Review of Application of Analysis
Air Pollution lames P. lodge, l r . Division o f Air Pollufion, Roberf A. Tuff Sanitary Engineering Center, Public Health Service, Cincinnati 26, Ohio
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HIS REVIEW covers the years 1959 and 1960, which have seen great activity in the air pollution research field. It supplements the previous review (185), with the exception that the growth of the literature has been SO great that explicit coverage of radioactive pollutants has been omitted from this review. The trend toward increased interest in automotive exhaust and atmospheric carcinogens, noted in the previous review, has continued. I n addition, there lias been a renewal of interest in atmospheric lead. For the most part, these observations hold only for the United States. The bulk of research in Europe continues to be directed toward improved methods for measurement and control of sulfur dioxide and dust. Meetings and conferences were numerous. The nnnual symposia organized by the Committee on Air Pollution, American Chemical Societ,y, featured sessions on automotive exhaust and on polynuclear hydrocarbons in 1959, and on photochemistry and fine particles in 1960. The Air Pollution Control Asociation continued its regular schedule of mcctings. A conference on air pollution research was sponsored by the C. S. Public Health Service in Xew Orleans in enrly 1960, continuing a series of meetiiig~intended primarily for the Public Hrnlth Service contractors and grantees in the field. More specialized meetings included a conference on dust in Vienna, one on adhesion of fine particlos a t Leatherhead, England, and a symposium a t Oxford on atmospheric diffusion and turbulence. Increasing public intt2rCst iu air pollution reyulted in the puhlication of a hrge number of papers intended priniwily for public consuniption. These are too numcrous and in gencml too lacking i n n o v ~ l t yto warrant mention h u e . On the other hand, a substantial number of books and r w i w articles of :i generd nature were published having high sciontifie merit. h careful study of tlie diversity of forms in \rhic.h air pollution measurement,s are reported led to a recommendation of the use of
metric units and Celsius temperatures throughout (348). Faith (98) published a short monograph on air pollution control in all its aspects, aimed a t the technically trained nonspecialists and the educated laymen. The technical literature also yielded summaries of unsolved research problems in the field (618,363). The American Industrial HJ g’iene Association published the first volume of a n air pollution manual (24). This volume of contributions by a variety of specialists in the fields of industrial hygiene and air pollution is primarily devoted to the evaluation of air pollution. A compilation of standards on methods for atmospheric sampling and analysis was published by the American Society for Testing Materials (27). This included a set of definitions, a sampling philosophy, and methods for fluoride, nitrogen oxides, odors, oxidants, particulate matter, and sulfur dioxide. Air pollution research sponsored by the American Petroleum Institute )vas the subject of both a review and an annotated bibliography (26, 176). The preponderance of this work relates to pollution of the type found in Los Angeles, though other studies concerned the oxidation of sulfur dioxide to sulfur trioxide, effluents from oil-fired furnaces, and the use of tracers to study dispersion from a single source, among other things. The proceedings of the conference on atmospheric diffusion held a t Oxford, England, previously mentioned, were published as a monograph (108). Four papers constituting a symposium on air pollution instrumentation were published in book form by the American Society for Testing Materials (26). il more extensive survey of automatic recording instruments was given by Giever and Cook (116). Jacobs has published a substantial volume on the chemical analysis of air poliutant. (170). This book covers the entire field from fundamental definition?, sampling, and gas volume measurement through listings of specific methods for most inorganic species. b e e very fen- techniques for organic compounds have been reduced to the
simplicity of a dustfall measurement, the chapter on organics has less of a cookbook character, and is more in the nature of an excellent review of existing methods. Radiochemical techniques are included. The Industrial Hygiene group of the Los -4lanios Scientific Laboratory has published a compilation of their analytical procedures for a number of air contaminants, some of which are of air pollution interest (233). A similar compilation was made of methods used by the industrial hygiene staff of Montecatini (390). A short Public Health Service monograph discussed exposure chambers for research in animal inhalation (107). Despite the emphasis on tovicological application, much of the discussion is pertinent to the general problem of maintaining known concentrations of substances in a defined air volume. Another paper of chemical interest, despite its medical orientation, is a review of medical research in air pollution sponsored by the Public Health Service (149). A group of Russian publications related to air cleaning and to the definition of allowable concentrations in the general atmosphere are now available in translations prepared by Levine (253, 254, 286, 365). There is also a manual on the determination of atmospheric pollutants by Alekseeva and Ryazanov (8) and a monograph discussing the occurrence of 3,4-henzpyrene in air by Shabad and Dikun (327)* Lent (203) has reviewed the air pollution situation in Germany in a pnper in English, while Goetz (121) has reviewed the Los Angeles pollution situation in German. The relationship between space-average concentrations and permitted concentration levels was discussed by Koch (190). A volume on the atmospheric chcmistry of chlorine and sulfur compounds appeared (BIO), including an extended section on analytical techniques. Junge published two discussions of atmospheric chemistry, including both urban and natural atmospheres (178, 179). Finally, it is worthwhile to note the apVOL. 33, NO. 5 , APRIL 1961
