i m mm mm] Air Pollution Aspects of Emission Sources NITRIC ACID MANUFACTURING A Bibliography with Abstracts '•X"""X" llll; i • • • • U. S. ENVIRONMENTAL PROTECTION AGENCY ------- AIR POLLUTION ASPECTS OF EMISSION SOURCES: NITRIC ACID MANUFACTURING- A BIBLIOGRAPHY WITH ABSTRACTS Office of Technical Information and Publications Air Pollution Technical Information Center ENVIRONMENTAL PROTECTION AGENCY Air Pollution Control Office Research Triangle Park, North Carolina May 1971 For sale by the Superintendent or Documents, U.S. Government Printing Office, Washington, D.C., 20402 - Price 45 cents Stock Number 6603-0004 ------- The AP series of reports is issued by the Air Pollution Control Office to report the results of scientific and engineering studies, and information of general interest in the field of air pollution. Information reported in this series includes coverage of APCO intramural activities and of cooperative studies conducted in conjunction with state and local agencies, research institutes, and industrial organizations. Copies of AP reports are available free of charge to APCO staff members, current contractors and grantees, and nonprofit organ- izations - as supplies permit - from the Office of Technical Information and Publications, Air Pollution Control Office, Environmental Protection Agency, P.O. Box 12055, Research Triangle Park, North Carolina 27709. Others may obtain copies from the Government Printing Office. Air Pollution Control Office Publication AP-93 ------- BIBLIOGRAPHIES IN THIS SERIES AP-92, Air Pollution Aspects of Emission Sources: Municipal Incineration —A Bibliography with Abstracts AP-93, Air Pollution Aspects of Emission Sources: Nitric Acid Manufacturing —A Bibliography with Abstracts AP-94, Air Pollution Aspects of Emission Sources: Sulfuric Acid Manufacturing —A Bibliography with Abstracts AP-95, Air Pollution Aspects of Emission Sources: Cement Manufacturing —A Bibliography with Abstracts AP-96, Air Pollution Aspects of Emission Sources: Electric Power Production —A Bibliography with Abstracts III ------- CONTENTS INTRODUCTION vii ANNOTATED BIBLIOGRAPHY A. Emission Sources 1 B. Control Methods 3 C. Measurement Methods ....11 D. Air Quality Measurements (None) E. Atmospheric Interaction , 14 F. Basic Science and Technology 16 G. Effects - Human Health 18 H. Effects - Plants and Livestock 20 I. Effects - Materials .21 J, Effects - Economic 22 K. Standards and Criteria ...23 L. Legal and Administrative . 24 M. Social Aspects (None) N. General (None) AUTHOR INDEX 25 SUBJECT INDEX 27 ------- AIR POLLUTION ASPECTS OF EMISSION SOURCES: NITRIC ACID MANUFACTURING - A BIBLIOGRAPHY WITH ABSTRACTS INTRODUCTION Nitric acid manufacturing contributes significantly to the overall air pollution level in the United States. To aid efforts to improve air quality, the Air Pollution Technical Infor- mation Center (APTIC) of the Office of Technical Information and Publications, Air Pollu- tion Control Office, has compiled this bibliography relevant to the problem and its solution. Approximately 81 abstracts have been selectively screened from the contents of APTIC's information storage and retrieval system to cover the 14 categories set forth in the table of contents. The compilation is intended to be representative of available literature, and no claim is made to all-inclusiveness. Subject and author indexes referjtothe abstracts by category letter and APTIC accession number. Generally, higher accession numbers, representing the latest acquisitions, cover the most recent material. All documents abstracted herein are currently on file at the Air Pollution Technical Information Center, Air Pollution Control Office, Environmental Protection Agency, P. O. ,Box 12055, Research Triangle Park, North Carolina 27709. Readers outside the Environ- mental Protection Agency may seek duplicates of documents directly from libraries, pub- lishers, or authors. VII ------- A. EMISSION SOURCES 01583 R.W. Gerstle R.F. Peterson ATMOSPHERIC EMISSIONS FROM NITRIC ACID MANU- FACTURING PROCESSES - A COMPREHENSIVE SUMMA- RY. Preprint. (For Presentation at the American Inst. of Chemical Engineers, Detroit, Mich., Dec. 8, 1966.) Atmospheric emissions from nitric acid plants depend on plant operating conditions, production rates, and the use of control devices. Data in this article show that plants operating within design capacities and producing 55-60% nitric acid can limit the nitrogen oxides concentration to 0.3% in the stream leaving the absorption tower. This is equivalent to about 50 pounds of nitrogen oxides per ton of nitric acid (100% basis) produced. Installation of scrubbers or catalytic reduction equipment can reduce these emissions by 50 to 97%. Emissions during startup or shutdown usually do not create any special problems. (Author summary modified) 13698 Mohrnheim, Anton F. AIR POLLUTION AND THE METAL FINISHING INDUS- TRY. Plating, March 1969. The role of nitrogen oxides in air pollution is discussed in order to inform those who work with nitric acid and aqua regia of their capacity for creating or preventing air pollution. Nitrogen dioxide itself is toxic and, in addition, contributes to chemical smog production through a photochemical chain reac- tion. Even though the metal manufacturing and finishing indus- try uses larger quantities of nitric acid than the precious metal industry, the latter may release comparable amounts of nitrogen dioxide. This is demonstrated by the quantititive reac- tion of gold and nitric acid. In the precious metal industry, closed systems should be used with only stoichiometric amounts of aqua regia. For pickling and similar work in the metal manufacturing and finishing industry, mist collectors or air scrubbers should be used. 16699 British Oxygen Co. Ltd., Glasgow, Scotland CURRENT METHODS OF COMMERCIAL PRODUCTION OF NITROUS OXIDE. APPENDIX 1. Brit. J. Anaesthesia, vol. 39:440-442, May 1967. Nitrous oxide is produced on a commercial scale by passing an ammonium nitrate solution through a primary scrubbing tower to a gas-heated reactor. As decomposition takes place, nitrous oxide leaves the reactor, together with steam, ammonia, nitric acid, nitrogen, and traces of nitric oxide and nitrogen dioxide. Initial cooling of the merging gases causes most of the am- monia and nitric acid to revert to ammonium nitrate, which is returned to the reactor. Residual ammonia and nitric acid are removed by a water scrubber; higher oxides, by caustic/per- managanate scrubbers; and ammonia traces, by an acid scrubber. When free of all impurities except moisture and nitrogen, the gas is compressed and dried in an alumina drier battery. The dry, compressed gas is next liquefied to release nitrogen and evaporate pure nitrous oxide. The evaporated nitrous oxide is then compressed to cyclinder pressure and passed through a second alumina drier battery to a cylcinder filling line. In purity tests for nitric oxide and nitrogen dioxide determination, the gas leaving each drier is passed through a visual bubbler containing an acid potassium permanganate solution and a Saltzman reagent. An alarm is automatically sounded if nitric oxide and nitrogen dioxide concentrations reach 1 vpm. 17076 Belaga, M. B. and P. N. Maystruk SANITARY PROTECTION OF AIR IN VINNITSA. U.S.S.R. Literature on Air Pollution and Related Occupational Diseases, vol. 8:241-246, 1963. (B. S. Levine, ed.) (Also: Gigiena i Sanitariya, 26(l):73-76, 1961. CFSTI: 63-11570 Plans are presented for the purification of discharges from dif- ferent shops and departments of a superphosphate plant which currently emits 10.5 tons of sulfur dioxide, 6.5 tons of nitric acid, 1.2 tons of sulfuric acid, 0.5 tons of fluorides, and one ton of superphosphate and tricalcium dust each day. Even at a distance of 2000 meters from the plant, the maximum fluorine concentrations are 13 times in excess of the allowable limit. Similarly, sulfur dioxide concentrations at 1000 meters and sul- furic acid aerosols at 500 meters have been found to exceed allowable limits. The maximum concentration of dust at 200 m from the plant is 15.4 mg/cum, or thirty times in excess of the allowable limit. Dust samples collected at 200-1000 meters from the plant showed a fluorine content of 0.8 to 1.4%. Soil samples at 200, 500, and 1000 meters contained 16.9, 9.61, and 8.7 mg of fluorine per 100 g of soil. Among the measures being taken to reduce pollution are the elimination of gas leaks by equipment hermetization, the installation of dust catching and gas purification equipment, and the construction of high stacks for greater dispersion of pollutants. It is further recommended that the sulfuric acid department build a separate housing for its exhaust fans, use filters to raise tail-gas utilization efficien- cy, and build a warehouse to store the apatite concentration. 18305 Lindau, L. Am POLLUTION AND THE MANUFACTURE OF INOR- GANIC CHEMICALS. (Luftfororening vid framstalhiing av oorganiska baskemikalier.) Text in Swedish. Statens Natur- vardsverk, Stockholm, Publikationer No. 4, 66p., 10 refs. The investigation deals with air pollution problems in connec- tion with the manufacture of basic inorganic chemicals such as sulphuric acid, hydrochloric acid, phosphoric acid, ammonia, nitric acid, chlorine and sodium hydroxide. The report con- tains a survey of present conditions, an analysis of various technical methods to reduce the emissions, and a discussion of the economic consequences of these methods. The purpose of the survey is to supply information to the Swedish authorities dealing with air pollution control. The rates of emission from the chemical plants are described as kg/ton product. The costs of air pollution abatement vary. In certain cases, e.g., the recovery of sulphur in connection with the production of am- ------- NITRIC ACID PLANTS monia, the necessary investments can be written off. In other cases, e.g., introduction of the double-contact process for the manufacture of sulphuric acid, the increasing yield can only partially motivate the investments required. There are also cases when the costs entirely belong to the air pollution ac- count. A comparison between Swedish and foreign plants in- dicates that emissions are of the same magnitude. Essential improvements are possible to obtain in new plants and the latest Swedish production units have applied this to a great ex- tent. 21204 Hals, Finn A. ENVIRONMENTAL POLLUTION CONTROL THROUGH MHD POWER GENERATION. Combustion, 41(ll):27-29, May 1970. In addition to offering advances in power technology of sig- nificant benefit to society, magnetohydrodynamics (MHD) shows promise of solving serious air and thermal pollution problems faced by steam-electric power plants. The use of MHD-steam power plant could significantly reduce thermal pollution of water since, due to higher efficiencies, less than half the amount of cooling water used by conventional fossil- fueled steam power plants would be required. Since the sup- plemental steam turbine can be replaced with a supplemental gas turbine, MHD generators can be designed to reject all heat into the atmosphere and none to water. With no cooling water necessary, MHD generators can be located in water-poor but fuel-rich areas, opening them to industrialization. Particulate emission would be controlled by careful electrostatic precipita- tion, since the economic operation of the plant requires the recovery of an alkali seed impurity added to enhance electrical conductivity of the combustion gases. Particulate removal in excess of 99% is, therefore ensured. The temperatures at which MHD generators operate make the recovery of nitrogen oxides and sulfur oxides in the form of nitric and sulfuric acid technically feasible and economically attractive. 22877 Stuttgart Univ. (West Germany), Inst. fuer Verfahrenstechnik und Dampfkesselwesen KEEPING THE AIR PURE. (Reinhaltung der Luft). 58p., 1968. 25 refs. Translated from German. Belov and Associates, Denver, Colo., 80p., Feb. 5, 1970. A review of technical articles relating to air pollution is presented. Sampling techniques and statistical evaluation of results are discussed. The effects of gaseous impurities on hu- mans and plants are briefly mentioned. Maximum emission values for nitric oxide, nitric acid, chlorine, hydrogen chloride, hydrogen sulfide, and sulfur dioxide are tabulated. Measure- ment methods, including filters, absorption bottles, and vari- ous continuous methods are described. SO2 is generally mea- sured by the silica gel method, the West Gaeke method, the 'Ultragas 3' method, the Pico-flex instrument, or by infrared spectrophotometry. Isopropanol is a good absorption medium for sulfur trioxide. Dewpoint measurement and detectors are mentioned. NO2 can be measured by the Saltzman method, and by photometric or colorimetric means. Measurement of H2S and fluorine emissions may be done by the sodium hydroxide method. Methods for carbon monoxide and dioxide are mentioned. Organic compounds are measured by gas chro- matography. Methods for measuring and counting dust con- taminants, and stack sampling are discussed. Optical and elec- trostatic methods of determining smoke shade are described. The Konimeter, impinger, and dust fall methods are con- sidered. A disucssion of plume behavior, including stack height, turbulence, diffusion, and winds, is presented. Several laws regarding emissions are mentioned. 26226 Perrine, Richard L. and Limin Hsueh POWER AND INDUSTRY: CONTROL OF NITROGEN OXIDE EMISSIONS. In: Project Clean Air. California Univ., Berkeley, Task Force 5, Vol. 1, Section 9, lip., Sept. 1, 1970. 32 refs. When fossil fuels are burned with air some of the nitrogen reacts with oxygen forming nitrogen oxides; the major source of emissions of NOx in California is motor vehicles, but sta- tionary power sources and others also contribute large quanti- ties. The higher the peak combustion temperature the more nitric oxide is formed. Most current efforts to deal with the problem are centered on developing improved combustion processes and on the design of the burner and type of firing. Some improvement may be obtained through combustion process modifications, but these are constrained by existing designs, stable operating requirements, and adverse secondary effects. Some basic approaches which have been developed for removal of NOx emissions from nitric acid plant stack gases include catalytic decomposition, catalytic reduction, ab- sorption on solids, and caustic scrubbing. A number of modifi- cations to operating conditions or burner design include low excess air combustion, flue gas recirculation, steam and water injection, burner configuration, and fluidized bed composition. The complex interaction of mixing, heat transfer, fluid mechanics, and chemical kinetics within the burner needs to be understood. Simplified models of the combustion process are necessary to aid in the understanding of the critical processes controlling nitric oxide formation and to provide a means for the systematic analysis of cause-effect relationships. ------- B. CONTROL METHODS 00587 J.A. Brink, Jr., W.F. Burggrabe, L.E. Greenwell MIST REMOVAL FROM COMPRESSED GASES. Chem. Eng. Progr., 62(4):60-66, April 1966. Fiber mist eliminators have been successfully used to purify gases and solve difficult air pollution problems involving: methanol synthesis gas, sulfonation and chlorination process gases, nitric acid process gases, chlorine, and compressed air. Extensive research and development work resulted in the development of fiber mist eliminators for the collection of sub- micron mist particles. The first plant-scale installations were made for the control of air pollution from sulfuric and phosphoric acid plants. After full-scale units had been proven highly efficient on stack gases containing submicron particles, further research was undertaken to develop fiber mist elimina- tors which would be most economical for the collection of par- ticles which are predominantly 1 to 20 microns in diameter. The installation of fiber mist eliminators within various processes to purify gases was started after several difficult air pollution problems had been solved. The widespread applica- tion of fiber units to chlorine plants was reported in detail, but the applications to many other processes has not been re- ported previously. It should be noted that mists are present in many chemical processes at pressures ranging up to 5,500 Ib./sq. in. gauge. The temperatures at whcih mists are present are usually moderate since many mists vaporize at higher tem- peratures. 00959 B. B. Sundaresan, C. I. Harding, F. P. May, and E. R. Hendrickson A DRY PROCESS FOR THE REMOVAL OF NITROGEN OX- DDES FROM WASTE GAS STREAMS IN NITRIC ACD) MANUFACTURE. Preprint. (Presented at the 59th Annual Meeting, Air Pollution Control Association, San Francisco, Calif., June 20-25, 1966, Paper 66-96.) Experimental studies were conducted using a commercial zeolite to remove NOx from waste gas streams in a nitric acid plant. NOx retained in the bed was recovered as enriched NOx and HNO3 gy regenerating the bed at elevated tempera- tures with hot air and/or steam. Test results indicate that such a system could be incorporated into an existing nitric acid plant, thereby eliminating release of significant quantities of NOx into atmosphere. The conclusions are enumerated below: (1) A process to remove NOx from the waste gas streams of nitric acid plants has been found; (2) Complete NOx removal as proved by this system will eliminate release of NOx into the atmosphere; (3) Commercial zeolite used in this process can remove NOx along with most of the moisture present in the tail gas; (4) NOx and H2O retained in the bed has been recovered as enriched NOx and HNO3 for possible feedback into the process stream; (5) It has been estimated that in a 300 ton acid plant by feeding back the recovered NOx into the process stream, about 4 to 5 tons per day of 60% HNO3 now being wasted could be added to production; and (6) The in- creased production should offset the additional investment for such a system, making the process economically feasible. (Author summary and conclusions) 01125 D. Zanon and D. Sordelli PRACTICAL SOLUTIONS OF Am POLLUTION PROBLEMS FROM CHEMICAL PROCESSES . (Realizzazioni nel Campo delia Prevenzione dell' inquinamento Atmosferico di Origine Industriale.) Translated from Italian. Chim. Ind. (Milan), 48(2):251-261, March 1966. A strict control of pollutant to be dispersed in the atmosphere offers technical and economic problems, both in the design and the operation of chemical processing units. Three exam- ples of processes for which pollution control has been established are described: SO2 derived from contact sulfuric acid and from hydroxylamine sulfate plants, nitrous gas from low and high-pressure nitric acid plants, and fluorine-contain- ing effluents from hydrogen fluoride production. The general approach, kind of abatement process adopted, materials and construction costs are discussed. 02051 J. Feist. THE CATALYTIC REDUCTION OF NITROUS GASES DUR- ING THE MANUFACTURE OF NITRIC ACID. Die Kata- lytische Reduktion Von Nitrosen Abgasen Sei Der Erzeugung Von Salpetersaure. Proc. (Part I) Intern. Clean Air Cong., London, 1966. (Paper VI/15). pp. 199-202. Discusses a catalytic reduction process for reducing nitric oxide present in the waste gases from nitric acid for manufac- ture to a concentration of 100 ppm. Flow sheets illustrate ther- mal integration of the catalytic process with the overall process. Discusses the use of metal and ceramic catalysts. (Author abstract) 04658 R. W. Bayley DESORPTION OW WASTE WATER GASES IN ADI (PART 1). Effluent Water Treat. J. (London) 7, (2) 78-84, Feb. 1967. The air stripping of volatile or gaseous polluting constitutents from industrial waste waters in desorption units is used for pretreatment of the waste prior to descharge to a public sewer or stream. Where an air-pollution problem exists, the desorbed gas must be dispersed by stacks or the desorbed constituent recovered. The design of such desorbing units based on known chemical engineering principles is illustrated by examples of the removal of the cyanide from the effluent of a gas plant and ammonia from the effluent from a nitric acid plant. The desorption unit may use either duffused air bubbles passing through the liquid or counter-current towers packed with Rasching rings. 