Proposed initial studies of the relationship of community air pollution to health

ENVIROZhIENTAL

2, 102-13.3

RESEARCH

Proposed

Initial

Community THOX~S

Department

of

F.

(1969)

Studies Air I\lr\~c~w~

of the Pollution AND

J.

Relationship

of

to Health SOLON

Occupational Health, Graduate Cmioersity of Pittsburgh

School

MORDELL of Public

Health,

FOREWORD

In preparation for an organized program of research to determine the relation ship of air pollution to health, it was decided in the early part of 1955, within the Division of Special Health Services of the Public Health Service, that a basic statement should be developed outlining the research avenues to be explored and the kinds of studies which should be undertaken. The impetus for this activity stemmed from the mounting concern about the problem of air pollution, which. in the latter part of 1954, prompted the convening of an ad 110~ committee to determine what the role of the Federal government might be in this question. The committee was composed of representatives from each of the Federal agencies having a direct interest in the problem. The committee, in its report, pointed out the need for a consolidated program of research in order to evaluate present and potential effects of air pollution, and the possible measures for control and abatement. It was some months later that the Congress enacted legislation to provide for research and technical assistance in this field. In March, 1955, arrangements were made within the Division of Special Health Services for a S-month program of activity directed toward exploration of the approaches to be taken in a coordinated medical research program in this problem area. It was hoped, within this limited period of time, that as much as possible of the basic groundwork would be developed to serve as a guide for future endeavor, and that an initial assembly of broad projects would be outlined. Primary attention was focused on the need to find out the health effects, if any, of long-term exposure to low levels of atmospheric pollution. At the outset it was necessary to learn something of the background in the field-the various disciplines which have been involved, and the new ones which might be called into play; the questions which remain unanswered; and the general status of knowledge concerning the medical aspects of air polhtion. This was followed by the exploration of various ideas as nuclei for generating research effort. Visits were made to numerous authorities in various parts of the country in an effort to assemble the research tools which might be applied. In view of the relative paucity of information and accomplishment ill the medical phases of the question it \vas necessary to explore the ways in which the various disciplines might be applied, regardless of whether or not they had been previously utilized in the specific area of air pollution research. For example, having ascertained that current toxicological methods and tests 10”

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on organs or systems of the body are not adequate for detecting the effects of exposure to atmospheric pollutants, particularly long-term exposure, consideration was given to the feasibility of applying to this problem various testing and experimental techniques not previously used for this purpose. A number of the studies presented evolved from this type of exploration. As originally planned, conferences were to be held for each of the given subject areas, after the basic ideas had been examined and discussed in inhad been assemformal personal visits, and an adequate core of information bled. The purpose of these conferences, attended by persons competent in the particular field, was to provide a means of free, informal discussion which might aid in decisions as to the validity of the proposed research approach. For example, conferences were held on the subject of sources of morbidity and mortality data and their application to various epidemiological studies which might be undertaken; the feasibility of tissue cultures as a toxicological tool; and the status of organ function tests. Time did not permit the convening of such conferences for all of the topics concerned. The proposed studies as of 1955 are “initial” in that they represent some of the broad areas which should be pursued. Obviously, any number of corollary studies may evolve from those described. Furthermore, there are additional areas which could not be covered during this initial stage and which warrant further investigation. In presenting these initial studies, two major groupings are used: Epidemiological Studies and Studies of Biological Effects. Each of these two major study groups (“I” and “II”) is broken down into significant study subjects (“A,” “B,” “C,” etc.) under which specific projects (“1,” “2,” “3,” etc.) are described. Thus, project I-A-l is in major Group I (Epidemiological Studies), under principal study Group A (Community Air Pollution and Mortality and Morbidity Trends, by Residence), and is project No. 1 (Geographical distribution of mortality by death residence). In some instances a project may involve several steps, in which case it is further enumerated according to each step (e.g., I-A-la). The order of presentation of the studies does not necessarily indicate the order in which the studies should be conducted. I’KOPOSED

I.

EPIDEMIOLOCXCAL

STLJDIES STUDIES

General Statement The available biological tests and means for measuring or determining physiological or pathological changes which may be due specifically to atmospheric pollutants are extremely limited. Similarly, toxicological data are lacking with respect to long-term exposure of humans and animals to low concentrations of the various chemical substances involved. The utilization of the epidemiological approach in connection with community air pollution medical research therefore is of special importance at this time in the determination of any health effects for the population exposed. This would be concerned with the search for significant sickness or death characteristics peculiar to urban areas where there has been

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human exposure for many years to various types and degrees of community air pollution. It is necessary to determine whether morbidity and mortality data differ among population groups exposed and those not exposed to specific types or combinations of pollutants. These determinations will be meaningful only if the data are related to the years of residence for the population under study in a given area. The study of the geographic distribution of disease and death for its possible relationship to atmospheric pollution may be approached in three general ways. One approach would be to avoid any preconceived ideas about the effects of pollution, and to conduct a systematic study of mortality in cities of a selected population size. Such differences as might be found could then be further studied for possible association with community air pollution. Another approach would consist of grouping or comparing communities with similar atmospheric pollution experience. A third approach would be the study of intracity variation in morbidity and mortality and its relationship to the problem. In all three methods, cognizance must be made of the fact that variations in degree and type of pollution may occur in various time periods in the same locality. These epidemiological studies may also provide clues as to the specific organs or body systems which appear to be affected. The development of organ function, or other biological tests may then be directed to the organs or systems thus delineated. The following sets forth some of the broad epidemiological studies to be considered and the initial individual projects to be undertaken within each study. There is also included a discussion of resources to be utilized in the conduct of these studies. A. Community

Air Pollution

and Mortality

and LMorbidity

Trends

by Residence

Objectives It is necessary to determine whether persons residing in one area are at a greater risk than those in another area, in a certain time period, as may be reflected in a particular cause of death or age at death, and whether persons in some particular place have been at a greater risk during one time period than during another. Thus, basic to any study of place factors is a systematic study of geographical distribution of specific causes of death and disease during several time periods. This study of general geographical distribution, as well as comparisons of metropolitan1 vs. nonmetropolitan areas, and metropolitan VS. metropolitan areas may provide the initial leads for further epidemiological efforts and medical investigation. Finally, such refined morbidity and mortality data may be effectively coordinated with existing information on the geographical concentration of sources of pollution in particular areas or cities. Factors

to be Considered

The detection 1 As

defined

by

of possible influences the

U. S. Bureau

of the

of air pollution Census.

on morbidity

and mortality

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trends cannot satisfactorily bc accomplished at this time by the application of toxicological data. Such data have been developed for only a small number of the dozens of contaminants thus far identified, each of which may have its ox\-n data are lacking as to the effect mode of action on the body. Furthermore, of exposure to low concentrations over long periocls of time. The possible interaction of chemicals in the air to form substances having 7nultiplc~ or s!.ncrgistic effects f77rthcr complicates the problem. In view of the limited availability of toxicological data, a basic appro:7ch is to establish the csistcnce of any gcographiral differences in morbidity and Iii this con77ectio77 it mortality, according to various factors of residcncc. should be noted that there may be a significant increase in morbidity of a specific disease or illness, over a long period of time, which may or may not be rcflccted in the mortality patterns for the broad categories of causes of death. In addition, the effect on life expectancy of place factors such as atmospheric pollution should also be considered. The first poi77t of departure is to determine geographical mortality differc77ces according to residence at the date of death (“death rcsiclcnce”). 177 this con ncction. cha7xteristic.s of the popuIations u77der stud!, markcdlv influe77ccb geographical morbidity and mortality patter77s. Also. it is necessary- to be able to compare smaller subdivisions ( cens77s tracts) vvithin any given geographical arca. Finally, it is indispensable that comparisons be made and differences dctectcd at the most distinctive level, that is. by as 7na77y of the specific C;III,SC‘S of deatl7 as possible instcacl of the broad categories. The only published geographical 7norality data available ( 1955) on a national basis, by death residence, are as follows: By State, for 256 specific causes of death, by sex, and race. and, for 64 specific cau~s, bv age, sex, and race; bv corns!/, nunil~er of deaths for each of 32 broad catcgorics of c;mscs of death: bv meiropolitcln and ~lonmetrn)~olitlrn areas. for 32 broad categories of causes of death, by age, sex, and race (data by each characteristic. not cross-related ) : also b!size of community for the years 1920, 1939. 1940, a77d 1950. For o77r p77rpos:s. it is necessary to obtain data for an expanded list of specific causes of death, as vvrell as to consider additional pop77lation charnctcristics such as country of birth and socio-economic status. It is also necessary to obtain data by c:lnsus tracts wherever possible. Morbidity data currently available arc not adequate for the types of studies which wonId be required to establish geographical or other morbidity differences. If the basic data referred to are not obtained, it will be diffic77lt if not impossible to make proper compariso77s and to proceed to the further refinement needed for epidemiological evaluations. The second point of departure is to determine morbidity, mortality, and life expectancy differences according to years of residence in the locality (“residenct exposure years”). In order to determine whether such differences occur in cities having different types and sources of atmospheric pollution, it is necessary to study general population groups; as well as to identify specific population groups (“cohorts”) by location and by adequate length of residence, for observation ovw long periods of time (“longitudinal studies”). If, for example, we wish to

