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The smoke is beginning to clear: Our capacity to lick air pollution makes for optimism about our social tools

It's another hazy day in New York as I write this; smoke is drifting out of the four smokestacks I can see from my window. It would be easy to be depressed about this further evidence of the unpleasant side of urban living. Yet I'm filled with optimism about our ability to solve this problem-to clean the air in our cities and around our factories. And from that optimism springs a conviction that the technical and social approaches we're developing to solve this problem can, in other forms, solve other problems of a complex, urbanized society.

My bright view on a hazy day comes from reading Seymour Tilson's piece about air pollution, which starts on the next page, and from surveying some of the legislative active ity in this field, particularly the Clean Air Act of 1963. Tilson's article demonstrates that the technical problems, while complex, are entirely soluble. Sure, there is much we don't understand about the photochemistry of smog formation or about the weather patterns that cause New Yorkers to inhale some of Philadelphia's exhale. But technology already exists to stop most pollution at the source, and the remaining more refractory sources--automobile exhausts are one-should yield to the research and development efforts that are being mounted in response to the new concern about the quality of our urban air.

So we possess the technical instrumentalties for cleaning our air; do we have the social instrumentalities for ensuring that we will employ them? Certainly it takes more than self-interest. Air-cleaning equipment is usually just an added cost and can return its investment only in those rare cases where the reclaimed material has value in the marketplace. One needs then new ways to encourage the installation of air-cleaning equipment and to penalize those who pollute the air.

Here again I'm optimistic, for we seem to be finding and refining such mechanisms. For example, the Clean Air Act provides for federal grants to match local expenditures for controlling air pollution. This seems an excellent way to strengthen local efforts without involving the federal government unduly. However, because pollution is a regional concern. the federal contribution is scaled up when two or more municipalities or states join in a regional pollution-abatement campaigna nice bit of social innovation.

Also in the wind is a mechanism to encourage private efforts at air cleaning by providing faster write-off for capital investment in air-cleaning equipment. That sort of tax relief is a proven mechanism for encouraging socially useful investment; it's worked for capital investment generally and it will, I'm sure, go a long way to make companies invest in air cleaning.

Of course, the companies are not completely unwilling, and that is another, more subtle social mechanism. In the last few decades there has been a growing appreciation, particularly on the part of larger companies, of corporate social responsibilities. If for no other reason than to avoid public pressure and governmental interference, company after company has done on its own what the public would have them do.

Finally there is research and development as a social mechanism. Yes, a social mechanism, for that is what it is.

First of all, by accelerating the rate of innovation, we in the technical community speed the rate at which new plant is built, the rate at which smokeless nuclear power plants supplant the fossil-fueled sort, for example. Indirectly, research means a wealthier society, a society that can more readily afford the luxury of not treating the air as a sewer.

Secondly, the engineer's approach to problems like air pollution causes at least some of the issues to be reduced to quantitative terms. We can be rational about the relative contributions of auto exhausts and factory smoke stacks to the pollution in any area when we can put numbers on those contributions. This rationality has the effect of putting a vector on all the other social mechanisms I discussed; it becomes possible to describe the problem in terms of the sources of pollution, the limits to atmospherie dilution, the limitations in measurement, etc. In place of an emotional inveighing against all but the purest air, one has a basis for putting private and public concerns onto a scale. A rough scale, for there is still much we don't understand about pollution, but a scale nonetheless.

You have to be a natural-born optimist to believe that these new and sometimes fragile mechanisms will alter the self-interested patterns that have built up across the centuries. But I am an optimist, and, ... look, the sun's shining !--Dan Cooper


by Seymour Tilson associate editor

The problem and approaches to solving it have come a long way since smoke chasing days. Recent intusions of public concern and federal money may make it a systems problem more challenging than reaching for the moon

