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Mr. RUCKELSHAUS. Thank you, Mr. Chairman. Is I indicated yesterlay I would like to discuss the problem of nitrogen oxides today. Accompanying me are two gentlemen with whom I would hope most of the questions would be directed are Dr. Stanley Greenfield, who is the Assistant Administrator for Research and Monitoring, and the primary science advisor within the agency to the Administrator, and Dr. John Finklea, who is the Director of the National Environmental Research Center at Research Triangle Park in North Carolina. This center is one of four National Environmental Rese:urch Centers that ure have established that deals primarily with health effects.

Both of these gentlemen have impressive backgrounds. Dr. Finklea is an M.D., Dr. Greenfield has his Ph. D. in meteorology and both of them have a long background in dealing with the health effects of various pollutants, particularly air pollutants and I think they can provide to the committee the best testimony that our agency has as to the health effects of the various pollutants that we are dealing with todav.

They do have a presentation to make with some charts indicating some additional information.

I would like to start off by making a short statement, The 1976 motor vehicle emission standard requires a 90 percent reduction in nitrogen oxide emissions calculated from an uncontrolled vehicle. The requirement of that standard is interwoven not only with the other motor vehicle control requirements of the act, but it is inextricably linked to the national ambient air quality standards. In our consideration of the 1976 nitrogen oxide standard we must not lose sight of the overall context, which includes the national ambient air quality standards.

The ambient standards are premised upon an administrative determination of fact, i.e., what are the limits of constituents of ambient air bevond which health and welfare will be impaired. On the other hand, the motor vehicle emission standards are legislatively fixed and designed as necessary steps toward the achievement of the national ambient air quality standards.

First of all, there is the question of how the health-related national air quality standard for nitrogen dioxide was derived. This standard ras set at 100 micrograms per cubic meter as an annual average, The national standard itself was based largely on the results of 1968-69 study on the occurrence of respiratory illness among school children in Chattanooga. The air quality reference measurement standard used to monitor the levels of exposure in Chattanooga has since been shown to be unreliable for general use. When this became apparent last year, we initiated

a reappraisal of the Chattanooga results using air quality data gathered by another measuring method in Chattanooga during a

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period just prior to, and somewhat overlapping, the start of the study of schoolchildren.

The nitrogen dioxide standard, therefore, is open to some question, but the uncertainties about it are all in a direction which indicates that it does adequately protect public health. We have, of course, inaugurated the necessary epidemiological, clinical, and laboratory studies to gain additional knowledge on both the long- and short-term effects so as to enable us to make a determinaton on whether any revision in the standard is warranted.

Dr. Greenfield will dwell at some greater length on just what that necessary research effort is.

Next, there is the question of the degree of nitrogen oxides control needed for attainment of the national standard. Our initial judgment on the extent to which the national air quality standard was being exceeded was based on measurements made with the same method used in the Chattanooga study. During our review of State implementation plans, State air quality control officials brought to our attention their belief that the reference method we had recommended was in error.

At that time we called this to the attention of the staff of this committee and of the House Subcommittee on Public Health and Environment and further advised those staffs of our intention to attempt to verify the reliability of the method. This was last summer.

Over the past year, therefore, we have been measuring nitrogen dioxide levels by various measurement methods at some 200 sites across the country, including sites in the 47 air quality control regions where we originally believed that the national standard was being exceeded. A full report on this study will be available very shortly.

As indicated in my testimony, February 28, 1973, on the House side, on extension of the Clean Air Act and before other groups, nitrogen oxides may not be the problem we and this committee once thought they were.

Our study shows that there are just two regions—Los Angeles and Chicago—in which nitrogen dioxide is a significant problem. It is expected that the measures to be taken to deal with the photochemical oxidant problem in Los Angeles, will also solve the nitrogen dioxide problem.