051511 B. A. Kerns CHEMICAL SUPPRESSION OF NITROGEN OXIDES. Westinghouse Electric Corp., Pittsburgh, Pa., Headquarters Mfg. Lab. (1964). 6 pp. ------- NITRIC ACID PLANTS An approach to NO and NO2 fume control by eliminating the fumes before their release from pickling, milling and bright dipping solutions was investigated. Since classical chemistry shows a reaction between most primary amines and the oxides of nitrogen, a study of an available, inexpensive, and readily adaptable amide, urea, was undertaken. The investigations in- cluded a thorough study of the urea-nitric acid-nitrogen oxides reactions for both copper and iron-68 analyses of the urea (for purity), and of the evolved gases; and the effect of the urea nitric acid system on the various types of stainless steels and other metals which could be employed. A thorough study of the possible hazards of the urea-nitric acid system was un- dertaken also . In the case of chemical milling urea sucessfully lowered the NO2 fumes to almost undetectable levels, but this treatment did not suppress the HNO3 vapors which coin- cidentally are released from these hot chemical milling solu- tions. Thus a small water scrubbing apparatus is still required to prevent these vapors from being released to the at- mosphere. The use of a HN03-urea solution system produces a satin finish in less than half of the time now required to bright dip and release no toxic fumes to the atmosphere. 05309 E. C. Betz and H. J. Feist CATALYTIC AFTERBURNING OF ORGANIC AIR POLLU- TANTS. Technik (Berlin) 20 (6), 395-400 (June 1965). Ger. (Tr.) Newly developed all-metal catalysts are discussed which are designed on the basis of the building block assembly system; in practice, they achieve an average running time of 25,000- 35,000 working hours. A catalyst, which speeds up a reaction because of its presence, without itself participating in the reac- tion, reduces the decomposition temperature during com- bustion. A reaction temperature of 250-350 C was achieved with all-metal catalysts developed for catalytic exhaust gas pu- rification. The cold exhaust gases flow through a heat exchanger and are preheated. Then they are heated by means of oil burners, gas burners, or electrical heating elements until they reach the catalytic reaction temperature. A fan then moves the exhaust gases to the catalyst where the irritants are oxidized. The heat released during catalytic combustion is lar- gely recovered in the heat exchanger and it is used for heating the cold exhaust gases as combustion here is exothermal. At a reaction temperature of about 250-350 C, all combustible com- ponents are oxidized in the exhaust gas. As a result of the temperature increase in the exhaust gas in the catalyst, the positive heat change of this reaction can measured which gives a figure directly proportional to the irritant concentration. The catalytic exhaust gas purification unit thus serves as a mea- surement instrument for the concentration of the exhaust gas. A measurement system used for continual surveillance is presented in diagram. Applications of catalytic afterburning are discussed in relation to the following: drying and hardening processes, phthalic acid and maleic acid anhydride production, nitric acid production, NO/NO2 reduction. 05401 ATMOSPHERIC EMISSIONS FROM NITRIC ACID MANU- FACTURING PROCESSES. Public Health Service, Cincinnati, Ohio, Div. of Air Pollution and Manufacturing Chemists As- sociation, Washington, B.C. 1966. 96 pp. (999-AP-27.) Emissions to the atmosphere from the manufacture of nitric acid were investigated jointly by the Manufacturing Chemists' Assoc., Inc. and the U.S.P.H.S.; the study was the second in a cooperative program for evaluation of emissions from selected chemical manufacturing processes. The report describes the growth and potential of the nitric acid industry, the principal processes for production of nitric acid, process variables, emissions from plants under normal operating conditions, and the methods and devices used to limit and control emissions. The sampling and analytical techniques by which emissions were assessed are presented in detail. (Author's abstract) 06123 O. Jeitner, and K. Konig ELIMINATION OF NITROUS GAS EMISSION BY CATA- LYTIC REDUCTION. Beseitigung der Nitrosegasemission durch katalytische Reduction. Chem. Tech. (Berlin) 19, (3), 166-9, Mar. 1967. Ger. At the nitric acid plant in Piesteritz, East Germany, NO in the waste gas was to be catalytically reduced by hydrogen. The hydrogen was a by-product and contained 0.1% by volume of H2S and 0.05% by volume of PH3, both toxic to the Pd catalyst used. Therefore, the hydrogen had to be washed by passing it through two washing towers containing 30% HNO3. One tower also contained 15% NaOH and the other water. Complete elimination of the NO was possible using 0.4 to 0.6% more hydrogen than the stoichio metrically required volume. If the flow of hydrogen through the catalyst is closely controlled, the resulting nitrogen is virtually free of oxygen and hydrogen. 06844 H. C. Anderson, P. L. Romeo and W. J. Green A NEW FAMILY OF CATALYSTS FOR NITRIC ACID TAIL GASES. Engelhard Ind. Tech. Bull. 7 (3), 100-5 (Dec. 1966). The palladium unitory ceramic catalyst remove oxides of nitrogen from tail gases produced during the production of nitric acid was evaluated. The new catalyst, provides excellent abatement at 100 p.s.i.g., using space velocities of 100,000. Even at 150,000, 94% of the NOx was removed, with ammonia in only slight excess over the NOx. Bench-scale and field ex- perience have shown that the unitary ceramic catalyst is well adapted to the treatment of nitric acid stack gases. 07093 REVIEW OF RESTRICTING GAS EMISSION FROM NITRIC-ACID PLANTS. ((VDI (Verein Deutscher Ingenieure) Kommission Reinhaltung der Luft, Duesseldorf, Germany,)) (VDI No. 2295.) (July 1963) Ger. (Tr.) 12 pp. The control of nitrogen oxides during the production of nitric acid was discussed. Nitrogen oxides emissions are restricted by absorption, suitable discharge outlets, and on the basis of missions. Because of the particularities of nitrous gases, the content of the waste gases cannot be completely controlled. 07535 W. Leithe CLEAN AIR MAINTENANCE - AN IMPORTANT TASK FOR CHEMISTRY AND ECONOMY. (Reinhaltung der Luft ein dringendes Anliegen fur Chemie und Wirtschaft.) Text in Ger- man. Allgem. Prakt. Chem. (Vienna), 18(8):239-241, Sept. 10- 17, 1967. 4 refs. This article is a summary of two lectures given at meetings of chemical societies. The problem of air pollution and some con- trol methods are outlined. Typical examples of well-known air pollution problems are mentioned: London's smog chiefly caused by domestic heating, the smog of Los Angeles due to automobiles, the sun, and temperature inversions, and the in- dustrial air pollution of the Ruhr Valley. Some characteristic data for all three examples are quoted. The techniques for the control of dust emissions are farthest advanced. This is ------- B. CONTROL METHODS verified by the fact that in Germany, emission of cement dusts decreased to one third while the production of cement tripled in the last 17 years. Far less satisfactory is the control of SO2 emissions. About twice as much sulfur is blown into the air than is used for the production of sulfuric acid. Some wet and dry processes for the elimination of SO2 from smoke are men- tioned, but no method is known today which is both effective and economical. The chemical industry tackled its problems mostly by reducing the emission of air polluting substances by increasing the efficiencies of the relevant chemical processes. Examples are the production of sulfuric acid and nitric acid. Organic compounds can be recovered by either absorption on activated charcoal or oxidation by catalytic afterburners. 07552 Billings, Charles E., Charles Kurker, Jr., and Leslie Silverman SIMULTANEOUS REMOVAL OF ACID GASES, MISTS, AND FUMES WITH MINERAL WOOL FILTERS. J. Air Pollution Control Assoc., 8(3):195-202, Nov. 1958. 20 refs. (Presented at the 51st Annual Meeting, Air Pollution Control Assoc., Philadelphia, Pa., May 26-29, 1958.) Investigations have indicated that two in. thick filters at four Ib/cu. ft. packing density will remove up to 80% of acid mist and up to 99% of acid gases and fumes. Total filter life de- pends upon concentration of contaminant in the entering air. A summary of filter performance is given. Estimated operating life based upon one use of the filter material can be obtained from the data given. With particulates such as iron oxide and fly ash, it has been found possible to wash and reuse filters about ten times. When iron oxide was collected simultaneously with SO2, filters were reused about eight times. Acid gas col- lection is significantly improved by the presence of moisture on slag wool filters. Mineral wool filters have several features such as, low cost (about 1 cents/lg.), small fiber diameter (4 micron and ability to withstand high temperatures (1000 deg F.). Slag wool will simultaneously remove sub-micron particu- late materials with 90 to 99% efficiency. Resistance to flow through two in. slag wool filters (with an HF efficiency of 95%) is on the order of one or two in. of water, or if continu- ously moistened, at most 6 in. of water. 09773 FAN SCRUBBER HALTS CORROSION ENDING NEED FOR ROOF REPAIRS. Chem. Process., 31(4):67, April 1968. The manner in which escaping acid fumes were controlled at a particular plant is described. An existing system of water scrubbers was supplanted by a separator based on a centrifu- gal fan. Flow through the separator is 14,000 cfm of an ex- haust containing 750 ppm of nitric acid and nitrogen oxides and 350 ppm of hydrofluoric acid. Most of the fumes are separated by centrifugal force in the fan, into which 6 gpm of water is sprayed. The partially cleaned exhaust then passes through a 48 x 80 x 6 in thick polypropylene filter which removes nearly all of the remaining wetted fumes. Fumes leav- ing the separator were reduced to trace amounts. Scrubbing water requirements were reduced by 34 gpm. The complete system was installed at a cost of $8100, less thatn $.70 cfm. 09981 Tikhonenko, A. D. and M. N. Nabiev NATURAL-GAS CATALYTIC REDUCTION OF NITRIC OXIDE TADL GASES FROM NITRIC ACID PRODUCTION. Translated from Russian. Uzbesk. Khim. Zh., ll(4):6-9, 1967. 2 refs. CFSTI: PB 178106T The catalytic reduction of nitrogen oxides is the most progres- sive means of purifying tail gas from nitric acid production. The process of catalytic reduction of nitric oxides by methane in the form of natural gas at atmospheric pressure with the use of platinized nickel-chromium foil and a two-layer catalyzer is described. In operation over 710 hrs, the nickel-chromium foil showed sufficient thermal stability under conditions assuring complete purification of the gas; catalyst activity significantly decreased and was reduced with H2 at 320 deg. C. The condi- tions for complete nitric oxide reduction were found and also those for achieving the sanitary norm of NO+NO2 content (0.02 percent). In a two-layer catalyst it was possible to decrease the temperature of the gas entering the catalyzer to 450 deg. and the resulting CH4:O2 ratio was 0.8. 10017 Bloomfield, Bernard D. CONTROL OF GASEOUS POLLUTANTS. Heating, Piping, Air Condition ing, 40(1): 195-206, Jan. 1968. 26 refs. Control technology in relation to air pollution involves the ap- plication, singly or in combination, of tall stacks for dispersio process changes, and control equipment. Most gaseous con- taminants can be controlled using the techniques of absorp- tion, adsorption, direct flame combustion, and catalytic com- bustion. The theoretical principles of design and operation preclude under most circumstance the use of any of the shelf items for air pollution control purpose Good design, construc- tion, and proper operation are the requisites of a satisfactory system. The special characteristics of a number systems are described. A table of selected air quality standards i given for such pollutants as SOx, NOx, CO, H2S, and ozone. 10159 Atroshchenko, V. I., and E. G. Sedasnova RATE OF NITROGEN OXIDES ABSORPTION BY AL- KALINE SOLUTIONS AND NITRIC ACID. Zh. Prikl. Khim., 25(11):! 143-1150, 1952. 13 refs. Translated from Russian by B. S. Levine, U. S. S. R. Literature on Air Pollution and Related Occupational Di- seases, Vol. 6, 299p., April 1961. CFSTI: TT 61-21982 The absorption of nitrogen oxides by alkaline solutions has be- come economically advantageous to the nitric acid industry. In connection with the complex processes which take place in the for mation of nitric acid and alkaline nitrates from nitric oxide, an experimental study was made of the relative velocity of the total nitric oxide conversion at different ratios between acid and alka line absorption. The results of the study demon- strated that a functional relationship existed between the degree of nitrogen oxides absorption and the increase in the specific gravity of al kaline absorbers, accompanied by a cor- responding reduction in the degree of nitric acid absorption. The results also established that at the combined production of nitric acid and sodium nitrate by the method of increasing the degree of nitrogen oxides absorp tion by alkaline solution, the reaction volume can be reduced considerably. 11058 W. Teske IMPROVEMENTS IN THE PROCESSES AND OPERATION OF PLANTS IN THE CHEMICAL INDUSTRY LEADING TO REDUCED EMISSION. Staub (English translation), 28(3):25- 33, March 1968. CFSTI: TT 68-50448/3 The emissions from chemical plants can be reduced, in special cases, by changing the production process or, in general, by using a gas cleaning method. Change in the production process ------- NITRIC ACID PLANTS may be achieved by a basic alteration of the process itself, by changing the mode of operation, by modifying the equipment and by using a different raw material. For this purpose, the doublecontact method for sulphuric acid production, the pres- sure method for nitric acid recovery and the introduction of a covered carbide furnace are mentioned as examples. The su- perphosphate process, viscose process, production of betanaphthol, production of thermal phosphoric acid and production of calcium chloride are given as examples for waste gas cleaning. (Author's summary) 11549 Bingham, E. C. Jr. NITRIC ACID PLANT'S CATALYTIC BURNER PREVENTS TAIL GAS STREAM AIR POLLUTION. Preprint, Farmers Chemical Association, Inc., Tyner, Tenn., 3p., 1968. Air contamination is prevented from a ton per day nitric acid manufacturing plant by passing the tail gas through a catalytic burner which reduces residual oxides of nitrogen into a color- less stream. After purification in the combustion chamber, which contain a catalyst charge, the exhaust stream can be safety directed to a turbine expander for power recovery to assist in driving the main compressor of the acid manufactur- ing unit. The catalytic reaction also increases the life of the expander because the afterburner exhaust stream has no nitric acid carry over that could eventually strip out the turbine blades. Tests conducted during the first six months of opera- tion of the charge showed a cleanup of NO2 pollutants ranging between 95 and 98 percent. The unit maintained the high rate of reduction of fumes while operating at space velocities in the order of 120,000 cubic feet of gas per cubic foot of catalyst system per hour. 12637 W. Teske EMISSIONS AND ABATEMENT OF OXIDES OF NITROGEN IN NITRIC ACID MANUFACTURE. Chem. Eng., No. 221, CE263-266, Sept. 1968. The emission problem in the manufacture of nitric acid results from incomplete conversion of nitrous oxide to nitric acid. Some of the processes for reducing the emissions which are discussed briefly include: Alkaline absorption with milk of lime or aqueous ammonia; oxidation with hydrogen peroxide or ozone; absorption in an aqueous solution of magnesium ox- ide; removal as nitrosylsulfuric acid by treatment with a sul- furic acid, nitric acid mixture; and catalytic reduction processes. 13202 Schmitt, Karl, Wilhelm Ester, Hans Heumann, and Harry Pauling NITROGEN OXIDE CONVERSION. (Hibemia Chemie GmbH, Gelsenkirchen-Buer, Germany, and Harry Pauling, Munich, Germany) U. S. Pat. 3,453,071. 7p., July 1, 1969. 4 refs. (Appl. May 16, 1966, 29 claims). In the production of nitric acid and other nitrogenous products, exhaust gas is produced which contains significant quantities of nitrogen oxides, particularly NO and NO2. A process for absorbing these oxides and recovering them as am- monium nitrite includes adjusting the mole ratio of NO to NO2 to 1 and then introducing the adjusted gas into an ammoniacal solution of ammonium nitrate. The ammonium nitrate content of the absorbent solution is controlled so that the solution viscosity at any given temperature is higher than the viscosity of water at the same temperature. When the ammonium nitrate concentration is maintained at about 40 to 50 weight percent and the absorption process is operated at 20 to 30 C, at least half the ammonium nitrite formation takes place at the liquid- vapor interface. The remainder of the ammonium nitrite is produced in the gas phase by successive absorption of small amounts of gaseous ammonia in the vapor space, where it is neutralized with water vapor and nitrogen oxide to form am- monium nitrates as well as the ammonium nitrites. These dis- solve in the absorbent solution. By preventing the develop- ment of easily decomposable ammonium nitrite mists, the process minimizes efficiency losses and explosion dangers. 13205 Markvart, Miroslav and Vladimir Pour SELECTIVE REDUCTION OF NITROGEN OXIDES WITH AMMONIA. (Selektivni redukce kyslicniku dusiku amoniakem). Text in Czech. Chem. Prumysl (Prague), 19(1):8- 12, 1969. 12 refs. In manufacturing nitrogen acids, catalytic reduction of nitrogen oxides in fall gases is the most effective method of neutralization. Using ammonia as a catalyst, nitrogen oxides can be selectively eliminated. The consumption of fuel using ammonia is approximately ten times lower than with other reducers. Tests were conducted to gain more information about the method. All measurements were taken under at- mospheric pressure, and the reaction took place in the kinetic range. Nitrogen oxides were detected by the standard titrimet- ric method. Catalyzers were prepared by depositing active metal on aluminium. In the absence of oxygen, the reduction is fastest on platinum catalyzers; 95% conversion is reached with temperatures above C. In the presence of oxygen on the same catalyzer, the temperature may be as low as 180 C. The increase in speed of reaction is most evident with small con- centrations. The activity of the catalyzer is greatest when the amount of Pt is 1%. In all of the tests, the greater the speed of the gases, the higher the temperature must be. The only disad- vantage of this method is that ammonia salts are generated that may deposit on the cool parts of the reactor. 