14,000, and 17 persons died. Those present in the town during the period remarked on the heaviness of the fog, and on the intensity of the familiar odor of sulfur dioxide coming in large part from a local zinc roasting plant. Autopsies were performed on five of the dead; a common finding was acute irritative changes of the lungs.

In London, in December of 1952, the weather produced a pea soup fog and for a period of four days stilled the atmosphere to bring about an accumulation of pollutants. A few months later, when mortality statistics were reviewed, it was discovered that the city had experienced 4,000 excess deaths in a 7 day period which started with the first of the fog.

There have been other recorded episodes and some probably unrecorded. As recently as 1963, during a fifteen day period of acute air pollution in New York City, the average number of deaths exceeded the average number for corresponding periods in other years by 647. The combination of air pollution, cold weather, and influenza has been cited as the cause of the New York episode. I would like to point out here, Mr. Chairman, that we have today no foolproof scheme by which we can predict the potential for an air pollution episode and on the basis of such prediction take timely action to prevent an episode. Virtually all our metropolitan areas and a great many industrial towns have the potential for an air pollution episode. They have the sources of pollution, and they experience to some extent the meteorological stagnations that cause pollutants to accumulate. The degree to which we can predict an air pollution episode depends not only upon our assessment of what will be discharged to the atmosphere some hours or days hence, but also upon the accuracy and reliability with which we can predict the weather at that time. Although the art of forecasting weather conditions conducive to the buildup of pollutants has been slowly but surely developing, this art has hardly been brought to the point where we can entrust it with our health and welfare.

At the present time meteorologists from the Environmental Sciences Service Administration of the Department of Commerce, on assignment to the Division of Air Pollution, forecast air pollution potential advisories daily. The areas covered by the individual advisories are at least 75,000 square miles, which is roughly the size of Oklahoma; and the lines defining the advisory areas are roughly 100 miles wide. The micro-climatic conditions prevailing in any partic ular communty depend upon a great many factors additional to those which produce these large scale anticyclones. While our Department, Mr. Chairman, has encouraged the States and local governments to use these air pollution advisories as one of the precautionary steps that can be taken to prevent mass tragedy, we consider this weather advisory activity only as supplementary to the control of air pollution.

Of even greater concern to us than the episodes of high levels of air pollution and their immediate effects are the effects on human health of long term exposures to low levels of air pollution, levels that routinely occur in virtually all of our metropolitan areas and in countless industrial towns throughout the United States. I would like to clear up any possible confusion on this matter of the health effects of chronic exposures to ordinary levels of air pollution. We are still accustomed to thinking that a disease state is brought about by a single cause a carryover from public health history when almost total emphasis was placed on the bacterial or viral agent that had to be present before a particular communicable disease could be diagnosed. This postulate has served us well and continues to serve us well. However, the idea that one agent is wholly responsible for any one disease state cannot provide the solutions we need today in dealing with the increasing incidence of chronic disease. There is a considerable body of evidence which makes it unmistakably clear that air pollution is associated with chronic respiratory disease. Various studies have shown that death rates from cardiorespiratory causes correlate in general with air pollution levels. Other studies have shown that asthma attacks have correlated with variations in sulfate pollution and with the incomplete burning of refuse. One study demonstrated that persons living in a town where air pollution is high displayed significant differences in average airway resistance when compared with persons living in a town where pollution levels were lower. The result of laboratory studies involving exposure of animals, and in some cases humans, to controlled concentrations of ozone and sulfur dioxide agree generally with the results of these epidemiological studies. One significant investigation resulted in the development of lung cancer in laboratory animals infected with influenza virus

and later exposed to inhalation of an artificial smog of ozonized gasoline. These are but a few highlights of investigations that have been carried on and which indicate conclusively that air pollution is associated with the important chronic respiratory diseases of lung cancer, emphysema, chronic bronchitis, and asthma. But this is not to say that air pollution is the cause or the agent which brings on any one or all of these diseases. There may be several agents. Chronic bronchitis, for example, which has been established in Great Britain as a specific disease entity, develops over a long period of time and may become crippling through a combination of many factors-air pollution, smoking, repeated bouts with infectious agents, occupational exposures-all affected, perhaps, by hereditary predisposition. The point is, Mr. Chairman, whether we call air pollution one of sveral causes or name it as a contributing factor, the evidence is abundantly clear that air pollution is a hazard to health.

As Undersecretary Cohen has pointed out, there are many cogent reasons why we must control air pollution. But by far the most compelling reason, the principal reason why the American public and its representatives have demanded that we restore the atmosphere, is that air pollution contributes to illness and death.

