GLENN R. HILST

Vice President

The Travelers Research Center, Inc.

Hartford, Conn.

In introducing the topic of this session, "Applying Our Monitoring and Measuring Know-How,” I should like to take a few minutes to set in perspective the problem of applying that know-how to the solution, or at least the partial solution, of our air pollution problems. To do so, let me offer a somewhat irreverent paraphrase and near-inversion of the Biblical injunction for practical brotherly love, namely, "Cast thy wastes into the atmosphere and they will probably show up in unexpected places and in unexpected forms." And we may add, somewhat parenthetically, "and cause unexpected results."

The key word here is "unexpected,” implying as it does our lack of complete knowledge of the complex system of sources, atmosphere, and receptors which comprise this problem of air pollution. If we knew the space and time dependence of all sources of air pollutants, the atmospheric transport and diffusion of these materials, and their interaction with each other or other indigenous materials, then we would have no need for measurements and monitoring of air pollution levels. They would be precisely predictable and, supposedly, controllable to tolerance levels.

We do not have this knowledge now; pollutants do show up in unexpected forms and places and produce inexplicable results. And yet, if we are to maintain a reasonable degree of control of air quality, it is essential that we have basic information as to what the forms and levels of air pollution are and what they have been. Why? Because without this information we are totally in the dark in assessing the magnitude and form of our air pollution problems and we cannot even begin to grapple with the problem of what must be done to keep pollution levels within tolerance limits. Inciden

tally, these measurements are just as necessary and useful in determining that we do not have a pollution problem as they are in showing that we do.

For some pollutants, such as malodorous gases, eye irritants, and visibility-reducing suspensions, the human senses are effective qualitative measuring devices and, along with human physical and psychological responses, quickly tell us if an air pollution problem exists. There are other pollutants which defy detection by human senses and call for instrumental measurements. Perhaps the best known of these are ionizing radioactive materials. In either case, we generally try to achieve an objective, quantitative measure of pollution levels so that we can attach numbers to this problem. Implicit in this approach is the underlying assumption that the air pollution problem is a deterministic one, susceptible to quantitative cause-and-effect relationships in part and in toto. On the basis of what we know now, I will venture the opinion that this is true; that is, for given source and atmospheric conditions there is only one distribution of pollutants, although this applies only to fairly long periods of averaging, say for 24 hours or more. For shorter periods of averaging we may, in fact, be dealing with a probabilistic problem, in that a whole range of pollution distributions is permissible for a given set of conditions.

I introduce this thought because it has an important bearing on how we design our pollution sampling or measuring system, a problem I hope will receive some attention here this afternoon. However, regardless of this point, measurements of air pollution levels are fundamental to the definition of our air pollution problems today and to any program designed to control air pollution levels. They are both fundamental and, at least

for now and the immediate future, the only source of the information we need, the alternative understanding of the pollution system being denied us.

Recognizing this basic requirement for air pollution measurements, a whole host of questions regarding the amount and use of this information remain to be answered. To what degree of completeness must we determine the time and space variability of air pollution levels in an urban area? Is one measurement site sufficient for control purposes? If not, how many are required? Recognizing the large variability of pollution levels due to the diurnal cycles of sources and to atmospheric dispersion properties, how frequently must we sample the air to properly define pollution levels? What materials should we measure? How well can we measure them? To what extent should air pollution measurements be designed to assist in clarifying the roles of pollution sources and atmospheric dispersion in the pollution system? Who should have responsibility for making these measurements? For their evaluation and interpretation? How can these measurements be best used to develop and enforce control measures on air pollution levels?

It is to these and similar questions that we address ourselves this afternoon. They are not simple questions and definitive answers may not be forth

coming. However, while our ignorance is large, our knowledge is sizable also, and it is to be expected that useful and valuable guides to the use of measuring and monitoring know-how in the control of air pollution today can and will emerge. It is implicit in the title and subject matter of this Conference that we can do useful and practical things to control air pollution now and in the near future. It is necessary and desirable for us to recognize also the things we cannot do, and continue to reduce the number of those things by effective research and development. But in the meantime, we need not wring our hands in despair.

In summary, continuing measurements of levels for various air pollutants are essential to the definition of the magnitude of our air pollution problems and to the effectiveness of our control procedures. The information derived from these measurements, taken in conjunction with knowledge of the effects of these pollutants and their sources or genesis, provides us with incomplete but useful tools for maintaining tolerable levels of air pollution concentrations now.