13689 Atroshchenko, V. I., A. N. Tseytlin, A. P. Zasorin, and V. S. Zolotarev UTILIZATION OF NITROGEN OXIDES - BY-PRODUCTS OF CERTAIN INDUSTRIES. (Utilizatsiya okislov azota otk- hodov nekotorykh proizvodstv). Text in Russian. Khim. Prom. (Moscow), 1(1):79- 80, 1960. Production of nitric acid from exhaust gas with high NO con- tent as compared with exhaust gas with low NO content plus NO2 is discussed. A method is described which involves cool- ing the gases to 25-30 C, introducing additional air, and carry- ing out oxidation in a cooler-oxidizer. About 8% absorption is achieved with 35% nitric acid absorbent. Specifications for an operating installation which produces 2500 kg of 55% acid are given. A modified version using oxygen rather than air is men- tioned. 13893 Anderson, H. C., P. L. Romeo, and W. J. Green A NEW FAMILY OF CATALYSTS FOR NITRIC ACID TAIL GASES. Nitrogen, no. 50:33-36, Nov./Dec. 1967. 6 refs. A unitary ceramic cartridge was designed to act as a precious metal catalyst support. The support consists of a block of ceramic, through which a multitude of small parallel channels pass which are coated with the precious metal. Bench-scale and field experience have shown that the unitary catalyst is ------- B. CONTROL METHODS well-adapted to the treatment of nitric acid stack gases. Using natural gas as a fuel, decolorization of stack gases is effected using palladium as the catalyst on the ceramic support. The ceramic structure is well designed for the two-stage catalytic removal of NO and NO2 in gases containing more than the 3% maximum oxygen level required for one stage removal. By ap- plying platinum-alumina on the ceramic cartridge, excellent abatement (94%) of the nitrogen oxides present in the gases is achieved at 100 psi and space velocities up to 150,000. 13899 Varlamov, M. L., G. A. Manakin, Ya. I. Starosel'skiy, and L. S. Zbrozhek INVESTIGATION OF THE AMMONIA METHOD OF REMOVING NITROGEN OXIDES FROM THE EXHAUST GASES OF A NITROGEN-OXIDE NITRIC-ACID TOWER SYSTEM. I. (Issledovaniye ammiachnogo metoda ochistki ot okislov azota otkhodyashchikh gazov bashennoy nitroznoy semokislotnoy sistemy). Text in Russian. Nauchn. Zap. Odessk. Politekhn. Inst., vol. 40:24-33, 1962. 4 refs. Data from laboratory study of the removal of low concentra- tions of nitrogen oxides using gaseous ammonia and ammonia water are presented. The use of gaseous ammonia, in conjunc- tion with acoustic coagulation with an aerosol, yielded an average degree of removal of 85% when incoming gases were highly oxidized. Nitrogen dioxide, and an equimolecular mix- ture of NO and NO2, reacted with 82-93% completeness with gaseous ammonia, this value increasing slightly with increased reaction volume. A gas lift using ammonia water yielded 63.6% purification with a 40% content of nitrogen oxides. The degree of oxidation of industrial exhaust gases is an important factor determining the degree of purification by this method. The data given correspond to an equimolecular NO and NO2 mix- ture. 14007 Hsieh, Yu Hsioh AN EXPERIMENT IN THE PRODUCTION OF NITROGEN FROM NITRIC ACID PLANT TAIL GAS. (Ts'ung hsiao suan wei ch'i chih ch'i fan ch'i ti shih yen). Text in Chinese. K'o Hsueh T'ung Pao, vol. 10: 307-308, 1957. 6 refs. By passing nitric acid tail gas first an alkali scrubbing tower to remove CO2 and then through a catalyst reactor to reduce NO2 and O2 in the presence of excess hydrogen, it was found practical to recover nitrogen. Three types of catalysts were made by depositing Cu and Ni on soil diatoms: CuO:diatoms, NiO:diatoms, and CuO plus NiO:diatoms, all in a 1:9 ratio. The highest absorption rate could be attained with a sodium hydroxide concentration of 1% and a gas linear velocity of 0.2 m/sec. The concentration of CO2 could be reduced to 30 ppm. By using CuO with a firebrick carrier at a temperature of 600- 650 C, a space velocity of 6000 reciprocal hours, and 4-6% ex- cess hydrogen, it was possible to produce a gas with 1-5 ppm NO, 10-20 ppm 02, and 400 ppm NH3. By using the copper- nickel catalyst with diatoms as carriers at a temperature of 300-500 C, a space velocity of 1500 reciprocal hours, and 5% excess hydrogen, a gas with 0.4-0.7 ppm NO, 10-20 ppm 02, and 300-500 ppm NH3 could be produced with the content of noxious gas within acceptable limits. The temperature of reac- tion increases rapidly with oxygen content of the tail gas and with space velocity. Since the reactor was of simple construc- tion, there was no way to control the temperature, and no tests were performed under conditions of low temperature and high space velocity. 14382 Pozin, M. E., B. A. Kopylev, and G. V. Bel'chenko ABSORPTION OF NITROGEN OXIDES WITH A SODA SOLUTION IN A FOAM APPARATUS FOR THE PRODUC- TION OF SODIUM NITRATE. (Pogloshcheniye okislov azota sodovym rastvorom v pennom apparate dlya proizvodstva nitrata natriya). Text in Russian. Tr. Leningr. Tekhnol. Inst. Imen. Lensoveta, vol. 36:120-32, 1956.12 refs. A foam apparatus proved effective for the alkaline absorption of nitrogen oxides for the purpose of producing nitrates and decreasing the loss of nitrogen oxides in the production of nitric acid. The coefficient of efficiency of a single platform- cascade apparatus was decreased from 30 to 16% on increas- ing the linear gas flow rate from 0.5 to 3 m/sec in a cross sec- tion of the foam apparatus. The coefficient of absorption in- creases with increase in the linear flow rate of the gas, attain- ing a value of 1860 kg/sq m-hr-kg/cu m, which was approxi- mately 6-7 times larger than the value of the absorption coeffi- cient for a packed column under laboratory conditions, and 20- 25 times greater than for factory-type scrubbers. With increase in the rate of flow of the liquid, the efficiency of a single plat- form of the apparatus and the coefficient of absorption in- creased insignificantly. Thus, increase in the rate of flow of the liquid by 3 times (from 1 to 3 cu m/hr) at a gas flow rate of 1 m/sec leads to an increase in efficiency of 22-24%. In- crease in the concentration of absorbent in solution from 5 to 20% Na2CO3 at a linear gas flow rate of 1 m/sec leads to a decrease in efficiency from 26 to 16%. Correspondingly, the coefficient of absorption is also decreased. If the initial con- centration of nitrogen oxides in the gas is increased from 0.05 to 1.4% at a linear gas flow rate of 1 m/sec, the value of the efficiency of a single platform of the apparatus increased from 8 to 25%. Choice of the number of platforms in the apparatus can be based on the data for a single platform in accordance with the required degree of absorption of nitrogen oxides. 14387 Nabiyev, M. K., A. A. Kulik, P. T. Merenkov, and A. D. Tikhonenko PURIFICATION OF NITROGEN OF EXHAUST GAS IN THE PRODUCTION OF WEAK NITRIC ACID FOR THE SYNTHESIS OF AMMONIA. (Ochistka azota vykhlopnogo gaza pri proizvodstve slaboy azotnoy kisloty dlya sinteza am- miaka). Text in Russian. Dokl. Akad. Nauk Uz. SSR, 20(11): 17-20, 1963. 9 refs. The small amount of nitrogen oxides in exhaust gases was reduced by natural gas using a nickel catalyst. On a platinum- nickel catalyst, a volume rate of 2800 cu cm was obtained. Complete purification occurred at 500-600 deg. The resulting gas containing 93.85% nitrogen, can be used for the synthesis of ammonia. A method is proposed for a single-step conver- sion to a nitrogen-hydrogen mixture using water vapor and nitrogen obtained by catalytic purification of exhaust gas. 14481 Van Der Drift, J. CATALYTIC REMOVAL OF NITROGEN OXIDES FROM WASTE GASES OF NITRIC ACID PLANTS. A METHOD FOR THE PREVENTION OF Affi POLLUTION. (Katalytische verwijdering van N-oxyden uit afgewerkte gassen van salpeter- zuurfabrieken. Een methode voor de bestrijding van luchverontreiniging). Text in Dutch. Chem. Tech. (Amster- dam), 24(10):301-305, 1969. 11 refs. Removal of nitrogen oxides from nitric acid plants can be achieved by catalytic decomposition or reduction. The cata- ------- 8 NITRIC ACID PLANTS lytic decomposition follows the reaction 2NO yields N2 plus O2. With a copper-silica gel catalyst, the nitrogen oxide con- tent of waste gas was reduced from 892 to 277 ppm at 510 C. The reduction method uses hydrogen, natural gas, or ammonia as reducing agents. Various installations for the removal of nitrogen oxides from waste gases are described. A heat exchanger is used to lower the temperature of waste gases from around 515 C to 300 C after reduction. Several commer- cial catalysts are described. In an experiment using Honeycombgrid HCM-S-900 and ammonia, waste gas of 100,000 vol/vol catalyst/hr containing 0.3% nitrogen oxides and 3% O2 (inlet temp. 286 C) was reduced to 50 ppm NO2 and 86 ppm NO plus NO2. Using 0.3% Pt on a Torvex ceramic honeycomb and natural gas, waste gas of 100,000 vol/vol catalyst/hr containing 0.3% nitrogen oxides and 2.58% O2 (in- let temp. 440 C) was reduced to 58 ppm nitrogen oxides. 14533 A METHOD FOR THE RECOVERY OF NITROGEN OXIDES. (Werkwijze voor het winnen van stikstofoxyden). Text in Dutch. (Universal Oil Products Co., Des Plaines, HI.) Dutch Pat. 6,607,036. 13p., Nov. 25, 1966. (Appl. May 23, 1966, 8 claims). The system is particularly suited to handling tail gases from a nitric acid factory and from the lead chamber process of a sul- furic acid factory. This method also gives a distinct improve- ment in the output of a nitric acid plant. The waste gas is passed over a bed of adsorbing coal particles followed by a hot fluid desorption medium to remove the adsorbed nitrogen oxides from the particles. The desorption medium consists of steam at about 10 atm at a temperature greater than 157 C and preferably more than 177 C. The nitrogen oxide-containing steam is cooled and the mixture obtained is returned to the ad- sorption zone of the nitric acid plant. The desorption medium can also be hot air. The depth of the bed should not exceed 0.3m to prevent a large pressure drop. The stream waste gas through the adsorption bed is diverted upon saturation with nitrogen oxides to another bed of adsorbing coal. The coal in the first bed is then desorbed until the second bed is saturated and the cycle is repeated. Waste gas from sulfuric acid plants is treated the same way. The advantages of this method are better removal of nitrogen oxides with cost reduction, since no extra fuel is required. Due to integration of the units for preparation of acid and for recovery, higher output is ob- tained; output of a nitric acid plant can be increased by 5% by more complete use of NO2. 14568 Safiullin, N. Sh. and M. I. Olevinskiy RENDERING HARMLESS THE WASTE GASES FROM SUL- FURIC ACID TOWER SYSTEMS. (Obezvrezhivaniye otk- hodyashchikh gazov bashennykh sernokislotnykh sistem). Text in Russian. Khim. Prom. (Moscow), no. 3:132-136, 1955. It is reported that a complex consisting of a precipitation sec- tion irrigated with strong acid and a moist electrofilter will as- sure reliable purification of waste gases from tower systems. Such a system reduces the aerosol and vapor sulfuric acid content to 0.04-0.10 g/cu m, a 20-fold reduction. Complete ab- sorption of an equimolar mixture of nitrogen oxides results in a reduction in specific consumption rate of nitric acid by 6-8 kg/ton. Absorption of nitrogen oxides and reduction of nitric acid discharge rate may be increased significantly by supplying the equipment with nitrogen oxides with a degree of oxidation of 45-50%. In order to assure normal operation of the equip- ment, the amount of original sulfuric acid circulating in it must be not less than 88%. Joint operation of both the irrigating system and the electrofilter is imperative for proper purifica- tion of waste gases. 14664 Atsukawa, Masumi, Yoshihiko Nishimoto, and Naoyuki Takahashi STUDY ON THE REMOVAL OF NITROGEN OXIDES FROM EFFLUENT STACK GASES. Mitsubishi Heavy Industries, Ltd., Tech. Rev., 5(2):129-135, May 1968. 9 refs. Pilot plant tests of the Mitsubishi process for removing nitrogen oxides from stack gases demonstrate that nitrogen ox- ides can be economically reduced to less than 0.02% of gas content. By limiting threshold concentrations of nitric acid to 200 ppm or below, the method should meet the removal requirements of the major sources of nitrogen oxide emis- sions: metal pickling plants, nitric acid plants, chemical plants using nitric acid, nitrate, and nitrite plants. Nitric oxide is con- verted to NO2 by either homogeneous or catalytic oxidation, while nitrogen compounds are recovered through absorption of stack gases in wetted-wall towers packed with PVC sheets. Homogeneous oxidation is a slow process and requires large equipment. However, this equipment is easy to operate. Cata- lytic oxidation can be performed on small-scale equipment, but the catalyst is affected by water, dust, and mist present in the effluent gas and regeneration is necessary. The PVC equip- ment has a large absorption coefficient and a small pressure drop. 15152 Schwanecke, Rudolf WASTE GAS CLEANING THROUGH COMBUSTION OF NITROGEN OXIDES. (Abgasreinigung durch Verbrennen von Stickstoffoxyden). Text in German. Zentr. Arbeitsmed. Ar- beitsschutz, 19(9):262-264, 1969. 3 refs. Various methods for elimination of NO and NO2 from waste gases are reviewed. Absorption of the nitrogen oxides on silica gel has recently interested the nitric acid plants. Water vapor is used for desorption, and the recovered nitrogen oxides are returned to the nitric acid plant. If no recovery of the nitrogen oxides is desired, they can be removed from waste air by scrubbing with water or bases such as sodium hydroxide or ammonia water. The reaction follows the equation 3NO2 + H2O yields 2HNO3 + NO. As can be seen, only NO2 is removed. A patented process for dissociation of NO and NO2 in the reducing part of the flame is based on the reaction of carbon monoxide with NO2 and NO in a flame sustained in an atmosphere of low air. The reaction follows the equation 2NO + 2CO yields N2 + 2CO2. It has also been discovered that the nitrogen oxides dissociate in an atmosphere of 20% or more excess air. The process depends on the thorough mixing of the gases with the flame, as accomplished by atomization. In a chemical plant, NO and NO2 are eliminated by a combination of scrubbing and combustion. Nitric oxide escapes from the scrubber at a rate of up to 30 cu m/hr with a temperature of 30 C. It is mixed with air and atomized with the fuel oil in a muf- fle furnace; it serves as combustion air and as an atomizing agent for the fuel oil. About 3 to 5 ppm of NO and NO2 were measured in the waste gas of the furnace. 16726 Kazakova, E. A., R. Z. Khiterer, and V. E. Bomshtein PURIFICATION OF EXHAUST GASES FROM NITRIC ACID PLANTS. Brit. Chem. Eng., 14(5):667-668, May 1969. The presence of unabsorbed nitrous gases in the tail gases from nitric acid plants created a serious pollution problem and ------- B. CONTROL METHODS efforts to deal with it have followed various lines. In this arti- cle a pilot plant that applies the principle of adsorption of the nitrogen oxides by a fluidized stream of silica gel particles is described. The pilot plant consisted of an adsorption column operating at 5.5 atm and a desorber operating at atmospheric pressure. In the adsorption column, fluidized silica gel flows counter-current to the gas stream. The NO is partly oxidized to NO2 and adsorbed on the silica gel. The adsorbent satu- rated with NO2 is withdrawn from the adsorber base and passes to the desorption column. Here the adsorbent is heated with steam to 180 to 190 C while a current of air desorbs the silica gel. The desorption products, after dedusting in a cyclone are returned to the process. 19847 Kazakova, E. A., R. Z. Khiterer, and V. E. Bomshtein PURIFICATION OF EXHAUST GASES FROM NITRIC ACID PLANTS. Brit. Chem. Eng., 14(5):667-668, May 1969. (Also: Khim. Prom. (Moscow), vol. 7:517, 1968.) A method for adsorbing the exhaust gases from a nitric acid plant is discussed. Exhaust gases were cooled with water and brine to O C, and after separation of condensate, entered the 500 mm diameter adsorption column. This has 22 trays spaced at 400 mm, and fluidized silica gel flows from tray to tray, countercurrent to the gas stream. Nitric oxide is partly ox- idized to nitrogen dioxide and is adsorbed on the silica gel. The adsorbent saturated with NO2, is withdrawn from the ad- sorber and passed to the desorption column. This column is heated with steam to 180 to 190 C, while an air current desorbs the silica gel. The desorption products, containing 65% acid vapor, water, NO2, nitrogen, and oxygen, after dedusting in a cyclone, are returned to the process. It was found con- venient to locate the adsorption column above the desorber, and to conduct both operations at 5 atm. A gate valve controls the flow between columns; a penumatic conveyer transfers the adsorbent from column base to column head. By raising the temperature in the desorber to 190 C, the nitrogen oxides con- centration can be reduced to 0.01%. 20313 Newman, Daniel J. and Jorge M. Malta APPARATUS FOR NITROGEN OXIDES ABSORPTION TO PRODUCE CONCENTRATED NITRIC ACID. (Chemical Con- struction Corp., New York, N. Y.) U. S. Pat 3,499,734. 7p., March 10, 1970. 4 refs. (Appl. Jan. 5, 1967, 14 claims). An apparatus is provided for the absorption of nitrogen oxides from a gas stream into an aqueous absorbent solution to form nitric acid, in which re-oxidation of nitric oxide also takes place. The apparatus is provided with a lower combination heat exchanger-absorber section in which the simultaneous ab- sorption of nitrogen dioxide, re-oxidation of nitric oxide, and cooling of the liquid phase takes place. Two or more heat exchanger sections may be provided in series. A gas-liquid contact section such as a packed section or a plurality of per- forated trays is provided above the heat exchanger sections. The feed gas stream containing nitrogen oxides and excess free oxygen is passed into the apparatus below the heat exchanger sections, while the aqueous absorbent solution is admitted above the upper gas-liquid contact section. (Author abstract) 20775 Ermenc, E. D. CONTROLLING NITRIC OXIDE EMISSION. Chem. Eng., 77(12):193-196, June 1, 1970. 1 ref. Industries using nitric acid in their processes should now be planning to meet the anticipated legal standards, which may limit emissions of nitrogen oxides to about 500 ppm. Data for controlling emissions are presented. The reaction kinetics of nitrogen and oxygen in air are characterized at high tempera- tures by standard second-order equations, while the reaction becomes zero orders at temperatures below 2000 F. Because the reverse reaction rate is many times greater than the for- ward rate, cooling must be very rapid to retain nitric oxide, and very slow to promote its reversion to oxygen and nitrogen. The problem of pollution control is that most processes involv- ing high temperatures are designed for minimum residence time (i.e., rapid cooling) to reduce capital requirements. Below 3200 F, the rate of formation controls nitric oxide production; above 3200 F, the reverse rate is the controlling factor. Nitric oxide production departs from equlibrium at a maximum around 2800 F, and then approaches equilibrium at 3200 F. As 3200 F is passed, the departure from equilibrium becomes more pronounced with rising temperature, showing the effect of the reverse reaction rate. Emissions could be lowered by some of the following means: better recovery through refrigeration, cooler circulating acid, or the compression of nitrogen oxides after the condensing phase; a good balance of oxygen after condensation to oxidize nitric oxide; catalytic in- cineration of tail gases to reduce nitrogen oxides to nitrogen and oxygen; and further absorption tail gases in an alkaline tower followed by catalytic incineration. Besides being a func- tion of temperature, the formation of nitric oxide also depends on the amount of excess air used in a process. 