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study the possible relationship of atmospheric pollution to the health of those who have been living for 20 years in a given locality, the population concerned (at risk) must be properly identified. There are a number of reasons for using residence exposure years as the basic factor in epidemiological evaluations of the cumulative effects of long-term exp:lsure to atmospheric pollutants. In studying diseases having long latent periods, it should be noted that the current place of residence of population groups under study may not be the place of “exposure.” This applies to the following types of current residence: death residence; place of retirement; place where special medical or surgical care is being utilized; place to which there has been significant migration because of attractive climate and job opportunities; and places within a city to which there have been population shifts with respect to race, nationality, and socio-economic status. These types of current residence, singly or in combination, bring about shifts in the age distribution of the population as well as in the causes of death, thereby affecting the mortality pattern of the given locality. This demonstrates the need for age-specific morbidity and mortality rates by residence exposure years, in studying the effects of long-term “exposure.” In the development of these data, it is essential that the information derived for women and children be as comprehensive as possible. In evaluating the potential effect of atmospheric pollutants in a given locality, it is necessary to eliminate, or at least ascertain, the extent of the influence of occupation as usually associated with the male population. Thus, the female and child populations serve as a basis of comparison with the males in evaluating the disease or death pattern of the locality. At the same time, in the course of preparing these data, it is necessary to consider the possible occupational variables within the female population as well. Projects to be Undertaken I-A-l.

Geographical

distribution

of mortality,

by death residence

In the development of this project, the principal factors to be considered have been described above. In order to accomplish the objectives for this study, tabulations are proposed as follows: a. Number of deaths by age, sex, race, and for 100 selected causes of death, for the 3-year period, 1949 through 1951, are to be tabulated from data of the National Office of Vital Statistics for: (1) Each census-designated metropolitan area in the United States, subdivided into : (a) The county in which the central city is located; (b) Other counties within the metropolitan area. (2) Each census-designated non-metropolitan area. b. Number of deaths by age, sex, race, and specific cause of death, for a consecutive number of years as well as for several different significant time periods (minimum of 5 years each), for each county within a State, or for selected areas, are to be tabulated from State or county records whenever special county or other area studies are required. The aggregate number of years covered should

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be large enough to allow for a postulated the causes of death under study. I-A-2.

Gcographicnl residence

distribution

latent

of mortality,

TO

period

by

107

HEALTH

associated

corrntry

with

of birth.

each

hy

of

death

The following tabulations arc intended to compare foreign born. non-n,hitcb, and native white, for specific causes of death. on a county and on a metropolitan area basis, for both sexes. For example, it is known that the incidence of cxnc’cr of certain sites is significantly in excc~ for non-\-\hites as compared n+th lvhitcs. This excess is also true for the foreign born as compared with the native lvhite. For certain sites the reverse is true. This type of iilformntion can then be applied in any given geographical analysis in order to adjust for the influence of natkity and color. There are two sources for this type of data. In the cast of data of the National Office of Vital Statistics, the information is presentl! (as of 1955) available in terms of total foreign born (not by countq. of birth), for the year 1930. Data b,r specific country of birth, over a period of man\’ !~~rs, arc available from the States. born. and spc‘cific cause a. h;umbcr of deaths by agz. sex, race‘, total foreign of death, for the year 19SO by State and by metropolitan arca, are to be tabulated from data of the National Office of \‘ital Statistics. 1,. Number of deaths by age, sex, race, country of bir’J~. and specific c;.u~sc’ of death. for thtl desired number of years, by State, county. and by mctropolita!I area, are to be tabulated from State records.

In the development of this project, the factors to be considered have been described. In addition to the determination of significant geographical differences according to death residence (I-A-I ), further definitive studies should be conducted in order to evaluate the relationship of years of residence to mortality. Wherever possible the populations must be identified by length of residence so that age-specific morta!ity rates may be calculated according to rrsidence exposure years. a. General population. One method of obtaining geographical differences in mortality by residence exposure is to survey the population of the given area or city in order to identify those residing there during the survey year who were also born tliere. For such persons, it is assumed that the given city represents their predominant place of residence up to the time of the survey. Then, of those who died in the same city in the same year, identification is made of those who had been residents thereof and who had also been born there. From this, age-sex-specific mortality rates according to causes of death can be computed for the given city. These can then be compared with other cities in which similar data have been obtained. In this connection it may be noted that related information obtained during the Federal decennial census shows the State but not the city in which the individual was born. It is suggested that the city of birth be determined during the next census, so that comparisons can be made for any series of cities in the country.

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b. CO~OT? popuhtions. Another method of detecting differences in life expectancy and specific causes of death, according to residence exposure, is to study populations over a prolonged period of time, by the application of the cohort principle. ( 1) Community

cohorts

(a) In selected areas a master roster of residents, by age and sex may be established for all, or for a sample of those who were living in the area in a given single year (e.g., 1940), or during a given group of years (e.g., I940 through 1943). These would then constitute a cohort to be followed for an adequate number of years in order to determine those of the cohort who died, causes of death, and age at death, so that mortality and life expectancy patterns may be constructed. This master roster can be developed through questionnaires or by direct household survey, or by mail. This may be supplemented or assisted by such sources as: Federal census data, for obtaining total population data for desired area, according to age, sex, and race distribution; employee records obtained from all employment sources, including Bureau of Old-Age and Survivors Insurance; city directory; voting registers; records of telephone and other utility companies, hospitals, churches, schools, credit bureaus, and department stores; life and health insurance records; death or birth certificates; relatives; pertinent data which may be contained in State or area morbidity studies. To determine the deceased who were originally within the master roster or cohort and their ages at that time, it will be necessary to review each death certificate and check it against the names on the master roster. (b) A master roster of children, by birth date, sex, and race, may be established by determining those who were born during the selected time period. This cohort would then be followed for a consecutive number of years and, in addition, rosters may be established at 5-year intervals so that several of these cohorts may be compared for different time periods. Deaths, by cause and age at death, may then be determined as for the rosters previously described. Concurrently, a master roster of the mothers of these children, as well as one for the fathers, by age and race, may be established and studied in the same manner. (2)

Life insurance (a)

Ordinary

and retirement

life insurance

system cohorts

policy-holders

Tabulations are proposed for comparable cohorts of long-term residents in selected cities, using those who had ordinary life insurance coverage. Those accepted for insurance are individuals who have been identified by characteristics such as age, sex, race, country of birth, occupation, health status, residence, and amount of insurance. This permits the formation of comparable cohorts for conducting longitudinal studies according to residence exposure years. Years of residence may be established either from company data which may indicate actual places of residence; or, lacking this, by determining, among those insured, those who were born in the same city where the policy was issued and who died in the same city. In the latter method it is assumed that if birth,

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issuance of policy, and death all occur in the same city, it indicates predominant residence in that city. By this method, the cohorts would consist of those in a specific age group (e.g., 30, 35, 40, etc. ) entering insurance coverage in any selected previous year which will allow for an adequate period of observation (e.g., the year 1935 for those insured at age 30 who subsequently died in the game city). Survivorship and mortality patterns can be constructed for comparisons between similar cohorts in different cities. Other comparisons can be made using various combinations of the three factors of city of birth, city of policy issuance, and city of death. Tabulations for the cohorts would be made by age at time of entrance under coverage, by sex, by race, by age at death, by cause of death, and by years of residence. (b)

Industrial

(“group”)

life insurance

policyholders

Comparable cohorts of industrial (“groups”) policyholders covered by insurance in different types of major industries, would be followed over a period of many years, and tabulated by age at time of entrance under coverage, sex, and race; by age at death and cause of death; by industry group. The same procedure with respect to residence and comparative stud& may be used here as described under (a) above (ordinary life insurance policyholders). In some instances group insurance coverage includes dependents of the insured employee. This permits study of comparable cohorts made up of dependents. The mortality patterns for husbands in one industry group may be compared with the patterns for their wives (or other dependents), and these may then be compared with the husband-dependent patterns in other industry groups. (c)

Retiremwt

system beneficiaries

Comparable cohorts of retirement system beneficiaries in special population groups such as railroad workers, machinists, postal workers, and others, would be tabulated by age at time of entrance into the system, sex, and race; by age at death and cause of death; by industry group; by place of employment. Comparisons can be made of cohorts of the same industry group located in different cities. Observations can also be made on a husband-dependent basis as in the case of those covered under industrial (group) life insurance. Retirement system data are to be used. These data include information similar to that provided by insurance company data and therefore permit the identification of comparable cohorts which may be observed for long periods of time according to residence exposure years. The data obtained in (a), (b), and (c) may provide a clue to the method for studying the mortality patterns of the general population which may be exposed in areas where the major types of industries concerned are located. I-A-4.