Just as our perception of the nature of the air pollution problem has changed drastically in the past few decades, so has the problem changed, and so has our ability to deal with it changed. In 1955 when the Federal air pollution program was initiated, there was little exact knowledge of the kinds and quantities of pollutants in the air, or of the mechanisms by which they accumulate or are dispersed. The National Air Sampling Network and the Continuous Air Monitoring Program, both operated by this Department have since gathered extensive data on the amounts and chemical composition of particulates in the air, and the concentrations of such gaseous pollutants as nitrogen dioxide, nitric oxide, carbon monoxide, oxidants, total hydrocarbons, and sulfur dioxide. Advances in meteorology have enabled us to gage the atmosphere's total mixing or absorptive capacity over a particular geographic region, and thus to estimate the degree of air pollution control needed for a given area.

The technological means of controlling the sources of air pollution have also been rapidly developed in the past several years. Particulate pollutants can be removed by devices which employ principles of filtration, electrostatic precipitation, or centrifugal force. Gaseous pollutants can be taken out through liquid scrubbing, vapor recovery, combustion, and solid absorption. Open burning once widely employed to dispose of a city's trash and to get rid of leaves, upholstery in scraped automobiles, battery cases, tires, etc., can and has been in some cases replaced by processes which do not pollute the atmosphere. Smoke pollution from domestic, commercial and industrial incinerators, boilers, and heating systems can be largely eliminated through improved fuel burning equipment and proper firing practices. Carbon monoxide and unburned hydrocarbons discharged from the gasoline powered motor vehicles have been brought under partial control. In fact, through control devices or through process modification most sources of air pollution in the United States today can be brought under control.

It seems to me, then, Mr. Chairman, that we have two fundamental realities to face concerning the problem of air pollution in the United States today. First of all, air pollution is today a major problem in this country. It not only costs the country billions of dollars each year in agricultural losses, transportation delays, and material and structural damage, it contributes in a very real way for most Americans to the incidence of disease and the premature occurrence of death. Further, all the major trends of growth in our society-increasing population, increasing urbanization, increasing industrialization, increasing use of fuels, increasing use of motor vehicles-all project a severely worsening air pollution problem in the near future. The 1965 population of 195 million is expected to swell to 250 million in 1980. A larger percentage of this larger population will be living on roughly the same land area presently occupied by our current urban population. The gross national product, probably the best indicator of our overall economic activity and therefore the best indicator of the demands on our environment, is expected to climb from the 1965 level of $650 billion to $1010 billion in 1980. Last year's fleet of 85 million motor vehicles is expected to climb to 120 million in 1980. And our present discharge to the atmosphere of the United States of roughly 24 million tons of sulfur dioxide will, if present trends continue, soar to almost double that amount, or 43.6 million tons by 1980.

The other reality we must face, Mr. Chairman, is that in spite of the fact that we presently have the technology for controlling most sources of air pollution, we are not by any means applying that technology in adequate measure. The Clean Air Act and its amendments have stimulated an unprecedented expansion in the efforts to control air pollution in this country. Totally, including both Federal and non-Federal contributions, the funds available for State and local air pollution control programs have increased by about 65 percent since the adoption of the Act in 1963. On an annual basis, some $20 million is now being invested in State and local programs as compared with $12.7 million in 1963. As a direct result of Federal grants, efforts are now being made which, if successful, will bring a total of 70 new air pollution control programs into being. In addition, 40 existing agencies are improving their programs as a result of Federal grants. The Federal Government has initiated interstate abatement actions that will ultimately benefit millions of people; we have published standards which will bring all new automobiles under partial control commencing with the 1968 model year; we have stepped up our research efforts and have progressed toward the control of gaseous pollutants that once were clearly beyond our reach. In all parts of the country the public is demanding better control efforts at all levels of government, and there is no question that these demands will accelerate. But we have a very long way to go. Although 33 States now have air pollution programs, many of them have neither the authority nor the resources needed to carry on effective control activities. Only a half dozen State agencies engage in more than a nominal degree of abatement activity, and by far the great majority of States are not even serving those communities which are too small to operate their own local programs but are nonetheless affected by serious air pollution problems. For the most part, efforts at the local level are equally deficient. Our most recent estimate indicates that only 58 percent of the urban population of the United States is served by local air pollution programs. On a per capita basis, annual spending for local programs has increased from a median figure of 10.8 cents to 15.2 cents. This increase is hardly adequate in the light of estimates that an effective control program for a middle-sized city requires an expenditure of at least 40 cents per capita.