21232 Hunter, J. B. PLATINUM CATALYSTS FOR THE CONTROL OF AIR POLLUTION. A TAIL GAS REDUCTION SYSTEM FOR NITRIC ACID PLANTS. Platinum Metals Rev., vol. 9-12:2-6, 1965-1968. 1 ref. Effective reduction of nitrogen oxides, hydrocarbons, and or- ganic vapor is obtained by the use of platinum catalysts sup- ported by a ceramic honeycomb. Use of the ceramic honeycomb support overcomes the two principle objections to platinum as a catalyst in pelletized form, pressure drops across pelleted beds, and loss of fines. Other important advantages for honeycomb catalysts are the elimination of hot spots, more uniform gas distribution, greater structural strength, and no channelling. From the standpoint of system design, the rigid structure also provides greater process flexibility. Horizontal as well as vertical reactors may be used. In nuclear power in- stallations, intense radiation causes the decomposition of water into a hydrogen/oxygen mixture. Platinum honeycomb catalysts are effective as hydrogen/oxygen recombiners. 23372 Teske, W. EMISSIONS AND ABATEMENT OF OXIDES OF NITROGEN IN NITRIC ACID MANUFACTURE. Chem. Engr. (London), 46(7):263-266, Sept. 1968. The 12 nitric acid factories of West Germany, producing acid mainly for use in fertilizers, emit a total of about 100 tons/day of nitric oxide. Stack gases have a brown color, due to a visi- bility limit of 200 ppm NO. New plant construction is of the pressure type, in which the NO content of the stack gases is about half that of older plants. The NO content of these gases is due to the incomplete conversion, or the absorption yield, of NO to nitric acid. Thus, to eliminate the NO in the waste gases, the absorption yield must be increased or the NO destroyed. Various absorption processes are briefly reviewed ------- 10 NITRIC ACID PLANTS in terms of possibilities for accelerating absorption, but total absorption in an acid system is not practical. Catalytic reduc- tion processes reduce nitrogen oxides by means of hydrogen, hydrocarbon gases, or ammonia, and can be carried out in two stages: partial reduction of the NO2 to NO (decoloring the waste gases), and total reduction of NO and NO2 to N2. Because the price of the reducing agent is a decisive factor, an attempt should be made to decompose the nitrogen oxides directly, which would permit general adoption of catalytic pu- rification by the nitric acid industry. 23880 Stankus, L. NAPCA'S SEARCH FOR FLUE GAS DESULFURIZING PROCESSES. Preprint, 22p., 1969 (?). (Presented at the Gor- don Research Conference, Aug. 18-22, 1969.) The National Air Pollution Control Administration's work on sulfur oxides and nitrogen oxides control is summarized by briefly stating the scope of major investigations, showing prin- cipal concepts generated, and indicating present achievements and possible future developments. There are several methods for desulfurizing flue gases under investigation, such as am- monia scrubbing and aqueous scrubbing. Organic liquids, such as olefins, carbohydrates, and amines, appear promising for extracting sulfur dioxide from flue gas. Solid organic materials including newsprint, sawdust, and cotton are capable of ab- sorbing SO2. The most suitable catalyst for oxidizing SO2 to SOS is vanadium pentoxide. Several methods for reducing SO2 to elemental sulfur were also investigated. Coal gasification was studied as a method for eliminating the varous forms of sulfur contained in coal. Methods for reducing nitrogen oxides emissions include catalytic reduction, staged combustion, and fuel combustion with oxygen. Combustion with low excess air, steam or water injection into the fuel burning zone, and flue gas recirculation into the fuel-air mixture were also in- vestigated. A study on the availability and use of natural gas as a sulfur-free fuel for power generation was conducted. The principal chemical reactions that occur with these control methods are included. 25714 Funk, Andrew B. and James C. Moore CHEMICAL SUPPRESSION OF NITROGEN OXIDES. (Grace (W. R.) and Co., New York) U. S. Pat. 3,528,797. 5p., Sept. 15, 1970. 2 refs. (Appl. Nov. 8, 1967, 6 claims). A scrubbing apparatus containing urea is provided which sub- stantially eliminates all nitrogen oxides that are formed as by- products of the phosphate fertilizer manufacturing process. Urea when dissolved in water reacts with nitrogen oxide and nitrogen dioxide gases to produce nitrogen, carbon dioxide, and water. The preferable range of urea is 0.1 to 0.3 weight percent, based on the total weight of the batch size, and it may be employed in an aqueous scrubbing tower or added to the acidulation mass. 26071 AIR POLLUTION. Chem. Process., 16(11):11, 13, Dec. 1970. 7 refs. Nitric acid manufacture, nitrogen processes, and dissolving operations using nitric acid contribute the major portion of ox- ides of nitrogen emitted to the atmosphere by non-combustion processing. Several methods which exist for the control of these oxides from stack gases include catalysis, adsorption, absorption, and direct flame incineration. Palladium on a par- ticulate alumina support and a ceramic catalyst are recom- mended for nitric acid tail gas purification. Adsorption on molecular sieves appears economically attractive where high oxygen concentrations preclude non-selective catalysis. Ab- sorption in liquids, while technically feasible, usually in- troduces by-product disposal problems. Direct flame incinera- tion is most effective for reduction of nitrogen dioxide to nitric oxide. Modifications for combustion processes include low excess air, staged combustion, flue gas recirculation, steam and water injection, combustion with oxygen, and fluidized bed combustion. ------- 11 C. MEASUREMENT METHODS 02570 M.D. Manila V.P. Melekhina A SPECTROPHOTOMETWC METHOD FOR THE DETER- MINATION OF NITRIC AND HYDROCHLORIC ACIDS IN THE ATMOSPHERIC ADX IN THE PRESENCE OF NITRATES AND CHLORIDES. (Spektrofotometricheskii metod opredeleniya azotnoi i solyanoi kislot v prisutstivii nitratov v atmosfernom vozukhe.) Hyg. Sanit. 29, (3) 62-6, Mar. 1964. CFSTI: TT65-50023/3 A spectrophotometric method for the determination of hydrochloric and nitric acids in the presence of nitrates and chlorides is described. This method is based on the determina- tion of the optical density of colored aqueous solutions con- taining the above acids after the addition of methyl red in ethanol. The sensitivity of the method is 0.18 microgram of HcL per ml and 0.31 microgram of HNO3 per ml. Other acids and bases interfere with the assay. CO2 and SO2 always present in atmospheric air do not interfere with the spec- trophotometric determination of hydrochloric and nitric acids when this is carried out under the conditions described. 04257 E. Kh. Gol'dberg PHOTOMETRIC DETERMINATION OF SMALL AMOUNTS OF VOLATDLE MINERAL ACIDS (HYDROCHLORIC AND NITRIC) IN THE ATMOSPHERE. (Fotometricheskoe opredelenie malykh kolichestv letuchikh mineral'nykh kislot (solyanoi i azotnoi) v atmosfernom vozdukhe.) Hyg. Sanit. 31, (9) 440-3, Aug. 1966. Russ. (Tr.) CFSTI: TT 66-51160/7-9 A spectrophotometric method was recommended for the anal- ysis of low concentrations of mineral acids in the atmosphere. However, it is not always possible to use this method at the laboratories of the district sanitary-epidemiological centers because of the absence of a spectrophotometer. Modification of the spectrophotometric method for purposes of photometric determinations with a photoelectrocolorimeter required a calibration graph for the relationship between the optical den- sity and the concentration of hydrogen ions in micrograms per 1 ml for an FEK-56 photoelectrocolorimeter. Standard solu- tions were prepared from fresh 0.005 N HC1 and HNO3. Solu- tions were made containing 0.005 to 0.02 microgram/ml H+. A zero solution (distilled water) was prepared simultaneously. In all cases, an addition was made of 0.4 ml 0.01% alcohol solu- tion of methyl red. The optical density of standard solutions and of a zero solution with the methyl red reagent was deter- mined with respect to distilled water. This photometric technique made possible the establishment of constant optical densities of aqueous solutions of acids in the standard scale, independent of the pH of the distilled water used. The sen- sitivity of the photoelectro colorimetric method and the sam- pling procedure are the same as for the spectrophotometric method. Studies were also made of the possibilities of visual colorimetric determinations. It was found that in the absence of a photoelectrocolorimeter the solutions can be determined colorimetrically by visual means by the method of standard se- ries with an artificial scale. 06889 Antoshechkin, A. G. INSTRUMENT FOR DETERMINATIONS OF THE CONCEN- TRATIONS OF NITROGEN OXIDES AND NITRIC ACID FUMES IN AHi. (Pribor dlya opredeleniya kontsentratsii okislov azota i parov azotnoi kisloty v vozdukhe.) Hyg. Sanit. (Gigiena i Sanit), 30(2):234-236, Feb. 1965. Translated from Russian. CFSTI: TT 66-51033 The author designed and tested an instrument for the deter- mination of the concentrations of nitrogen oxides and nitric acid fumes in air. The action of the instrument is based on measurements of the electrical conductivity of a solution ob- tained by drawing the air with nitrogen oxides through distilled water. The instrument is portable, its design is simple and it can be constructed under laboratory conditions. Its sensitivity is from 0.0003 to 20 mg nitrogen oxides per 1 liter of air. One analysis takes 1 to 2 min. Thirty ml of distilled water is in- troduced with the syringe into the upper tube and into the ves- sel. The water cannot leave the vessel because of the valve, and it forms a 1 cm layer between the two electrodes, now the pump is attached and 5 1 of air are drawn in distilled water. Nitrogen oxide from the air combines with water to produce nitrous acid. The higher the concentration of nitrogen oxide in the air, the higher will be the concentration of the HNO2 solu- tion in the vessel. Since HNO2, like HNO3, is a strong elec- trolyte and completely dissociated to ions in dilute solutions, the electrical conductivity of the solution is proportional to the concentration. The electrodes are fed with a constant voltage from a 4.5V source. In using the instrument, one must re- member that interference is caused by gases that are readily soluble in water and produce a strong electrolyte on solution (the sulfuric acid fumes). After suitable graduation, the instru- ment can also be used for the determination of sulfuric acid fumes in air. 11130L Saltzman, Bernard E. METHODS OF MEASURING AND MONITORING AT- MOSPHERIC NITROGEN OXIDES AND THEIR PRODUCTS. (Part I.) World Health Organization, Geneva, (Switzerland), WHO/AP/68.31,99p., 1968. (93) refs. A working text of NOx measurement methods in common use is presented. Sufficient details are provided so that no addi- tional material should be needed to conduct the analysis. How- ever, abundant references are provided. The actual texts of methods whic have been selected by appropriate organizations are quoted in exact form. Measuring and monitoring at- mospheric nitrogen oxides are complex because of the fact that many interrelated oxides and products exist. These un- dergo chemical reactions and equilibria both in the atmosphere and in air sampling apparatus. The effects of the various sub- stances are different. Their interferences also differ for vari- ous analytical procedures. Therefore to fully expoun the problems in making these measurements, an introductory sec- tion is presented giving chemical and physical properties, vari- ous reaction rates, and equilibrium data. In these analyses we ------- 12 NITRIC ACID PLANTS are seeking to measure concentrations that vary both in time and space. Rational design of a sampling program therefore requires a knowledg of these distribution patterns. Only then can we clarify the effects of sampling time, numbers of sam- pling locations, numbers of samples collected, and correlate these with the objectives which ar sought. These topics there- fore also are included. 18226 INVESTIGATION AND APPRAISAL OF FLU-GAS DAMAGE. (Untersuchung und Begutachtung von Rauchschaden. Part I.), Translated from German. Hamburg Staatsinstitut fur Ange- wandte Botanik Jahresbericht, 5(119-120), 1938. 3 refs. Plants exposed to flue gas showed definite damage from fluorine (F) and acids of sulfur and nitrogen. A crystalization method utilizing the microscopic identification of silico-sodium fluoride proved best for qualitative fluorine analysis of the 102 samples examined through 1936. As in previous studies, the samples tested showed that F was taken in through the branch bark and leaves of cherries and pears. For the first time, how- ever, the fruit itself was damaged and F detected there. Black, hard disks had formed around the flower and in the fruit ad- jacent to the flower. Samples examined long after damage took place showed no F present. Twenty-one samples were ex- amined for acid damage. Large concentrations of nitrates were detected in the specimens by means of the diphenylamine-sul- furic acid reaction. Different plant species showed markedly different sensitivities to flue gases. 23560 Aleksandrov, Yu. I., V. D. Mikina, and G. A. Novikov CORRECTION FOR OXIDATION OF NITROGEN IN THE DETERMINATION OF HEAT OF COMBUSTION. Tr. Vses. Nauch.-Issled. Inst. Metrol., 111(171):95-102, 1969. 11 refs. Translated from Russian by D. P. Biddiscombe, Ministry of Technology (England), Div. of Chemical Standardds, lip., March 1970. CFSTI: N70-28918 At present, the heat effect due to oxidation of nitrogen in a calorimetric bomb is computed on the basis of determination of the amount of nitric acid after the calorimetric experiment by titration of the bomb liquid with a 0.1-N solution of alkali; methyl orange is used as indicator. Results obtained during a prolonged period of work, by titration of bomb liquid after combustion of benzoic acid, differed one from another more than was to be expected from the errors of the titration method. Analysis of literature data on the formation of nitric acid does not give a thorough explanation of this discrepancy in titration results. To elucidate the reasons for this discrepan- cy, a study was made of the dependence of the amount of nitric acid formed upon the ageing time of the combustion products in the bomb, upon the initial concentration of nitrogen, upon the size of the flame, and upon the pressure of oxygen in the bomb. Study of the process of oxidation of nitrogen in the calorimetric bomb has established that, by the end of an experiment, when the bomb is opened, the reaction between nitrogen dioxide and water is not complete, and thus the end-product contains not only nitric acid, but also nitrogen dioxide. By the end of the main period, the amount of each component depends upon the initial concentration of nitrogen in the oxygen, the size of the flame during combustion of the substance, and the time of flushing of the bomb with oxygen. The amount of nitric acid formed depends upon the time of ageing of the combustion products in the bomb. In calorimetric practice at the present time, only the process of nitric acid for- mation is taken into account. On the basis of the investigations carried out, a procedure for determining the correction for ox- idation of nitrogen, taking account of the incomplete conver- sion of oxides of nitrogen into nitric acid, is advised. In order to determine more precisely the make-up of the correction, the methods of its determination must be changed. To calculate the correction, it is necessary to determine the amount of nitric acid formed by the end of the main period of a calorimetric experiment and thus establish the amount of nitrogen dioxide present at that time in the gas phase in the bomb. 23771 Patton, W. F. and J. A. Brink, Jr. NEW EQUD7MENT AND TECHNIQUES FOR SAMPLING CHEMICAL PROCESS GASES. J. Air Pollution Control As- soc., 13(4): 162-166, April 1963. 7 refs (Presented at the Air Pollution Control Association, 55th Annual Meeting, Chicago, May 20-24, 1962.) When the need for improved sampling equipment and techniques was recognized at Monsanto a number of years ago, a cascade impactor suitable for adiabatic measurements on process gases was developed. Simpler equipment, suitable for routine control of air pollution, can determine accurately the weight or chemical composition of the particles in a gas stream, as well as separately determine the loading of particles greater than three micron in diameter from particles smaller than this. The dust or mist sampling device is contained in a small case with a carrying handle and removable sides similar to an Orsat analyzer. Gases first enter the cyclone where the larger particles are collected, while the smaller particles are carried over and collected by the filter. Sampling preparations are discussed for large particles, fine particles, and isokinetic sampling. The procedures for sampling are outlined, as well as an example for sulfuric acid mist. Calculations of loadings from sampling data are also indicated. Eight sets of the sam- pling equipment have been utilized for sulfuric, phosphoric, and nitric acid mists, mercury mist, various phosphate salt dust, ammonium chloride fume, ammonium nitrate fume, and several organic mists. 24725 Lesoine, L. Grant EFFECT OF PARTICLE SIZE ON THE DETERMINATION OF INORGANIC SULFUR IN COAL. In: Report of Bitu- minous Research Activities. Pennsylvan State Univ., Universi- ty Park, Dept. of Fuel Technology, Serial No. 57, p. 1-8, 1956. 8 refs. The effect of reducing the standard 60-mesh coal samples to micron size was investigated to determine if the size of the coal materially quantitatively affects the determination of inor- ganic sulfur using the Eschka, and Powell and Parr Methods. A significantly higher inorganic sulfur content was obtained with micron-size coal. The pyritic iron content also increased in the same proportion. This leads to the conclusion that finely divided pyrite is intimately associated with the coal substance and is made more amenable to reaction with nitric acid when ground to micron size. Since both the sulfur and iron contents increased proportionally, it appears doubtful that any sulfur- bearing inorganic material other than pyrite is present in any significant quantity in the occluded matter. The iron content calculated to percent sulfur was greater in all cases than the actual total inorganic sulfur. Hence, it is assumed that acid ex- traction of the coal did not remove organic sulfur from these coals. The difference in values leaves a question as to the de- pendability of the usual inorganic sulfur analysis or to the validity of the term 'inorganic' sulfur as applied to acid-ex- tractable sulfur. (Author summary modified) ------- C. MEASUREMENT METHODS 13 24975 Grigorescu, I. and L. Bengeanu SPECTROCOLORIMETRIC DETERMINATION OF HEX- ACHLOROCYCLOHEXANE IN THE ATMOSPHERE. (Dozarea hexaclorciclohexanului in atmosfera prin metoda spec- trocotorimetrica). Text in Rumanian. Rev. Chim. (Bucharest), 18(9):565-566,1967. 