Document YjrG5geOVQJm4VKqL1VrvZ4VK

422 GEORGE D. CLAYTON and pine. Table 1, prepared by Zimmerman, shows comparative suscepJtMS various Bpeoies. , JsSIi TABLE 1 Comparative Susceptibility of Various Species to Hydrofluoric Acid Concen Time of exposure tration (av. p.p.m.) Buck- Sweet To wp wheat potato Peach mato Corn Be|| 2 hr. 10 min. '4$i1.48 4 -- 4 4 4 2 hr. 10 min. 4 hr. 7 hr. 30 min. J0.67 3 3 3 1 3 0.27 3 2 2 0 0.135 3 3 303 4 hr. 6 hr. 40 min. 4 hr. "sa0!l3 0.085 1 1 1 1 1 0 1 Q-l 1 0 0 oM 0.07 0 0 0 0 0 . sm 0 Extent of severe injury. injury is indicated as follows: 0, no injury; 1, slight; 2, medium; 3j'iOT Ammonia, hydrogen sulfide, mercury vapor, ethylene, and carbony<;:m* gases are also toxic to plants in relatively high concentrations. Homvie number of reputed cases of injury involving these gases is not sufficieht f detailed discussion here. .'-4 From the foregoing,_it is apparent th^atjixppilutaatU^aJinalL^M can ahd'dcTaffect vegetation, that certain plants are more susceptible tn and that each pollutant often produces a characteristic damage: identifiable. These factors very often make plants ideal "instruments" for measuring!, pollutants. The aluminum industry has for years planted gladibli_"a?'ij^til plants and trees in circles as far as 10 miles from the plant, in prd,^;^5*ajg| fluoride damage. The use of indicator plants for evaluating the prior to the construction or enlargement of a plant, where the efflueiiirrtVi;ifiX to be injurious to plants, is sound practice. It is especially so, if ft^prpwT plant is in an industrial area where the effluent from other plants mayShfr^'. sufficient to cause damage under unfavorable meteorological coiidi'feoh'jbS^d*8 "plants can:be..used~for routine evaluation of certain air pollutants^ &jfjSjjj| ............. .. ' D. EFFECTS ON STRUCTURES " Another familiar effect of atmospheric pollution is diBeolorati'ohlotiEl ibU'mMBB -.including-Stbner-bmkr-arid-p'ainted-surfa'cesr'Bla'CkeHSd^surfaces tions of sooty material frequently obliterate essential lines end Jocnramf^ They disfigure a building and seriously reduce its aesthetic and More serious, however, is the corrosive action of acid gases oii builainra^fipS of the effects of this reaction is the formation on stone surfaces df'h'ini^^g AIR POLLUTION 423 aggg^^^m^that tends to blister and exfoliate. It has been reported that sheets SJjfj^fanized iron had a life span of 3 to 6 years in Pittsburgh, prior to its active j^^^^^^t'control program, as compared with 7 to 14 years in a smoke-free SfeS^SnitviVand that, at the same time, copper would last only 10 to 20 years in ^^^^l^&hereas it would be good indefinitely where there is relatively little ^pollution. The effect of certain acid gases on paint is well known, as by the blackening of white lead-base paint by hydrogen sulfide. III. Economics of Air Pollution Possible to state a figure that would accurately proclaim the cost of Kurban dweller, farmer, retailer, and industry. No one can deny, ^^IfjSir pollution has a serious effect on the economics of an industrial ^Klihough the extent varies by community, and even by individual eracPperson. Some industries, because of their air pollution, have been ^^^^purts to close their plants or install expensive control procedures. ^SMthe economic hardship due to air pollution is almost overwhelming. lf|||()ple suffer physically because of an allergy to some contaminant in iplflmist leave the community in order to obtain relief. ||||Jtgrganizations have given "guesstimates" of the cost of damage due ^ffion, in the United States. The Commerce Department estimated the ecPfiroth 8 to 20 dollars per inhabitant annually. The United States ^^^feweyTeported-tbat-smoke-damage-to merchandise-and buildings was ggghgralp^re per year. In 1953 an economic loss of 3 million dollars on only raKjywaa attributable to smog in Los Angeles. Gibson11 estimates the *^hpmi^;loss to the United States to be at least lVa billion dollars SSgfair pollution plays in causing the decay of--certain areas of our <B^^jjw:here. businesses move to outlying areas of?iHe city, is.impossible &g^gj..safe to assume, however, that it is an important consideration Iljllprpendous loss of tax revenue to the local government. One of /the |||i|jjnf this large economic loss is sulfur dioxide..It has been estimated12 sulfur compounds emitted to the atmosphere from various [^M^hanriihe-presenWorld-production-Df-mative-slI^ahd'pj^ites- the question as to the extent air pollutants pan, be recovered ^gKffl'amortizing the cost of installation of control equipment, or to ^^^^]that is a definite asset to the company. Some instances``of re- . feketomtecLare-.... . ^ ............ ... pfggptility company achieved control of fly ash at a considerable ` l.c fly ash at a substantial profit. Natl. Air Pollution Symposium, 1st Symposium, Pasadena, Calif. J. Cole, Ind. Eng. Chem., 42, 2258 (1950). ' arala grogp