Update item information
Title Let's Clear the Air
Subject Air--Pollution
Description The Thirty-Sixth Annual Frederick William Reynolds Lecture.
Creator De Nevers, Noel, 1932-
Publisher The Frederick William Reynolds Association
Date 1973-02-20
Date Digital 2008-05-29
Type Text
Format image/jpeg
Digitization Specifications Original scanned on Epson Expression 10000XL flatbed scanner and saved as 400 ppi uncompressed tiff. Display images generated in PhotoshopCS and uploaded into CONTENTdm Aquisition Station.
Resource Identifier,1266
Source TD883 .D45 1973
Language eng
Relation Digital reproduction of "Let's clear the air," J. Willard Marriott Library Special Collections
Rights Digital Image Copyright University of Utah
Metadata Cataloger Seungkeol Choe; Ken Rockwell
ARK ark:/87278/s6ht2m87
Setname uu_fwrl
Date Created 2008-07-29
Date Modified 2008-07-29
ID 320531
Reference URL

Page Metadata

Title Page22
Description 22 THE THIRTY-SIXTH ANNUAL REYNOLDS LECTURE engineering is done via models. For example, we have simple models of how steel beams behave when loaded, which we use to select the right size beam for any specific load in a building. Unfortunately, we are far from having the confidence in our air pollution models that we have in the models in many other kinds of engineering. If we could test air pollution models as easily as we test steel beams in the laboratory, we would be much further along this road than we are now. For the beam, the model testing problem is relatively simple, because we can duplicate in the laboratory the situation it will face in its ultimate application. But, for air pollution, we cannot do this, because the question we need answered is harder. The question typically asked is, "If we decrease the pollutant emission rate from plant X by amount Y, what is the change in annual average concentration of this pollutant at point Z?" To test this in the laboratory, we would need a laboratory experiment which duplicated the climate and mixing of pollutants in the whole atmosphere for the whole year. To date, this is far beyond our laboratory capabilities. For this reason, the mathematical models we use can only be tested by comparing their predictions with full-scale results in real locations with the real atmosphere. This is slow and expensive. In this situation, with these deadlines, EPA felt that it was required to proceed with models for which we have never obtained real experimental verification. Two were selected, with the states given their choice of which to use. The first is a very simple model which assumes that the concentration at any point is a linear function of the total pollutant emission rate in the region. This allows one to make a very simple calculation of the required reduction in emission rate. But, the result is only likely to be an accurate prediction of what we will observe in some very unusual circumstances (e.g., perfect mixing of all air over a metropolitan area). This model is quite unlikely to give accurate predictions of the effects of the selective reduction of emissions from some source (e.g., power plants) without corresponding reductions in all others (e.g., household furnaces). The second model is one which takes into account the variabilities of the atmosphere, and the various locations and rates of all the emission sources in the metropolitan area. It is long and complex to describe, and requires several hundred dollars worth of computer time to run for a large city. It should make more accurate predictions than the simple model, because it takes into account more of what we know. But, it also has not been thoroughly tested. When the state plans arrived to be evaluated by EPA, most of them had used the simple model and were easily checked. EPA knew the limitations of that model but accepted the plans based on it, for want of
Format image/jpeg
Identifier 024-RNLT-DeNeversN_Page22.jpg
Source Original Manuscript: Let's Clear the Air by Noel de Nevers.
Setname uu_fwrl
Date Created 2008-07-29
Date Modified 2008-07-29
ID 320524
Reference URL