7 rets. This broad-spectrum insecticide is finding an increasing use, so that accurate detection measures are necessary for its proper control. A method has been adapted by the Central Toxicology Laboratory of the Rumanian Ministry of Chemical Industries, which makes use of chloride-free toluene, sodium hydroxide dissolved in 0.1 N ethyl alcohol, a 1% solution of ferric ammonium sulfate in 15% nitric acid, a 0.1% solution of mercuric sulfocyanide in 96% ethyl alcohol, and a standard solution of HCH prepared by dissolving 0.5 g of lindane in 100 cc of toluene, from which a working standard is prepared by dilution, which contains 500 micrograms per cubic centimeter of HCH. Air samples are collected with an impinger containing 100 cc of toluene, through which the air is caused to flow at the rate of 10-15 cu m /minute, the total volume of the sample being dependent on the suspected amount of atmospheric HCH, on the average about 10 cu m. Given the extent of the sample-collecting time, the presence of chlorine and inorganic chlorides in the atmosphere will not create interference with the determinations, but special care must be taken to eliminate all chloride impurities from the reagents used. Testing of the method indicates that the margin of error can amount to plus or minus 10%, with an average error of 3%. The amount of time required for determination is 20 minutes, on the average. 25381 (Inventor not given.) DETECTION OF MISSILE FUELS IN GAS ATMOSPHERES. (Mine Safety Appliances Co., Inc., Pittsburgh, Pa.) Brit. Pat. 1,151,594. 3p., May 7, 1969. 5 refs. (Appl. May 26, 1966, 16 claims). A simple, rapid, and reliable method is described of detecting the presence in a gas of a volatile nitrogen compound of the group consisting of hydrazine, hydrazine hydrate, red fuming nitric acid, nitrogen dioxide, unsymmetrical dimethyl hydrazine, and alkyl hydrazines. A variety of volatile nitrogen compounds are used as components of missile fuels, and vari- ous hazards are attendant upon the fueling, handling and stor- ing of missiles propelled by such liquids. In the presence of the above mentioned nitrogen compounds, and also nitrogen dioxide, a particularly effective color change is produced when a hexavalent chromium compound and the pentavalent phosphoric acid are present in proportions providing from 0.0145 to 2.6 grams of hexavalent chromium and from 0.022 to 24 grams of pentavalent phosphorus, per 100 ml of carrier. 25925 Cauer, H. SOME PROBLEMS OF ATMOSPHERIC CHEMISTRY. In: Compendium of Meteorology. T. F. Malone (ed.), Boston, American Meterological Society, 1951, p. 1126-1136. 60 refs. Satisfactory methods for the chemical analysis of air will evolve only when analytical chemists are also adequately trained in physical chemistry and physical meteorology. A second requirement is further development of methodology. Not until the development is more or less complete will it be possible to undertake a third major task, that of making many parallel investigations in micrometeorological as well as world- wide networks under the most varied atmospheric conditions and at various heights above the ground. Of the chemical methods available today, two methods developed in Europe are briefly discussed: the absorption-tube method for detecting the presence of secondary gaseous substances, and the con- densation method for the analysis of water-soluble atmospher- ic constituents which form condensation nuclei. Results ob- tained by both methods are evaluated and suggestions are made for further research. To explain condensation (cloud for- mation), the chemist must have recourse to intermolecular forces and, in the last analysis, to processes of atomic energy. Four types of short-range molecular forces are discussed in light of existing knowledge. It is anticipated that the first chemical techniques developed for the field of dynamic meteorology may be connected with determinations of the pH value and the reduction power of aerosols. Such uses would provide accurate information about the motion of air masses and the degree of turbulence. ------- 14 E. ATMOSPHERIC INTERACTION 14408 Rhine, P. E., L. D. Tubbs, and Dudley Williams NITRIC ACID VAPOR ABOVE 19 KM IN THE EARTH'S AT- MOSPHERE. Appl. Opt., 8(7):1500-1501, July 1969. 6 refs. Atmospheric data obtained from balloon flights by other in- vestigators suggested that previously unreported atmospheric bands at approximately 30 km and a solar zenith angle of 90 deg were caused by the association of nitric acid vapor with the ozone layer. To estimate the amount of nitric acid vapor in the atmosphere at this altitude, atmospheric nitric acid vapor was experimentally measured in an absorption cell in the spec- tral regions of 1240-1380 inverse cm and 810-940 inverse cm. Laboratory and atmospheric data were compared by integrated spectral absorbance. Approximately 10% of the total ab- sorbance in both laboratory and atmospheric spectra is as- sociated with Q branches at the overlapping bands 879 and 897 inverse cm, and it is concluded that any observable nitric acid vapor contributions to solar absorption spectra at low altitudes would be connected with these band Q branches. Production of nitric acid vapor in the ozone layer may proceed according to the reactions H plus O3 yields O2 plus OH*, or OH plus NO2 yields HNO3. The second reaction is presumed to be enhanced by darkness. 21534 Leighton, Philip A. REACTIONS AND EQUILIBRIA OF THE OXIDES AND OXY ACIDS OF NITROGEN. In: Photochemistry of Air Pollution. New York, Academic Press, 1961, Chapt. 7, p. 184-200. Certain reactions involving the oxides and oxy acids of nitrogen occur simultaneously with the photochemical reac- tions of these products. Both the equilibrium and the rate of reaction of nitric oxide with molecular oxygen have been established over a broad temperature range. Reactions involv- ing nitrogen trioxide which are necessary to explain the major behavior of the oxides of nitrogen are given. The reaction of nitric oxide and nitrogen dioxide with water to give nitrous acid has been quantitatively studied. Nitrogen dioxide reacts slowly with unsaturated hydrocarbons, even in the dark. Pure nitric acid can be stored in contact with liquid olefins for days without reaction, but if a trace of nitrogen dioxide is present, reaction occurs. There is no evidence that the reactions of ox- ides and oxy acids with aldehydes, organic acids, and other or- ganic compounds are fast enough to be of any importance. Rates and equations for the various reactions are discussed. 21642 Leighton, Philip A. ABSORPTION RATES AND PRIMARY PHOTOCHEMICAL PROCESSES. In: Photochemistry of Air Pollution. New York, Academic Press, 1961, Chapt. 3, p. 42-99. For any photochemical reaction, the primary chemical process is the first chemical step following the act of absorption of radiation. In the lower atmosphere, the absorbers will be the species which absorb in the photochemically active region of the solar spectrum. Ordinary oxygen absorbs very faintly in the red end of the visible spectrum. Gaseous ozone absorbs strongly in the region 2000-3500 A. Nitrogen dioxide absorbs over virtually the entire visible and ultraviolet range of the solar spectrum in the lower atmosphere. Gaseous sulfur diox- ide shows absorption consisting of bands with sharp rotational structure. Nitric acid and the organic nitrates show continuous absorption which extends to some extent into the solar ul- traviolet. Compounds containing a carbonyl group all show ab- sorption in the solar radiation range. Acyl and peroxyacyl nitrates and nitrites are discussed at length. Reactions follow- ing absorption by particulate matter are discussed. Rates and equations of the various reactions are included. 22407 Vohra, K. G. and P. V. N. Nair RECENT THINKING ON THE CHEMICAL FORMATION OF AEROSOLS IN THE AIR BY GAS PHASE REACTIONS. Aerosol Sci., vol. 1:127-133, 1970. 11 ref Possible mechanisms of formation of aerosols in the air by chemical reactions in the gas phase are described. In the basic reactions, formation of hydrochloric acid, sulfuric acid, and nitric acid molecules from chlorine, sulfur dioxide and oxides of nitrogen, in the presence of water vapor, are considered along with the role of solar radiations, ionizing radiations, electric discharges and ozone in the formation of these acids. Formation of nuclei by the hydration of acid molecules and their reaction with other organic and inorganic trace gases are also discussed. The reactions important in the formation of Aitken nuclei and aerosols are mainly oxidation, hydration, acid-base reactions and addition and recombination reactions. In these reactions, the combined role of solar and ionizing radiations are considered. The formation of embryos and growth of particles in the humid air are discussed on the basis of Raoult's law. The important role of chemically formed par- ticles in the atmospheric processes and the possible impact of nuclear power production on the nuclei content of the at- mosphere are suggested. (Author abstract modified) 23037 Altshuller, Aubrey P. THERMODYNAMIC CONSIDERATIONS IN THE INTERAC- TIONS OF NITROGEN OXIDES AND OXY-ACIDS IN THE ATMOSPHERE. J. Air Pollution Control Assoc. 6(2):97-100, 1956. 15 refs. (Presented at the Air Pollution Control Associa- tion, 49th Annual Meeting, Buffalo, N. Y., May 20-24, 1956.) Equilibrium constants, calculated from recent spectroscopic and structural measurements, are reported for some nitrogen dioxide reactions. From these constants, estimated concentra- tions of gaseous nitrogen oxides and oxy-acids in urban at- mospheres were calculated. It is emphasized that the equilibri- um conditions to which the data apply may be reached very slowly or rapidly, or at some intermediate rate. Determination of this rate is a problem for experimental kinetics rather than thermodynamics. The value of thermodynamic information is that it can tell whether a small or large amount of a given reactant will exist at equilibrium. The present thermodynamic ------- E. ATMOSPHERIC INTERACTION 15 study indicates that among the nitrogen oxides and oxy-acids, nitric oxide, nitrogen dioxide, and nitric acid are probably the most prevalent in polluted urban air. Nitrous oxide is also present in urban air but is of less importance because of its lower chemical reactivity. 23604 Nicolet, M. THE ORIGIN OF NITRIC OXIDE IN THE TERRESTRIAL ATMOSPHERE. Planetary Space Sci., 18(7):1111-1118, July 1970. 32 refs. Recent observations in the stratosphere, mesosphere, and ther- mosphere indicate that nitric oxide is present in significant amounts, even though its local production seems to be very small. Reactions which might account for an indirect way of production are discussed. Nitric oxide in the stratosphere and mesosphere may be due to downward transport from the ther- mosphere. Photochemical reactions, including photodissocia- tion, are described. Balances of reactions of formation and removal of nitric oxide and atomic nitrogen are considered. In the lower thermosphere, the downward current of NO molecules depends on the value of the eddy diffusion coeffi- cient. In the stratosphere, the final sink of NO and NO2 is the formation of HNO2 and HNO3 by reactions with HO2 and H202. A small eddy diffusion coefficient is required. 24015 Altshuller, Aubrey P. THERMODYNAMIC CONSIDERATIONS IN THE INTERAC- TIONS OF NITROGEN OXIDES AND OXY-ACIDS IN THE ATMOSPHERE. Preprint, Robert A. Taft Sanitary Engineering Center, Cincinnati, Ohio, 16p., 1956 (?). 16 refs. The thermodynamic equilibrium constants are computed for a number of chemical reactions involving nitrogen oxides and oxy-acids. The nitrogen oxides likely to be present in any sub- stantial quantity in the atmosphere are nitrous oxide, nitric ox- ide, and nitrogen dioxide. The concentrations of reactants and products in these reactions at chemical equilibrium are given, and the rates at which these reactions proceed towards equilibrium are discussed. Most of the reactions considered are 'dark' reactions, but the importance of photochemical reactions involving ozone is pointed out and the photolysis of nitrogen dioxide is discussed in detail. The varying importance of the individual reactions of nitrogen oxides in air pollution problems is emphasized. (Author abstract modified) ------- 16 F. BASIC SCIENCE AND TECHNOLOGY 01619 NITRIC ACID MANUFACTURE (INFORMATIVE REPT. NO. 5). J. Air Pollution Control Assoc. 14, (3) 91-3, Mar. 1964. (TI- 2 Chemical Industry Committee). Nitric acid manufacture by the ammonia oxidation process and the concentration process are described. The control aspects are discussed. 10160 Ganz, S. N. EFFECT OF HYDRODYNAMIC CONDITIONS ON RATE OF NITROGEN OXIDES AB- SORPTION BY Ca(OH)2 SOLU- TION, WITH THE AID OF A MECHANICAL AB- SORBER UNDER SEMI-INDUSTRIAL CONDITIONS. (COMMUNICA- TION I.) Zh. PrikL Khim., 30(9):1311-1320, 1957. 5 refs. Trans- lated from Russian by B. S. Levine, U. S. S. R. Literature on Air Pollution and Related Occupational Diseases, VoL 6, 299 p., April 1961. CFSTI: TT 61-21982 The effect of hydrodynamic conditions on the rate of nitrogen oxides absorption by a solution of Ca(OH)2 was studied with the aid of a rapidly rotating mechanical absorber under semi- industrial conditions, using industrial gas from a nitric acid shop. The in vestigations were conducted in 2 stages: 1) a study of the effects of the system's hydrodynamic, physical and chemical factors on the absorption rate; during this study the installation was operating periodically for time intervals determined by the requirements of each test; the phases in- vestigated were: the effect of the peri pheral speed of discs, the volume rate of gas flow, the quantity of liquid in the ab- sorber, the CaO and nitrite-nitrate salt concen- trations in the solution, the degree of gas oxidation, etc.; 2) during the second stage, the installtion operated continually under one set of conditions, selected on the basis of results obtained during the first stage of the investigation; results of the second stage indicated that the process of nitrogen oxides absorption had to be based on a rationally (empirically) developed and controlled technological procedure. The first study stage extended over more than 1-1/2 months, and the second stage over more than 2-1/2 months. More than 3,000 analyses of the gaseous and liquid phases were made, which yielded sufficient experimen- tal data for the determination of optimal technological condi- tions. 13415 Haseba, S., T. Shimose, N. Kubo, and T. Kitagawa NITRIC OXIDE EXPLOSION. Chem. Eng. Progr., 62(4):92-96, April 1966. 8 refs. A method was found to analyze low-concentration hydrocar- bons assumed to have contributed to an explosion in the second heat exchanger of a nitrogen wash unit. Acetylene, 1,3- butadiene, and allene existed in the crude gas in the order of 2 to 3 ppm, 0.2 to 0.5 ppm, and 0.2 to 0.3 ppm, respectively. Nitric oxide was detected at concentrations in the order of 0.005 to 1 ppm through oxidation with permanganate and sul- furic acid, followed by calorimetric detection with the Griess- Saltzman reagent. Findings showed that more than 90% of NO entered the unit accumulated in the second heat exchanger, most of it oxidized to nitrogen dioxide and nitrous anhydride, which is more reactive with hydrocarbons than NO. Experi- ments confirmed the possibility of spontaneous ignition in the second exchanger and the composition of reaction products between nitrogen and conjugated dienes. An adsorption process is now used to remove NO, in which Na2CrO2 or C12 are added to the wash-water circuit. 13481 Kirk, Donald G. NITRIC ACID BLEACHING OF HARDWOOD NEUTRAL SULFTTE SEMICHEMICAL PULP. Tappi, 51(4): 145-151, April 1968. 26 refs. (Presented at the Fourth International Pulp Bleaching Conference jointly sponsore by the Technical As- sociation of the Pulp and Paper Industry and the Technical Section, CPPA, held in Toronto, Ont., May 1-4, 1967.) Use of nitric acid in place of chlorine as a first stage bleaching agent for a hardwood NSSC pulp has been studied. The pur- pose was the production of a high nitrogen effluent from which a fertilizer material might be recovered and marketed. Study of nitric acid stage variables showed the necessity of keeping the temperature low and Obleaching duration short to prevent strength loss. This required the application of high nitric acid concentrations, which made reuse of the acid an economic necessity. Modifications using alcoholic nitric acid or nitric-sulfuric acid mixtures showed some potential strength benefits, while nitrous acid appeared to cause severe degrada- tion. Extraction stage variables within broad limits were found to have little effect on pulp quality. Ammonia was found to have little effect on pulp quality. Ammonia was successfully substituted for caustic soda to increase the nitrogen content of the effluent solids. In general, substitution of nitric acid for chlorine in the first stage of a chlorine-extraction- hypochlorite sequence can be made to produce a pulp at least equivalent to the control pulp in all respects except for a slight yellowing ef- fect. Chemical costs are high enough to render the process economically unattractive unless a fertilizer by-product can be marketed. (Author abstract) 13680 Atroshchenko, V. I., V. M. Kaut KINETICS OF NITROGEN OXIDE ABSORPTION BY CON- CENTRATED NITRIC ACID. (Kinetika pogloshcheniya okislov azota kontsentrirovannoy azotnoy kislotoy). Text in Russian. Zh. Prikl. Khim., vol.31: 352-360, 1958. 11 refs. New experimental data regarding the kinetics of absorption of nitrogen oxides by concentrated nitric acid are presented. De- pendencies between the absorption rate coefficient and basic physicochemical factors such as NO2 and N2O concentration in the gas phase, content of nitrogen oxides in the gas, HNO3 concentration in the acid, N2O4 content of the solution, and temperature are established. A dependence between absorption rate coefficients and basic hydrodynamic factors is demon- strated. ------- F. BASIC SCIENCE AND TECHNOLOGY 17 13948 Foerster, F., T. Burchardt, and E. Fricke PRODUCTION OF CONCENTRATED NITRIC ACID FROM NITROUS GASES. PARTS A AND B. (Ueber die Gewinnung konzentrierter Salpetersaeure aus nitrosen Gasen). Text in German. Z. Angew. Chem. (Weinheim), vol. 1:113-117, May 11, 1920. PARTS C, D, AND E. Ibid., p. 129-132, May 25, 1920. 10 refs. A detailed description and discussion is presented of two se- ries of experiments on the formation of nitric acid from nitrous gases. In the first series, a mixture of gaseous nitrogen dioxide and oxygen was passed through a bell-type wash tower filled with a nitric acid solution. In the second series, oxygen was passed through a mixture of nitric acid and liquid nitrogen dioxide or else known amounts of oxygen and that mixture were thoroughly shaken together. Conclusions are as follows: 1. The notion derived from previous experiments that the process of nitric acid formation from gaseous NO2, O2, and water cannot proceed beyond the nitric acid solution with the lowest vapor pressure, is erroneous. 2. The rate of this process in the range of concentrations of nitric acid at the lowest vapor pressure is so low that an enrichment of nitric acid beyond this range requires a rather long reaction time. 3. For such an enrichment, the smallest possible excess of oxygen and a low rate of flow of the mixture are preferable. 4. With sufficiently long test durations and with progressively decreas- ing utilization of the NO2, even under the most favorable test conditions, nitric acid concentration rarely goes above 80%. 5. The reason for this is that when a steaming gas mixture is used, the conditions favoring a good utilization of NO2, name- ly, a small oxygen excess and low rate of flow, are highly un- favorable for the thorough mixing of the reaction solution with oxygen which is also required. 6. However, one can easily at- tain even the highest nitric acid concentrations if one mixes less concentrated solutions of it with an appropriate amount of liquid NO2 and shakes this mixture thoroughly with oxygen. 