EMICALS 



Figure X-2 — POLLUTION — AN ENVIRONMENTAL PROBLEM 



The picture illustrates the multiple problems of pollution encountered in a small 

 city in western Pennsylvania. In the first instance, the gaseous effluents from the 

 industrial complex form a cloud over and downwind of the city. This cloud, in 

 addition to causing changes in the local radiation balance and possibly other local 

 changes, is composed of water vapor mixed with pollutants such as sulfur dioxide 

 that cause damage to plants, animals, and man. The city is located on a river 

 into which industrial and municipal wastes are dumped; in earlier days there was 

 no need to worry about the consequences of such action and now, although funds 

 are becoming available to help build water-treatment plants, it is difficult to keep 

 up with the need. The question of solid waste disposal presents yet another 

 unsolved problem. The original city dump along the river only makes the water 

 pollution worse. Incineration causes air pollution. Sanitary land fills use up large 

 quantities of desirable land. Shipping the wastes by rail or barge may help the 

 local problem but does not eliminate it. Furthermore, all these problems spill over 

 into downwind or downstream localities. 



laboratory experiments on haziness 

 modification. He has shown that in 

 many typical atmospheres the tur- 

 bidity measured by his instrument 

 correlates closely with the mass of the 

 particles present. 



The Environmental Protection 

 Agency (EPA) maintains monitoring 

 and surveillance activities in most of 

 the major U.S. cities, and some local 

 agencies are measuring their own pol- 

 lution problems. However, most of 

 the widely used techniques are five to 

 twenty years old and are less effec- 

 tive than most recently developed 

 methods. Nearly all of them lack 

 precision and specificity, and thus the 

 results are affected significantly by 

 the presence of pollutants not being 

 measured. 



The Measurement Problem — Be- 

 fore newer techniques are accepted, 

 verifiable standards need to be estab- 

 lished for precision, specificity, and 

 accuracy in measuring pollutants at 

 concentrations as low as one part in 

 a billion parts of air and in the pres- 

 ence of equal or larger amounts of all 

 other possible pollutants. This meas- 

 urement problem is not only unre- 

 solved, but there has been no agency 

 with the explicit and exclusive re- 

 sponsibility for evaluating proposed 

 analytical methods. Only recently 

 has a group been created with the 

 responsibility of evaluating existing 

 methods of atmospheric analysis, and 

 it is not yet certain to what extent 

 this group will be successful. Mean- 

 while, there is a strong tendency to 

 use old techniques, which at least 



provide numbers, even thougl 



may be some uncertainty as to the 



physical meaning of those numbers. 



Neio Attitudes — The immediate 

 past has seen remarkable changes, not 

 so much in the state of knowledge 

 as in the state of mind of the at- 

 mospheric research community. Not 

 many years ago, an announcement of 

 plans to study atmospheric chemistry 

 in the tropics invited accusations of 

 junketing from one's colleagues. Only 

 a short time past, many scientists felt 

 that usefulness tainted research re- 

 sults; today "relevant" research topics 

 are eagerly sought by formerly "pure" 

 scientists. 



New Methods — Older research 

 tools have been improved and simpli- 

 fied and new tools have been devised. 

 Gas chromatography with more sensi- 

 tive detectors, atomic absorption, neu- 

 tron activation, chemiluminescence 

 and fluorescence quenching — all these 

 and others provide the means to ana- 

 lyze even smaller, more dilute, and 

 more complex samples. 



This combination of new methods 

 and progressive attitudes in environ- 

 mental study summarizes the current 

 status of trace chemistry of the atmos- 

 phere. While recent achievements are 

 not great, there is now an expectancy 

 and readiness for major scientific ad- 

 vances in this field. 



Needed Scientific Activity 



This mood of expectancy has led 

 no fewer than a half dozen groups 

 around the world to examine the pos- 

 sibility of routine monitoring of sev- 

 eral major contaminants in the air. 

 Carried out at sites remote from local 

 pollution, such work could provide 

 for the first time true "benchmark" 

 measurements against which future 

 changes in the atmosphere can be 

 gauged. Recently, a number of groups 

 within the United States independ- 

 ently concluded that a saturation 

 study is needed of pollution in a 

 single city, ranging from the point 



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