Mr. Chairman, I have presented this, perhaps long, introduction on the problem of air pollution because I want to strip away any possible misconceptions of what our basic needs are in coming to grips with the problem. The problem of air pollution has grown so enormously in such a relatively short period of time that we have found ourselves rather suddenly confronted with, if you will, an enormous aid pollution gap. Let there be no mistake about it, that gap fundamentally is the application of controls to the sources of air pollution. The activities carried out under the Clean Air Act have stimulated all levels of government, industry, and the public to exert greater efforts in bridging that gap. But we have barely started. The problem of air pollution continues to grow faster than the combined Federal, State, and local efforts to deal with it. President Johnson summed it up in his February message to the Congress on Preserving Our Natural Heritage:

"The Clean Air Act of 1963 and its 1965 Amendments have given us new tools to help attack the pollution that fouls the air we breathe. We have begun to counter air pollution by increasing the tempo of effort at all levels of government. . . . I am heartened by the progress we are making. But I am mindful that we have only begun our work."

We recognize, Mr. Chairman, that the Federal Government must assume leadership in this field, but the Federal Government cannot alone do the job. State and local government and industry must assume additional responsibilities in controlling air pollution, and the public must be more fully informed of the very real hazards associated with air pollution. The pressure of public opinion must be brought to bear against the indiscriminate discharge of pollution into what is unmistakably in the public domain, the atmosphere. In short, Mr. Chairman, the course is clear. We must now and in the immediate years ahead greatly accelerate our efforts to control the sources of air pollution. We have very real social and economic incentives, we have the governmental framework throngh which we can get at the problem, and we have the technology with which we can in large measure bring the problem under control.

None of this is to say that we can afford to be complacent about the presently available technology for controlling air pollution. There are some pollutants, like the nitrogen oxides, which today, rarely, if ever reach what are thought to

be harmful levels in many regions of the country. We do not have adequate technology for controlling nitrogen oxides.

There are some pollutants, like the sulfur oxides, which today almost constantly reach harmful levels in most of our metropolitan areas, and the increasing use of sulfur bearing fuels for energy and other purposes will undoubtedly aggravate this problem in the years ahead. We have reached the prototype stage in one approach to controlling the sulfur oxides, but for the most part we can control sulfur pollution today only by using low sulfur fuels. There are some sources of pollution, like the automobile, whose emissions we can today partially control, and the Federally required national application of this control to new cars in the fall of next year will be a significant step in halting pollution from the motor vehicle. But the rapidly increasing number of automobiles will in the next two decades wipe out the gain from today's partial controls. Further, Mr. Chairman, we can not be complacent about the attractiveness of much of the technology for controlling air pollution. Pollution controls generally do not increase the efficiency of industrial production or improve the quality of the product. In fact, since in our marketplace the focus is on minimizing costs and maximizing returns, present day pollution controls, which add to costs and not to returns, are frequently considered an impediment by those who operate the sources of pollution. We can expect that this attitude will prevail as long as regulation of pollution varies from place to place, or until the technology of pollution control is developed to the point where control is not considered to be an economic impediment by industry.

I would like in the remainder of my statement, Mr. Chairman, to review in some detail the current adequacy of technology for controlling air pollution, and to describe the efforts the Federal Government is making to advance this technology.

MOTOR VEHICLES

Certainly one of the major sources of air pollution in this country is the gasoline powered motor vehicle. Today's motor vehicle discharges four significant pollutants to the atmosphere: carbon monoxide, which is a toxic gas; hydrocarbons, which in the presence of sunlight react with nitrogen oxides to form photochemical smog, which in turn has been widely observed in its damage to plants and its irritating effects on the eyes; the nitrogen oxides, which not only contribute to smog but which in high enough concentrations are hazardous themselves; and lead, which is receiving increasing attention by the Public Health Service of this Department and others because of the possibility that, even in very low concentrations in the environment, lead may have adverse effects on certain segments of the population.