7. The process proceeds especially rapidly when the excess of liquid NO2 is so great that, due to its limited solubility in nitric acid, the liquid mixture is heterogeneous and remains so dur- ing the reaction. 8. When nitrous gases act on water, from the equilibrium 2NO2 yields N2O4, the latter is dissolved in water and yields the primary reaction N2O4 plus H2O yields HN03 plus HNO2. 9. The dissociation of the nitrous acid into nitric acid, nitric oxide, and water (3HNO2 yields HNO3 plus 2NO plus H2O), and the rapid oxidation of the latter, effects the transformation of the nitrous gases into nitric acid up to its highest concentrations. 14303 Von Semel, Georg and Heinz Lehmann METHOD OF PRODUCING CONCENTRATED MIXTURES OF NITRIC AND PHOSPHORIC ACID. (Pintsch Bamag A.-G., Berlin) U. S. Pat. 2,901,340. 2p., Aug. 25, 1959. 4 refs. (Appl. Dec. 26, 1956, 7 claims). A method was devised for obtaining higher concentrations of mixtures of nitric and phosphoric acids by using a phosphoric acid solution instead of water. The method consists of passing a nitrogen oxide gas and an oxygen-containing gas into a dilute phosphoric acid solution with an inorganic nitrate or sulfate salt dissolved in it in an amount between 1% by weight and the solubility limit of the salt. The nitrogen oxide gas absorp- tion is promoted by the inorganic salt which converts it to nitric acid. Thus, a concentrated solution of phosphoric and nitric acid is formed. 15087 Mucskai, Laszlo THE PROCESS OF OXIDATION OF NITROGEN OXIDES IN THE PRESENCE OF EQUEMOLECULAR NO + NO2 AB- SORPTION IN THE DILUTE TAIL GASES OF NITRIC-ACID PLANTS. (Nitrogenoxid oxidacioja hig nitrozus gazokban ek- vimolekularis NO + NO2 folyamatos abszorpcioja mellett). Text in Hungarian. Magy. Kern. Folyoirat, 67(11):488-490, 1961. 1 ref. A differential equation is derived that gives the incremental change in the partial pressure of nitrogen dioxide as a function of incremental change in nitric oxide concentration, oxygen concentration, the concentration of an inert gas, and the total pressure. The above conditions refer to the tail gas of a stack at a plant where nitric acid is manufactured from nitric oxide, sodium carbonate, and water; the tail gas (NO and NO2) con- centration is 0.7-1.0 vol%. Subsequently, the equation is used to derive another differential equation rendering the time needed to accomplish an incremental change in NO concentra- tion. This latter differential equation is considerably simplified so that it can be integrated. The resulting equation is presented in the form of a nomogram that can be used to calculate the volume of the absorber column or the oxygen concentration or the time needed to perform the reaction. 23882 Satterfield, Charles N. and Douglas H. Cortez MASS TRANSFER CHARACTERISTICS OF WOVEN-WDJE SCREEN CATALYSTS. Preprint, Massachusetts Inst. of Tech., Cambridge, Dept. of Chemical Engineering, 38p., 1969 (?). 19 refs. Gauze catalysts woven from a fine platinum-rhodium wire have long been used in the partial oxidation of ammonia for the industrial manufacture of nitric acid. An investigation of the possibility that the catalytic oxidation of hydrocarbons in air might under some circumstances proceed by initiation of reaction on a catalyst surface followed by propagation of the reaction into the surrounding gas, or so-called hetero- homogeneous catalysis, is described. The rate of oxidation of hexene or toluene in excess air on platinum screen catalysts under mass transfer controlled conditions is used to calculate 'j' factors. Previous literature data on heat and mass transfer are re-examined and re-correlated and the transport charac- teristics of screen catalysts are shown to be very similar to that of infinite cylinders. There is no positive evidence that any of the hydrocarbon oxidation in these studies or that of the oxidation of ammonia on platinum gauze under industrial conditions occurs as a homogeneous process. (Author abstract modified) ------- 18 G. EFFECTS-HUMAN HEALTH 01049 R. L. Larkin and R. E. Kupel QUANTITATIVE ANALYSIS OF POLYVINYLPYR- ROLIDONE IN ATMOSPHERE SAMPLES AND BIOLOGI- CAL TISSUES. Am. Ind. Hyg. Assoc. J. Vol. 26(6):558-61, Dec. 1965. A quantitative method for the analysis of polyvinylpyrrolidone (PVP), collected in atmospheric samples or extracted from biological tissues, is described. PVP is a component in many aerosol hair sprays. A 0.4M citric acid solution is used to col- lect or extract the PVP. The color is developed by using a potassium iodide reagent, and the intensity of the color is read on a spectrophotometer at a wavelength of 432 millimicrons. The low limit of detection for this method has been established at 0.5 microgram of PVP per nuHiliter of final solu- tion. (Author abstract) 06552 A. Goetz AN INTERPRETATION OF THE SYNERGISTIC EFFECT OF AEROSOLS BASED UPON SPECIFIC SURFACE-ACTION OF THE AIRBORNE PARTICLES.Preprint. (1956). Experiments to determine the survival time of test animals (mice) exposed to toxic vapor without and with the addition of an aerosol of defined particulate constitution were conducted. As toxic vapor, three different substances were used, (each for itself, i.e. not as mixtures): two aldehydes (formaldehyde and acrolein) and evaporated nitric acid; the concentration of these vapors was kept constant in the presence and absence of the aerosol addition, and it was selected so that the vapor alone caused commensurable survival periods of the animals. None of the aerosols caused, in the absence of the toxic vapors, any significant change in the test animals. However, when co-existent with the toxic vapors the aerosols caused very marked differences in the mean lifetime of the test animals and proved that certain types of particles produce a Substantial identification of the toxicity of the vapor (shorten- ing of the lifetime), while others had an attenuating effect (lengthening of the lifetime), and also that the attenuating, or the intensifying properties of a particular aerosol, depended to a large extent on the nature of the toxic vapor. These in- vestigators have attempted to interpret their results qualitative- ly (and to some extent even quantitatively) by assuming that the vapor be absorbed by the aerosol, i.e. by the gradual incor- poration of the vapor into the particle. In view of the fact that the experimental data as well as the manner in which they were obtained, appear to have an unusually significant bearing upon the mucous irritation caused by smog, the present in- vestigation has attempted to interpret this data in terms of nuclear condensation of the toxic vapor, (i.e. of a surface ac- cumulation on the airborne particles). 11378 Melekhina, V. P. THE PROBLEM OF COMBINED ACTION OF THREE MINERAL ACIDS. In: Biological Effect and Hygienic Sig- nificance of Atmospheric Pollutants, Book 1/9, V. A. Ryazanov and M. S. Gol'dberg (eds.), Translated from Russian by B. S. Levine, U. S. S. R. Literature on Air Pollution and Related Occupational Diseases, Vol. 16, pp. 76-81, 1968. ((6)) refs. CFSTI: PB 179141 The following concentrations of odor perception thresholds was established: 0.80 mg/cu m for sulfuric acid, and 0.40 mg/cu m for hydrochloric acid; corresponding H-ion equivalents are as follows: 0.01099, 0.01203, and 0.01053 mg/cu m. Any combination of 2 or 3 acids was clearly odor percepti- ble if the sum of their concentration fractions in corresponding relation to their individual threshold concentrations exceeded unity. Perceptible concentrations expressed in H-ions exceed the 0.01 mg/cu m level. Threshold reflex effect concentrations, as studied by eye adaptation to darkness, were on the level of threshold odor perception, or just above it. The reflex effect of nitric, sulfuric, and hydrochloric acids in atmospheric air of inhabited areas is a condition of H-ion concentration. The sanitary-hygienic condition of atmospheric air containing mineral acids can be reliably evaluated on the basis of H-ion concentration for the sum of the three acids under considera- tion as well as for each acid individually based on the H-ion index should not exceed 0.010 mg/cu m. 16460 Podgornova, N. S. HEALTH PROBLEMS IN THE INSTRUCTION OF STU- DENTS IN A CHEMICAL TECHNICAL SCHOOL. (Gi- gienicheskie voprosy obucheniya studentov khimicheskogo tekhnikuma). Text in Russian. Gigiena i Sanit., no. 9:112-114, 1966. Psychological and physical studies were made of 85 students aged 15-18 years enrolled in three courses of study at the Moscow Chemical-Technological school during one semester. In Course I, students had 5 weeks of classroom work, 4 weeks of shop work, and then returned to classrooms for the remainder of the semester. Students in Course II had 6 hours of laboratory work one day a week in addition to daily class- room work. Students in Course III had classroom instruction all semester. At the end of the semester, all groups showed a decrease in work capability and physiological changes which were more marked in students in Courses I and II. No decrease in function was noted at the end of the day in stu- dents having shop or laboratory work. More control by the in- structor is recommended in order to decrease fumes of nitric acid in laboratories. 16613 Prys-Roberts, C. PRINCIPLES OF TREATMENT OF POISONING BY HIGHER OXIDES OF NITROGEN. Brit. J. Anaesthesia, vol. 39:432-439 May 1967. 39 refs. The main methods of treatment for patients exposed to the noxious effects of nitric oxide, nitrogen dioxide, or the fumes of nitric acid are outlined. High concentrations of nitrogen ox- ides cause reflex inhibition of breathing with laryngospasm. In- ------- G. EFFECTS-HUMAN HEALTH 19 tense cyanosis develops rapidly. Therefore, severe hypoxia may occur. There is a tendency for the ventilatory frequency to increase, and pulmonary edema may occur in the acute phase. Oxygen therapy is recommended which consists of ad- ministering 100% oxygen, either by spontaneous or artificial ventilation in order to compensate for the decreased oxygen capacity and content of the arterial blood. Reconversion of methemoglobin by the use of methylene blue (2mg/kg) initially is advocated, with subsequent dosage titrated against the methemoglobin concentration in the blood. Prevention and treatment of chemical pneumonitis combines endobronchial and parenteral administration of corticosteroid preparations, together with bronchial lavage and suction. The metabolic component of acid-base derangement is corrected by in- travenously administering sodium bicarbonate. Artificial ven- tilation by intermittent positive pressure ventilation may be in- dicated in patients who demonstrate ventilatory failure manifested by a rising arterial carbon dioxide pressure. Circu- latory therapy is accomplished by the use of vasopressor agents to combat severe systemic hypotension. Associated drug therapy using dimercaprol is advocated in severe cases in view of the protective action of this type of agent against the higher nitrogen oxides. Bronchodilators may be indicated in order to alleviate bronchospasm arising from the irritant ef- fects of the inhaled gases. (Author conclusions modified) 21307 Ellis, Richard E. and Ronald M. Bishop OXIDES OF NITROGEN ARE HEALTH HAZARDS. J. En- viron. Health, 32(6):676-677, May/June 1970. 4 refs. Oxides of nitrogen are extremely toxic. Nitrogen dioxide and tetroxide are most prevalent. Both the threshold limit value and ceiling are 5 ppm and should never be exceeded. Occupa- tional exposure is encountered in nitric acid manufacture, nitration of cellulose and inorganic materials, etching, pickling of metals, certain welding operations, explosives manufacture and use, and engine exhausts. The gas combines with water to form nitrous and nitric acid which, in turn, react with salts in the tissues of the respiratory tract to produce irritating nitrites and nitrates. Exposure to high concentrations may be fatal. Persons suspected of having been exposed should be kept under observation at rest for 25 hours. Persons known to have been Exposed should be hospitalized at bed rest. Administra- tion of oxygen and corticosteroids is indicated and may be life-saving. 23738 Gray, Edward Le B., Stanley B. Goldberg, and Francis M. Fatten TOXICITY OF THE OXIDES OF NITROGEN. HI. EFFECT OF CHRONIC EXPOSURE TO LOW CONCENTRATIONS OF VAPORS FROM RED FUMING NITRIC ACID. Arch. Ind. Hyg., Occupational Med., vol. 10:423-425, 1954. 5 refs. In contrast to animals exposed for four hours a day, five days a week for six weeks to 9-14 ppm nitrogen dioxide, rats, mice, and guinea pigs exposed for four hours daily, five days a week for six months to 4 ppm vapors of red fuming nitric acid ex- hibited no toxic effects. In fact, the lower concentration of NO2 produced a significant prophylactic effect, since the degree of pulmonary congestion was less in the exposed animals than in control animals. The results lead to the conclu- sion that the maximum allowable concentration of nitrogen ox- ides should be set at 5 ppm. 24588 Gray, Edward LeB., James K. MacNamee, and Stanley B. Goldberg TOXICITY OF NO2 VAPORS AT VERY LOW LEVELS. A PRELIMINARY REPORT. Arch. Ind. Hyg. Occupational Med., vol. 6:20-21, July 1952. 9 refs Forty rats were divided into groups of 10 and exposed to red fuming nitric acid containing 9-14 ppm nitrogen dioxide for four hrs at a time. Total exposure for the different groups ranged from 40-96 hrs. Animals examined shortly after the ter- mination of exposure had inflammatory respiratory tracts and exhibited evidence of severe rhinitis and tracheitis in the upper portion of the tract, along with less severe pneumonitis. Pneu- monia developed in a few of the animals. In many of the animals sacrificed eight or more weeks after exposure, the in- flammation had subsided, but there were localized areas of emphysema in all lobes of the lungs. With the exception of moderate congestion, liver, spleen, kidney, and brain showed no pathological changes. Length of exposure had no effect on the changes observed. In view of the fact that nitrogen dioxide concentrations higher than 8 ppm produce damage in rats, it is concluded that the maximum allowable concentration of 25 ppm, the value set by the American Standards Association and others, is too high. ------- 20 H. EFFECTS-PLANTS AND LIVESTOCK 22622 Noack, Kurt INVESTIGATIONS OF SMOKE GAS DAMAGES TO VEGETATION. (Untersuchunge uber die Rauchgasschaden der Vegetation). Z. Angew. Chem. (Weinheim), vol. 42:123-126, Jan. 3, 1929. 6 refs. Translated from German. Belov and As- sociates, Denver, Colo., 12p., May 27, 1970. Investigations were conducted to determine if nitrous gas, hydrochloric acid, and ammonia cause plant damage similar to that caused by sulfur dioxide, and to determine the participa- tion of the iron contained in chloroplasts in this disease process. The assimilation apparatus in the moss fontinalis was primarily affected by nitrous gas and these effects cor- responded to the effect of SO2; HC1 had a lesser effect, and ammonia was not considered to be an assimilation poison. Clover, tobacco, and spinach plants exposed to nitrous gas became withered and bleached with inhibited assimilation after exposure to light. Plant damage by SO2 and nitrous gas con- sists of a fixation of iron followed by a photooxidative poison- ing of the protoplasm by chlorophyll. Tests on corn were con- ducted to determine if the water soluble part of iron increases after introducing assimilation poisons. Pre treatment with fum- ing nitric acid resulted in a water soluble iron content four times higher than normal. The effect of smoke gases on plants consists of a direct cancellation of the catalytic activity of the iron in the chloroplasts. The photooxidative poisoning of the protoplasm is considered to be a secondary effect. 25481 Clark, J. F. ON THE TOXIC EFFECT OF DELETERIOUS AGENTS ON THE GERMINATION AND DEVELOPMENT OF CERTAIN FILAMENTOUS FUNGI. Botan. Gaz., 28(5): 289-404, Nov. 1899. 47 refs. An experiment designed to determine the relative and absolute toxic properties of several chemical compounds, as shown by their influence on the spores, mycelium, and the fructification of certain of the mold fungi, is described. The procedures used to select the medium, the method of culture, and the experi- mental equipment and conditions are described. Cultures were examined at intervals of 3-6 hr for the 14 hr following their ex- posure to the various chemical agents, until the fungus had matured, or the spores in the cultures which had failed to ger- minate were transferred to pure beet infusion to test their vitality. The cultures in which the spores failed to germinate were divided into two classes; inhibited and killed. The cul- tures which did germinate were also divided into two groups; those which matured a fair crop of conidia in about the normal time and those which presented a markedly retarded mycelial development and generally failed to fruit. The types of chemi- cal agents tested, in various strengths, include sulfuric, hydro- cyanic, hydrochloric, nitric, and acetic acids, several metal sulfates, chromates, nitrates, and formaldehyde. The results indicate that fungi are generally more resistant than higher plants, although different species of fungi and different forms of the same species present considerable variation in re- sistance. ------- 21 I. EFFECTS-MATERIALS 13877 McLeod, W. and R. R. Rogers CORROSION OF METALS BY AQUEOUS SOLUTIONS OF THE ATMOSPHERIC POLLUTANT SULFUROUS ACID. Electrochem. Technol., 6(7 to 8): 231-235, July to Aug. 1968. 7 refs. The corrosion rate of a metal in an acid with a normality between N/l and N/10,000, such as H2SO3, HNO3, H2SO4, or HCL, was found to be related to the concentration of the acid in accordance with the equation Corrosion rate equals a x (Acid Normality) to the b power, where a and b are constant for each combination of acid and metal and where temperature is 25 C. By determining the values of a and b for a number of acid-metal combinations, it was possible to compare the corro- sion rates of the various metals in sulfurous acid with those of the same metals in nitric, sulfuric, and hydrochloric acids, and to determine the corrosion rate of the metals in sulfurous acid of different normalities. Data obtained show that nonstainless steel, with or without nickel, is highly susceptible to sulfurous acid corrosion. However, when a substantial proportion of chromium is present in an alloy which contains nickel, steel is free from corrosion by either sulfurous acid or nitric acid. Copper and chromium are not appreciably susceptible to sul- furous acid corrosion in solutions lower than N/l.3. Tin cor- rodes more rapidly than other nonferrous metals between N/100 and N/1000, but less than cadmium and zinc at N/10. Cadmium, Lead, and zinc corrode more rapidly in sulfurous acid than in nitric acid. Lead corrodes less rapidly in sulfurous acid than in nitric acid. Aluminum is rapidly corroded by hyperchloric acid but less so by nitric or sulfurous acid. The study concludes that sulfurous acid solutions causing the greatest damage in urban and industrial areas have abnormali- ties between N/l and N/10,000. 