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pearance of two different volumes in nonchemical fields-the glossary of meteorology (167) and a digest of state air pollution laws (278). BIOLOGICAL INDICATORS
One of the primary reasons for public concern over air pollution is the effect of pollutants on biological systems, including man. Many organisms are extremely sensitive to a very narrow spectrum of pollutants. Although it is often difficult to quantitate the response of biological systems to toxic materials, they frequently represent a simple tool for the characterization of pollution. Todd (355), studying the effects of ozone on a number of enzymes in vitro, found papain particularly sensitive to inactivation by ozone. Goetz and Tsuneishi have shown a relationship between the general irritant quality of aerosols and their toxicity toward the bacterium Escherichia coli (185, 126). Magdefrau showed a general relationship between urbanization and the absence of lichens, highly suggestive that lichens may be usable indicator plants (624). At least two papers have appeared on the use of higher plants as air pollution indicators (80, 222). The known response of plants to the compounds formed in olefin-ozone reactions has been used in studies aimed at characterizing the specific phytotoxicant (31, 81). Air pollution effects have been noted on conifers (43, 187), on the lupine (91), and on tobacco (148). Amdur was successful in using the respiratory resistance of guinea pigs as a measure of irritation caused by low concentrations of toxicants (63). Hine and coworkers were unable to show corneal injury in rabbits from eye irritants (163). Finally, in the area of human response, a new device has been described for the determination of odor threshold (63) as well as a simple technique for the field determination of odor intensities (131). Even human response to electric space charges have been discussed (194). SAMPLING TECHNIQUES
Since no analytical result is better than the technique which produced the sample, a considerable preoccupation with improved sampling techniques is natural. The careful study in Sheffield, England, has yielded valuable information on the number and location of instruments necessary to determine true concentrations within a previously selected range of error (68). Studies in San Francisco suggest that a properly scheduled mobile station can 4 it
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ANALYTICAL CHEMISTRY
yield data more or less equivalent to results from a large number of stationary samplers (88). Two new lightweight pumps have been described for field use, one for line operation, and one for use with a battery (208). A sampling aspirator operating on compressed Freon has been described (286). Gage has discussed the calibration of hand pumps for air sampling ( l o g ) , while Harrison and coworkers devised two constant flow regulators for the high-volume air sampler (142). eerosol Sampling. Two basic studies relating to the collection of aerosols have appeared-a paper on adhesion of particles to surfaces (193) and a study of dust re-entrainment (38). Aerosol sampling techniques in general are reviewed by Gelman, and analytical techniques are discussed as well (114). Breitling described a new approach to stack sampling for particulates (60), and Wasser gave a general review of stack sampling methods (876), There were several discussions of the shape of sampling probes, and the effect of isokinetic sampling of gas streams (35,36,382). The cascade impactor was the subject of a review which included a new calibration of the commercial instrument (207). An improved version with round jets was evaluated (235). A new multiple jet impactor with a large number of stages, intended primarily for bacterial sampling, was described by Anderson (28). A liquid impinger characterized by vortical motion of the sampling liquid was described by Shipe and coworkers (330, 362, 363). I t was suggested that qualitative sampling can be performed with an improvised electrostatic precipitator consisting simply of a small plastic rod which has been charged by rubbing (849). German researchers produced a number of papers on the theory of thermal precipitation, including discussions of fractionation effects (318, 319, 344, 854). Kruse and Bianconi compared the results of the standard British thermal precipitator with data obtained with a membrane filter sampler (196). Cadle and Thuman described a process of producing filters having organic fibers below 1 micron in diameter. The technique involved the spraying of solutions of polystyrene by a high velocity air stream (67). Spurriy discussed a sampling device called the concentrometer, which facilitates the determination of dustiness by visual comparison with standards (336). Some of the operating characteristics of the American Iron and Steel Institute's automatic smoke sampler were described (8.53),and a modification of the instrument was suggested to increase its versatility (841). Two papers dealt with the use of