Geographical di.sttiOzttion of mortality, by economic industrial and socio-economic characteristics

szlbregions,

and b!y

In selected counties or areas having a predominant type of industry, or a single specific industry, mortality differences may occur among the employed

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males which would assist in evaluating the long-term influence of given types of industry on a community. Likewise, mortality data for the employed females should be studied. Comparisons can be made between males and females employed in such an area with those in another area having the same predominant or specific type of industry, as well as with those in areas having a different predominant or specific type of industry. In addition, special studies can be made within the given area to compare the employed females with nonemployed females (housewives, etc.) ; and to compare the employed married males with their wives (properly identified as to occupational or nonoccupational exposure). In all of these comparisons the groups should be identified according to residence exposure years so that the same residence factor applies to all. Just as occupation, country of birth, or race may influence mortality patterns, so may the socio-economic status of a given population. Therefore, it is necessary to identify population groups and their mortality patterns according to socioeconomic factors so that significant characteristics may he identified as baselines for future reference. This may then indicate the advisability of comparing, by census tracts within a given area, populations having similar socio-economic characteristics and adequate years of residence in tracts situated adjacent to different sources and types of pollution. These tracts within a giv-cn area would also be compared with similar ones in other areas. Correlations of mortality differences for specific cause of death in different census tracts with the types and concentrations of atmospheric pollution currently prevalent, must take into consideration the latent period of the suspected specific cause of death. Therefore, the types and concentrations of pollution prevalent 20 or more years ago may have more bearing on the interpretation, particularly when related to the residence exposure years of the population in the census tracts under study. The factors discussed (industrial and socio-economic characteristics) are two of the elements included in a Bureau of the Census geographical grouping of areas, which constitute uniform statistical units, and are identified as “economic subregions.” These economic subregions can be identified by predominant types of industry groups and by specified metropolitan areas of different sizes. Mortality data can be tabulated geographically according to any of these subdivisions, for purposes of comparison in order to detect significant differences. The following procedures are proposed for obtaining this information: a. As related to economic subregions. Number of deaths, by age, sex, race, and specific causes of death, by economic subregions, for the 3-year period, 1949 through 1951, are to be tabulated from data of the National Office of Vital Statistics. b. As related to industrial characteristics of an area. Number of deaths are to be tabulated from State records, by age, sex, race, country of birth, and specific causes of death, by death residence; for a consecutive number of years as well as for several different significant time periods; for the counties or areas selected with respect to predominant or specific type of industry.

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These data can then be studied as follows: First, with respect to a consecutive time period (20 years or more), trends in specific causes of death in ;I given area may be identified and compared with other areas having the same or different industries in existence for similar periods of time; second, with respect to selreral time intervals, mortality patterns can be compared in a given area, for an adequate period of time, before and after the entrance of the industry into the area, taking into consideration the postulated latent period associated with each of the causes of death under study. In addition, mortality patterns can be compared by 5year periods for the time the industry has been in operation, in order to detect periodic differences due to variations in the latent periods for the different specific causes of death. C. As related to socio-economic characteristics of (~1 areu. Number of deaths by age, sex, race, socio-economic status, and specific causes of death, by residence exposure years, by census tracts as previously described, are to be tabulated from county and city records. I-A-5. Geogruphical distribution of morbidity by residence exposure years a. Selected diseasesin metropolitan and nonmetropolitan areas, and census trwts. In the development of this project, some of the principal factors to be considered have been described above. The purpose of the project is to determine the prevalence of certain diseasesin various areas having different degrees of atmospheric pollution, according to residence exposure years of the persons concerned. At the same time, data on socio-economic characteristics would be elicited in order to establish economic and educational levels for purposes of correlation. The plan of the project would follow the pattern of cancer morbidity studies conducted by the National Cancer Institute in 1938 and 1948 in 10 metropolitan areas (Atlanta, Birmingham, Dallas, New Orleans, San Francisco, Denver, Chicago, Detroit, Philadelphia, and Pittsburgh). Since these cancer morbidity studies have been demonstrated to be practical methods of study and the information derived has proved valuable, it appears worthwhile to extend these morbidity studies beyond cancer and to selected specific diseases in which confirmation of diagnosis by a physician would be required. Leads to such selection may be derived from findings of toxicological studies, or from the studies of the geographical distribution of , mortalit)l in which certain causes of death may occur in significant geographical patterns. ( 1) Tabulations would be made to establish and compare the morbidity rates of specific diseasesin selected metropolitan and nonmetropolitan areas, and census tracts, according to residence exposure years, age, sex, race, marital status, and socio-economic characteristics. The procedure for collecting data concerning cancer morbidity would be utilized for other diseases. By this method, data concerning morbidity of a specific disease would be collected from every physician, hospital, and clinic in the areas under study. In addition, the records of the local vital statistics offices would be searched for information concerning deaths from the particular dis-

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ease, as a partial check upon the completeness of reporting. This method of study would supply information concerning every known case of the disease in the area and make possible the computation of morbidity rates. It is most important that the cities or metropolitan areas selected for study show a statistically significant range of difference among themselves according to some common index of atmospheric pollution, as determined for a period of many years. This is necessary in order to permit evaluation of any differences in the morbidity of specific diseases which may be detected among the cities, in relation to air pollution. Thus, statistical studies of morbidity, identified by specific diseases, would be conducted not only among the metropolitan areas, but also in nonmetropolitan areas with long-term esposure to atmospheric pollution and in nonmetropolitan areas which have been relatively free from atmospheric pollution. The principal difference in the conduct of the presently proposed morbidity studies is the inclusion of the factor of residence exposure years, and for this purpose residence histories would bc required for each of the disease casescos cerned. The residence data for these morbidity studies should not be as difficult to secure as those associated with the mortality studies. If necessary, residence history for persons having the disease under study may be constructed by determining those who were born in the same city in which they are residing at the time of the survey. For such persons, it is assumed that their residence was predominantly in that city up to the time of the survey. In order to establish morbidity rates it would also be necessary to determine those in the rest of the population of that city who were born there and who are residing there at the time of the survey. Thus, individuals in specified age groups, having a specific disease, who were born in the city and who are residing in the same city may be compared with similar specific disease groups in other cities. b. Relation of cancer morbidity to residence exposure years and socioeconomic characteristics, in 10 nzetropolitan areas. In this project, the data of the 1948 cancer morbidity study conducted by the National Cancer Institute in 10 selected metropolitan areas would be utilized. In the 1948 study, the incidence and prevalence rates of cancer according to age, sex, race, stage at diagnosis, and survival rates were determined, in addition to other data. It is proposed that the contemplated study by the National Cancer Institute to obtain data on socio-economic characteristics of the population and of cases of cancer included in the 1948 study. be further extended to include residence histories, by specific years, if obtainable; or by the alternative method described under “a” above. The purpose of this proposed study would be to reconstruct the cancer morbidity rates according to residence exposure years and to compare the 10 metropolitan areas studied. In this manner the degree and significance of any difference that may exist between morbidity rates of lung cancer, for example. based on residence at time of survey and that based upon residence exposure years could be determined, and may be of significance in other studies. (1) Tabulations would be made to compare cancer morbidity in the 10 metropolitan areas by residence exposure years and socio-economic characteristics, by age, sex, and race.

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C. Total morbidity lcithin and low levels of atmospheric

IS

metropolitalz polhtion,

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and nonmetropolitan areas with high years. accordin, 0 to re.sicfence exposure

In this project total morbidity is to be determined as well as specific illnesses in relation to residence exposure years for populations under study in areas of long-term high and low levels of atmospheric pollution. It is proposed that the household survey approach be utilized, for groups of families and daily records of illnesses. Particular attention should be directed to the women and children, in order to offset occupational influences with respect to the wage earner. III addition, the socio-economic status, number of children, and extent of intramural crowding are factors which may require special attention. In previous studies of this type, limited or no statistical consideration was given to the number of years the family being studied had resided in the area. -4s pointed out earlier, this factor is basic to proper evaluation of an)’ relationship to atmospheric p011~1tion. Residence histories would be recorded covering as long a period as possible. Such information would be of value for both morbidity and mortality studies. ( 1) Tabulations would be made of total as well as specific illnessesin farnil) groups, according to residence exposure years in areas of long-term high and lo\\atmospheric pollution, by age. sex, and race. I-A-6.

Geographical

distribution

of populations

according

to biological

findings.

