PART X — ENVIRONMENTAL CONTAMINANTS 



of individually emitted pollutants to 

 the far downwind zone where pollu- 

 tants merge with the general atmos- 

 phere. 



Studies of (a) urban pollution, (b) 

 analytical methods, and (c) laboratory 

 models of reactions producing, alter- 

 ing, and removing contaminants are 



three areas of atmospheric chemis- 

 try that require immediate attention. 

 These studies alone are not sufficient, 

 however, to solve the environmental 

 problem. Supporting work needed in 

 the biological sciences is lagging for 

 lack of precise methods to assess the 

 ecological impact of contaminants; 

 there must be innovation in city plan- 



ning, architecture, engineering, and 

 related fields; and behavioral research 

 is essential to understand why people 

 elect to pollute and how they may 

 be dissuaded from polluting. With 

 population increase, restraints inevi- 

 tably increase; acceptance of these re- 

 straints will be necessary to preserve 

 and nourish other freedoms. 



Atmospheric Contaminants and Development of Standards 



Atmospheric contamination can be 

 considered on the global, national, 

 state, regional, and local scales, each 

 of which has its own vertical and 

 temporal scales. (See Figure X— 3) The 

 temporal scales have two aspects — 

 the time-scale of the adverse effects 

 associated with the contaminant, and 

 the time-scale required for effective 

 action for its control. These two time- 

 scales tend to be similar in magni- 

 tude for each of the horizontal scales 

 noted above. 



One example of the global system 

 is the postulated effects on the earth's 

 temperature when carbon dioxide and 

 particulate matter build up in the at- 

 mosphere, affecting global heat bal- 

 ance. Another example is fallout from 

 testing of nuclear weapons in the at- 

 mosphere. Neither of these problems 

 can be resolved unilaterally by any 

 one nation. Hence the time-scale for 

 resolution is that of action by inter- 

 national organizations. 



On the national scale, which in the 

 United States is synonymous with the 



continental scale, we are concerned 

 with the buildup of the background 

 contaminant concentration of the non- 

 urban air mass and with interstate 

 transport of contaminants. Experi- 

 ence has shown us that these take 

 years to resolve. 



Within the confines of a state, our 

 problems are those of urban-subur- 

 ban-rural contaminant transport and 

 reactions and of the impact of large, 

 single contaminant sources on the 

 land areas within their range of in- 

 fluence. In such matters, we would 

 expect a state to be able to initiate 

 controls, if not effectively accomplish 

 them, in a matter of months. 



In the United States, we are com- 

 mitted to the regional concept of air- 

 pollution control — the region being 

 generally a multi-county area, either 

 intra- or inter-state, which contains 

 the principal sources of its pollution 

 and the principal receptors adversely 

 affected thereby. The principal time- 

 scale with which a region must con- 

 cern itself is the so-called air-pollution 



Figure X-3 — ATMOSPHERIC SCALES 



"episode" — the build-up of pollution 

 during a stagnation of horizontal and 

 vertical atmospheric transport mecha- 

 nisms extending over a matter of sev- 

 eral days. Therefore, although the 

 region may adopt a larger time-scale 

 for attack on the basic causes of its 

 contaminant problem, it must also 

 be prepared to react to an occurring 

 episode on a same-day or next-day 

 basis. 



The smallest scale is that of the 

 locality, covering several city blocks, 

 in which traffic builds up for several 

 hours each morning and afternoon. 



Our concern for atmospheric con- 

 tamination globally is for the integrity 

 of the earth as a planet on which hu- 

 man life can exist without extinction 

 by freezing, overheating, inundation, 

 or starvation. Nationally, regionally, 

 and locally we see atmospheric con- 

 tamination as having adverse effects 

 on our health, on vegetation, livestock, 

 materials, structures, and the atmos- 

 phere itself. All these elements of 

 damage are associated with costs to 

 society and to our economy; and all 

 the means for control of contaminants 

 have within them certain inherent 

 costs. Our general view is that it costs 

 us more to have pollution than to 

 control it. 



Measuring Air Quality 



If one views air pollution as a sys- 

 tem (see Figure X-4), we find that a 

 convenient starting point is "Sources 

 and Their Control." Our knowledge 

 of the principal pollution sources and 



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