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geles Society of Internal Medicine; a member of the New York Academy of Sciences; fellow of the Symposium Society of Los Angeles; fellow of the American Society of Internal Medicine; fellow of the International Society of Internal Medicine; past chairman of the Air Pollution Committee of the Los Angeles County Medical Association; and chairman of the Public Health Committee of the Los Angeles County Medical Association.

My studies, investigations, and experience have led to my opinion that it is likely that severe illness, and even premature death, can be related to the air pollution episodes that presently occur in Los Angeles County. I refer, of course, to such chronic disorders as pulmonary emphysema and what is described in the medical literature as chronic bronchitis. The contribution of air pollution, both to the initial occurrence of chronic bronchopulmonary disorders and to the manifestations of the symptoms of these disorders, must be viewed as important aspects of this general problem. Indeed, it is my opinion that the very existence of certain chronic respiratory disorders may be linked causally to air pollution levels frequently occurring in Los Angeles County.

In reaching these conclusions, I have carefully surveyed evidence derived from three different scientific methods, each capable of eliciting certain types of information relating to the causation of physiological disorders.

The first method may be described as the experimental method. In this approach, experimental conditions are established in which variables that can affect physiological processes are subject to rigid control. In the case of air pollution studies, single contaminants may be utilized at varying levels, and various physiological responses may be noted as the levels of these contaminants are varied. This kind of experimental study has resulted in a body of research data which suggests the threshold levels at which various physiological processes may be impaired. Our ability to extrapolate practical and usable information from this kind of data is dependent on the scope of the studies, the precision with which the research has been completed, and the experimenter's ability to duplicate naturally occurring pollution.

The second method may be described as the clinical approach. Much of the progress that has been made in medicine through the years has been a result of clinical experience. This approach, too, is somewhat experimental in character, although the variables are not so rigidly controlled, and the evidence acquired is more a byproduct of practical experience than a primary focus of the activity.

The third type of approach may be described as epidemiological method. This involves the treatment of statistical data in order to determine the existence of correlations between disorders and conditions.

Normally, it is desirable to utilize all three approaches in diagnosing the cause of the disorders and in prescribing an appropriate method of treatment.

Of these three general types of investigative methods, my own work has been mainly in the field of clinical experience. However, I have also conducted studies that combined some of the features of the clinical and experimental methods.

In these studies, I collaborated with Dr. Hurley L. Motley. Patients with chronic pulmonary disease, and particularly emphysema, were studied by pulmonary function tests after several days exposure to Los Angeles air pollution. They were restudied, using the same techniques, after being placed in filtered rooms for varying periods of time. Most of the patients in that study were under my professional care before, during, and after the studies, which were performed in the University of Southern California Cardiorespiratory Laboratory.

This study showed that several consecutive days of Los Angeles air pollution aggravated the respiratory handicaps of persons suffering from such chronic respiratory diseases as emphysema. The results of this study, therefore, indicate to me that Los Angeles air pollution adversely affects the many thousands of persons residing in the area, who are afflicted with chronic respiratory disorders. During air pollution episodes in Los Angeles County, many of these individuals are exposed to a measure of stress that cannot be tolerated by their physiology, with the results that the symptoms of their disorders become aggravated.

My clinical experience also strongly indicates the same results. I care for a large number of patients with pulmonary emphysema and other chronic pulmonary diseases. For more than a decade, using clinics and laboratories established by me and colleagues, we have had available ideal facilities for evaluating various types of chronic pulmonary diseases. We have gathered much useful data on the causes of such diseases, on patient response to various types of treatment, and on the effects of environmental factors such as air pollution on bronchopulmonary disorders.

With very few exceptions, the shortness of breath and other symptoms of patients with bronchial asthma, chronic bronchitis, and pulmonary emphysema are aggravated during periods of moderate to heavy air pollution.

Patients with significant pulmonary disease have been almost unanimous in volunteering the information that their condition is much worse during these pollution episodes. Many of them have reported that they obtain relief by leaving the Los Angeles Basin, or by installing air conditioners or charcoal filters in their homes.