Further, in the Chicago region, we estimated that the current Federal motor vehicle standards, coupled with transportation controls required to meet the oxidant and carbon monoxide standards for this region, will be adequate. To obtain the standard by 1975 elsewhere, it is clear that major cutbacks in nitrogen oxides emissions clearly are not necessary at this time and will not be necessary during the next several years. Moreover, the exact level of nitrogen oxides control required to ensure continuing maintenance of the national standard cannot, at this time, be well defined.

Given these circumstances, the Environmental Protection Agency shortly will reclassify all the air quality control regions, except Los Angeles and Chicago, which originally were judged to exceed the health-related standard. The effect of this reclassification will be to remove requirements for adoption of a control strategy for nitrogen oxides. States that have already adopted such a control strategy will have the option of modifying it. And in cases where the Environ

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mental Protection Agency had proposed regulations to control nitrogen oxides emissions from stationary sources, the proposals will be withdrawn.

As for motor vehicle emissions, a 90-percent reduction in nitrogen oxides is, in my judgment at this time not necessary. We are undertaking further analysis to determine exactly what such a standard would be. Given the need for this further analysis, coupled with the ongoing studies of the health effects of nitrogen oxides, it is my judgment that a new nitrogen oxides emission standard should not be legislatively mandated, but rather that the Environmental Protection Agency should continue setting the standard under the provisions of section 202(a) of the Clean Air Act, in lieu of the present requirement for a 90-percent reduction in 1976 under section 202(b). We have drafted an amendment which would accomplish this purpose and request that it be considered by the committee.

This concludes my prepared remarks, Mr. Chairman, I would be happy to answer any questions you might have.

Mr. Chairman, I do not make a statement like this lightly because I believe it is very important before this committee to change any such legislative mandate standards as applies to nitrogen oxides, that there be a full public hearing of what we are recommending.

Starting last summer and intensifying in the late fall and early winter, I several times, as did the Deputy Administrator, Mr. Fri, made statements to the same effect as it made in this statement before congressional committees and in various public presentations.

The impact of those statements was I think to say the least largely ignored or missed by the public and it is for that reason that I would recommend and will carry out the recommendations myself that we publish not only this statement, but the analysis behind it which has led us to this conclusion, in the Federal Register requesting the public over a period of time, say 30 to 60 days, to comment on this analysis and give us the benefit of the best scientific advice we can get outside of the Agency and from the public at large as to whether our analysis in fact is correct.

At the end of that period of time, I think these comments should be forwarded to the committee along with this continued recommendation if our further analysis warrants that for whatever action the committee would want to take.

There is some degree of urgency that this matter be considered by the committee because where the nitrogen oxide levels are finally set has a tremendous impact on the kinds of technology that can be available to control hydrocarbons and carbon monoxide.

So I think we ought to set a schedule for consideration of this problem with some degree of urgency so that there can be a signal given to the automotive industry as to precisely what standards they have to meet, and what they should shoot at.

For that reason, I am recommending since we have not been able to generate very much public comment by any other method that we have adopted that we do publish this in the Federal Register and request public comments whích, of course, will be made available to the committee.

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Senator MUSKIE. I am sure there are a lot of questions on the part of the committee. Would you like to proceed with the presentation of the Doctor?

Mr. RUCKELSHAUS. Yes I think it would be beneficial to the committee to see what has led us to this tentative conclusion and the analysis that lies behind it.

Senator MUSKIE. Let me ask just two questions, then.

Maybe these will help lay the basis for their presentation. Once you spoke of an analysis that you would publish in the Federal Register. Is that analysis now available? Is this the analysis they are going to make?

Mr. RUCKELSHAUS. This is in summary form the analysis. We do not have a document that is presently ready to be published in the Federal Register. We do have an almost completed document on the measurement problem itself; that is obviously an integral part of this analysis.

That along with the conclusions that has led us to this is what we will publish and we will, of course, make that available to the committee also.

Senator MUSKIE. Will there be a document describing the analysis at some point?

Mr. RUCKELSHAUS. Yes. There will be.
Senator MUSKIE. When? Can you give us the time on that?

