PART X — ENVIRONMENTAL CONTAMINANTS 



variations in source strengths and 

 character and in transport, diffusion, 

 reaction, and scavenging factors, air 

 quality will show considerable vari- 

 ability. However, by increasing the 

 averaging time of air-quality data, we 

 can suppress enough of this variabil- 

 ity to interpret the data meaningfully. 



Technological Shortcomings — 

 There are scientific shortcomings in 

 each stage of the process described 

 above. The transport and diffusion 

 phase takes place in the lower reaches 

 of the atmosphere, above most 

 ground-based instrumentation and be- 

 low most aircraft and satellite-borne 

 instrumentation. It occurs over popu- 

 lous areas and in airport traffic pat- 

 terns where we are not free to operate 

 balloons, drones, towers, rockets, 

 dropsondes, and other means of prob- 

 ing the atmosphere for meteorological 

 and pollution information. To the ex- 

 tent that much of our measurement 

 technology lacks sophistication, our 

 knowledge of the phenomenon meas- 

 ured falls short of the optimum de- 

 sired. Because of the complexity of 

 the potential chemical and scavenging 

 reactions among all the pollutants 

 present in the atmosphere, we have 

 only scratched the surface of under- 

 standing these phenomena. 



Our knowledge of air quality is 

 limited, furthermore, to just a few 

 places on earth that have been able to 

 afford the installation and operation 

 of air-quality monitoring equipment. 

 Commercial vendors of such equip- 

 ment have tended to await demand, 

 with the result that there has been a 

 proliferation of instruments to meas- 

 ure a few well-publicized pollutants 

 and a paucity of instruments for 

 monitoring the less "popular" con- 

 taminants. 



Data Base — We have given the 

 name "air-quality criteria" to tabula- 

 tions of cause-effect data relating var- 

 ious concentrations of contaminants 

 with the effects observed on people, 

 vegetation, livestock, materials, struc- 

 tures, and the atmosphere. These ob- 

 servations encompass studies in the 



laboratory and the field and, in the 

 case of people, involve epidemiologi- 

 cal and clinical studies. Our "people" 

 data is the weakest because airborne 

 contaminants are only one class 

 among many of stresses on population 

 and the attribution of health effects 

 to any one class is very difficult. Since 

 these latter data form the basis for 

 establishment of "air-quality stand- 

 ards," and thus the base for regulatory 

 control, they are the most contro- 

 versial of all the data in the whole 

 field of air pollution. 



The setting of "air-quality stand- 

 ards," and the derivative establish- 

 ment of "emission standards" to limit 

 the emission of specific classes of 

 sources, calls forth not only data from 

 the physical and biological sciences, 

 but also involves trade-offs and deci- 

 sions that deeply involve the social 

 and political sciences and interactions 

 with other elements of the ecological 

 and economic system. Decisions as to 

 how we control air pollution can af- 

 fect water and land pollution, and 

 vice versa. Decisions on pollutant 

 levels can affect the energy supply 

 for our economy and reflect on the 

 nationwide and worldwide trade in 

 fuels. Considerable public contro- 

 versy is likely, therefore, as to the 

 desirable uniformity of air quality 

 and national emission standards. 



Modeling — To help resolve some 

 of these problems, mathematical mod- 

 eling is increasingly being applied, 

 both to the gross model of the whole 

 air-pollution system and to more de- 

 tailed models of individual elements 

 of the system as, for instance, the 

 transport and diffusion model. These 

 latter models have been used exten- 

 sively in setting the geographic 

 boundaries of the "air-quality control 

 regions" currently being designated 

 by the federal government in various 

 urban areas of the United States. 



What We Need to Know 



Data — More than anything else, 

 we need to know the effects of pol- 



lutants in the atmosphere on the ex- 

 posed population. Much of our past 

 knowledge has been of the effects of 

 certain pure substances on experi- 

 mental animals or healthy adults. 

 What we need is knowledge of how 

 the mix of pollutants as they really 

 exist in the atmosphere affects the 

 actual mix of the exposed population. 



Technology — Our greatest air- 

 quality measurement and monitoring 

 need is for remote means of probing 

 hundreds or thousands of feet through 

 the air for an information return of 

 pertinent chemical and physical data. 



In the area of control technology, 

 our greatest need is to test prototypes 

 and pilot plants preparatory to pro- 

 duction and commercial action. 



Air-Quality Management — Fi- 

 nally, we need better understanding 

 of air pollution as a system, of the 

 interaction within the system and be- 

 tween it and other systems in the eco- 

 logical and economic whole. In effect, 

 we need to learn how better to man- 

 age the air-quality system. 



Institutional Resources — To do 

 these things requires trained people 

 and facilities in which to train them. 

 Much of the money that is now being 

 spent in contract research could be 

 better spent in building and equipping 

 facilities for air-pollution research and 

 training, preferably at universities, of 

 a type that does not now exist in the 

 United States. As an example, the 

 Japanese government has built several 

 large low-velocity wind tunnels for 

 air-pollution research; in the United 

 States, the federal air-pollution au- 

 thorities have built none. All the large 

 new smog chambers for the study of 

 atmospheric chemical reactions are in 

 the laboratories of private research 

 organizations; they are not available 

 for student training. The list could go 

 on and on. Clearly, a redirection of 

 effort is needed if tomorrow's prob- 

 lems are to be solved. 



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