IN BRIEF: The idea that polluted urban air is dangerous, widespread, costly, unpleasant, and perhaps unnecessary in societies afluent enough to pollute it so extensively has gained wide currency in recent years. The U. S. Clean Air Act of 1963 is the most far-reaching embodiment of this attitude; it authorized the Department of Health, Education and Welfare to spend $95 million through 1967 for a wide variety of research and control measures. This beginning promises to stimulate badly needed derelopments in many areas of meteorology. atmospheric chemistry and photochemistry, fuel chemistry, sensing and monitoring de. vices, and control devices for automobiles and industrial pollution sources. A pivotal need for a more systems oriented approach to air-pollution control is the definitive set of air-quality criteria which the Act charged HEW with developing. Innumerable technical and social difficulties stand in the way of establishing these, and of translating them into effective community control measures. It seems clear that a much larger commitment to safe, clean air will be needed to really do the job.--S. T.

such a non-pollutant as ordinary carbon dioxide, contributed by man's burning of fossil fuels, may turn out to have unwelcome effects on the climate, geology, and ecologic balance of the entire planet before the century ends.

Most immediate concern centers however on the health hazards of polluted air, and here the statistical and epidemiological portents are suitably harrowing. Over the long run. breathing polluted air may make us more susceptible to lung cancer, emphysema, bronchitis, and asthma--not to mention acute nonspecific upper respiratory diseases as well as good old-fashioned pneumonia. Over the short run, when pollutant concentrations become high enough, those with cardio-respiratory insufficiency who also happen to be very old, or even very young, are likely to stop breathing. The list of horrors could be extended in rather more exotic directions, if men were mice and responded to certain pollutants in the way that laboratory creatures do.

Documenting these health hazards—especially the ones which result from chronic longterm exposure to the characteristically exceedingly minute concentrations of pollutants-is a complex, tedious task. It's the subject of most current research in the air-pollution field. In spite of difficulties documentation is growing rapidly, but not as rapidly as the growth of pollution itself. This imbalance promises to be redressed, however, as rising public concern makes itself felt in many urbanized parts of the world. This concern crys. tallized in the U.S. two years ago when Congress passed a far-reaching Clean Air Act which authorized the Department of Health. Education, and Welfare to spend $95 million over the next few years on a broad spectrum of training, R&D, and control activities. The Act specifically focused technical attention on three major interrelated problems—motor vehicle exhausts, sulfur-containing fuels, and the development of air quality criteria. Pollution sources and the research door

Motor vehicle exhausts are the chief contributor to the air pollution syndrome that once used to be known to the rest of the world, mostly through comedians' jokes, as Los Angeles smog. It involves a variety of unpleasant pollution effects which center around the photochemistry of dilute mixtures of hydro

Researchers at General Motors are studying smog. They produce it artificially, in a chamber, by diluting automobile exhausts with air and irradiating the mixture with simulated solar ultraviolet. And they use a 5-stage filtering system to purify outside air to the levels required by their experiments. Nobody appreciates the irony of this more than those who are professionally concerned with the larger problems posed by polluted air.

Polluted air--to which auto exhausts are one contributor-is bad. they say. It's bad for people, plants, and materials. It's bad for aesthetic reasons and economic ones. It consumes ingenuity in sophisticated activities such as smog-chamber experiments, cleanroom technology, and corrosion control. It poses unsolved risks whenever your plane is delayed or makes a blind landing made neces. sary by fog. which is up to twice as prevalent in polluted urban atmospheres as it is in clean air. Pollutants have changed the weather over urban areas in other ways also, mostly unpleasant and perhaps unhealthy. And some say the accumulation in the atmosphere of even


This is an ash-soot-sulfur dioxide-sulfate complex to which industrial, electric power generating, and domestic heating exhaust streams are the chief contributors.

Hydrocarbon compounds that may number into the thousands and that include carcinogenic polycyclic members of the family—such as 3-4 benz-pyrene-nitrogen oxides, sulfur dioxide, sulfates, soot (mostly carbon), and Ay ash are not the only things present in re

Fig. 1. European moth species named Biston betularia adapted to pollution, in the Birmingham industrial district of England, by changing from dominantly light colored to dominantly dark in less than 100 years. Dark form, known appropriately as carbonaria, is safer from preying birds when it rests on soot-blackened trees; thus the gene for dark coloring has become more abundant in the population. Man's problems with polluted air are not so simple, nor so easily solved.