adhesive foil for sampling. Hage and coworkers particularly noted variations from one edge to the other of foils which were improperly exposed (137). An artificial test material was used and dispersed a t a known rate from a simulated source. Effenberger measured natural dustfall with a grid of 15 foils laid at various points on a horizontal roof (94). Inaccuracies caused by the air flow pattern over the roof were detected by statistical means. A group of papers dealt with the aerosol spectrometer developed by Goetz and coworkers (122, 125, 124, 238, 261). These concerned the construction and calibration of the instrument, some useful modifications, and its application to several field situations. Gas Sampling. Baker and Doerr evaluated several types of plastic film with regard to their effect on a number of typical air pollutants (39). Several were found generally suitable for use as sampling bags, and for other applications of this sort. A slightly modified midget impinger could be used to sample a number of vapors by low temperature condensation (204). Carbon adsorption was evaluated by Smith and Grant (334). They left unsolved certain problems with regard to desorption of higher molecular weight materials, but showed that a twosection system a t temperatures no C. could collect colder than -78' even methane quantitatively. A report on the removal of sulfur dioxide by chemisorption on dry ion exchange resins, intended primarily as an air cleaning study, raises the interesting possibility that this might also be used as a sampling technique (71). Holm-Jensen described a helical contacting device capable of excellent collection efficiencies with a liquid volume of 0.5 ml. of absorbing fluid. He also described a micro technique for carbon dioxide which employed this apparatus (158). Other, more established types of absorbers were evaluated for a variety of vapors (110, 274). The concept of a simple, prepackaged sampling and analysis kit appears to have been a popular one. Several packaged systems were described (61, 92, 220). A coordinated sampling and analysis system for flue gases was also set forth (17f).
ANALYSIS OF AEROSOLS
A number of reports related to properties and measurements of aerosols in the abstract, rather than to detection of individual species in them. A substantial volume on fine particle measurement was published by Orr and Dallavalle (252). Kogan described two aerosol nephelometers of Russian manu-
facture for aerosol studies (192). Pollak reviewed techniques and applications of Aitken nucleus counters (258). Rich gave a modification which permitted determination of average particle size (270). The attenuation of ultrasonic energy was proposed as a basis for a device to determine aerosol concentration (257). It was also suggested that the particle size distribution could be determined by a method which involved both the charging rates of the particles, and the mobility of the resulting large ions (89). Reed reported a statistical study of the accuracy of visual smoke density estimation, both with the Ringelmann chart and the Telesmoke (263). He concluded that the latter instrument is somewhat more accurate. Several papers relating to thc determination of the size of water droplets are worth noting for possible later application to air pollution; most are intended for studies in cloud physics (53, 54, 83, 186, 230, 264). Harris described a method for replicating nonvolatile droplets for electron microscopic study (1.40). The aerosol collected in Los Angeles during smog episodes gave a characteristic polarographic pattern (251). Two waves were noted, one of which was identified as due to lead, and the other was attributed t o somr product of the reaction of nitrogrn oxides and olefins. Measurement of Dusts. Foitzik reviewed t h e properties of a variety of natural atmospheric dusts (104). ‘rwo British papers contained statistical aspects of dust counting, and pointed out errors in presently accepted techniques, with particular regard to the thermal precipitator (32, 271). Still another paper concerned n i t h dust statistics pointed out the advantages of espressing particle sizes in terms of gromctric mean diameter (132). A number of new techniques for partick measurement were reported. It was suggested that the dust concentration in a strc.am of dust-laden air could bc. measured by a sensitive determination of the drag on a small sphere or cdinder placed in the stream (118). Yhr determination of particle size by $ back-scattering ivas proposed by Conner and coworkers ( 7 4 ) . Mass determination by p gage techniques for the evaluation of samples on filter tape were discussed in two papers. Nader and Allen described a device having a separate carbon-14 source; if the source w r e removed. t h P rsdioactivity of the sample could also be dctermined (242). Spuriy and Kubie used membrane filters which were already radioactive (558). An apparatus for the estirnation of the electricai charge was also discussed (2.34). German researchers devoted a great deal of interest to the measurement of