~1. Lwi~~ cancer deaths, hi/ occlrpatio~~al esposure, smokingr history, and residerrcc expo.swe years. Three ctiological factors currently are commanding atten-

tion in relationship to the rising trencl of lung cancer in urban’ areas. They art’ tobacco smoking, occupational exposure to carcinogens, and atmospheric pollution. Opinions as to the degree of importance to be attached to each of these factors vary among members of the medical profession and research workers concerned. Since it has been established that among residents in urban areas there is a great excess of lung cancer over those in rural’ areas, questions have been raised as to why this is so. The availability of medical care and improved diagnosis does not account for all of this increase in the urban areas. It seems advisable therefore to undertake a project which would attempt to determine the relative importance of these three factors and particlllarly that of atmospheric pollution. A lung cancer study planned by the National Cancer Institute in relation to smoking habits could be utilized in the conduct of such a project by including data on residence and occupational history and country of birth. The Institute plans to make geographical comparisons of lung cancer deaths in 1956 as related to the smoking habits of the deceased. The population characteristics and smoking history data obtained at the time of the United States census of 1950 would be utilized as a basis of statistical comparison. It is suggested that complete residence histories be obtained at the time that the informant is being questioned concerning smoking habits. This would make it possible to prepare statistical tabulations by residence exposure years for ’ “Urban” and “rural” asused here and subsequently,refer to the general and not to the specialdefinitionsusedby the U. S. Bureauof the Census.

sense

of he

terms

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various urban and rural areas to observe the relationship, if any, of residence and of smoking habits to type of geographical location. In order to establish the employment history of the deceased, a reliable source is the records of the Social Security Administration. These records include the employment history of individuals covered under the Act, dating back to January I, 1937’. They provide the names and addresses of all employers, the dates of employment, and the four-digit industrial classification for each place of employment. The social security number of the deceased may be obtained from the informant; or from the death certificate; or from the Bureau of Old-Age and Survivors Insurance, Social Security Administration, Baltimore, Maryland, by furnishing the Bureau with the names of the parents of the deceased, the birth date, and certain other identifying data. Through the use of these data, the lung cancer cases can be studied on the basis of industry and residence exposure years, and smoking habits. Any significant relationships which may be observed among these factors can then form bases for further research. ( 1) Tabulation of lung cancer cases, to permit comparison, on a metropolitan-nonmetropolitan area basis, according to smoking history (type, quantity per selected unit of time, and total smoking years), and residence exposure years, by age, sex, race, and country of birth. (2) Tabulation of lung cancer cases, to permit comparison, on a metropolitan-nonmetropolitan area basis, according to years of employment (by industry classification) and residence exposure years, by age, sex, race, and country of birth. (3) Tabulation of lung cancer cases, to permit comparison between metropolitan areas, according to smoking history and years of employment (by industry classification), by age, sex, race, and country of birth. b. According to histological types of lung cancer. Histologically, the epidermoid (squamous cell) type of lung cancer is generally believed to be the type most likely to have an environmental etiology. Since there has been a significantly greater increase in the incidence of lung cancer in urban rather than in rural environments, a study of the geographical distribution of cases by histological type is indicated. Metropolitan-nonmetropolitan comparisons by type would then be made in order to see if the urban increase in lung cancer can be related to type. Secondly, it would be necessary to determine whether there are areas where certain histologic types may be endemic. In making these studies, observations would have to represent a period of many years, by residence exposure years, in order to ascertain geographical trends of histological types in different time periods. (1) Review and identification of microscopic file at the Armetl Forces Institute of Pathology

slides of lung cancer tissw on

Case histories and slides of all lung cancer cases011 file from 1930 to date would be studied. Residence history would be constructed, and supplemented where necessary, through cooperative arrangement with the Veterans Administration and with other military sources. The slides for each case would be reviewed by one pathologist. in order to obtain uniformity of diagnosis.

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(a) Tabulation to compare incidence for all cases under study, by histological type, over a period of 20 years or more, by age at death, sex, race, and country of birth. (b) Tabulation to establish the geographical distribution by State or geographical region, of histological types, according to age at death, sex, race, country of birth, and residence exposure pears. ( Set I-A-3b ( 1) (a ) for sources for obtaining residence history data.) (c) Tabulation to compare histological types according to metropolitan and nomnetropolitan residence, by 5-year periods, and by residence exposure years.

(2) Review and identification of microscopic slicks of lung cancer tissue of cases occurring in areas having certain topographical or i~wteorological characteristics condrtcke to the accnmdfftion rind Ijcrsiste-ncc of ritmosplteric pollzitiott owr a period of ntnq years The purpose of this project is to determine which histological types are endemic in this type of locality and their relationship to any increase in lung cancer. Microscopic slides of lung cancer cases in Los Angeles, California would be utilized. Previously, necropsy data for 508 cases of lung cancer occurring among a total of 6,074 malignant tumor casesat the Los Angeles County Hospital for the period of 1918-1947 were studied by Dr. Paul E. Steiner of the University of Chicago School of Medicine, according to various characteristics, exclusive of histological type. For the proposed project described here, arrangements would be made with a pathologist in California for the reexamination and classification of the 508 cases by histological type, and by residence exposure years for the individual cases concerned. Similar examination would be made of the lung cancer caseswhich will have come to autopsy between 1947 and 1957, and comparisons made, by histological type, by lo-year periods from 1918 to 1957. (a) Tabulation to compare hm g cancer cases by histological type, by loyear periods from 1918 to 1957, according to age at death. sex. race, country of birth, and residence exposure years.

(3) Rerjiezc and identification of microscopic slides of lung cancer tissue of in CLState in which a difference in metropolitan-nonmetropolitan cnncer has been estcct7lislted for females clnd for males

cctses occurring r&es for lung

The sex distinction permits an evaluation of the influence of occupation as compared with the possibility of atmospheric pollution as a factor. All the lung cancer cases which occurred during a selected period of years could be established on a State-wide basis for both males and females, and residence histories constructed. as described in I-A-3b( 1) (a). The microscopic sections would be obtained from the hospitals or physicians who diagnosed the lung cancer cases, and then submitted to the pathologist conducting the review of casesfor the project at the Armed Forces Institute of Pathology (See I-A-6b( 1) ). (a) Tabulation according to histological types, by residence exposure years, by metropolitan and nonmetropolitan afeas, by sex, race, and country of birth.

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(4) Review and identification of microsco& slides of lung cancert&sue of cases represented in the cancer morbidity studies conducted by the Public Health Service in ten metropolitan areas Cases of respiratory cancer existing among males and females in these ten areas were determined through various sources, including hospitals, physicians. and clinics. These studies were conducted in 1938 and 1948, with respect to cases existing in those years. Identification of the lung cancer casesby name and address, as well as the medical and hospital records are available for locating the histological sections for the 1948 cases, but not for those of 1938. However, the study is to be repeated in 1958, and a comparative study of the histological sections can then be made for the two time periods-1948 and 1958. Supplementary residence history data would have to be obtained for the cases which were reported in 1948, and residence data for the 1958 cases would be made a part of the study planned for that year. It would also be advisable to record the individual’s Social Security number, in case it becomes necessary to conduct subsequent analyses related to previous employment, (a) Tabulation to determine comparative trends in the histological types of lung cancer for each of the ten metropolitan areas, for the two time periods, by sex, age, race, and residence exposure years. As the opportunity arises to utilize other biological findings, such as biochemical or toxicological determinations, they can be studied in the same manner as described for histological types of lung cancer (I-A-6b). B. Community

Air Pollution

and the Medically

Impaired

General statement On the assumption that those suffering from various types of illness or disease may be more sensiti1.e to harmful environmental factors than those not so affected, it is advisable to examine causes of death and life expectancy among such groups in order to detect whether in fact they differ from the rest of the population. If those having various types of illness or disease are grouped from the standpoint of residence for long periods of time in areas of different types and degrees of air pollution, it will then be possible by comparisons of these groups to see if any differences occur which may be directly referable to the geographical areas concerned. Further refined study can then be conducted to determine whether there are any specific factors in the area which may be of significance. If a relationship with community air pollution should eventually be established, this would yield two significant results. First, it would provide the means for instructing groups having a specific illness or disease as to precautionary measures for minimizing their exposure to the sources of irritation, as well as a guide for physicians. Second, it would provide leads to the organs or systems which should be the subject of further epidemiological studies. An important factor in the whole problem of the relationship of commmlity air pollution to health is that while single, momentary physiological changes may exhibit significant temporary functional effects, the cumulative effect of such changes re-

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peated over a long period of time is not yet identifiable. Since our only alternative at present is to see whether epidemiological methods can help identify sensitive tools any cumulative effects, it is necessary to search for potentially such as may be provided by a study of the medically impaired.

Projects to De under&ken: Mortality, life expectancy, and morbidity among the medically impaired, by residence exposure years a. The medically impaired, among life insurance policyhoklcrs, irrespecticc of impairment. Studies of mortality and life cxpcctancy among insured persons I-R-1.

who had certain medical impairments when admitted to insurance coverage have been prepared by life insurance companies. The Society of Actuaries has conducted two medical impairment studies ( 1929 and 1951), which may be adapted to the objectives discussed above in the “General Statement” for section I-R. For this project, cohort groups would be established from among the total number of persons in selected States, counties, or census tracts, who entered insurance coverage with any medical impairment included in the 1951 study regardless of type of impairment. These cohorts of the Society of Actuaries, would consist of individuals having the same characteristics with respect to age, sex, race, and year of entrance into insurance coverage, and by years of residence. Tabulations would be prepared to permit analysis for any differences in mortality patterns and life expectancy which may exist between similar cohorts in different areas. Residence exposure may be determined as described under the study of cohorts of ordinary life insurance policyholders [ I-A-3b ( 2 ) ( a ) 1.

11. The medically impaired, among life insurance policyholders, by specific impairments. In the “Impairment Study, 1951,” (Society of Actuaries) 625,000 persons with specific medical impairments, to whom policies were issued at standard and substandard rates, between 1935 and 1949, were traced to polic) anniversary in 1950. It is suggested that this insured study group be classified according to residence history so that mortality determinations may be made according to residence exposure years in metropolitan and nonmetropolitan areas. This longitudinal study, in essence, will provide the comparison of resident cohorts with the same characteristics and medical impairments entering insurance coverage as of a specific year, in different metropolitan and nomnetropolitan areas, in order to detect differences geographically in life expectancy and causes of death as well as age at death, by specific cause. Residence exposure may be determined as described under the study of cohorts of ordinary life insurance policyholders [I-A-31) (2) (a) 1.