Thee are four sources of emission in conventional motor vehicles: the tailpipe, which is the most important source of hydrocarbons and the only significant source of nitrogen oxides, carbon monoxide, and lead; the crankcase, which receives unburned hydrocarbons blown by the engine pistons and which until recent years vented to the atmosphere through a tube; and the gas tank and carburetor, both of which permit hydrocarbons to evaporate to the atmosphere. Under the 1965 Amendments to the Clear Air Act Secretary Gardner has issued emission standards for all new gasoline-powered automobiles and light trucks sold in the United States commencing with model year 1968. These standards require 100 percent control of crankcase emission, and limit the concentrations of hydrocarbons and carbon monoxide that can be discharged from the tailpipe. The standards apply for the life of the vehicle, which is defined as 100,000 miles. Crankcase blow-by can be burned by returning it to the engine intake system. This practice is not new to European car makers and has been used for years in America on certain special-purpose vehicles. There are variations in design: some return the blow-by to the dirty side of the air cleaner, others to the clean side, and still others to the intake manifold through a variable-orifice metering valve. A further variation, now required in California, consists of dual return paths of blow-by gases-to both the intake manifold and the air cleaner.

The principal approach to controlling tailpipe emissions is through engine modification. In meeting the Federal standards on tailpipe emissions, all but one of the country's car makers is expected to us what has been termed manifold air oxidation. Air is introduced under pressure to the exhaust manifold near each exhaust valve. This additional air at this high temperature location oxides some of the unburned exhaust hydrocarbons and some carbon monoxide. The system is accompanied by minor changes in carburetion.

The other type of engine modification system is achieved by a combination of the following changes:

(1) Leaner carburetor calibration under idle and road load conditions. The leaner fuel-air mixture promotes more complete combustion.

(2) Slightly earlier choke release.

Since time is reduced during which a rich fuel mixture is fed to an engine, the amount of unburned hydrocarbon exhausted is reduced.

(3) Increased closed-throttle air flow. This provides a leaner mixture while idling.

(4) Retarded ignition at idle. This provides more complete combustion of the leaner idle mixture and minimizes the effect of increased air flow on idle speed.

The control valve senses (5) A vacuum advance control valve. Retarded ignition timing produces increased hydrocarbon emission during deceleration. the higher manifold vacuum associated with deceleration and advances the timing to normal.

None of these engine modifications decreases the emissions of oxides of nitrogen. Some may even increase them. Complete combustion of the hydrocarbons produces higher combustion temperatures; and the higher the combustion temperature, the greater the oxidation of the nitrogen in the combustion air. This Department is currently carrying on intensive research on the control of nitrogen oxides, and we expect that development of controls will progress so that nitrogen oxide emission standards can be established for 1970 model year vehicles. Two specific techniques now under study are exhaust gas recirculation and water injection, both of which reduce peak combustion temperatures.

The

Another approach to automotive pollution control is through afterburners which oxidize the products discharged from the engine exhaust. Both catalytic and direct flame afterburners were intensively developed primarily by automotive accessory manufacturers, to meet the 1959 California standards for emissions of hydrocarbons and carbon monoxide. By June 1964 three catalytic afterburners were approved for use on new cars in California and one direct flame afterburner was approved for use in both new cars and used cars. approval by the California Board of more than one afterburner for new cars triggered a requirement that the majority of 1966 model year cars sold in California meet the standards adopted in 1959. Shortly after the standards were triggered, the automobile manufacturers announced that their high volume production 1966 cars to be sold in California would meet the standards through engine modifications, and the new car market for afterburners in California was essentially destroyed for the time being.

This market situation for afterburners can be changed by any of several happenings. First, the approval by the California Board of a second afterburner for used cars would trigger the requirement for their installation on most used cars in the State. Second, the necessity of meeting more stringent exhaust standards than the present ones may cause afterburners to become more competitively attractive to the auto makers, either in addition to or instead of engine modification. Third, the prospect, in the not too distant future, of If the ultimate standards for oxides of nitrogen in the exhaust should cause a second round of development of catalysts that will remove these oxides. route to oxides of nitrogen abatement is by catalytic reduction, it becomes more attractive to build oxidation catalysts for hydrocarbon and carbon monoxide removal into the same device. Lastly, the elimination of lead from gasoline could conceivably result in an afterburner which would last the life of the car or at least that of the other components of the engine exhaust assembly. A device which has this life, and which combines an oxide of nitrogen reducer and a hydrocarbon and carbon monoxide afterburner, and which is attached to the exhaust manifold of an engine having modifications to reduce pollutant emissions, should continually provide an emission essentially free of all the principal exhaust pollutants. That would be a combination hard to beat.

Fuel modification is being studied as a means of lowering hydrocarbon emissions. However, the only regulation of fuel composition in the United States intended to abate automotive emissions is a Los Angeles requirement that no gasoline may be used which has a degree of unsaturation greater than Bromine Number 20. This limits the olefin content of gasolines; certain olefins are more active than other components in producing photochemical smog. The drawback to this regulation is that the automobile engine cracks gasolines to produce olefins even if olefins are not originally present in the fuel.