It is with real pleasure that I now call upon our distinguished speakers and discussants to develop this topic of applying our measuring and monitoring know-how to clearing the air.

AUGUST T. ROSSANO, JR.

Visiting Professor of Environmental Health Engineering California Institute of Technology Pasadena, Calif.

I. INTRODUCTION

In step with the rapid expansion of population and industrial activity in the United States, there has been a concomitant increase in the volume and complexity of community waste products-solid, liquid, and gaseous. The gaseous wastes pose a special problem since they cannot conveniently be stored for subsequent disposal under more favorable conditions, as in the case of some liquid and solid wastes. Gaseous effluents in general must be released at their point of origin as fast as they are generated.

The atmosphere, because of its immense volume and ubiquitous nature, is a logical medium for the disposal of airborne waste products. Paradoxical as it may seem, however, the capacity of the atmosphere for this purpose is not unlimited. Within recent years many communities have frequently witnessed the phenomenon in which the rate of pollutant emissions exceeded the ability of the air to dilute and disperse the pollutants. The result has been intense atmospheric pollution with all of its attendant undesirable and, in severe cases, lethal effects.

There are certain communities such as Los Angeles where, because of its population density and industrial activity as well as meteorological and topographic factors, the dilution capacity of the atmosphere is exceeded quite regularly throughout the year. When these conditions prevail, the concentrations of air contaminants become high enough to cause annoyance to the senses, economic damage, and actual or suspected injury to health.

A logical objective of an air pollution control pro

gram is the attainment and maintenance of an atmospheric environment of sufficient purity to prevent discomfort, inconvenience, illness, and hazards to personal safety and possessions. Perhaps a more realistic goal would be the guarantee of air quality such as to promote better health and well-being of persons, animals, and vegetation. This implies a condition of air cleanliness in which concentrations of significant pollutants are kept below those levels at which adverse effects can occur.

Quite obviously then, a basic need in air conservation is a program for the measurement and identification of air pollutants. Fundamentally, the problem of air pollution represents the interactions of three variables, namely, a source of emissions, the atmosphere which acts either to dilute or concentrate airborne concentrations, and sensitive receptors animal, vegetable, or mineral. A rational program of abatement must be based on a thorough knowledge of the nature and interrelationship of these three factors. A complete air measurement and monitoring program must include provisions for the systematic collection and analysis of data on the type, number, and strength of polluting sources; the influence of the meteorological and topographic variables; levels of air contaminants; and the type and magnitude of measurable effects on man and his environment.

II. AIR POLLUTANTS, EFFECTS, AND METHODS OF MEASUREMENT

The basic question arises, what pollutants should be measured? Virtually any solid, liquid, or gaseous substance which is not a component of normal

Pollutants

Methods of measurement

2. Suspended particulates:

A. Nonspecific.....

B. Toxic dust, fumes, and mists:
Lead, fluorides, sulfuric acid.
C. Pollen and biological agents.

3. Dustfall....

4. Visible smoke.

5. Odors....

6. Photochemical pollution: Hydrocarbons, oxides of nitrogen, ozone and other oxidants, aldehydes, aerosols,

etc.

7. Radioactive gases and aerosols.

health effects.

Dust nuisances.

Health effects. Soiling nuisance.

Nuisance....

Gas scrubbers, indicator tubes, automatic analyzers, test specimen (plants, materials, and treated papers).

Filter papers; inertial, thermal, and electrostatic precipitators; test specimen.

Jars, trays, adhesive films. Ringelmann chart, transmissometer.

Human observer panels.

Gas chromatography, flame ionization, spectrophotometers, rubber strips, human observer panels, test plants.

Same as for items 1 and 2 above, and radiometric instruments and techniques.

air is a potential pollutant. Thus the list of candidates is almost inexhaustible. Over the years, however, research and experience have uncovered many specific substances which are of hygienic importance. Doubtless, continued progress in air pollution research and investigations will yield many more pollutants of significance. The contaminants and effects to be measured depend upon the nature of a particular problem. Each air monitoring program must be geared to the needs and resources of the individual community.

Table 1 represents an attempt to list some of the more commonly occurring pollutants of recognized importance. Also included in this table is a listing of the more obvious potential effects from exposure to the selected pollutants. The last column indicates some of the methods generally employed for atmospheric sampling, analysis, and measurement.

The table is intended merely as a guide, since details of specific methods of sampling, analysis, and measurement are beyond the scope of this paper. For additional information the reader is referred to the many excellent reports by Federal, State, and local air pollution agencies; professional societies; and private and university research laboratories. The two-volume treatise entitled "Air Pollution" recently published by the Academic Press contains. many valuable technical details on methods and techniques.

