of automobile exhaust gas to atmos pheric pollution has led to many recant studies of the miner constituents of ex haust gas* such as incompletely burned hydrocarbons, carbon monoxide* and the oxides of nitrogen and sulfur-0 However* no recent work has been reported on the pariiculate load compounds which are present also to a small degree in most automobile emissions.- These lead compounds are present because virtually all automotive gasolines contain tetraethyllead (TEL) in concentrations up to 3 c.O milliliters par gallon (Of113 wt, porcent lead}-. TEL has been used in this manner since 1926 and has helped to provide economically the improved antiknock quality cf fuolo which has been required to keep pace with the introduction of more efficient engines having higher compression ratios,., In addition to TEi,; commercial antiknock fluids also contain ethylene di bromide and ethylene dichloride., These compounds., which era known as scavengers.; arc necessary to prevent the accumulation of lead oxides in engins combustion chambersr Their function in to convert lead oxide into lead halides9 which have greater .volatility at engine temperatures and can be expelled from the engineTherefore* the elimination of lead from engines would be expected to be accompanied by the discharge of particulate oxides and halides of lead. When TEL first cams into use* there was apprehension on the part of publichealth authorities as to the degree of hasard which it might create* Because of tlxis& extensive investigations were carried cut in this and other countries to determine the physiological offsets caused by exposure to the products cf combustion of leaded fuels (1,, 2 S 3 S ii)c These studies shewed that there was no need for concern at normal concentrations of TEL even under the most adverse K 0013U0 u( conditions such as in tunnels, confined garages and in heavy traffic5 inasmuch as provisions for ventilation vers required to prevent excessive concentrations of exhaust gas and carbon monoxide.- The conclusions reached in these early studies have been entirely borne out by experience in the ensuing years* Rot only has no trouble due to lead poisoning developedj. but analyses of air in any cities in. recent years have shown no instances in which lead in the air has been more than a small fraction of the accepted concentration limit These analyses have suggested that much of the lead burned in gasoline is not exhausted in forms which can be suspended in the atmospheres and because of this studies have beer: made to determine the manner in which lead compounds are exhausted from modern cars and from laboratory engines* These studies have been directed toward de termining the amounts, composition,; and particle sines of the exhausted lead ccr.v pounds- Reported investigations of suspended solids in urban atmospheres have sham-, that particles larger than three microns in diameter were present rarely., and that most of the suspended particles wars less than two microns in slue ($>}< B e cause of this., the exhausted lead compounds have been classified into two bread sice ranges, fines up to S> microns in diameter* and coarse particles larger thav % microns* Further classification cf the fines into one micron size ranges lias been accomplished in most of the- work,; The studi.es of exhausted lead compounds have evolved through several phases Initially* the exhausted material was collected from single-cylinder engines with only a minimum length of e:aaaust pips,- Following this* dynamometer tests ware made with a passenger car engine equipped with its complete exhaust sys terns; and finally to simulate passenger-car service under city-driving conditions^ chassis dynamometer tests were mads with two cars of different makes.- Evaluations wore made of the effects of operating conditions and of three fuel variables.. TEL concentration., sulfur concentration,, and phosphoras-contaamng additives