Dr. GREENFIELD. As a matter of fact, Mr. Chairman, I think a preliminary document which covers most of the points on the measurement analysis has already been made available to your staff.

Senator Muskie. Is this the one that you pointed out to me earlier this morning?

Mr. RUCKELSHAUS. No. That is not. That is a different document.

Senator MUSKIE. This is the assessment of the analytical document available for the determination of nitrogen oxide and ambient air.

Dr. GREENFIELD. That is right. That is the one prepared on February 24. It is being updated. It is the basis for the measurement portion of the analysis.

Senator MUSKIE. The second question I would like to ask refers to your statement in which you say that over the past year we have been measuring nitrogen dioxide levels by various measuring methods at some 200 sites across the country, including sites in the 47 air quality control regions where we originally believed that the national standard was being exceeded. A full report on this study will be available very shortly.

Is that full report essential at all to the conclusion which you have stated here in this statement this morning?

Dr. GREENFIELD. Yes. It is because if those measurements which lead you to what we might call a reclassification of the 47 air quality regions.

Senator MUSKIE. Does the fact that the Administrator has reached his firm conclusions as stated this morning indicate that he has had access to essentially all of that information?

Dr. GREENFIELD. Yes. He has.

Senator Muskie. So the preparation of the report is simply a matter of typing and putting it in form. The substance of that report is in part the basis of your conclusions this morning ?

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Senator Muskie. I will withhold any further questions until we have had the full presentation. Do other members of the committee have questions?

Dr. GREENFIELD. Because of my close quarters, I wonder if it might be better if I remained seated, and you can all see the charts?

Senator Vuskie. I think that would be fine. Dr. GREENFIELD. The first chart described is the four basic methods that have been considered. The first is a Federal reference method, four columns, the sampling technique used there is a 24-hour bubbler. That means whether or not it happens in 24 hours or whether it is continuous measurement, which means you take measurements every few minutes during the day.

This third column is the question of whether or not this method had been field tested when the standard was set. The fourth column is a set of remarks which I will get to.

The first row is the current Federal reference method, the so-called Jacobs-Hachheiser technique. It is a 24-hour bubbler. It had been field tested when the standard had been set, but we did not know at that time of a problem that cropped up subsequently relating to the collection efficiency. At the time that method was setSenator Muskie. When was that time?

Dr. GREENFIELD. This was the time just prior to the setting of the standard itself and the publishing of that method as a standard reference method.

Senator MUSKIE. Was this before 1969 or 1970?
Dr. GREENFIELD. 1971; 1971 officially.
Senator Mrskie. After the enactment of the legislation?

Dr. GREENFIELD. Yes; but in setting up this as the Federal reference method, it was assumed that it had a 35-percent collection efficiency which was constant across all concentrations.

The Griess-Saltsman method is a continuous sampler. It too was tested at the time. It was the one used in the camp stations and the Chattanooga abatement studies. It does not give reliable measurements at low levels of NOx and oxidants and others may be a problem. The third method is the so-called arsenite bubbler. There are several versions of that. They too are 24-hour bubblers. They were not field tested at the time the standard was set. However, they do appear to have a stable collection efficiency over a wide range of NO, concentrations. There may be some interferences but they are not yet completely contemplated. It appears to be relatable to the Saltsman observation. That is a very key point.

The fourth method is the so-called Chemluminescent method. It is a continuous method. It had not been tested at the time of the standards. It avoids the drawback of wet chemicals. There is an additional field testing now underway. It has the ability of providing short-term air quality standard measurements.

To get at the moment of the problems of the collection efficiencies, this is a graph which plots up the side collection efficiency or overall efficiency and percentage and along the bottom concentrations of nitrogen dioxide sampled. On the bottom it rums 30 micrograms per cubic meter to 750, certainly covering the range of our interest. The collection efficiency runs from zero up to 80 percent. The dotted line

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