work where we exposed plants to sulfur dioxide and ozone together, and when this was accomplished we found considerable injury at such concentrations of the individual pollutant that would not damage these plants at all. We call it a synergistic effect. It is more than additive. It is one that helps the other. This is the situation. we are faced with, although at the experimental station we used one toxic and one other. It is a cumulative effect that we must be concerned with.

Senator SPONG. What bothers us is that there is some feeling, although I do not think it is conclusive, that some of the hardware on automobiles in California, while doing something to arrest the carbon dioxide, is increasing the nitrogen oxide. This is what the people in your line of work are very much concerned with.

Mr. HEGGESTAD. You stated the problem very well. Until this is accomplished, some control over the nitrogen oxide, we can look to increased damage because we do have enough hydrocarbons around even from plants to an extent that can participate in this reaction to produce the ozone.

Senator SPONG. Thank you.

Senator TYDINGS. Do you have any figures or any estimate on the amount of crop damage done in say, the State of Maryland last year by pollution, a general estimate-air pollution?

Mr. HEGGESTAD. There really are no figures. I would say that this one grower that we looked over had a fourth of his crops lost and he wasn't an isolated case. We saw that same year damage, in that same period, really within the year, damage in all of the tobacco producing counties. It was less, to be sure, at some places than others but it is a rather unfortunate thing in some ways that it is the better cropsthe growers who produce the better crops are the most sensitive. The ones who do the poor job, the ones with the poorer ones do not have so much.

Senator SPONG. With the tobacco industry having troubles of its own, I find it rather ironic that they are affected by air pollution.

Mr. HEGGESTAD. It is a useful indicator of air pollution and I agree with you.

Senator TYDINGS. Thank you very much, Mr. Heggestad. We appreciate your testimony before the subcommittee and your complete statement will be included in the record in its entirety at this point. (Statement referred to follows:)

STATEMENT OF HOWARD E. HEGGESTAD, PLANT PATHOLOGIST AND LEADER PLANT AIR POLLUTION LABORATORY, CROPS RESEARCH DIVISION, AGRICULTURAL RESEARCH SERVICE, U.S. DEPARTMENT OF AGRICULTURE PLANT INDUSTRY STATION, BELTSVILLE, MARYLAND

AIR POLLUTION INJURY TO AGRICULTURAL CROPS AND OTHER VEGETATION IN MARYLAND Research in 1958 by the U.S. Department of Agriculture at Beltsville, Maryland, and at the University of California, Riverside, where ozone fumigation studies were conducted by Dr. John Middleton and associates, proved for the first time that the inciting agent of tobacco weather fleck, a leaf spot disease, is high concentrations of the air pollutant ozone. Since 1954, and perhaps earlier, weather fleck in varying degrees of severity has been observed in tobacco plots at Beltsville, about 6 miles northeast of the District of Columbia line. The characteristic pattern of injury that ozone produces on tobacco and other plants can be distinguished from injury by other air pollutants and disease organisms. The lesions occur primarily on the upper leaf surface of recently mature leaves. Most of the leaf surface may be affected, and the whole leaf may

die prematurely. Visible symptoms appear about one day after injury by the gas. New lesions tend to be dark-colored and older lesions light-colored; consequently, even without instrumentation we can make some judgment as to when the air pollution injury occurred. We also know something about the level of air pollution by the severity of injury on individual leaves and the number of leaves affected on the plants.

The source of the ozone was of concern, especially in our earlier studies in 1958 and 1959. We believe that the results which were obtained continue to apply. In cooperative research with R. C. Wanta, meteorologist, we established that the source of pollution at Beltsville was in the direction of nearby Washington, D.C. The weather parameters associated with 5 high-ozone days during September and October 1958 were evaluated. The high-value days were identified by means of a Mast Ozone Recorder which produces a continuous record of oxidant primarily ozone concentration.

Our studies revealed that the surface winds during the 2-hour period preceding the peak ozone level on each of the 5 days were from a sector that included the eastern portion of the Washington metropolis south of Beltsville. The convective or mixing layer at the time of peak ozone levels at Beltsville was bounded on top by an inversion layer. Depending on the day, the depth of the convective layer from the surface to the base of the inversion was only 200 to 4700 feet. The surface wind direction was SE to SSW, varying from 3 to 9 miles/hour. There was much sunshine and no rain on any high-value day. We adopt the theory advanced by Professor A. J. Haagen-Smit of the California Institute of Technology on formation of ozone in urban air. Ozone is produced by a photochemical process; that is, action of sunlight on the waste products of fuel combustion, especially the nitrogen oxides and hydrocarbons. This is a continuous process as long as there is adequate sunlight and good supply of fuel combustion products. At night, ozone concentrations are low. nearly zero, because none is formed to replace the ozone which is removed as it reacts with vegetation and other living and non-living organic matter that it may contact.