Many patients have asked me if their breathing might be improved by moving from the Los Angeles Basin, and I have advised hundreds of patients having severe emphysema to live elsewhere so that they may avoid the harmful effects of air pollution. Many of them have taken this advice, and later told me their symptoms were alleviated and their breathing improved by living in a clean atmosphere. In many cases, these pulmonary disorders were found to recur when the patient returned to the area.

In my opinion, this is substantial evidence that these disorders are traceable to air pollution conditions existing in the Los Angeles area.

This clinical experience also has been shared by many other practicing physicians in Los Angeles. In 1961, the Los Angeles County Medical Association conducted a survey among the physicians active in this area.

The responses indicated that, in the year of 1960, more than 10,000 patients were advised to leave the Los Angeles Basin because of air pollution. The survey showed that 77 percent of Los Angeles physicians believe that Los Angeles smog adversely affects the health of their patients. Air pollution was mentioned by two-thirds of the responding physicians as a culprit in chronic respiratory diseases, and slightly more than one-third had advised one or more patients to leave the Los Angeles area because of air pollution. Of the more than 10,000 patients so advised, at least 2,500 had acted on that advice, and nearly one-third of the physicians themselves had considered moving from Los Angeles to escape air pollution effects.

Information available from the other investigative methods; namely, experimental medicine and the epidemiological approach, tends to confirm the suspicions long held by the clinician that community air pollution is a significant factor in public health. However, the results of these studies are not yet conclusive. Mainly this is because relatively little time has passed since the first real concern with communitywide air pollution of a nondisaster nature stimulated such studies, and these invesitgations are, therefore, far from complete. But this does not argue that remedial steps should not be taken.

As Dr. Leroy E. Burney stated at the National Conference on Air Pollution in Washington, D.C., in November 1958:

In law, the suspect is innocent until proved guilty beyond a reasonable doubt. In the protection of human health, such absolute proof often comes late. To wait for it is to invite disaster, or at least to suffer unnecessarily through long periods of time.

Although there is not always general agreement, I believe that most practicing physicians tend to be more concerned with the effect of air pollution on the health of the individual than does the laboratory physician or the epidemiologist.

This is so because the latter two scientists are working to establish from large masses of data quantitative relationships on which to act, while the relationships observed by the clinician are, for the most part, qualitatively derived from an examination of numbers of specific patients.

A very obvious parallel is the connection between smoking and lung cancer. For a great many years, the medical profession has felt that smoking certainly was not good for the individual; for the past several years many strongly believed that smoking was causally involved with the development of lung cancer. Such beliefs often led to strong recommendations to individuals, if not the public as a whole, that they should refrain from the use of cigarettes in the interest of their own personal health.

Had these physicians awaited more quantitative results, such as those recently published by the U.S. Public Health Service, they would have done great disservice to the patients involved. With those quantitative results now available, it is perhaps possible to bring more forceful argument to hear on the matter of smoking. But the emergence of these quantitative statistics has in no way changed the basic causal relationship—it has only served to bring it more vividly into focus.

In extending the parallel to the present state of air pollution medical knowledge, we may cite the discussion group on the health effects of air pollution, which stated in its recommendations to the National Conference on Air Pollution in Washington, D.C., in November 1958:

It was recognized that intensification of control efforts should not and cannot await the definitive answers to many of the medical problems. However,

there was agreement that it is imperative that such answers be found at the earliest possible time since they will serve to better guide the development and design of control programs.

Obviously the man in the street cannot simply hold his breath until the expert determines to the 10th decimal place the precise quantitative relationship between air pollution and human health. By the same token, however, a concentrated effort in all three fields-clinical study, epidemiological investigation, and laboratory research-must be made so that the practicing physician, the public health official, the air pollution control official, and that man in the street, can be guided in taking remedial steps.

In particular, much work must be done to provide information to be used in establishing ambient atmospheric standards for acceptable air quality. And by "acceptable" we must mean levels that will not be_injurious to the most sensitive groups in the population.

In California, the State department of public health has established standards with respect to a few contaminants. Many important contaminants are not now included, however, because of a lack of definitive information that can only be acquired through vigorous prosecution of a well-planned research program. Among the air contaminants that must be intensively studied so that standards can be established as soon as possible are lead, carcinogens, and oxides of nitrogen.