III. OBJECTIVES OF AIR POLLUTION MEASUREMENTS

As previously indicated, a program of air pollution measurements and monitoring is basic to the conservation of our air resources. Objectives of air measurements fall into two broad categories. The first of these can be termed surveillance. A. Surveillance

A program of surveillance can serve a number of very useful purposes. Continuous air monitoring data help to establish short-term patterns of air pollution concentrations, diurnal or seasonal, as well as long-range trends. Information of this type is also useful in evaluating the efficacy of control measures in existing air pollution abatement programs, and in the prediction and prevention of large-scale air pollution disasters.

1. Monitoring Networks

Constant surveillance is the key to a successful pollution abatement program, both from the standpoint of day-to-day control operations and from that of air pollution disaster prevention. Within the past 7 years several air monitoring networks have been established at the local, State, and National levels.

Local

The Los Angeles County network consists of 14 stations, each of which collects and reports information on as many as 6 key contaminants and such effects as eye irritation and plant damage (1). Six of these stations continuously monitor four contaminants as required by the disaster prevention program. Many other cities likewise operate local networks.

Statewide

On a statewide basis, Montana is operating a network of seven air monitoring stations in an attempt to determine the cause of high lung cancer rates in counties where there are many smelters and wood-waste burners.

New Jersey operates 35 monitoring stations gathering data on the soiling properties of the atmosphere, in order to categorize communities on the basis of air cleanliness.

Other States operating sampling networks include California, Maryland, Massachusetts, New York, Texas, and Washington.

Nationwide

(a) National Air Sampling Network.-By far the best known and most comprehensive air monitoring program is that of the National Air Sampling Network conducted by the U.S. Public Health Service (2). It had its modest beginning in 1953, and today includes 250 representative urban and nonurban sampling stations operating on the basis of every year or every other This is a voluntary year. cooperative program in which the communities contribute the manpower needed to operate the samples, while the U.S. Public Health Service provides the sampling equipment and supplies, performs the analyses, reduces the data, and publishes the results. There are two phases to the National Networkthe sampling and analysis of suspended particulate matter, and the measurement of gaseous pollutants. The main objectives of the NASN are to determine in general the extent and nature of air pollution in the United States, to study the trends in concentrations of selected pollutants in the air, and to investigate the interrelationship beween air pollution and local factors such as topography and meteorology, population density, and the industrial complex. Network data are also useful in epidemiological studies, selection of sites for new facilities, and planning and zoning.

The particulate sampling equipment consists of a high-volume blower drawing about 45 cubic feet of ambient air per minute through an 8- by 10-inch filter paper made of fine glass fibers. The efficiency of this material is extremely high for particles as fine as one-seventy-five thousandths of an inch. A 24-hour sample is obtained every other week on a random time basis. Collected samples are mailed to the Public Health Service Robert A. Taft Center in Cincinnati where they are subjected to a thorough analysis.

The determinations made on the samples include total weight of particulate matter, organic fraction, beta radioactivity, nitrates and sulfates, and as many as 23 metals such as antimony, bismuth, cadmium, vanadium, zinc, and others. The detailed results and findings of the National Air Sampling Network are contained in two voluminous reports, one published in 1958 and the other released just before this conference (3, 4), as well as other publications (5).

About 2 years ago the scope of this network was increased to include measurements of gaseous pollutants. About 45 of the network stations collect gaseous samples along with particulate samples. Currently being monitored on an experimental basis are sulfur dioxide and nitrogen dioxide by means of specially designed sampling kits consisting of plastic bubblers connected through critical orifices and membrane filters to a pump (6).

(b) Continuous Air Monitoring Program-To supplement the NASN operations, about 1 year ago the Public Health Service, in cooperation with State and local agencies, initiated a program of continuous gas monitoring in six of the largest metropolitan areas in the United States (7). Included in this program are stations locally operated in three other cities. By means of sensitive automatic instruments, the air is monitored on a continuous round-the-clock basis for six gaseous pollutants. Each automatic gas analyzer makes a continuous record of the pollutant concentrations on a strip chart. In addition, the same information is punched out on a digital tape readout, each entry representing the average concentration over a 5minute period.

The punched tapes and other records are sent to the Taft Center, where the data are processed by means of an electronic computer which yields statistical summaries of pollutant levels. These data, along with weather observations, will supply valuable information on air pollution patterns and