(1) Chronic

bronchitis

as the specific impairment

III this project, those who had a history of chronic bronchitis when they cntered insurance coverage would be followed for an adequate number of years, in order to observe mortality and life expectancy patterns, geographically. The

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Society of Actuaries study of 1951 covered those who became insured between 1935 and 1949, inclusive. The period of observation for this group has been increased by the additional interval between I949 and the present. It is estimated that, in this way, a total of approximately 10,000 cases of bronchitis among the insured will have been observed, on whom residence history and mortalit! and life expectancy data will have been obtained. These data can then be sorted and rated by residence exposure in the various metropolitan and nonmetropolitan areas, in order to detect area differences. It would be desirable at some time in the future if a study could be made of females having this specific impairment, in order to offset as much as possible any occupational factors more commonly associated with the male segment of a study group. Should this initial project on chronic bronchitis demonstrate that further application is justified, then other specific diseases such as heart disease and asthma can be similarly studied. c. The medically impaired, among populations of selected areas, by specific impairments. For the projects detailed below, identified groups would be established in the same manner as described in project I-A-5a, and representing persons having specific diseases who have been exposed for varying periods of years (e.g., 2, 4, 6, 8, 10, etc.) to subacute or chronic conditions of atmospheric pollution in selected areas. These identified groups of disease-affected residents, made up preferably of women, housewives, and children can be classified by resident exposure years and by age distribution, and can be studied as follows: (1) To determine any aggravation or change in the preexisting disease. (8) To determine the relationship of types of symptom complaints to residence exposure years. What types of symptoms occur for each disease group as residence exposure years increase? Do people become adjusted to atmospheric pollution, or is the reverse true? (3) To compare those having a specific preexisting disease and who have lived a given number of years in the area under study, with those not having any disease but who have lived the same number of years in the area. d. The totully disabled, by type of disability. The totally disabled represent another study group for whom observations may be made analagous to those proposed for medically impaired groups who are not disabled (I-B-la and 1,). For this purpose, totally disabled veterans, particularly those who have been disabled because of diseasesof the trachea and bronchi, and those disabled because of diseasesof the heart, constitute an especially acceptable study group. The most suitable segment of the veteran population on which to base the study would be the group of white veterans of 1liorld War I who were alive. totally disabled, and receiving compensation on January 1, 1947. This group is now entering the years of moderately high mortality rates and should most rapidly reflect in excessive mortality the effect of influences deleterious to health. There are four ad\Tantages of selecting men who are being compensated through the ‘i’eterans Administration, namely: The influence of occupational factors is diminished; it would he possible to construct their residence histor)

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at least from the time of initiation of the disability; some totally disabled men, depending on the nature of the disability, may be expected to be more sensitive than men generally; and finally, since the medical diagnoses and care received by veterans are comparable. regardless of location complete and commensurable medical records would be available throughout the period of observation, until death. Each regional office of the Veterans Administration maintains a so-called Running Award file on punch cards, which is an index to all persons receiving compensation or pension through that office. From this file, together with the Terminated Award file, it is possible to construct, geographically, a roster of persons totally disabled, for any desired set of causes, as of any date since establishment of these files. For this project, cohort groups would be established of veterans totally disabled because of diseases of the trachea and bronchi; and also those totally disabled because of diseases of the heart. Furthermore, these cohorts would consist of individuals having the same characteristics with respect to age, SW race, initial year of compensation for total disability, and residence exposure years, by metropolitan areas. Tabulations would be prepared to permit analysis for any differences in mortality patterns and life expectancy which may exist between similar cohorts in different metropolitan areas. This study is predicated on cooperative assistance from the Veterans Administration and the National Research Council. The Veterans Administration would furnish the basic records, and the facilities of the Council would bc used with respect to their program of medical follow-up studies of veterans. I-B-2.

Populations

preciously

affected

by atmospheric

pollution

a. Military occupation personnel in Yokohama. Occupation troops in the L. S. Army stationed in Yokohama in recent years have experienced asthmatic attacks which have been associated with atmospheric pollution of unidentified etiology. Initial epidemiological and clinical observations indicate this phenomenon has occurred among the native residents for many years. Army medical research has demonstrated that filtered air will relieve and prevent the syndrome and that reexposure to unfiltered air in the area concerned will precipitate asthmatic attacks. At least 300 medically diagnosed cases of environmental asthma have been officially recognized among the occupation troops in Yokohama. The number of cases among military personnel which have not come to the attention of the medical staff, as well as the prevalence of this asthmatic syndrome among the native residents, have not been established. This endemic problem warrants study, not only because of the military implications, but also because of the opportunity to determine whether atmospheric pollution can actually produce asthma or aggravate a preexisting disease (asthma) when the persons affected return to the urban areas of the Iinited States. The following projects are proposed, to be conducted in cooperation with the Department of Defense, the Veterans Administration, and the National Research Council:

120 (I) Rosters of personnel stationed in Yokohama during certain periods of years would be established, inclusive of their medical records. Medical contact would be maintained with those who return to the United States, and observations recorded of medical care provided. Determinations could then be made as to whether there has been any aggravation of the asthma. This could be correlated with determinations of biological and chemical composition of the atmosphere in the areas of residence to which the individuals returned. (2) In addition to certain investigations already conducted by Army medical research groups, further research is indicated in order to obtain epidemiological data and information concerning the physical, chemical, and microbiological spectrum of the atmosphere in Yokohoma. Since there is a seasonal trend, concentrated efforts are required to discover the specific etiological agents involved. Such a restudy of the Yokohama area may be required by a combined research team representing all the agencies and interests concerned: Department of Defense, Public Health Service, Veterans Administration, and National Research Council. b. Donora, Pennsylvania. This study is concerned with those who were affected by the acute episode of atmospheric pollution which occurred in Donora, Pennsylvania in October, 1948. The Public Health Service comprehensive study of the Donora population at the time of the acute episode revealed that 42.7% of the population, or 5,910 persons, were affected and that 20 deaths occurred. The etiology of the causes of death or the illnesses which occurred were not determined. Now that 7 years have elapsed, and since all of the rosters and medical records needed for such a study are available, an epidemiological follow-up of those affected would seem warranted. The purpose of the study would be a determination of what has happened to the approximately 6,000 persons who became ill during the episode. This would include observations relative to the development of subsequent disease or disability; any effect on those with preexisting disease, such as heart disease or asthma, and changes in mortality patterns or life expectancy. For this study, cooperative arrangements could be made with the Graduate School of Public Health, University of Pittsburgh. C. Resources

for the Conduct

of Epidemiological

Studies

In connection with the epidemiological phases of the air pollution medical studies, and the surveys which will have to be conducted, the question arises as to the availability of qualified and interested persons who would be willing to undertake given assignments in the different geographical areas concerned. The operations necessarily would involve a considerable volume of field investigations; the biostatistical preparation and analyses of various assemblies of data; and any number of special survey activities. It appears that the number of persons available in the field of epidemiology who could provide the necessary technical direction, planning, and evaluation for these operations is limited. It is possible that the Schools of Public Health, Schools of Medicine, and the State health departments might provide the mechanism for conducting these studies. In addition, as an important concomitant of

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this approach, these studies could be utilized as project material for the establishment of training programs within the schools and health departments. These training programs would provide for the development of qualified personand field interviewers needed nel such as epidemiologists, biostatisticians, in the epidemiological studies of air pollution. It is recognized that the epidemiological sections of the Schools of Public Health and Schools of Medicine historically have concerned themselves with acute communicable diseases and that faculty additions and redirection of objectives toward the field of noncommunicable or chronic diseases would be required. However, the national interest in air pollution and the increasing research needs generated by the Federal legislation providing for air pollution research and assistance, require that thcsc training centers be established to relieve the scarcity of technical personnel, Furthermore, it may prove ndvantageous to establish a center for the coordination and planning of these epidemiological studies in order to avoid duplication of effort and to provide the resources for the creation and development of more effective methods for the conduct of these studies. II.