It is known that atmospheric levels of lead are increasing with increasing use of leaded fuels. Moreover, there is evidence to suggest that some of the newer lead gasoline additives are potentially more hazardous to public health than the compounds previously used. These facts, plus the additional one that the effect of lead is additive, insist that greater effort be exerted on this subject.

The need for further study of the levels of carcinogens in the air we breathe is clear. Epidemiological studies made to date strongly suggest significant casual relationships between community air pollution and lung cancer in several areas of the country.

We dare not delay further research on this subject.

Levels of oxides of nitrogen also are increasing rapidly in the major communities of California, and projections show they will continue to do so. This is due in part to increased emissions resulting from our growing population. In addition, photochemists tell us that the levels will increase at an accelerated rate as motor vehicle hydrocarbon emissions are controlled, because less of the oxides of nitrogen will be used up. These considerations emphasize the immediate need for obtaining the information necessary to establish standards for this contaminant as well.

In addition to determining standards for contaminants not now included, there also is need for more definitive evidence to be used as a touchstone for reviewing the existing standards so as to insure their adequacy.

This is not a criticism of the present standards; rather, it is a realistic recognition of the paucity of information available to those working in this relatively new branch of public health.

Finally, when discussing public health in abstract and general terms, we must not lose sight of a most important fact. The public is made up of individuals. So whatever his field, the physician, in the

last analysis, is dealing not with faceless masses, but with individual human lives that must be preserved and protected with whatever abilities we are given to use. [Applause.]

Senator MUSKIE. Thank you very much, Dr. Smart, for your excellent statement.

I think we will proceed with Professor Haagen-Smit's prepared testimony and then direct questions at both of you.

STATEMENT OF DR. A. J. HAAGEN-SMIT, PROFESSOR OF BIOLOGY,

CALIFORNIA INSTITUTE OF TECHNOLOGY, PASADENA, CALIF.

Dr. HAAGEN-Smit. Mr. Chairman, members of the committee, you have heard what Los Angeles smog is made up of and I mention here, briefly, Los Angeles type of smog is caused by a release of reactive organic material, mostly of gasoline origin and oxides of nitrogen. A contribution to the haze is made by oxides of sulfur and dust and fumes.

Certain hydrocarbons in the presence of oxides of nitrogen under the influence of sunlight are converted into materials which irritate the eye, cause plant damage, and high levels of ozone, and form particles which decrease the visibility. In Los Angeles County, 2,500 tons of organics, 700 tons of oxides of nitrogen, are emitted daily to the air, mainly by its 3.5 million motor vehicles. Attempts are being made to prevent these emissions by control measures on the automobile. Crankcase vent devices will be on all cars in 1966. Devices to curtail the emissions from the exhaust are presently being tested by the State motor vehicle control board. Laboratory studies have shown that an efficient control of hydrocarbons or control of oxides of nitrogen will lead to a disappearance of smog symptoms. Emphasis at present is on hydrocarbon control, although it has become clear that the other component of the smog, the oxides of nitrogen, will have to be controlled. The reason for this is that it is practically impossible to obtain the desirable degree of control in a car population. Moreover the cost of control rises sharply with greater efficiency. It would therefore be more advantageous to control both components with methods, and at a price which is reasonable.

For both controls, such methods are now available.

While such methods in their present form will tide us over for a dozen years, the increase in population will neutralize any gains which have been made. It is therefore essential that research be continued on improvement of engineering control for motor vehicles as well as stationary sources.

The chemistry and physics of atmospheric reaction should be studied further. Basic information should be available on the reasons why there are emissions of hydrocarbons and oxides of nitrogen. Such work would lead to improvement in performance without the use of costly apparatus. Some of this type of work has been initiated for hydrocarbon control and oxides of nitrogen, and should receive priority support. Research on the effects of photochemical smogs on human beings, animals, plants, and materials has to be extended.

There is so much to be done on the emissions of cars that we just have begun to get some of the material.

I might mention that I had the idea to have the Los Angeles taxpayers some money, that the right thing to do would be to put all the

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