Document gD1wz7K4JBXjNbD1Jxqr5Xevq

APPROVAL OF TECHNICAL PUBLICATION To: Members of the Technical Publications Committee E. Bartholomew H. R. Berg J. E. Boudreau J. J. Prey (2) Attached is an:____ outline; tion by: W. T. Hack J. H. Schaefer J. B. Macauley B. B. Turner M. Morgana R. B. Weston R. K. Scales Y _abstract;_:--final draft of a technical paper recommended for publics- v-.r-.rA Assoclate Director D&ec 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 U ml TEL (and credit us with this effort), since they show that only part 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 Wish to see final draft Disapprove Do not wish to see final draft No opinion Comments Signature Date C0KFID2BTIAL Barticiunto Lead Comooundo In Aa.tcciob5.lo Exhaust Gar-. ----- -------------- n---------1 ir.i i r n ~~i mj Preface WMUUlAIMRMi Since this report has been prepared for potential release outs5.de of the Coiapanjr, codes hare been used to designate tho cars and phosphorus fuel additives which were used* These are as follows: Engine 3 Gar B Gar II Phosphorus Additive A Phosbhorua Additive B 195*0 Chevrolet 1951): Ford Wo, 392 1953 Cadillac 62, Ko. 385 IGG TCP KF iJ 23003 N15310.01 Draft No, 1 Confidential D0 A, Hirsehler & L,, F. Gilbert 12/9/55 (Proposed Research Memorandum for Release to Customer Companies) Particulate Lead Compounds in Automobile Exhaust Gas 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 iatraethylleado No studies were made of the exhausted carbon and organic particulate matter0 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 - n v o o u l - percent of the lead to be exhausted over a 20,000 to 30,000/gperiod of city and country driving. Lead emission 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 lea\d 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 servicee 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 service0 :| The exhausted particles ranged in size from 0o005 micron to several milli i s';*-, ; co meters in diametero Particles smaller than one micron were by far the most o numerous, but accounted for less than 5 weight percent of the exhausted leado o Heavy particles 5 microns and larger, which might be expected to settle rapidly, U represented about 25 percent of the exhausted lead under city-typo driving but increased to about k0 percent under accelerating conditions<> The lead was exhausted principally as mixtures of FbCl^Br, and forms of NHljCX0 2PbCl<5Br5 and 2MHiiGlc' FbClBr 5 together with small amounts of FoSQJj and -' "''D0E"-CT-V.-Q in the fool.- about of T'.u'd : f'.z- Vv was exhausted as 3Fb3(PO|i)gFbCl f'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 compositiona 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 factorse Since lowar~spaed driving conditions as are encountered to congested areas tend to min.l!ip.ze lead eKdssions this fact probably explains why the reported analyses of urban air show lead concentrations which are lew in respect to hygienic standards* and in respec to the amount of lead burnedn KB 0 3 \ Introduction The current interest in the contribution of automobile exhaust gas to atmos pheric pollution has led to roan" recant studies of the miner constituents of ex haust gas* such as incompletely burned hydrocarbons, carbon monoxide & and the oxides of nitrogen and sulfur However* no recent work has been reported on the particu late lead 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 3c0 milliliters per gallon (CL113 wt, percent lead}-. TEL has been used in this manner since 19265 and has helped to provide economically the improved antiknock quality of fuolo which has been required to keep pace with the introduction of more efficient engines having higher compression ratios. In addition to TE% corosnsreioi antiknock fluids also contain thylena dibromide and ethylene dichloride,. These compounds., which are known as scavengers.; arc necessary to prevent the accumulation of lead oxides in engine combustion chambers Their function in to convert lead oxide into lead halidese 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 hazard which it might create Because of tills extensive investigations were carried cut in this and other countries to determine the physiological offsets caused by exposure to the products of combustion of leaded fuels (1* 2S 3* U) These studies showed that there was no need for concern at normal concentrations of TEL even under the most adverse K 0013 u 01u conditions such as in tunnels* confined garages and in heavy traffic5 inasmuch as provisions for ventilation ware required to prevent excessive concentrations of exhaust gas and carbon m0n03cS.de- The conclusions reached in these early studios have been entirely borne out by experience in the ensuing years0 Not only has no trouble dtie to lead poisoning devolopedf but analyses of air in many 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 atmosphere$ and because of this studies have been made to determine the manner in which lead compounds are eschausted from modern cars and from laboratory engines< These studies have been directed toward de termining the amount/, composition* and particle sines of the exhausted lead com pounds* Reported investigations of suspended solids in urban atmospheres have sheet that particles larger than three microns in diameter were present rarely., and that most of the suspended particles were less than two microns in size (5') .- Be cause of this* the exhausted lead compounds have been classified into two bread size ranges* fines up to S> microns in diameter* and coarse particles larger than 5 microns* Further classification cf tho fines into one micron size ranges lias been accomplished in most of tho work,; The studi.es of 2:hauste& lead compounds have evolved through several phases Initially* the exhausted material was collected from single*eylinder engines with only a minimum length of eidmst pips,, Following this* dynamometer tests ware made with a passenger car engine equipped with its complete exhaust system^ arc. finally to simulate passenger-ear service under city-driving conditions,., chassis dynamometer tests were reads 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 phosphojrus- containing additives K 0013007