STUDIES

OF

BIOLOGICAL

EFFECTS

These studies are concerned with the biological (e.g., physiological, toxicological, pathological. psychological) effects of air pollution on the individual, as differentiated from epidemiological studies of patterns of effects among groups of individuals. Gerleral Statement In order to determine whether there are specific effects resulting from exposure to atmospheric pollutants, either as the cause of a particular disease, or in the aggravation of existing diseases, or as a cause of death, more sensitive and definitive methods of detecting biological change than are presently available are required. This need is further enhanced by the fact that existing methods are inadequate to determine whether there are cumulative effects resulting from long-term exposure of humans or animals to low concentrations of specific chemicals or groups of chemicals. There is little or no knowledge of what tissues. organs, or systems of the body are being affected, if at all, either by single chemicals or by the possible synergism of two or more chemicals. The principal objective is to detect any biological differences which may occur in humans or animals exposed to pollutants over a number of resident years as compared with similar groups not so exposed. To date ( 1955), toxicological experiments with animals exposed to atmospheric pollutants have yielded little or no significant results. In the search for possible methods for definitive measurement of effects? consideration has been given to the adaptation to this problem of various test media such as tissue culture, chick embryo, enzymes, microorganisms, or other one-celled organisms of the Protista group. Another consideration in the evaluation of medical effects which may be due

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to atmospheric pollution has to do with the changes in virulence and viabilit) which may occur among airborne microorganisms when subjected to different types and degrees of air pollution. In addition, the role of the air as a mode of transmission of disease to humans, animals, and plants has a direct bearing on the epidemiology of disease and requires extensive exploration. Related to this is the need to identify and establish the composition of airborne organisms in different areas of the country and under different environments. This information in turn may be correlated with concurrent studies of the other constituents of atmospheric pollution. The question as to whether there is any relationship between atmospheric pollutants and lung cancer is of major importance. This is emphasized by the marked increase in lung cancer in urban areas. Investigations to identify any carcinogenic chemicals that may exist among atmospheric pollutants in any geographical area represent a fundamental approach to the evaluation of this question. The epidemiological studies previously outlined will serve as one basis of evaluation, and the animal studies will serve to identify any atmospheric pollutants which may be carcinogenic. Another consideration is to determine the extent and type of relationship which may exist between atmospheric pollutants and the eye. Symptoms of smarting and tearing of the eye have been noted in persons exposed to polIution in certain areas. However, pathological or biochemical changes have not yet been identified. It is evident that more sensitive techniques of study are required. A. Atmospheric

Pollutants

and Tissue Culture

General Statement Tissue culture offers promise as a sensitive instrument for determination of the biological effects of atmospheric pollutants. In tests with intact animals various intervening factors, such as detoxification by the liver, and masking influences of other organs, make it difficult to detect subtle changes. The application of chemicals directly to the cells, as a basic toxicological screening step, avoids these complications and, it is hoped, will provide some indication of more sensitive organ function tests which should be developed for the purpose of detecting effects of the chemicals on humans and animals. Furthermore, the procedure makes it possible to carry out a series of experiments in a relatively short period of time. Since replicated cultures can easily be prepared, some of the samples in the series of cultures undergoing exposure can be sacrificed without affecting the entire series. Also, tissue cultures can be exposed to gases at a determined rate, thus permitting observations of the effect of different concentrations, as well as immediate and delayed effects. Certain chemicals, such as peroxides, which are highly explosive and dangerous if their use is attempted in the usual animal toxicological experiments, could be handled satisfactorily in tissue culture exposure. Another factor of importance is the recent development of a chemically defined culture medium in which cell proliferation occurs and which opens the way for adapting it to the culture

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of cell types in addition to those presently cultured. This chemically defined medium can also be used for the detection of chemical changes which ma) may occur as a result of experimental exposure of pollutants to the tissue culture. The series of projects to be undertaken have as their basic objective the development of highly refined observations on the biological effects of atmospheric pollutants on tissue cultures of established cell strains and of fresh11 removed tissue (primary explants). It is proposed that the studies be conducted by several investigators, each of whom would carry out some phase of an overall plan to be developed and coordinated by an advisory group. For example, each investigator, using the same chemical, would work on a different pure strain or explant culture. This would permit an assembly of observations on the effects of one specific chemical on cultures of different types of tissue. This procedure then would be repeated for other single chemicals, and finally, for combinations of chemicals. Similarly, observations can be made on samples of polluted air exposed to tissue cultures. Simultaneously, the supernatant fluid of exposed tissue cultures would be analyzed biochemically in order to detect any change which possibly may serve as an index of biological effect. The coordination of these tissue culture studies conducted by different investigators is an important factor to be considered. It is suggested that an advisory group be constituted to develop the overall plan of approach, designation of the individual research projects to be undertaken, and final correlation and evaluation.

Projects to be undertaken: II-A-l.

Atmospheric

pollutants

and pure strain tissue culture

There are several pure strains of tissue derived from laboratory animals, each originating from a single tissue cell, which have been established for many years and are readily applicable to the projects to be undertaken. For example, tissue culture from mouse liver has been maintained for 5 years or longer, and connective tissue of the mouse maintained in culture for 15 years. These cells can be readily prepared in qualitatively and quantitively rephcated cultures. Since all the cells grown under the conditions of tissue culture and grown for an extended period of time have ultimately and spontaneously assumed certain malignant characteristics, these low-grade malignant cells would appear to represent tremendously sensitive agents for toxiocological testing. These pure-strain tissue cultures can be carried for any length of time and various concentrations of atmospheric pollutants can be used on them. The culture vessel can be arranged so that a continuous flow of a fised concentration of any gas (except nitrogen) can be kept rumling through it and examination can be carried on visually, photographically or micro-cinematoLgraphically. The tissue cultures can be grown in practically any amount that is desired. In this project it is necessary to establish certain “normal” levels of activit! and then to determine such morphological and physiological changes as ma) occur \\rhen the tissue cultures are exposed to atmospheric pollutants at differ-

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ent controlled concentrations. The cells could be fixed in a special fixative, and by enumerating the total number of nuclei in an aliquot of the culture, any increase or decrease in the population level of the culture can be determined. In order to detect the mechanism by which the culture population is being altered, the comparison micro-cinematograph at the National Cancer Institute, which has three optical systems electrically synchronized, would be utilized. A controlled replicated culture would be run under one optical system; and the other two optical systems would be used to examine two experimentally exposed cultures. Since each optical system makes a 35mm film recording, the three records can be examined by projection. It is possible then, through the use of the comparison micro-cinematograph, to take a record of about I50 cells simultaneously on a single frame with an optical resolution which would enable the investigator to pick up every mitosis undergone by those cells. On a SO-foot length of film, which can be analyzed rapidly, the investigator would obtain the analysis of changes which occurred within an interval of 8 hours, in the nuclei population in the 150 cells. This can be followed every 8 hours. In this manner, mitoses and cell necrosis would be detected, and the mechanism of alteration could be studied. The biochemical analyses of the supernatant fluid of the tissue culture would be carried out for each of the controlled exposure experiments in which different concentrations of the atmospheric pollutants were used. Observations would be made of any chemical changes which occur in the medium, and any subsequent effects when the cultures are fed certain nutrient agents. The experiments described apply to the use of certain cell strains from laboratory animals. This work would be extended to include the development of human cell strains from different organs and structures such as trachea, bronchus, lung, thyroid, adrenal, skin, cornea; and their use in exposure experiments such as those described above.

In addition to pure strain tissue culture, tissues freshly removed from either animals or humans can be explanted to culture, studied, and followed, relying on such indices as the rate of migration of the cells, the rate of proliferation, and the necrosis of the cells, upon exposure of the culture to pollutants. It is recognized that with most of the materials freshly removed from the body, they will bring along with them nutrient or humoral substances from the body itself. In that sense, they will reflect something of the behavior of the cells as they are at equilibrium with the body. It would be necessary to be very careful to see that the tissues were freshly removed at entirely comparable times. One of the limitations of this approach is that the cells in tissue culture might not show exactly the same responses as if they were within the body. The cells could be studied in the living condition or in fixed and strained preparations, and photographic or cinematographic records can be used. Consideration should be given to the question of whether freezing techniques should be employed, in order to minimize postmortem cell changes.

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a. Study atmospheric

of priuury

c. Study community

of primary atmospheric

POLLUTION

explants

IN

from

HELATIOK

animals

TO

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esperimentally

exposed

to .sitigle

Primary explants would be taken from living and from sacrificed animals who have been experimentally exposed to various known concentrations of a single atmospheric pollutant, and determinations would be made of any changes in cultures of these primary explants, in relation to the concentrations and time periods of exposure. Methods of study would be similar, where applicable, to those described in II-A-l. These experiments may be varied by using animals who have been placed in an atmosphere of subnormal concentrations of oxygen for a period of time and then exposing them to known concentrations of specific atmospheric pollutants. Similarly, tests could be made on the tissue cultures of explants from animals fed vitamin-deficient diets. As a corollary approach concomitant studies would be made on antibody formation of the animals. b. Study of primary explants from humans exposed to single occupational air pollutants. Primary explants from humans who have been exposed to single occupational air pollutants for various periods of time provide a natural source of “exposed” tissue for use in studying the effect of selected chemicals on various organs. Should this new toxicological knowledge be realized concerning the effects of long-term occupational exposure to specific chemicals, it would then be possible to derive meaningful interpretations concerning the effects of the same chemicals when dispersed as community atmospheric pollutants. Methods of study would be similar, where applicable, to those described in 11-A-l. The explants would be prepared from biopsies of living and postmortem tissue. As a corollary approach concomitant studies would be made on antibody formation of those under observation. pollutants.

explants pollution.

from

humans

nncl

animals

exposed

to actual

Primary explants of humans and animals who had been exposed to atmospheric pollutants for a number of residence years would also provide a ready-made source of “exposed” tissue for study. Since we are interested in determining the Ion,<-term cumulative effects on humans, we are particularlv interested in the tissues and organs of persons and animals who have lived for many years in an area exposed to atmospheric pollutants. In other Lvords, \ve wish to relate observations on these tissues or organs to residence exposure years.

Primary explants taken immediately after death of the various organs could be compared with nonexposed or normal tissues. The purpose of these experiments would be to detect whether any difference exists between tissue explants previousI>- exposed to atmospheric pollutants and those not exposed. Should a difference be detected the experiments could be repeated, decreasing the number of resident years of exposure of the human or animal from which the esplant was taken and in that mamler determine the least number of years in \vhich the change will occur.