Fig. 2. Limestone outside facing of the National Gallery in London (below) shows typical results of accelerated weathering caused by high concentration of so, in urban air. so, is oxidized and hydrated to sulfuric acidH,80,—which attacks limestone (CaCO,) and converts it into the hydrous mineral gypsum (Caso -2H,0). This re. action helps break up original surface and gypsum's greater solubility in rain water finishes the destructive job. The same difficulties, except for the last one, are encountered indoors, as in the Arena Chapel in Padua, Italy, where "Mission of Gabriel" fresco by Giotto show's tan powdery forescenec of gypsum crystals formed by H,SO, attack on lime in the underlying plaster.

carbons and oxides of nitrogen in the air. Automobile exhausts are a prime contributor of both of these raw materials, but large power plants add a fair share of nitric oxide, and open burning of wastes as well as imperfectly designed or operated incinerators add other organic materials to the picture. The problems caused by sulfurous fuels were formerly known as London smog, but they too are more widespread than the name suggests.

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markable tonnages in the air over cities large and small. Add to these, uncomfortably high amounts of carbon monoxide from auto exhausts, and chlorides, Aluorides, and ammonia from diverse sources and you begin to get the picture. Finally toss into the pot formaldehyde and other aldehydes, acrolein, and an array of intensely oxidizing substances including deadly ozone-which are just a few of the possible products of photochemical and other reactions among various of the contaminants and the ordinary components of air-and it becomes evident that the two problem areas that I described briefly above do only limited justice to the magnitude of the problems presented by polluted urban air.

But it is the third specific dictum of the Clean Air Act—which directs the Department of Health, Education, and Welfare, through the Public Health Service, to set up nationwide air quality criteria—that may really open the door to research opportunity. More to quality control than meets the eye

At first glance the problem of setting such concentration criteria for various contaminants in air seems simple. And so does using them for control purposes. Once the limitstated as a concentration that ought not to be exceeded when either averaged or integrated over a certain length of time-is set, a series of control steps seem to follow logically.

First, inventory the volume of air available—again either averaged or integrated over a meaningful time interval—for diluting pollutants over an urban region or throughout a regional airshed. Then inventory the sources of pollutants in the region, as well as the sources of those pollutants coming from upwind regions in the airshed, in terms of kind and amount. At this stage don't overlook the possibility-a likely one—that photochemical and ordinary reactions in both local and transported pollution clouds may make more harmful products of initially innocuous substances, and vice versa. Next determine limits for the emission of each pollutant from each source, under the worst possible dispersal conditions, so that the time-averaged or integrated total of their individual contributions to the ambient air remains below allowable limits. And of course develop and enforce the use of whatever changes in processes or equipment may be necessary to keep emissions from each source within indicated limits. Finally work out techniques for monitoring air in the region for conformance to the ambient air standardsand maybe even also techniques for spotting sources of trouble when monitoring shows that ambient standards are being violated.

Getting to the moon may be easier. Little more than a moment's reflection is required to appreciate some of the difficulties that develop at each stage of this more or less "ideal" solution to modern regional air pollution prob


lems. Political and economic factors are not the least of them.

Each step also presents major problems of meteorological understanding. Not so much on a scale as small as what happens to the pollution plume from a single exhaust stack, where much is known, but on a scale that permits fuller evaluation and prediction of the wind-stagnation and thermal-inversion conditions that can inhibit the ventilation of any region. Each step in control also poses largely unsolved problems and unprobed opportunities in chemical and meteorological sensing and monitoring, in atmospheric chemistry, in telemetry, and in data handling.

Controlling air quality is, in short, a systems problem of challenging magnitude in which social, political, economic, and technical factors mingle inextricably. Controls need not-should not—wait

In many ways the situation with regard to engineering of devices and hardware, and to improving process variables, is in or can easily be put in much the best shape. While there's always room for technical improvements and lowered costs, there has long existed a formidable arsenal of scrubbers, filters, electrostatic precipitators, centrifuges, and more recently sonic agglomerators that can take most particulate matter out of industrial exhaustgas streams. And burning waste dumps and faulty incinerators are largely political problems, not technical ones. Even the more recalcitrant problems of gaseous pollutants like SO.,, nitrogen oxides, and hydrocarbons promise to yield to research efforts that are now being prodded into higher gear.

If these efforts fail to produce results, there are always alternatives available—such as

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