settled dust, and both individual papers and symposia appeared on this subject (84, 112, 113, 133, 144] 150, 248, $50, 32.4). In the United States, the Air Pollution Control Association published a recommended standard method for a continuing dustfall survey (6). German researchers have also studied very carefully the use of the konimeter for the measurement of airborne dust. Particular interest now centers around the photometric evaluation of konimeter samples, thus avoiding the tedious process of microscopic evaluation (47, 52, 276, 277, 349). Two additional German papers were concerned with other aspects of particle size measurement over a range of particle sizes (680, 282). Dust Microscopy. Most new work in dust microscopy is of European origin. A study of the morphology of particles a t t h e various stages of combustion in a pulverized fuel flame was published by Alperin and coworkers (9). Impinger dust samples are occasionally found to be contaminated with mold spores (182), but this is an artifact which can be eliminated by scrupulous cleanliness. Three papers concerned the routine use of the electron microscope for particle size determination (314, 315, 381). Olaf discussed the use of the ultramicroscope for the same purpose (651). A number of papers related to the application of phase microscopy to the identification of fine particles The technique of Crossmon (78) was both the simplest and probably the least flexible. Schmidt described the morphology of various types of asbestos (3161, and listed a variety of liquids of different refractive indrxes with which membrane filters could be made transparent (317). Still more precise identifications can be made with a technique involving wave length variation of the illumination (177). S p u r i y gave a general classification of methods involving the use of the membrane filter (337). Finally, Salzenstein, in a semipopular article, described a project in progress to systematize the entire body of knowledge of morphological identification of fine particles ($90). Analysis of Inorganic Aerosols. Lodge revien ed chemical techniques for t h e identification of individual aerosol particles involving the use of the microscope (209). A method was also developed using impregnated gelatin for the specific identification of sulfuric acid mist (213). Tufts described related techniques for potassium IS59), fluorides (360), chlorides and sulfates (3621, and lead (368). A somewhat similar method for the field determination of lead fumes was developed by Dison and Metson (85). This was one of several methods published which constituted minor varia-
tions in the basic dithizone technique (86,196, 263). A number of papers related to the determination of beryllium. Suggested techniques include emission spectroscopy (49, 64), spectrophotometry of the complex with aluminon (77), and fluorometry of the morin salt (269, 331, 372). Single papers also concerned techniques for zirconium (58) and manganese (66). Several less common analytical techniques were suggested for specific analytical problems. Landy determined thallium by polarographic methods (200)while Hill and Murphy evaluated the use of electrochromatography for the same purpose (152). The latter technique was not entirely successful, since it caused dilution of the thallium in the sample. A general method of metal analysis by paper chromatography was suggested (172). A variety of metals could be determined by precipitation chromatography in sulfideimpregnated agar columns (335). The ring-oven technique was evaluated for the separation of cations from air samples (580). The possibility of detecting individual flashes of sodium light caused by the passage of single particles through a flame was suggested as the basis of a sodium particle counter (44). This appears to be the third time this technique has been discovered independently. A new colorimetric technique for chloride was developed (245) A differential technique, reputed to permit separate determination of chloride and hydrochloric acid aerosol, was reported in the Russian literature ( 7 ) . Johannesson described an ingenious method for the conductometric determination of sulfate in the presencr of chloride (178). Analysis of Organic Aerosols. Deof specific chemical velopment methods for t h e higher molecular weight hydrocarbons was almost entirely the project of Sawicki and his coworkers. Two methods were suggested for the detection of compounds related to cyclopentadiene (295, 3f2). Anthracene derivatives could be detected by a simple thermochromic test (145). Derivatives of pyrrne could likewise be specifically identified (305). Isatin was shown to be a useful reagent for both aromatic hydrocarbons and phenols ( % I ) , and a group of color tests were developed which were specific for the higher molecuIar weight polycyclic hydrocarbons (292 ) . Theqe were remarkable in that the principal absorption maxima Rere in the near infrared region. Thomas and his coworkers developed a fractional sublimation technique which permitted the separation of milligram amounts of polynuclear hydrocarbons (350). Smaller amounts of polyVOL. 33, NO. 5 , APRIL 1961
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nuclears were separated by paper chromatography (90). Hoffman and Wynder published a technique for the determination of several polycyclic hydrocarbons based primarily on partition between cyclohexane and water (157). Coordinated techniques were also reported by Falk (100), and by Sawicki et al. (297, 298, 310). Both remarked particularly on the applicability of fluorescence techniques, which were also utilized by Van Duuren (366) and by Thomas et al. (351). Lindsey’s technique is more dependent on spectrophotometry (206). KOloss of benzpyrene occurred during filter sampling a t room temperature (73). Volatility became significant, however, a t increased temperatures; a t approximately 200’ C., the loss of benzpyrene was complete after 5 minutes. A mechanism was suggested for the formation of 3,4-benzpyrene in the environment by Diels-Alder condensation of butadiene, followed by appropriate dehydrogenation (34). With regard to oxygenated species, Inglett and Lodge compared several spot tests for phenols, and applied them to a variety of atmospheric samples (168). Smith and coworkers evaluated a number of methods for the determination of phenols, and used them in a survey of phenol concentrations, both in air and in combustion products (332,333).