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Study of explants in blood serum

Consideration should be given to the testing of primary explants by growth in blood serum obtained from humans exposed for many years to a specific chemical air pollutant, as compared with explants grown in serum from nonexposed persons. Any differences in the growth potential of the two types of culture would be evaluated to determine whether there had been a change in the composition of the blood of exposed persons which may have been brought about by long-term exposure to atmospheric pollutants, Should such a change be determined, it may be the reflection of a change in some organ of the body.

B. Atmospheric The purpose used as a more as to provide that the series group.

Pollzctants and Chick Embryo of these studies is to determine whether chick embyros may be sensitive toxicological screening device for air pollutants as well some indication of potential biological effects. It is suggested of research projects in this area be coordinated by an advisory

Projects to be ~4ndertnken: 11-B-l. Exposure of normal chick embryos to specific atr pollutants In this project, the pattern of experiments conducted by Ridgway and Karnofsky,3 in which metals were utilized as exposure test substances, would be continued and explored further with specific air pollutants. The validity of this approach has been established through the observations which have been made on some 54 elements in various forms when injected into the chick embryos at 4 and 8 days of development. In those studies it was found that abnormalities in embryonic development were produced by thallium, chromium, lead, cobalt, boron, arsenic, rhodium, barium, and selenium. In the proposed experiments, air pollutants, singly or in combination, from different metropolitan or geographical areas, would be utilized together with the necessary antibiotics to enable the conduct of such exposure experiments. II-B-S. Exposure

of vitamin-deficient specific air pollutants

and otherwise impaired

chick embryo

to

The same type of experiments as described in II-B-1 would be carried out, except that the chick embryos used would be impaired by induced vitamin deficiencies. This may provide a more sensitive means of obtaining biological response following exposure to atmospheric pollutants.

C. Atmospheric

Pollzctants c4nd Enqmes

This group of studies is intended to investigate any effects which air pollutants may have on the enzymes of the body. It is recognized that this may involve a restudy of most of the biochemistry in animals who have been exposed to 3R~~~~~~~, LOIS P. AND KARNOFSSY, DAVID Embryo: Toxicity and Production of Ahnormalities York Acclrlem!/ of Sciewes, 55, 20:3, Article 2.

A.

“The Effects in Development.”

of

Metals on the Chick Ann~k

of Z’hc

New

AIR

pollutants. However, and it is suggested an advisory group.

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it is believed that this research area cannot be ignored, that the research activities concerned he coordinated by

Projects to be undertaken: II-C-l.

Exposure of enzymes to atmospheric

pollutants

This project is similar to II-A-l in that, in place of pure strain tissue cultures, experiments would be carried out to expose enzymes to controlled concentrations of single air pollutants. The purpose of such experiments would be to explore the possibility of using enzymes as a toxicoIogica1 screening device, as well as for a measure of response to specific air pollutants in low concentrations. It is recognized that if any changes are observed they may provide strong leads to further effort and to the possible development of organ function tests. 11-C-2. Enzyme studies on animals

exposed to atmospheric

pollutants

In this project animals would be exposed to experimentally controlled concentrations of single atmospheric pollutants, as in project II-A-2a. a. Effect of pollutants on enzymes. In place of tissue cultures, enzyme studies would be made to determine whether any changes occur when the animals are exposed to different concentrations of the air pollutants, and for different time periods. b. Efect of pollutants on the enzyme formation response to enzyme-eliciting substances. In this project, enzyme-eliciting substances would be fed to the animals, and observations would be made of the effect of the pollutant on the abiIity of the anima1 to form the enzyme. For example, tryptophane could be used to see whether there is any interference with the formation of the enzyme, tryptophanase, and therefore with the enzyme system involved. II-C-S.

Enzyme studies of humans exposed to occupational

pollutants

This project would be similar to 11-A-21), but in place of observations on tissue culture, studies of enzymes would be undertaken to determine any changes which may occur following exposure to certain occupational pollutants. The detection of any biochemical changes in this series of experiments would assist in the development of organ tests in humans. 11-C-4. Efect

of air pollutants

on lichens

Observations have been made in England on the effect of air pollution on lichens. It is proposed therefore that these plants be studied, particularly for the effects on their enzyme systems when the plants are exposed to specific air pollutants. D. Atmospheric

General

Pollutants

and Microorganisms

Statement

The role of microorganisms as a fundamental avenue of research in air pollution may be considered from two standpoints: First, the air as a mode of

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transmission and as an alterant of microorganisms; and second, the utilization of air-pollutant effects on organisms as a mechanism for toxicological screening. A significant segment of the proposals outlined in this section stems from discussions with representatives of the Georgia Institute of Technology. Studies made at the Institute, and elsewhere, show in a limited way, that atmospheric conditions may affect the behavior of airborne organisms. Certain factors have been uncovered which affect the vialibity or behavior of certain bacteria. Temperature and humidity conditions, and certain gaseous pollutants frequently found in the atmospheres of many cities have been found to exert these effects. Studies have also shown that the composition of the atmosphere can affect the ability of airborne organisms to propagate when they are transported to various surfaces. Certain other studies justify the hypothesis that the chemical composition of a microorganism may be affected by exogenous chemicals, by physical environmental factors, or by radioactive influences, resulting in alteration of the viability and virulence of the organism. Australian scientists recently have demonstrated that certain influenza viruses have a central chemical “heart,” and that different strains of the virus have different chemical composition. This has led to the belief that a slight rearrangement in the chemical structure of the virus could markedly enhance its virulence. Other investigators have found in experiments on plants that replacement of a constituent part of a virus by a closely related synthetic compound, interferes with the ability of the virus to reproduce. Similarly, it has been observed that virus diseases in plants may be kept from spreading from one generation to another by an inhibiting chemical present inside the plant seeds. Chemical analyses have shown the inhibiting chemicals to be protein in nature. Still other investigators have shown that when radioactive chemicals are exposed to the tubercle bacillus they have been shown to be taken up and found in the bacillary lipids. Certain clinical observations also demonstrate changes in microorganisms and their evolution, as a result of exposure to various chemotherapeutic agents. For example, it has been observed that the administration of antibiotics may suppress the normal intestinal flora, and micrococci which are not sensitive to the drug may multiply and become predominant, with resultant enteritis and colitis. Also, there are evolutionary changes in microorganisms such as the emergence of penicillin-resistant strains. These resistant strains have been shown to be mutants which may gain ascendancy and continue an infection. Often the emerging organism is found to be far more virulent than the one which originally caused the infection, Another illustration is the emergence of sulfonamide-resistant strains of Group A beta hemolytic streptococci in certain military camps where sulfonamides were being given to all personnel. This is significant in view of the fact that there are relatively few sulfonamide-resistant strains of this group of organisms. We do not know whether the increasing population density and changes in the aerial environment are establishing conditions for the advent of new epidemics in which air is the chief carrier. To explore adequately the potentialities of the air as a mode of transmission of organisms harmful to humans, animals, and plants, a survey of the micro-

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biological population of the air and a central coordinating group on research in this field would be required. The other related research objective previously mentioned has to do with the application of any findings of chemical alterations in microorganisms to the of atmospheric pollution; as development of microorganisms as “indicators” well as their use as a more sensitive means of toxicological screening of air pollutants. Projects II-D-l.

to be undertaken: The establishment of a coordi?zating group for studies of airborne microorganisms and their relation to atmospheric pollution and disease transmission.

It is essential that there be a central group charged with the responsibility of coordinating, on a national basis, studies relating to airborne microorganisms, and serving as a central clearing house for the collection and dissemination of information and research on this subject, Such a group would also be concerned with the development of methods and techniques for the conduct of experimental and field studies. The group would work in cooperation with all governmental and nongovernmental research groups interested in microorganisms and air pollution, e.g., university research centers; Communicable Disease Center of the Public Health Service; Biological Laboratories, U. S. Army Chemical Corps, Camp Detrick, Maryland; U. S. Army Chemical Corps Medical Laboratories at Army Chemical Center, Maryland; the Weather Bureau, Department Institute of Allergy and Infectious Diseases of the National of Agriculture, Institutes of Health Public Health Service; and the air pollution research and technical assistance program of the Public Health Service. It is recommended that this coordinating group be established at the Georgia Institute of Technology, Atlanta, Georgia, because of the basic research already carried out at that institution on aerosols and microorganisms. In addition, there is the advantage of cooperative scientific effort with the Communicable Disease Center of the Public Health Service, which has a governmental responsibilit). in this field and is also located in Atlanta. The Georgia Institute of Technology has carried out research toward the development of a satisfactory method for the evaluation of airborne bacteria. The following are s’ome of their activities which are basic to future research in this field: Evaluation of the variables involved in the operation of chambers for bacterial aerosols; a study of the variables involved in the dissemination of bacterial aerosols; a method for the estimation of the concentrations of chemical vapors in the air under the conditions of study; a thermal precipitator for aerosol sampling has been devised; and a technique for the evaluation of aerial bacteritides has been developed. II-D-2

The establishment of a national network of microbiological air sampling to determine the geographical distribution and identification of airborne organisms, inclusive of fungi, bacteria, viruses, and pollens