19325 Konda, Kiyoshi, Hisao Ito, and Atsuhiro Honda FIELD EVALUATION OF EXHAUST GAS FROM REFUSE INCINERATOR RELATED TO AIR POLLUTION AND METAL CORROSION. Trans. Soc. Heating, Air-Conditioning, and Sanitary Engrs. (Japan), vol. 7:95-104, 1969. A study of municipal incinerator exhaust gas composition con- ducted at five sites in Japan is described. The study was un- dertaken to obtain information on odor and metal corrosion problems. The exhaust consisted of sulfur oxides, nitrogen ox- ides, ammonia, sulfuric acid, nitric acid, organic acids, and hydrochloric acid. Volatile organic acids and hydrochloric acid are mainly responsible for the corrosion, with sulfuric and nitric acids only partially concerned. Percentages of exhaust products as a function of raw refuse input are tabulated. Con- tinuous firing rather than batch firing would limit noxious ef- fluents. Temperature and excess air control would also help. After-burning chambers should be installed to further reduce contaminants. ------- 22 J. EFFECTS-ECONOMIC 17203 Oels, Heinriche AIR POLLUTION PROBLEMS IN WEST GERMANY AND THE ROLE OF INDUSTRY. (Luftforurensningsproblemer i Vest-Tyskland industriens innsats). Text in Norwegian. Tek. Ukeblad (Oslo), 116(45): 1245-1247, Dec. 1969. West Germany has been occupied in the last decade with reducing emissions of dust and smoke. Effectiveness of dust filters has increased threefold, and filtration is more economi- cal. The dust content can now be reduced to 150 mg/cu m for an emission rate of 100,000 cu m/hr. In 1950, the dust output from the West German cement industry was 3.5% of the clinker produced; in 1967, it was 0.15%. Dust output from the manufacture of calcium carbide was reduced to 3 mg/cu m of exhaust gases. Attention now centers on reducing sulfur diox- ide emissions. An electric power plant in Essen absorbs it with a new type of activated carbon, recovering the SO2 for the manufacture of H2SO4, the cost per 1000 kWh being about 1 DM (25 cents), and this can be further reduced. Government standards now limit the sulfur content of fuel oils to 1.8%. About 20% of the total SO2 emission in West Germany comes from sulfuric acid plants. A new 'double contact' process can reduce SO2 emissions of such a plant from 17 to 3 kg per ton of H2SO4 produced. Nitrogen oxides emitted from nitric acid plants have been reduced by 50% with special absorption equipment. New legislation sets a maximum average of 2 mg/cu m for fluorine emissions, or 5 mg for short intervals. Readings as high as 2.7 mg have been recorded above the Ruhr from January 1, 1966, to December 31, 1968. During that period, industry in North Rhine-Westphalia invested 4,000,000,000 DM on air pollution problems related to existent operations and about 275,000,000 DM on those related to new ones. Exhaust purification for the 2-year period cost 3,000,000,000 DM, plus an additional 30,000,000 for research this in comparison with a gross national product of 300,000,000,000 DM per year. The total amount spent by in- dustry is small compared with the damage caused, which amounts to 50 DM per capita per year, or 3,000,000,000 for the entire republic, not including losses due to sickness or sanitation problems. ------- 23 K. STANDARDS AND CRITERIA 06778 (INDUSTRY AND ATMOSPHERIC POLLUTION IN GREAT BRITAIN.) Industrie et pollution atmospherique en Grande Bretagne. Centre Interprofessionnel Technique d'Etudes de la Pollution Atmospherique, Paris, France. (1967.) 6 pp. Fr. (Rept No. CI 310.) (C J.T.E.P.A. Document No. 24.) A summary of the basis of governmental action in Great Britain in the struggle against industrial emissions is outlined. The regulations imposed by the 'Alkali Act' are in most cases based on 'the most practical means.' Standards are given for chimney heights. Statutory limits are given for various materi- als emitted such as hydrochloric acid, sulfuric acid, nitric acid, hydrogen sulfide, chlorine, arsenic, antimony, cadmium, and lead. The construction of tall buildings tends to reduce the benefits obtained by tall chimneys. A better knowledge of the effects of pollutants should be obtained so as not to burden in- dustry with unnecessary expense in their control. It is urged that international standards for emission be adopted. 07197 RECOMMENDATIONS FOR ALLOWABLE CONCENTRA- TION (1966.) Kuki Seijo (Clean Air - J. Japan Air Cleaning As- soc., Tokyo) 4(4):62-66, 1966. Text in Japanese. A report is given by a committee of the Japanese Association of Industrial Health on 'Allowable concentration'. The values of allowable concentration are worked out for a healthy man working 8 hr per day doing moderate work. Proper considera- tion must be given to cases in which more than 8 hr of expo- sure take place, more than one pollutant is involved, or the concentration of pollutants increases suddenly during the work schedule. Included is a discussion on dust measurement. It is important to measure dusts having a Stokes radius of less than 5 microns, especially at a height of 1 to 1.5 m from the ground. The relation between the source of dust and the point of measurement is illustrated. 20121 RECOMMENDATIONS OF PERMISSIBLE CRITERIA OF HAZARDOUS WORKING ENVIRONMENTS BY JAPAN AS- SOCIATION OF INDUSTRIAL HEALTH. 1969. Sangyo Igaku (Jap. J. Ind. Health), 12(2):37-44, Feb. 20, 1970. 15 refs. The Japanese Association of Industrial Health annually recom- mends permissible concentrations of toxic gases, vapors, mist, and fumes in the working environment. The 1969 limit values for 86 toxic substances are shown in ppm and/or mg/cu m. Like the Threshold Limit Values established by the American Conference of Governmental Industrial Hygienists (ACGH), the concentrations are time-weighted average concentrations for an eight-hour working day. The table cannot be applied to works where exposure to toxic substances is extremely irregu- lar or short-term. The limit values for butyl acetate, buty al- cohol, carbon monoxide, p-dichlorobenzene, ethylene glycol dinitrate, nitrobenzene, hexane, selenium compounds, lead, nitric acid, styrene monomor, toluene, 1,1,1-trichloroethane, and trichloroethylene differ from those of the ACGH. Factors affecting the Japanese decision are discussed in the case of hexane, lead, styrene monomor, and toluene. The article also reviews permissible criteria for noise exposure, thermal stan- dards for high-temperature work, and permissible dust concen- trations. ------- 24 L. LEGAL AND ADMINISTRATIVE 05407 T. Toyama AIR POLLUTION AND HEALTH IMPEDIMENT. Japan J. Ind. Health (Tokyo) 8, (3) 45-8, Mar. 1966. Jap. (Presented at the 39th Annual Meeting, Japan Society of Industrial Medicine, Ube, Japan, Apr. 7-9, 1966.) The 39th Annual Meeting of the Japan Society of Industrial Medicine was held on April 7-9, 1966 in Ube, Yamaguchi-ken, Japan. The theme of one of the symposia was planning pro- grams for air pollution control in which air pollution and health impairment and the engineering and practice of air pol- lution control were discussed. The main health impairments covered deal with effects of pollution on the respiratory system and acute diseases resulting therefrom. Prior to World War II there were no legal problems in pollution control but by 1963, it was necessary to establish laws covering soot and dust control. City planning and building restriction ordinances have come into effect. Dust and soot fall have decreased by one-sixth in the past sixteen years. Millions of dollars have been paid by factories and industries for the establishment of dust collectors and SO2 counter-measures. Waste gas disposal in nitric and sulfuric acid plants has been brought under con- trol since 1964. Re-use of the waste gases has played an im- portant role in the economic feasibility of air cleaning. 07597 Heller, A. MAXIMUM PERMISSIBLE CONCENTRATIONS FOR AIR POLLUTION IN THE FEDERAL REPUBLIC OF GERMANY. Preprint, Federal Inst. of Hygiene for Water, Soil and Air, Berlin, Germany, 10p., 1963. (Presented at the Inter-Regional Symposium on Criteria for Air Quality and Methods of Mea- surement, Geneva, Switzerland, Aug. 6-12, 1963, Paper No. WHO/AP/8.) An advisory committee set up by the Federal Government gives expert advice on the proposals of the Clean Air Commis- sion of the Association of German Engineers regarding per- missible emissions as well as on the maximum concentrations of 'immissions' the MIK values for various air pollutants. The task of the Verein Deutscher Ingenieure Commission is to set scientific and technical bases for appropriate air pollution control measures. The main task of the Commission is to draft recommendations for new technical regulations as a basis for the determination and control of air pollution, as follows: Minimum requirements regarding the concentration and precipitation of dusts and gases in the atmosphere, bases for calculating the distribution of dusts and gases and for deter- mining the required height of chimneys, limits to the emission of dust and gas from sources of air pollution, and procedures for measuring dusts and gases. The provisions recommended for examining applications for licences to establish new plants or to alter existing plants are reviewed. Enforcement of these regulations will depend on the local situation, especially the existing pollution load. They will also depend on the extent to which further pollution could occur, without exceeding the tolerance limit or the MIK-value for the most sensitive among the reaction partners, whether human being, animal or plant, and on the technical processes of the industrial plant in question. In principle, all reasonable technical and economic possibilites for purifying waste gases should be exploited in equal fashin by similar industrial plants. Finally, industry should be prepared to bear more far-reaching demands regard- ing waste-gas removal, if a licence for a new industrial plant or for the extension of an existing plant is to be issued in an area already polluted. MIK-values have been set and are discussed for; sulfur dioxide, hydrogen sulfide, some nitrous gases and chlorine. ------- AUTHOR INDEX 25 ALEKSANDROV YU I C-23560 ALTSHULLER A P E-23037, *E-24015 ANDERSEN, H C B-06844 ANDERSON H C B-13893 ANTOSHECHKIN, A G C-06889 ATROSHCHENKO V I B-13689, *F-13680 ATROSHCHENKO, V I B-10159 ATSUKAWA M B-14664 B BAYLEY, R W B-04658 BEL CHENKO G V B-14382 BELAGA M B A-17076 BENGEANU L C-24975 BETZ, E C B-05309 BILLINGS, C E B-07552 BINGHAM, E C JR B-11549 BISHOP R M G-21307 BLOOMFIELD, B D B-10017 BOMSHTEIN V E B-16726, B-19847 BRINK: A JR 0-23771 BRINK, J A JR B-00587 BURCHARDT T F-13948 BURGGRABE, W F B-00587 CAUER H C-25925 CORTEZ D H F-23882 ELLIS R E G-21307 ERMENC E D B-20775 ESTER W B-13202 FEIST, H J B-05309 FEIST, J B-02051 FOERSTER F F-13948 FRICKE E F-13948 FUNK A B B-25714 G GANZ, S N F-10160 GERSTLE, R W A-01583 GOETZ, A G-06552 GOLDBERG S B G-23738, G-24588 GOLDBERG, E K C-04257 GRAY E L G-24588 GRAY E L B G-23738 GREEN W J B-13893 GREEN, W J B-06844 GREENWELL, L E B-00587 GRIGORESCU I C-24975 H HALS F A A-21204 HARDING, C I B-00959 HASEBA S F-13415 HELLER, A L-07597 HENDRICKSON, E R B-00959 HEUMANN H B-13202 HONDA A 1-19325 HSIEH Y H B-14007 HSUEH L A-26226 HUNTER J B B-21232 I ITO H 1-19325 JEITNER, O B-06123 K KAUT V M F-13680 KAZAKOVA E A B-16726, *B-19847 KERNS, B A B-05151 KHITERER R Z B-16726, B-19847 KIRK D G F-13481 KITAGAWA T F-13415 KONDO K 1-19325 KONIG, K B-06123 KOPYLEV B A B-14382 KUBO N F-13415 KULIKAA B-14387 KUPEL, R E G-01049 KURKER, C JR B-07552 LARKIN, R L G-01049 LEHMANN H F-14303 LEIGHTON P A E-21534, 'E-21642 LEITHE, W B-07535 LESOINE L G C-24725 LINDAU L A-18305 M MACNAMEE J K G-24588 MANAKIN G A B-13899 MANITA, M D C-02570 MARKVART M B-13205 MATTA J M B-20313 MAY, F P B-00959 MAYSTRUK P N A-17076 MCLEOD W 1-13877 MELEKHINA, V P C-02570, *G-11378 MERENKOVPT B-14387 MIKINA V D C-23560 MOHRNHEIM A F A-13698 MOORE J C B-25714 MUCSKAIL F-15087 N NABIEV, M N B-09981 NABIYEVMK B-14387 NAffi P V N E-22407 NEWMAN DJ B-20313 NICOLET M E-23604 NISHIMOTO Y B-14664 NOACKK H-22622 NOVIKOVGA C-23560 O OELS H J-17203 OLEVINSKIY M I B-14568 PATTON F M G-23738 PATTON W F C-23771 PAULING H B-13202 PERRINE R L A-26226 PETERSON, R F A-01583 PODGORNOVA N S G-16460 POUR V B-13205 POZIN M E B-14382 PRYS ROBERTS C G-16613 R RADELOFFH C-18226 RHINE P E E-14408 ROGERS R R 1-13877 ROMEO P L B-13893 ROMEO, P L B-06844 SAFIULLIN N S B-14568 SALTZMAN, B E C-11130 SATTERFIELD C N F-23882 SCHMITTK B-13202 SCHWANECKE R B-15152 SEDASNOVA, E G B-10159 SHIMOSET F-13415 SILVERMAN, L B-07552 SORDELLI, D B-01125 STANKUS L B-23880 STAROSEL SKIY Y I B-13899 SUNDARESAN, B B B-00959 TAKAHASHIN B-14664 TESKE W B-23372 TESKE, W B-11058, *B-12637 TIKHONENKO A D B-14387 TIKHONENKO, A D B-09981 TOYAMA, T L-05407 TSEYTLIN A N B-13689 TUBES L D E-14408 ------- 26 NITRIC ACID PLANTS V W Z VAN DER DRIFT J B-14481 ZANON D B-01125 VARLAMOV M L B-13899 ZJUNUIN, u B mu.3 VOHRAKG E-22407 ZASORIN A P B-13689 VON SEMEL G F-14303 WILLIAMS D E-14408 ZBROZHEK L S B-13899 ------- SUBJECT INDEX 27 ABSORPTION A-01583, A-18305, A-26226, B-00587, B-00959, B-01125, B-07093, B-07535, B-07552, B-10017, B-10159, B-12637, B-13202, B-13689, B-13899, B-14382, B-14568, B-14664, B-15152, B-16726, B-20313, B-23372, B-25714, B-26071, E-21642, F-10160, F-13680, F-15087, G-01049, J-17203 ABSORPTION (GENERAL) A-22877, B-07535, B-23880, J-17203 ACETIC ACID G-01049, H-25481 ACETONE K-07197 ACETYLENES F-13415 ACID SMUTS A-17076, B-26071 ACIDS A-01583, A-13698, A-16699, A-17076, A-18305, A-21204, A-22877, A-26226, B-00587, B-00959, B-01125, B-02051, B-04658, B-05151, B-05309, B-05401, B-06123, B-06844, B-07093, B-07535, B-07552, B-09773, B-09981, B-10017, B-10159, B-11058, B-11549, B-12637, B-13202, B-13205, B-13689, B-13893, B-13899, B-14007, B-14382, B-14387, B-14481, B-14533, B-14568, B-14664, B-15152, B-16726, B-19847, B-20313, B-20775, B-21232, B-23372, B-23880, B-25714, B-26071, C-02570, C-04257, C-06889, C-11130, C-18226, C-23560, C-23771, C-24725, C-24975, C-25381, C-25925, E-14408, E-21534, E-21642, E-22407, E-23037, E-23604, E-24015, F-01619, F-10160, F-13415, F-13481, F-13680, F-13948, F-14303, F-15087, F-23882, G-01049, G-06552, G-11378, G-16460, G-16613, G-21307, G-23738, G-24588, H-22622, H-25481, 1-13877, 1-19325, J-17203, K-06778, K-07197, K-20121, L-05407, L-07597 ACROLEIN G-06552 ADMINISTRATION B-23880, L-05407, L-07597 ADSORPTION B-00959, B-01125, B-05401, B-10017, B-13893, B-14533, B-16726, B-19847, B-26071, F-13415 ADVISORY SERVICES L-07597 AEROSOLS A-17076, B-14568, E-22407, G-01049, G-06552 AFTERBURNERS B-05309, B-07535, B-10017, B-11549, B-21232, B-26071, 1-19325 AIR QUALITY CRITERIA K-07197 AIR QUALITY MEASUREMENTS A-17076, A-22877, C-02570, C-04257, F-13415, 1-19325, K-07197, L-05407 AIR QUALITY STANDARDS B-10017, G-11378, G-21307, G-23738, G-24588, K-06778, K-07197, K-20121, L-07597 ALCOHOLS B-05309, C-24975, K-07197, K-20121 ALDEHYDES B-05309, G-06552, H-25481, K-07197 ALIPHATIC HYDROCARBONS B-02051, B-09981, B-10017, B-16726, C-24975, E-21534, F-13415, F-23882, G-01049, K-07197, K-20121 ALKALINE ADDITIVES B-23880 ALLENES F-13415 ALTITUDE C-25925, E-14408, E-21534, E-21642, E-23604 ALUMINUM 1-13877 AMIDES B-05151 AMINES B-01125, K-07197 AMMONIA A-01583, A-16699, A-18305, B-00959, B-04658, B-13205, B-13899, B-14007, B-14387, F-01619, F-13481, F-23882, H-22622, 1-19325, K-07197 AMMONIUM CHLORIDE C-23771 AMMONIUM COMPOUNDS A-01583, A-16699, A-18305, B-00959, B-04658, B-07552, B-12637, B-13202, B-13205, B-13899, B-14007, B-14387, C-23771, C-24975, F-01619, F-13481, F-23882, H-22622, 1-19325, K-07197 ANALYTICAL METHODS A-16699, A-22877, B-05401, C-02570, C-04257, C-11130, C-18226, C-23560, C-24725, C-24975, C-25381, C-25925, F-13415, G-01049, G-11378 ANIMALS G-01049, G-23738, G-24588 ANTIMONY COMPOUNDS K-06778 AROMATIC HYDROCARBONS B-11058, C-24975, F-23882, K-07197, K-20121 ARSENIC COMPOUNDS K-06778, K-07197 ARSINE K-07197 ASHES B-07535 ASIA B-14007, B-14664, E-22407, 1-19325, K-07197, K-20121, L-05407 ATMOSPHERIC MOVEMENTS A-22877, C-25925 AUTOMOBILES B-07535 AUTOMOTIVE EMISSION CONTROL A-26226 AUTOMOTIVE EMISSIONS A-26226, B-00959, B-07535, G-21307 AZO DYE C-11130 B BAG FILTERS A-17076 BELGIUM E-23604 BENZENES K-07197, K-20121 BERYLLIOSIS B-00587, C-02570, G-01049 BERYLLIUM K-07197 BIOMEDICAL TECHNIQUES AND MEASUREMENT G-11378 BODY CONSTITUENTS AND PARTS G-01049, G-11378, L-05407 BODY PROCESSES AND FUNCTIONS F-01619, G-01049, G-11378 BOILERS B-00959, B-07535, K-06778 BREATHING G-01049 BROMINE K-07197 BRONCHODILATORS G-16613 BUBBLE TOWERS B-10017 BUILDINGS G-16460 BUTADIENES F-13415 BY-PRODUCT RECOVERY A-18305, A-21204, B-11549, B-13202, B-14387 B-14533, B-15152, B-23880, J-17203 CADMIUM 1-13877 CADMIUM COMPOUNDS K-06778, K-07197 CALCIUM COMPOUNDS B-11058, F-10160 CALIFORNIA B-07535 CANADA G-01049 CARBIDES B-11058 CARBON DIOXIDE A-22877, B-14007 CARBON DISULFIDE B-05309, B-10017, K-07197 CARBON MONOXIDE A-01583, A-22877, B-10017, K-07197, K-20121 CARBON TETRACHLORIDE K-07197 CARBONYLS K-07197 CARCINOGENS A-01583, B-01125, C-02570, G-01049 CASCADE SAMPLERS C-23771 CATALYSIS A-01583, A-26226, B-00959, B-01125, B-02051, B-05309, B-06123, B-06844, B-09981, B-12637, B-13205, B-13893, B-14007, B-14387, B-14481, B-21232, B-23372, B-23880, B-26071, F-23882 CATALYSTS B-02051, B-05309, B-06844, B-09981, B-13205, B-13893, B-21232, B-23372, F-23882 CATALYTIC ACTIVITY A-01583, A-26226, B-09981, B-21232 CATALYTIC AFTERBURNERS B-05309, B-07535, B-10017, B-11549, B-21232 CATALYTIC OXIDATION B-01125, B-02051, B-05401, B-13893, B-14664, B-21232, B-23880, F-23882 CEMENTS B-07535, J-17203 CENTRffUGAL SEPARATORS B-19847, C-23771 CERAMICS B-02051 CHAMBER PROCESSING B-14533, B-14568 CHARCOAL B-14533 CHEMICAL COMPOSITION C-02570, F-13415, 1-19325 CHEMICAL METHODS C-02570, C-04257, C-11130, C-18226, C-23560, C-24725, C-25925, F-13415, G-01049 CHEMICAL PROCESSING A-01583, A-16699, A-17076, A-18305, A-26226, B-00587, B-00959, B-01125, B-02051, B-04658, B-05151, B-05309, B-05401 B-06123, B-06844, B-07093, B-07535 B-09981, B-11058, B-11549, B-12637 B-13202, B-13205, B-13689, B-13893 B-13899, B-14007, B-14382, B-14387, B-14481, B-14533, B-14568, B-15152 B-19847, B-21232, B-23372, B-26071 C-23771, F-01619, F-10160, F-13415, F-14303, F-15087, F-23882, G-21307 J-17203, K-06778, L-05407 CHEMICAL REACTIONS A-01583, A-13698, A-26226, B-00959, B-01125 B-02051, B-05309, B-06123, 8-06844* B-09981, B-12637, B-13205, B-13689' B-14007, B-14387, B-14481, B-14664 ------- 28 NITRIC ACID PLANTS B-15152, B-19847, B-23372, B-23880, B-25714, C-11130, C-23560, E-21534, E-21642, E-22407, E-23037, E-23604, E-24015, F-01619, F-13415, F-15087, H-22622 CHEMISTS C-25925 CHLORIDES C-24975 CHLORINATED HYDROCARBONS C-24975, K-07197, K-20121 CHLORINE A-18305, A-22877, B-01125, B-10017, K-06778, K-07197 CHLORINE COMPOUNDS B-00587, B-10017, C-24975, C-25925, E-22407, L-07597 CHLOROFORM K-07197 CHLOROPLASTS H-22622 CHROMATES H-25481 CHROMATOGRAPHY A-22877 CHROMIUM B-09981, 1-13877 CHROMIUM COMPOUNDS C-25381, H-25481 CHRONIC G-23738 CLOVER H-22622 COAL B-07535, C-24725 COAL PREPARATION B-23880 CODES K-06778 COLLECTORS B-00587, B-19847, C-23771, L-05407 COLORIMETRY A-16699, A-22877, C-02570, C-04257, C-11130, C-24975, C-25381, C-25925, F-13415, G-01049, G-11378 COMBUSTION A-26226, B-11549, B-15152, B-23880, F-13415 COMBUSTION AIR A-26226, B-23880, B-26071, F-23882, 1-19325 COMBUSTION GASES A-21204, A-22877, A-26226, B-01125, B-05309, B-06844, B-11058, B-12637, B-13689, B-13893, B-14007, B-14568, B-14664, B-16726, B-19847, B-21232, B-23372, B-23880, B-25714, B-26071, C-18226, F-15087, 1-19325, K-06778, L-07597 COMBUSTION PRODUCTS A-21204, A-22877, A-26226, B-00959, B-01125, B-05309, B-06844, B-07535, B-11058, B-12637, B-13689, B-13893, B-14007, B-14568, B-14664, B-16726, B-19847, B-21232, B-23372, B-23880, B-25714, B-26071, C-18226, F-15087, 1-19325, K-06778, L-07597 COMMERCIAL EQUIPMENT B-01125 COMPRESSED GASES B-00587 COMPRESSION A-16699 CONDENSATION (ATMOSPHERIC) C-25925 CONSTRUCTION MATERIALS B-07535, J-17203 CONTACT PROCESSING A-18305, B-11058 CONTINUOUS MONITORING A-22877, C-06889 CONTROL AGENCIES B-23880, L-07597 CONTROL EQUIPMENT A-01583, A-16699, A-17076, A-21204, A-26226, B-00587, B-01125, B-02051, B-04658, B-05151, B-05309, B-06123, B-07535, B-07552, B-09773, B-10017, B-11058, B-11549, B-14007, B-14382, B-14568, B-15152, B-16726, B-19847, B-20313, B-21232, B-23880, B-25714, B-26071, C-23771, 1-19325, J-17203, K-06778, L-05407 