90 



This data has been contrasted with the studies at the Shen- 

 andoah Park. I have, from an air resources specialist, received all 

 data that was published for the summer. This is a very, very poor 

 report. It is incomplete. There is simply not enough data here to 

 make any statement. In fact, one could make an erroneous state- 

 ment from this data if one looked at the mean visibility in the four 

 summers for which there is data. 



This is the mean haziness that would come out of that visibility. 

 This is an example of how one could take data and misuse it. One 

 could erroneously conclude there has been an increase in visibility 

 in this data. I don't believe that is significant. 



Let me summarize. Why is this happening? There are several 

 variables involved in the visibility issue one needs to look at. It is 

 not only the emission rate that is responsible. Other factors such 

 as climate and land use are very, very important. 



Robert Davis analyzed airport visibility for the Mid-Atlantic and 

 found after you allow for weather there is a significant increase in 

 visibility. My colleague, Jerry Stenger, and I recently published a 

 paper in the literature on how climactic change interacted with the 

 visibility problem. 



What we found was that the climate had changed in such a fash- 

 ion in the middle 1950's and in the 1960's as to increase the flow 

 of air from the source regions to the Shenandoah Park region. 



Since then, the net flow has declined. So some of the trends we 

 see in visibility are not due simply to emission, but also to weather. 

 It is important that we factor these things into any potential regu- 

 lation. It, unfortunately, complicates the situation, but it will cer- 

 tainly allow us to be scientifically based for regulation. 



The implications are obvious. There have been changes in emis- 

 sion, but there also have been simultaneous and significant 

 changes in climate. It is important these regulations be based on 

 science. Perhaps nowhere is it more important than in the environ- 

 mental sciences, because it is perceived reduction in visibility in 

 Shenandoah Park, which is not demonstrated by 100 independent 

 observers. If that is the basis for this regulation that basis appears 

 to be flawed. Thank you. 



[The prepared statement of Mr. Michaels and the chart referred 

 to follow:] 



