Document zzo5JaMqggvzMvrQ8RZQGOmj6

October 13, 19^9 Mr. Peter Altman, Vice President, Continental Motors Corporation, I470 Algonquin, : Detroit 1 ^, Michigan. : Dear Mr. Altman: . I shall undertake to answer the questions in, your letter of October 1 as veil as I can" I have no information on the characteristics of the type of engine which you describe, with respect, to the composition 'of the exhaust gases. I should imagine that M r / Bartholomew of Ethyl Corporation might have some information on engines of .t-his general type, and therefore he might be able to give you some answer to your question #5. I would have sent him a copy of my letter*, in the hope that he would follow up and answer this question, except for the fact that I did not wish to presume to discuss your problem with anyone else without your consent. It might be suspected that the exhaust gases would contain a very appreciable concentration of carbon monoxide, - that is to say, several per* cent. This may be a wild guess on my part, since I an not an engineer, but the exhaust gases of automo biles contain carbon monoxide within the limits of 3 to. 7 per cent under somewhat variable operating conditions. The two-cylinder engine.may give rise to more or less carbon monoxide than do automobile engines, for all I know on the subject. 1 . I know of no procedure that would reduce the percentage of carbon monoxide in'.exhaust gases, other- than that of -regulating carbureter mixtures so as to obtain maximum combust'5.on. 0 far as I know, there is nothing that can be added to gasoline that will materially influence the percentage of carbon monoxide or that would in any way neutralise its harmful effect. Undoubtedly the carbon monoxide issuing through- the exhaust system could be xydized, catalytically, to carbon dioxide, but this would re quire the passage of the ehtire exhaust gases through a chamber in the exhaust system in which an adequate quantity of catalyst was kepi in an active form at all times'.- The lead compound in the exhaust could be removed effectively by electrostatic precipitation. This has been done experimentally, but it reqilires relatively expensive equipment and a l s o :very good maintenance. This, I suspect, Would contribute unduly to expensive and troublesome maintenance operations. It seems quite unlikely to me that any additive, in the fuel could be expected Mr . Peter Altman. - (2/ - October 13, 19^9 to solve either of these problems. The only ansver to that at present is that of suitable local or general ventilation. The exhaust gases can bo piped out of the building in vhich they . are created, and in engine operations of this type it is customary to connect the exhaust system vith pipes or ducts . leading to stacks on the outside. Tunnels and certain types of enclosed spaces in vhich there is heavy vehicular traffic are ventilated in such manner as to dilute the exhaust gases to safe levels. All of the experimental evidence, as veil as the experience of the years, has indicated that if the carbon monoxide is diluted to a safe level, the hasard of exposure to lead is vholly negligible. Therefore, the question is that of diluting the carbon monoxide to the safe level. This brings us to your question ^2. The concentration of carbon monoxide in the air vhich is generally regarded as safe for an 8-hour period of exposure is lot) parts per million by volume. This standard is based on sound physiolo gical principles, and it is a satisfactory.standard xcept"athigh altitudes and under the conditions of reduced oxygen pressure, wherever this might occur. It is based on the fact that carbon monoxide; combines vith the hemoglobin of the hbod, as does oxygen, but vi t h approximately 250 times the avidity characteristic of oxygen. Therefore, there is" a virtual compe tition between the carbon monoxide in the air and the oxygen In the air, and if the carbon monoxide is present in the air in excess of the- standard referred to,oxygen vill be excluded to such degree that the individual suffers some of the symptoms of asphyxiation. A little calculation vill serve to shov vhat I mean. Assuming that the oxygen concentration of the atmosphere is 20^ in round numbers, l/25Gth cf this concentration of carbon monoxide (0.08$ of carbon monoxide in the atmosphere)vill saturate 1/2 of the hemoglobin of the blood if given sufficient time. This vill have essentially the same effect as reducing the concentration of .oxygen in the atmosphere by 1/2, although systemic effects vill be more serious than that of merely dropping the concentration of oxygen. Actually the concentration of carbon monoxide in the atmosphere bfeathed over an 8-hour period must be so low as to provide a negligible amount of saturation of the hemoglobin with .carbon monoxide. Anything in excess of a few per cent of s u c h saturation vill give rise to symptoms. I trust that this vill give you some help, but if I have misunder stood your questions in any manner, I should be glad to elaborate on whax; I have said. Very truly yours, F.AK ef Kobert A. Kehoe, M. D.