CONTROL METHODS A-01583, A-16699, A-18305, A-21204, A-22877, A-26226, B-00587, B-00959, B-01125, B-02051, B-05151, B-05401, B-06123, B-06844, B-07093, B-07535, B-07552, B-09981, B-10017, B-10159, B-11058, B-11549, B-12637, B-13202, B-13689, B-13893, B-13899, B-14382, B-14387, B-14481, B-14533, B-14568, B-14664, B-15152, B-16726, B-19847, B-20313, B-20775, B-21232, B-23372, B-23880, B-25714, B-26071, E-21642, F-01619, F-10160, F-13415, F-13680, F-15087, F-23882, G-01049, 1-19325, J-17203, L-05407 CONTROL PROGRAMS L-05407, L-07597 COPPER B-05151, 1-13877 COPPER COMPOUNDS B-14007 CORN H-22622 CORROSION 1-13877, 1-19325 COSTS A-18305, B-01125, B-02051, B-04658, B-07552, B-09773, B-23880, J-17203 COUGH G-16613 CRITERIA B-10017, K-07197, L-07597 CROPS H-22622 CYANATES K-07197 CYANIDES B-04658, C-24975 CZECHOSLOVAKIA B-04658, B-13205 D DECOMPOSITION A-26226, B-14481 DESIGN CRITERIA B-05309, B-19847, B-20313 DESULFURIZATION OF FUELS B-23880 DIFFUSION A-22877, E-23604 DIOLEFINS F-13415 DISPERSION A-22877, B-01125, E-23604, F-23882 DISSOCIATION E-23604 DISTILLATE OILS F-01619 DOMESTIC HEATING B-07535 DRUGS G-16613 DUST FALL A-22877, L-05407 DUSTS A-17076, A-22877, B-07535, B-11058, B-19847, C-23771, J-17203, K-06778, K-07197, K-20121, L-05407, L-07597 ECONOMIC LOSSES J-17203 ELECTRIC POWER PRODUCTION A-21204, A-26226, B-21232, B-23880, E-22407, J-17203, K-06778 ELECTRICAL MEASUREMENT DEVICES C-06889 ELECTROCHEMICAL METHODS C-23560 ELECTROCONDUCTIVITY ANALYZERS C-06889 ELECTROSTATIC PRECIPITATORS A-17076, A-21204, B-00587, B-07535, K-06778 EMISSION STANDARDS K-06778, L-07597 EMPHYSEMA G-24588 ENFORCEMENT PROCEDURES K-06778, L-07597 ENGINE DESIGN MODIFICATION A-26226 ENGINE EXHAUSTS B-07535, G-21307 ESTERS B-05309, K-07197, K-20121 ETHYL ALCOHOL C-24975 ETHYLENE B-10017, K-07197 EUROPE A-01583, A-16699, A-17076, A-18305, A-22877, B-00587, B-00959, B-02051, B-04658, B-05309, B-06123, B-07093, B-07535, B-09981, B-10159, B-11058, B-13202, B-13205, B-13689, B-13899, B-14382, B-14387, B-14481, B-14568, B-15152, B-19847, B-20313, B-23372, C-02570, C-04257, C-06889, C-18226, C-23560, C-24975, C-25925, E-23604, F-01619, F-10160, F-13680, F-13948, F-14303, F-15087, G-11378, G-16460, G-16613, G-21307, H-22622, J-17203, K-06778, L-07597 EXCESS AIR A-26226, B-23880, B-26071, F-23882,1-19325 EXPERIMENTAL EQUIPMENT B-10159, F-10160 EXPERIMENTAL METHODS B-04658, B-10159, B-16726, F-10160 EXPOSURE CHAMBERS G-01049 EYE IRRITATION G-11378 FEDERAL GOVERNMENTS B-23880, L-07597 FERTILIZER MANUFACTURING B-25714, C-18226 FERTILIZING B-11058, G-11378 FILTERS A-17076, B-07552, B-09773, B-14568, C-23771, J-17203 FIRING METHODS A-26226, B-23880, B-26071, F-23882, 1-19325 FLAME AFTERBURNERS B-10017, B-26071 FLARES B-10017 FLOW RATES B-00587, B-09981, B-10159, B-16726, C-24975, F-10160, F-23882 FLUID FLOW B-00587, B-06123, B-09981, B-10159, B-16726, C-24975, F-10160, F-23882 FLUORIDES A-17076, B-01125, B-07552, B-11058 FLUORINE A-18305, A-22877 FLUORINE COMPOUNDS A-17076, B-01125, B-07552, B-11058, C-18226 FLY ASH B-07552 FORMALDEHYDES G-06552, H-25481, K-07197 FRUITS C-18226 FUEL GASES B-06844, B-13893, B-14387, B-23880 FUEL OILS F-01619 FUELS B-06844, B-07535, B-13893, B-14387, B-23880, C-24725, C-25381, F-01619 FUMES B-01125, B-05151, B-07552, B-09773, B-09981, B-10017, K-06778, K-20121 FUNGI H-25481 FURNACES B-07535 G GAS CHROMATOGRAPHY A-22877 GAS SAMPLING A-22877, C-04257, C-11130, C-24975 GAS TURBINES A-21204 GASES A-01583, B-00587, B-05401, B-09981, B-10017, E-22407, F-10160 GASIFICATION (SYNTHESIS) B-23880 GERMANY A-22877, B-05309, B-06123, B-07093, B-07535, B-11058, B-13202, B-15152, B-23372, C-18226, C-25925, F-13948, F-14303, H-22622, J-17203 L-07597 GOVERNMENTS B-10017, B-23880, K-06778, L-07597 ------- SUBJECT INDEX 29 GREAT BRITAIN A-16699, B-04658, B-07535, B-19847, B-20313, G-16613, K-06778 GUINEA PIGS G-23738 H HALOGEN GASES A-18305, A-22877, B-01125, B-10017, K-06778, K-07197 HALOGENATED HYDROCARBONS C-24975, K-07197, K-20121 HEALTH IMPAIRMENT G-16460, L-05407, L-07597 HEAT OF COMBUSTION C-23560 HEAT TRANSFER B-20313, F-23882 HEMATOLOGY G-16613 HEMOGLOBIN INTERACTIONS G-16613 HEXANES C-24975, K-07197, K-20121 HEXENES F-23882 HUMANS G-11378, G-16460, G-21307, L-07597 HUMIDITY E-22407 HYDRAZINES C-25381 HYDROCARBONS A-22877, B-00587, B-02051, B-09981, B-10017, B-11058, B-16726, B-21232, C-24975, E-21534, E-21642, F-13415, F-23882, G-01049, K-07197, K-20121 HYDROCHLORIC ACID A-18305, A-22877, B-07552, B-10017, B-11058, C-02570, C-04257, E-22407, G-11378, H-22622, H-25481, 1-13877, 1-19325, K-06778, K-07197, L-07597 HYDROCYANIC ACID H-25481, K-07197 HYDROFLUORIC ACID B-01125, B-07552, B-09773, B-11058, K-06778, K-07197 HYDROGEN B-06123, B-06844, G-11378 HYDROGEN SULFIDE A-22877, B-05309, B-06123, B-10017, B-11058, C-25925, K-06778, K-07197, L-07597 HYDROXIDES B-23880, C-24975, C-25925, F-10160 HYPERVENTILATION G-16613 HYPOXIA G-16613 I IMPINGERS A-22877, G-01049 INCINERATION B-10017, 1-19325 INDUSTRIAL AREAS A-18305 INDUSTRIAL EMISSION SOURCES A-01583, A-13698, A-16699, A-17076, A-18305, A-21204, A-26226, B-00587, B-00959, B-01125, B-02051, B-04658, B-05151, B-05309, B-05401, B-06123, B-06844, B-07093, B-07535, B-09981, B-10017, B-11058, B-11549, B-12637, B-13202, B-13205, B-13689, B-13893, B-13899, B-14007, B-14382, B-14387, B-14481, B-14533, B-14568, B-15152, B-16726, B-19847, B-21232, B-23372, B-23880, B-25714, B-26071, C-18226, C-23771, E-22407, F-01619, F-10160, F-13415, F-13481, F-14303, F-15087, F-23882, G-11378, G-21307, 1-19325, J-17203, K-06778, L-05407, L-07597 INFRARED SPECTROMETRY A-22877, E-14408 INHALATION THERAPY G-16613 INORGANIC ACIDS A-01583, A-13698, A-16699, A-17076, A-18305, A-21204, A-22877, A-26226, B-00587, B-00959, B-01125, B-02051, B-04658, B-05151, B-05309, B-05401, B-06123, B-06844, B-07093, B-07535, B-07552, B-09773, B-09981, B-10017, B-10159, B-11058, B-11549, B-12637, B-13202, B-13205, B-13689, B-13893, B-13899, B-14007, B-14382, B-14387, B-14481, B-14533, B-14568, B-14664, B-15152, B-16726, B-19847, B-20313, B-20775, B-21232, B-23372, B-23880, B-25714, B-26071, C-02570, C-04257, C-06889, C-11130, C-18226, C-23560, C-23771, C-24725, C-24975, C-25381, C-25925, E-14408, E-21534, E-21642, E-22407, E-23037, E-23604, E-24015, F-01619, F-10160, F-13415, F-13481, F-13680, F-13948, F-14303, F-15087, F-23882, G-01049, G-06552, G-11378, G-16460, G-16613, G-21307, G-23738, G-24588, H-22622, H-25481,1-13877, 1-19325, J-17203, K-06778, K-07197, K-20121, L-05407, L-07597 INSTRUMENTATION C-06889, F-10160 INTERNAL COMBUSTION ENGINES B-07535 INVERSION B-07535, L-07597 IODIMETRIC METHODS G-01049 IODINE COMPOUNDS C-25925, G-01049 IONIZATION E-22407 IONS C-06889, G-11378 IRON B-05151, 1-13877 IRON COMPOUNDS C-24725, C-24975, H-22622 IRON OXIDES B-07552 JAPAN B-14664, 1-19325, K-07197, K-20121, L-05407 K KETONES G-01049, K-07197 KILNS B-07535 KONIMETERS A-22877 LABORATORY ANIMALS G-01049, G-23738, G-24588 LABORATORY FACILITIES G-16460 LEAD 1-13877, K-07197 LEAD ALLOYS 1-13877 LEAD COMPOUNDS K-06778, K-07197, K-20121 LEGAL ASPECTS K-06778, L-05407, L-07597 LEGISLATION K-06778, L-05407 LIGHT RADIATION B-07535, E-21642, E-22407, H-22622 LIQUIDS B-07552, C-23560, E-22407 LONDON B-07535 LOS ANGELES B-07535 LOWER ATMOSPHERE E-14408, E-21534 E-21642 LUNGS G-01049, G-23738 M MAGNESIUM COMPOUNDS B-12637 MAGNETOHYDRODYNAMICS (MHD) A-21204 MANGANESE K-07197 MATERIALS DETERIORATION 1-13877 1-19325 MATHEMATICAL ANALYSES A-26226 F-15087 MATHEMATICAL MODELING A-26226 MAXIMUM ALLOWABLE CONCENTRATION G-11378, G-21307, G-23738, G-24588, K-06778, K-07197, K-20121, L-07597 MEASUREMENT METHODS A-22877, C-04257, C-06889, C-24725 MEETINGS L-05407 MEMBRANE FILTERS A-22877 MERCURY K-07197 MERCURY COMPOUNDS C-23771, C-24975 METABOLISM G-11378, H-22622 METAL COMPOUNDS A-18305, B-06123, B-11058, B-12637, B-14007, B-14382, B-23880, C-23771, C-24725, C-24975, C-25381, F-10160, H-22622, H-25481, K-06778, K-07197, K-20121 METAL FABRICATING AND FINISHING A-13698, B-05151, G-21307 METALS B-02051, B-05151, B-05309, B-06844, B-09981, B-21232, F-23882, 1-13877, K-07197 METEOROLOGY A-22877, B-07535, C-25925, E-22407 METHANES B-02051, B-09981, B-16726 MICE G-23738 MICROMETEOROLOGY C-25925 MICROORGANISMS H-25481 MICROSCOPY C-18226 MIDDLE ATMOSPHERE E-23604 MINERAL PROCESSING J-17203 MINERAL PRODUCTS B-07552 MISSILES AND ROCKETS C-25381 MISSOURI A-01583, B-00587, B-00959 MISTS B-00587, B-05401, B-07552, B-11058, C-23771, K-20121 MONITORING A-22877, C-06889 N NAPHTHALENES B-11058 NATURAL GAS B-06844, B-13893, B-14387, B-23880 NICKEL B-09981 NICKEL COMPOUNDS B-14007, K-07197 NITRATES B-05401, B-10159, B-14382, C-23771, E-21642, G-21307, H-25481, K-07197, K-20121 NITRIC ACID A-01583, A-13698, A-16699, A-17076, A-18305, A-21204, A-22877, A-26226, B-00587, B-00959, B-01125, B-02051, B-04658, B-05151, B-05309, B-05401, B-06123, B-06844, B-07093, B-07535, B-07552, B-09773, B-09981, B-10017, B-10159, B-11058, B-11549 B-12637, B-13202, B-13205, B-13689, B-13893, B-13899, B-14007, B-14382 B-14387, B-14481, B-14533, B-14568, B-14664, B-15152, B-16726, B-19847, B-20313, B-20775, B-21232, B-23372 B-23880, B-25714, B-26071, C-0257o' C-04257, C-06889, C-11130, C-18226 C-23560, C-23771, C-24725, C-24975 C-25381, C-25925, E-14408, £-21534* E-21642, E-22407, E-23037, E-23604? E-24015, F-01619, F-10160 F-13415 F-13481, F-13680, F-13948, F-14303' F-15087, F-23882, G-01049, G-06552 G-11378, G-16460, G-16613, G-21307 G-23738, G-24588, H-22622, H-25481* 1-13877, 1-19325, J-17203, K-06778 K-07197, K-20121, L-05407, L-07597 NITRIC ANHYDRIDE (N2O5) B-07093 C-11130 ------- 30 NITRIC ACID PLANTS NITRIC OXIDE (NO) A-16699, A-22877, A-26226, B-01125, B-02051, B-05151, B-05309, B-06123, B-06844, B-07093, B-07535, B-09981, B-10159, B-11058, B-12637, B-13202, B-13689, B-13899, B-14481, B-14664, B-15152, B-16726, B-19847, B-20313, B-20775, B-21232, B-23372, B-23880, C-11130, C-23560, E-21534, E-23037, E-23604, E-24015, F-01619, F-13415, F-15087, G-16613 NITRITES B-10159, B-13202, G-21307 NITROGEN B-20775, C-25381, E-23604, F-13415 NITROGEN DIOXIDE (NO2) A-01583, A-16699, B-01125, B-02051, B-05151, B-05309, B-05401, B-06844, B-07093, B-07552, B-09981, B-10159, B-11058, B-13202, B-13689, B-13899, B-14007, B-14481, B-14664, B-15152, B-16726, B-19847, B-20313, B-21232, B-23880, B-26071, C-11130, C-23560, C-25381, E-21534, E-21642, E-23037, E-23604, E-24015, F-01619, F-13415, F-13948, F-15087, G-16613, G-21307, G-24588, K-06778, K-07197, L-07597 NITROGEN OXIDES A-01583, A-13698, A-16699, A-21204, A-22877, A-26226, B-00959, B-01125, B-02051, B-05151, B-05309, B-05401, B-06123, B-06844, B-07093, B-07535, B-07552, B-09773, B-09981, B-10017, B-10159, B-11058, B-12637, B-13202, B-13205, B-13689, B-13893, B-13899, B-14007, B-14382, B-14387, B-14481, B-14533, B-14664, B-15152, B-16726, B-19847, B-20313, B-20775, B-21232, B-23372, B-23880, B-25714, B-26071, C-06889, C-11130, C-23560, C-25381, E-21534, E-21642, E-22407, E-23037, E-23604, E-24015, F-01619, F-10160, F-13415, F-13680, F-13948, F-15087, G-16613, G-21307, G-23738, G-24588, 1-19325, J-17203, K-06778, K-07197, L-07597 NITROGEN TRIOXIDE (NO3) B-07093, C-11130 NITROUS ACID B-13205, C-11130, C-18226, C-23560, E-21534, E-24015, F-13481, G-21307, H-22622 NITROUS ANHYDRIDE (N2O3) B-07093, B-10159, C-11130, F-13415 NITROUS OXIDE (N20) A-16699, B-12637, C-11130, E-24015 NON-INDUSTRIAL EMISSION SOURCES A-21204, B-04658, B-07535, B-11058, C-25381, G-11378 NOSTRILS G-11378 NUCLEAR POWER PLANTS B-21232, E-22407 NUCLEATION E-22407 o OCCUPATIONAL HEALTH G-11378, G-21307, G-24588, K-20121 ODOR COUNTERACTION B-07535 ODORS B-04658, B-10017, G-11378, 1-19325 OLEFINS B-10017, E-21534, F-13415, F-23882, G-01049, K-07197 OPERATING VARIABLES A-26226, B-05401, B-09981, 1-19325 ORGANIC ACIDS B-05309, G-01049, H-25481, 1-19325, K-07197 ORGANIC NITROGEN COMPOUNDS B-01125, B-05151, B-25714, G-01049, K-07197, K-20121 ORGANIC SULFUR COMPOUNDS C-24975 OXIDANTS A-01583, B-05151, B-10017, E-21534, E-21642 OXIDATION A-01583, B-00959, B-13689, B-14664, B-19847, B-25714, C-23560, E-22407, F-01619, F-13415, F-15087 OXIDES A-01583, A-13698, A-16699, A-17076, A-18305, A-21204, A-22877, A-26226, B-00959, B-01125, B-02051, B-05151, B-05309, B-05401, B-06123, B-06844, B-07093, B-07535, B-07552, B-09773, B-09981, B-10017, B-10159, B-11058, B-12637, B-13202, B-13205, B-13689, B-13893, B-13899, B-14007, B-14382, B-14387, B-14481, B-14533, B-14664, B-15152, B-16726, B-19847, B-20313, B-20775, B-21232, B-23372, B-23880, B-25714, B-26071, C-06889, C-11130, C-23560, C-25381, E-21534, E-21642, E-22407, E-23037, E-23604, E-24015, F-01619, F-10160, F-13415, F-13680, F-13948, F-15087, G-16613, G-21307, G-23738, G-24588, 1-19325, J-17203, K-06778, K-07197, K-20121, L-05407, L-07597 OXYGEN A-01583, B-09981, B-20775, E-21642, F-13948 OXYGEN CONSUMPTION G-01049 OXYGEN LANCING B-07535 OZONE B-10017, C-25925, E-14408, E-21642, E-22407, E-24015, K-07197 PACKED TOWERS B-04658, B-10017, B-20313 PAPER MANUFACTURING F-13481 PARTICLE COUNTERS A-22877 PARTICLE GROWTH E-22407 PARTICLE SIZE B-00587, B-07552, C-23771, C-24725, K-07197 PARTICULATE CLASSIFIERS B-00587, B-07552, C-23771, C-24725, K-07197 PARTICULATE SAMPLING A-22877, C-23771 PARTICULATES A-17076, A-21204, A-22877, B-00587, B-01125, B-05151, B-05401, B-07535, B-07552, B-09773, B-09981, B-10017, B-11058, B-14568, B-19847, C-23771, E-22407, F-01619, G-01049, G-06552, H-22622, J-17203, K-06778, K-07197, K-20121, L-05407, L-07597 PENELEC (CONTACT PROCESS) A-18305 PEROXIDES A-01583 PEROXYACETYL NITRATE E-21642 PEROXYACYL NITRATES E-21642 PERSONNEL C-25925, L-07597 PESTICIDES C-24975 PH B-10159 PHENOLS K-07197 PHENYL COMPOUNDS K-20121 PHENYLS K-20121 PHOSPHATES A-17076, B-25714, C-23771 PHOSPHORIC ACID A-18305, B-00587, B-07552, B-11058, C-23771, C-25381, F-14303, K-07197 PHOSPHORUS COMPOUNDS A-17076, B-06123, B-11058, B-25714, C-23771, K-07197 PHOTOCHEMICAL REACTIONS A-13698, E-21534, E-21642, E-23037, E-23604, E-24015, H-22622 PHOTOIONIZATION E-22407 PHOTOLYSIS E-24015 PHOTOMETRIC METHODS C-04257 PHOTOOXIDATION H-22622 PHOTOSYNTHESIS H-22622 PHTHALICACID B-05309 PHYSICAL STATES A-01583, B-00587, B-05401, B-07552, B-09981, B-10017, B-14533, B-14568, C-23560, E-14408, E-22407, F-10160, G-23738, G-24588 PLANNING AND ZONING L-05407 PLANS AND PROGRAMS L-05407, L-07597 PLANT DAMAGE C-18226, H-22622, H-25481, L-07597 PLANT GROWTH H-22622, H-25481 PLANTS (BOTANY) C-18226, H-22622, L-07597 PLATINUM B-06844, B-09981, B-21232, F-23882 PLUME BEHAVIOR A-22877 PNEUMONIA G-24588 POLYNUCLEAR COMPOUNDS B-11058 PORTABLE C-23771 POWER CYCLES K-06778 POWER SOURCES A-21204, B-07535 PRESSURE B-00587, B-11058 PRIMARY METALLURGICAL PROCESSING K-06778 PROCESS MODIFICATION A-26226, B-05151, B-10017, B-11058, B-12637, B-23880, B-26071, F-13415, F-23882, 1-19325 PROTEINS G-01049 PULMONARY EDEMA G-16613 PYROLYSIS B-05309 R RATS G-01049, G-23738, G-24588 REACTION KINETICS A-26226, B-04658, B-10159, B-20775, E-21534, E-21642, E-24015, F-10160, F-13680, F-23882 REACTION MECHANISMS A-26226, B-25714, C-23560, E-23604, E-24015, F-13948, F-23882, H-22622 RECOMBINATION E-22407 REDUCTION A-01583, A-26226, B-01125, B-02051, B-06123, B-06844, B-09981, B-12637, B-13205, B-14007, B-14387, B-14481, B-15152, B-23372, B-23880 REGULATIONS K-06778, L-07597 RESEARCH METHODOLOGIES C-25925 RESEARCH PROGRAMS B-23880 RESPIRATORY DISEASES G-16613, G-24588, L-05407 RESPIRATORY FUNCTIONS G-01049, G-16613 RESPIRATORY SYSTEM G-01049, G-11378, G-21307, G-23738, L-05407 SALTZMAN METHOD A-16699, A-22877, C-11130 SAMPLERS A-22877, C-11130, C-23771, G-01049 SAMPLING METHODS A-22877, C-04257, C-11130, C-23771, C-24975, G-01049 SCRUBBERS A-01583, A-16699, A-17076, A-26226, B-00587, B-01125, B-0<«658, B-05151, B-06123, B-07535, B-09773, B-10017, B-11058, B-14007, B-14382, B-14568, B-15152, B-16726, B-20313, B-23880, B-25714 SELENIUM COMPOUNDS K-07197, K-20121 SETTLING PARTICLES A-17076, A-22877, B-07535, B-11058, B-19847, C-23771, ------- SUBJECT INDEX 31 J-17203, K-06778, K-07197, K-20121, L-05407, L-07597 SILICON COMPOUNDS B-07552, B-23880 SILICON DIOXIDE B-19847, K-07197 SINTERING K-06778 SMOG B-07535, G-06552 SMOKE SHADE A-22877 SMOKES A-22877, B-07535, H-22622, J-17203 SODIUM CARBONATE B-14382 SODIUM COMPOUNDS A-18305, B-06123, B-14382, C-24975 SODIUM HYDROXIDE A-18305, B-06123, C-24975 SOLAR RADIATION B-07535, E-21642, E-22407 SOLVENTS B-05309, B-21232 SOOT L-05407 SOOT FALL L-05407 SOURCE SAMPLING A-22877 SO2 REMOVAL (COMBUSTION PRODUCTS) A-18305, A-21204, A-22877, B-07535, B-11058, B-23880, J-17203 SPECTROMETfcY A-22877, E-14408 SPECTROPHOTOMETRY A-22877, C-02570, C-04257, C-11130, C-24975, C-25925, G-01049, G-11378 SPINACH H-22622 SPORES H-25481 SPRAY TOWERS B-06123, B-10017, B-14568 ST LOUIS A-01583, B-00587, B-00959 STABILITY (ATMOSPHERIC) B-07535, L-07597 STACK GASES A-21204, A-22877, A-26226, B-01125, B-12637, B-13689, B-13893, B-14568, B-14664, B-19847, B-21232, B-23372, B-23880, B-25714, B-26071, C-18226, F-15087, 1-19325, K-06778 STACK SAMPLING A-22877 STACKS A-22877, B-07093, B-10017, C-18226, K-06778, L-07597 STANDARDS B-10017, G-11378, G-21307, G-23738, G-24588, K-06778, K-07197, K-20121, L-07597 STEAM B-14533 STEAM PLANTS A-26226, K-06778 STEEL B-05151, 1-13877 STYRENES K-20121 SULFATES B-01125, C-24975, C-25925, H-25481 SULFIDES A-22877, B-05309, B-06123, B-10017, B-11058, B-23880, C-25925, K-06778, K-07197, L-07597 SULFITES C-25925 SULFUR COMPOUNDS A-22877, B-01125, B-05309, B-06123, B-10017, B-11058, B-23880, C-24725, C-24975, C-25925, H-25481, K-06778, K-07197, L-07597 SULFUR DIOXIDE A-17076, A-22877, B-01125, B-07535, B-07552, B-10017, B-11058, E-21642, E-22407, K-06778, K-07197, L-05407, L-07597 SULFUR OXIDES A-17076, A-18305, A-21204, A-22877, B-01125, B-07535, B-07552, B-10017, B-11058, B-14533, E-21642, E-22407, 1-19325, K-06778, K-07197, L-05407, L-07597 SULFUR OXIDES CONTROL A-18305, A-21204, A-22877, B-07535, B-11058, B-23880, J-17203 SULFUR TRIOXIDE A-22877, B-01125, B-07535, B-07552, B-11058, K-06778 SULFURIC ACID A-17076, A-18305, A-21204, B-00587, B-01125, B-07535, B-07552, B-11058, B-14533, B-14568, B-23880, C-06889, C-18226, C-23771, C-25925, E-22407, F-01619, F-13481, G-11378, H-25481, 1-13877, J-17203, K-06778, K-07197, L-05407 SURFACE COATING OPERATIONS B-05309 SURFACE PROPERTIES G-06552 SUSPENDED PARTICULATES A-22877, B-00587, B-01125, B-05151, B-05401, B-07535, B-07552, B-09773, B-09981, B-10017, B-11058, C-23771, G-06552, H-22622, J-17203, K-06778, K-20121 SWEDEN A-01583, A-18305, B-00587, B-00959, B-02051, B-04658, F-01619 SYNERGISM G-06552, G-11378 TECHNICAL SOCIETIES K-07197, L-05407 TEMPERATURE A-01583, A-26226, B-00959, B-05309, B-07552, B-09981, B-11058, B-19847, B-20775, 1-19325 TEMPERATURE GRADIENT L-07597 TESTING FACILITIES G-01049, G-16460 TETRAETHYL LEAD K-07197 TEXTILE MANUFACTURING B-11058 TEXTILES B-07552 THERMODYNAMICS E-23037, E-24015 THRESHOLDS G-11378, G-21307 TIN 1-13877 TISSUES G-01049 TOBACCO H-22622 TOLUENES C-24975, F-23882, K-07197, K-20121 TOXIC TOLERANCES F-01619, H-25481 TOXICITY G-16613, G-21307, G-23738 TRANSPORT E-23604, F-23882 TRANSPORTATION A-21204, B-07535 TREATMENT AND AIDS G-16613, G-23738 TURBULENCE (ATMOSPHERIC) A-22877, C-25925 u UNITED STATES B-05401 UPPER ATMOSPHERE E-23604 URBAN AREAS A-18305, E-23037 USSR A-17076, B-09981, B-10159, B-13689, B-13899, B-14382, B-14387, B-14568, B-19847, C-02570, C-04257, C-06889, C-23560, F-10160, F-13680, G-11378, G-16460 VANADIUM COMPOUNDS B-23880 VAPOR RECOVERY SYSTEMS B-10017 VAPORS B-14533, B-14568, E-14408, G-23738, G-24588 VEGETABLES H-22622 VEHICLES B-07535 VENTILATION (PULMONARY) G-16613 VENTURI SCRUBBERS B-01125, B-10017 VOLATILITY C-25381 w WATER B-07552, C-23560, E-22407 WATER POLLUTION A-21204, B-04658 WEST AND GAEKE METHOD A-22877 WET CYCLONES B-09773 WINDS A-22877 WOOLS B-07552 X XYLENES K-07197 ------- |