In another study reported by Wanta, Moreland, and Heggestad in 1961, a rubber-strip network was operated around Washington, D.C., in a radius of about 15 miles from the center of the city. (Figure 1.) The degree of cracking of special rubber strips in each 24-hour period of exposure is a dependable measure of relative ozone concentration. No cracking occurs in ozone-free air. Based on measurement of ozone with a Mast Recorder and plant damage, one high-value day occurred during the period of the experiment from September 21 to October 7, 1959. Meteorological analysis revealed that there had been a consistent flow of air from the south or southwest across the metropolitan Washington area. Rubber cracking at Beltsville downwind of the city was 2.29 as compared with 1.04, 1.01, and 0.98 upwind or crosswind at Herndon and Centerville, Virginia, and Brandywine, Maryland, respectively. (Figure 1.) Values for the central office of the Weather Bureau in the District of Columbia, Silver Hill, and Upper Marlboro, Maryland, were 1.24, 1.39, and 1.34, respectively. The relatively low value, 1.24 within the District of Columbia as compared to 2.29 at Beltsville, was ascribed to possible, insufficient irradiation of the precursor materials. The degree of rubber cracking clearly indicated, however, that the highest ozone concentration was at Beltsville. On the day in question, the air was coming from the direction of the central city (S, SW) at a rate of 7 to 8 miles per hour.

Our more recent studies and observations further indicate the degree and extent of air pollution injury to vegetation in Maryland. Comparison of plant growth in carbon-filtered and unfiltered air, for example, in 1963, 1964, and 1965, revealed varying amounts of injury and growth retardation of plants in the unfiltered air but freedom from injury and much better growth in the carbonfiltered air. In one study conducted from June 22 to July 26, 1965, the weight of a tobacco variety Bel-W3 was about 93% greater in filtered than unfiltered air. Plants in the carbon-filtered air showed no injury, whereas plants in the unfiltered air chamber showed ozone fleck on most of the leaves, and in addition, the lower leaves were yellowed and dead. The latter type of injury might be ascribed to other factors, as poor nutrition and inadequate moisture; however, conditions for plant growth were the same except the filtered and unfiltered air comparisons.

There is increased prevalence of air pollution injury on plants in greenhouses and fields at Beltsville. When ozone concentrations exceed .05 part per million, plant damage on the more susceptible species usually occurs. Dr. H. A. Menser,

an associate, and I have observed injury on many plant species by ozone, and to some extent, by peroxyacetylnitrate (PAN), another pollutant in photochemical smog. PAN produces underleaf surface injury primarily. Other pollutants than ozone and PAN may cause some of the plant damage observed at Beltsville. In spring and fall, during the heating season, sulfur dioxide is believed to contribute to plant damage.

We have observed air pollution type of injury on beans, cucumber, Chinese cabbage, sugar beets, spinach, tomato, sweet corn, oats, wheat, barley, red clover, tobacco, petunia, chrysanthemum, orchid, maple, elms, and pine. We have observed damage to tobacco in about all counties of Maryland that produce the crop; that is, Prince Georges, Anne Arundel, Charles, St. Marys, and Calvert Counties. In early August 1965, there was more damaged tobacco in Maryland than in any previous time known to us. Rainfall had been favorable for rapid plant growth, and it is well known that plants of all kinds, in a rapid stage of growth with thin leaves, are most sensitive to air pollution.

In a recent inquiry, Dr. Hugh Sisler, Plant Pathologist, University of Maryland, College Park, stated that air pollution injury was so severe at times in their greenhouses that sensitive plants could not be utilized in certain virus studies. Unwanted air pollution injury on the plants could not be separated from the effects of the viruses under study. The University greenhouses are about 3 miles northeast of the District of Columbia line, compared to about 6 miles for Beltsville.

Injury to vegetation in greenhouses at Beltsville is most severe during hot, humid days in spring, summer, and fall when ventilation is required. We have not surveyed commercial greenhouses in Maryland for plant injury by air pollution, but know that petunia plants have been damaged for several years in one commercial greenhouse at Oxon Hill, which is very near the District of Columbia. In summary, we have accumulated an increasing body of evidence to indicate that agricultural crops and other vegetation in Maryland near and some distance from metropolitan Washington, D.C., are damaged by air pollution.

Figure 1-Location of stations employed in the "rubber-strip" network during September and October 1959.

Senator TYDINGS. We will now recess the hearing until tomorrow morning at 9:30.