In order to relate laboratory research studies on airborne organisms to actual atmospheric conditions, a national network of microbiological and related ail

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sampling is necessary in order to determine the geographical distribution and identification of airborne organisms, The standardized air sampling techniques developed by the Georgia Institute of Technology for the collection, enumeration, and identification of airborne organisms could be utilized. Differences in antigenic response would be used in the identification of different viruses in different areas. Simultaneously, samples of the atmospheric pollutants present and prevailing meteorological characteristics would be obtained for correlation studies. These data would establish basic relationships of airborne organisms to the chemical composition, concentration, and particle size of air pollutants, in given physical environments, and under given meteorological conditions. In addition, this air sampling would identify geographical areas according to their degree of exposure to pathogenic airborne organisms. This sampling program is proposed as a possible collaborative effort of the Communicable Disease Center, Public Health Service; the Robert A. Taft Sanitary Engineering Center, Public Health Service; and the U. S. Weather Bureau. The sampling would be conducted over a number of years, in all seasons, in different areas, and at different atmospheric strata. This would include specific environments having a relatively isolated industrial plant which is engaged in the manufacture of a specific item, and from which the by-products liberated into the air are relatively few in number and are identifiable. A series of such single-operation areas would be sampled in order to provide an assembly of data which may permit analysis of the relationship of airborne organisms to any one of a number of specific atmospheric pollutants. This gradually would be extended from a single-industry environment to areas of multiple industrial activity. In addition to microbiological and related sampling of the extramural environment, studies would be conducted under the limited environmental conditions peculiar to places of public congregation and to more highly restricted locations such as hospitals, schools, and penal institutions. This would permit differentiation between natural environmental effects and those of the quasi-artiwhether ficial environment produced by man. It is essential to determine extramural air, under given circumstances, can be a general carrier for diseasecausing organisms or whether only intramural air in crowded areas can effectively act as such a carrier. Sampling would also be conducted in farm or other areas inhabited by animals or poultry, as well as in areas where plant disease is prevalent, to determine the role of the air as a carrier of organisms responsible for various animal, poultry, or plant disease, and the possibility of human infection by such transmission. 11-D-3. Survey

of the literature

pertinent

to the studies

of aerobacteriology

A complete survey of the literature pertinent to the studies of aerobacteriology and the effects of aerial environment would be carried out. This would include all data on the transmission of microorganisms and their ability to cause diseases in humans, animals, and plants. Material thus assembled would be

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classified uilder appropriate titles, abstracted, lished, and made readily available. 11-D-A. Physical and chemical microorganisms

TO

and indexed.

effecfs on the viability

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and virulence

be pub-

of airborne

a. It is proposed that studies concerned with the effects of temperature, relative humidity, and chemicals on airborne microorganisms, employing the techniques and test equipment such as have been developed at the Georgia lnstitute of Technology, be continued. hmong other considerations, it is known that significant amounts of protein exist in the air. It is necessary to determine, for example, whether the protein component of bacteria may be affected by other proteins, or by metal-protein complexes formed from the metals and the proteins in the air. b. It is proposed that a cooperative research project be undertaken with the Melbourne Institute of Medical Research, Australia, to conduct some of the experiments referred to previously. This research group delineated the chemical structure of the influenza virus and advanced the theory that alteration of the structure would alter the virulence of the virus strain. It is appropriate that work be undertaken to determine what atmospheric conditions, physical and chemical, may precipitate or generate such changes. Since the research activity and the facilities involved have been already established at the Melbourne Institute, it would be more practical and economical to endeavor to arrange for the additional phase of research to be included with their other studies. c. Inferacfion of air pollutants and microorganisms in the body. It has been observed that the inhalation of certain chemicals has been associated with the stimulation of arrested tuberculosis into an active infection, and has also induced pneumonitis. As another interesting observation, British investigators have noted a change in the usual color of the sputum of bronchitic persons who have been exposed to atmospheric pollutants. The question arises as to whether infectious processes resulting from the inhalation of chemicals, for example during occupational exposure, are due to some action of the chemical upon microorganisms in the body, or to the direct action of the chemical on the cells. Studies could be conducted with animals and with tissue cultures to determine whether various inhaled substances exert either a synergistic or an inhibiting effect in the development of infection. Should it be determined that the mechanism at play in the body is in the nature of an interaction between chemicals and microorganisms, this would he followed by a study to see whether a similar interaction takes place in the atmosphere. II-D-S.

The use of microorganism.p for the fosicological screenirq pheric pollutants

of

atnlos-

a. Effects of chemicals OIEmicroorganisms. Reference has been made to the essentially negative results of attempts to determine the toxicological effects of low concentrations of chemicals by means of the usual animal experiments. Proposed research studies with tissue culture, enzymes, and chick embryo have

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been described which would endeavor to develop more sensitive means of measurement of the effects of atmospheric pollutants. It is proposed that a series of studies be undertaken to explore the possibility of using microorganisms as another instrument for accomplishing these objectives, The studies could be directed toward a determination of the bacteria which respond to controlled exposures of specific chemicals in certain concentrations. Response could be measured in terms of viability, ability to reproduce, color changes, or other factors. The ultimate purpose would be to establish with bacteria the counterpart of the minimum lethal dose (MLD) associated with animal experiments. The studies could then be extended to determine the effects of graduated concentrations of various specific chemicals and, subsequently. combinations of chemicals. b. Determination of atmospheric pollution by the use of “indicator” microorganisms. Studies should be conducted in the development of a simplified procedure for the estimation of the amount and type of polhrtion present in a given location, through the use of “indicator” microorganisms. Such an indicator would be the counterpart of the I?. coli and oxygen demand criteria used in determining the extent of water pollution. c. Relationship of microorganisms to known chemical carcinogens. This rcsearch may be carried out in collaboration with British investigators. Attempts are being made in England to determine whether bacterial growth has any effect on benzpyrene. This carcinogen has been identified as an atmospheric pollutant. If there is any interaction between it and bacteria, this would have important implications with respect to the occurrence of cancer in sites such as the respiratory system and the large intestine, where there are abundant bacterial flora. E. Atmospheric Polllltants ancl Lung Cancer Epidemiological studies related to atmospheric pollutants and lung cancer are represented, in whole or in part, in projects I-A-1. 2, 4, 5, 6. Projects to be considered here primarily are concerned with the laboratory or toxicological appoach to the problem of lung cancer and atmospheric pollutants. The purpose of such projects would be to expose animals to atmospheric pollutants to determine whether any of the pollutants are carcinogenic and particularly whether any can produce lung cancer. Since some experiments already conducted have elicited pulmonary cancer in animals exposed to the exhaust fumes of automobiles, there is urgent need for further extension of these experiments and exploration of other air pollutants. Similarly, benzpyrene, a known carcinogenic agent, has been identified among the air pollutants in England, and raises the question of the extent of its presence and carcinogenic action in our country, It is proposed that in these series of studies, animal experiments would be carried out in different metropolitan areas and regions, in order to study the carcinogenic characteristics of the pollutants of those areas. Substances which are common to all areas would also be tested. It is suggested that an advisory group assist in the coordination of these research projects.

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and the Eye

The purpose of these projects is to determine whether there are any biological effects on the optical system following acute or long-term exposure to atmospheric pollutants. It is suggested that the projects be coordinated through an advisory group. Projects 11-F-l.

to be undertaken: Changes

in cornea1 epithelium

a. Animals would be experimentally exposed to controlled concentrations of single air pollutants over various time periods, and studies would be made of histological sections of the cornea1 epithelium. Chemical analysis of the cornea1 epithelium can be made in order to determine the absorption of any of the environmental chemicals by the epithelium. b. Clinical observations would be made of humans through the use of slitlamp microscopy. The scrapings from the epithelial lining of eyes would be examined by electron microscopy. In order to determine whether any changes which occur follow a geographical pattern, histological sections of eyes obtained in eye banks could be used for comparative study. Such studies on humans can be carried out initially in areas which have had long-term exposure to atmospheric pollutants of specific type or composition. In the examination of humans it is essential that the observations recorded be related to the residence exposure years of the individual studied. 11-F-2. Changes

in conjunctival

epitheliwn

Animals experimentally exposed, and selected human populations identified by residence exposure years, as described in II-F-l, would be observed in this series of studies. It has been shown that conjunctival epithelium may change under the influence of chemical irritants, and that the number of mucous cells may increase and their appearance may be altered. Epithelial cells from the conjunctiva could be studied by tissue culture methods also, using both human and animal cells. 11-F-3. Chemical

study

of tears

Animals experimentally exposed, and selected human populations, identified by residence exposure years, as described in II-F-l, would also be observed in this series of studies. The purpose of this project would be to determine whether any chemical changes occur in tears when animals or humans have been exposed to specific chemicals or air pollutants for certain time periods. Correlation studies therefore would be carried out to determine the relationship between air pollutants and any chemical changes in tears. Attention would also bc given to possible enyzme ( lysozyme ) effects in the eye. ADDENDUM The anthers understand that since the preparation research on air pollution, some of these projects have already initiated. There is, however, a striking parallel plan in 1955 and the present time.

in 1955 of this first national plan for been completed and possibly others are between the nerd for a national research