I would like to place into the hearing record at this point a statement by Dr. Harold Silver.

(Statement referred to follows:)

STATEMENT BY DR. HAROLD SILVER ON WHAT AIR POLLUTION MEANS IN THE DISTRICT OF COLUMBIA

My name is Harold M. Silver. I am a physician who has been active in pulmonary diseases from the standpoint of research, teaching, and, most important, patient care for more than ten years. I am Associate Clinical Professor of Medicine and Director of the Pulmonary Research Laboratory at The George Washington University School of Medicine. I am a charter member of The District of Columbia Thoracic Society, and have worked closely with the District of Columbia Tuberculosis Association.

As one who takes care of patients with emphysema, bronchitis and asthma. I am deeply concerned about our air pollution, as it relates to the well being and even survival of these people. The high level of atmospheric pollution in the Washington area constitutes a potentially explosive situation to which these patients are hostage. Current levels of air pollution may well aggravate the disease which these patients have, and are probably a contributing factor to the development of chest diseases in people who are still well.

Perhaps more important and certainly more alarming is the real risk of a major air pollution disaster which could cause hundreds of deaths and hospitalizations here in this area. Such catastrophies have occurred in New York, London, and Donora, and with certain weather conditions could occur here.

This situation is particularly unhappy and frustrating because the individual doctor and patient have no control over it. It differs from the personal form of air pollution, cigarette smoking, where the physician's firm advice and the patient's resolution can control it instantly and completely. To control atmospheric air pollution, community action in this entire geographic area is required. Only through community activity can this clear and substantial danger to the public health be improved, and people be spared the possible anguish of an air pollution disaster.

There is already ample knowledge for some action. We know that most harmful substances such as sulfur dioxide result from the combustion of fuels such as happens in open burning of garbage, and the use of coal, gasoline, and fuel oil. By putting an immediate stop to open burning, and by furthering the use of energy forms which minimize air pollution, this committee could take prompt positive action. By furthering electric mass transportation and by requiring devices on automobiles which reduce their discharge of pollutants, this committee could have an important impact on the problem now.

There is, however, a need for more research as well as for immediate action. Means must be developed for purifying air in the home, in the work situation. and possibly even in the streets. Research is required to study the long term effects of air pollution on the development and progression of obstructive lung disease. I have personally done research in the field of early recognition of these diseases and similar surveys in areas of high and low air pollution could be very valuable. I have also done research on the progression of these diseases in each individual patient and similar work in areas of high and lower air pollution could well reveal the exact quantitative effect of air pollution on the natural history of these diseases.

In summary, for the sake of those with lung disease immediate action is required to prevent an air pollution disaster. There is already enough knowledge to initiate some programs immediately. There is a need for further research to develop new information so as to provide a sound basis for better programs in the future.

(Whereupon, at 12 noon, the subcommittees took a recess until 9:30 a.m., Thursday, March 9, 1967.)

PROBLEMS OF AIR POLLUTION IN THE DISTRICT OF

COLUMBIA

(Air Pollution in the District Caused by the Federal Government)

THURSDAY, MARCH 9, 1967

U.S. SENATE,

SUBCOMMITTEE ON BUSINESS AND COMMERCE,
AND SUBCOMMITTEE ON PUBLIC HEALTH,

EDUCATION, WELFARE AND SAFETY

OF THE COMMITTEE ON THE DISTRICT OF COLUMBIA,

Washington, D.C. The subcommittees met, pursuant to recess, at 9:45 a.m., in room 6226, New Senate Office Building, Senator Joseph D. Tydings presiding.

Also present: Chester H. Smith, staff director; Fred L. McIntyre, counsel, and Howard A. Abrahams, assistant counsel.

Senator TYDINGS. We will call the hearing before the Subcommittee on Business and Commerce and the Subcommittee on Public Health, Education, Welfare, and Safety of the Senate Committee on the District of Columbia to order.

These hearings are being held on air pollution in the District of Columbia and today specifically we are concerned with air pollution by Federal buildings in the District of Columbia.

Our witnesses include Mr. Joseph Flanagan, Chief, Federal Facilities Section, Abatement Program, National Center for Air Pollution Control, Department of Health, Education and Welfare; Mr. William A. Schmidt, Commissioner, Public Buildings Service, General Services Administration, accompanied by Mr. Robert T. Davis, Director of Legislation, General Services Administration; Dr. Eloise Kailin, representing the District of Columbia Medical Society, and Hon. George Stewart, Architect of the Capitol.

I would like to call on Mr. Joseph Flanagan and ask if he will come forward, with any of his assistants.

We are delighted to welcome you before this subcommittee. Senator Spong will be here. He has been held up, but I expect him shortly.