The group associated with Sawicki developed a group of qualitative methods for carbonyl compounds. The reaction of arylidine arylhydrazones with diazonium salt was made the basis of a technique for differentiation of aromatic aldehydes and ketones (308). Other techniques were shown to be specific to aralkyl and dialkyl ketones (302) and to polynuclear diary1 ketones (340). Specific tests were also developed for various types of quinones (893, 294, 306, 307). A method was suggested for the identification of volatile organic acids based on the rate of diffusion from dilute solution to a pellet of sodium hydroxide (41, 146, 306). Carboxylic acids could also be detected in the infrared by the movement of specific absorption maxima as their environment was changed from acidic to basic (299). Solvent effects were also utilized in the visible and ultraviolet region (301). A new reaction was presented for the detection of primary aromatic amines (309). Polynitro aromatic compounds were determined by coupling with fluorene (304). Flavonoids derived from pollen in particulate samples were identified by their fluorescence colors on papers impregnated with metal salts (169). A series of general tests was applied to the measurement of nonvolatile organic matter brought down with rain and snow (247).
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ANALYSIS OF GASES
Inorganic Gases. The oxides of carbon received little attention so far as new analytical techniques are concerned. Holm-Jensen’s technique for carbon dioxide has already been mentioned (158). A spectrophotometric titration technique for carbon dioxide was also described (216). Lysyk et al. described a new technique of catalytic combustion of carbon monoxide to carbon dioxide, which was determined gravimetrically (217). A spectrophotometric technique utilizing the Shepherd indicator tubes was devised, for which accuracies of 1 to 6% were claimed in the range from 1 to 100 p.p.m. (89). The quantity measured was the time necessary for a certain absorbance value to be reached by a tube mounted within the spectrophotometer. Ayer and Saltzman called attention to substantial interferences by nitrogen oxides with carbon monoxide determination using Shepherd tubes (53). It was asserted that the nitrogen oxide could be removed by passage through a tube containing solid potassium permanganate and Ascarite. Available techniques of carbon monoxide determination were reviewed by Truhaut and Lemoan (356). Because of the similarity of analytical procedures, i t is convenient to consider certain compounds of nitrogen and sulfur together without respect to their physical state, or whether they are inorganic or organic. Field experience with several techniques for determination of sulfur dioxide were related by Welch and Terry (376). One of these methods, involving collection in a solution of sodium tetrachloromercurate and subsequent determination with the Schiff reagant, was also studied in detail by Nauman and coworkers (246). The sulfur dioxide was trapped as the dichlorosulfitomercurate (11), and the colored species in the final determination was a sulfonic acid. Still another field method for sulfur dioxide, using paper impregnated with zinc nitroprusside, was described by Hands and Bartlett (139). Two papers related to a modification of the Titrilog to give it sufficient sensitivity for field operation (223, 143). The modification consisted essentially of substituting a self-balancing potentiometer for the recording milliameter normally furnished with the commercial instrument. Details were given for a small sequential sampler for the determination of total gaseous acid, particularly inside living quarters (266). This was shown to be primarily sulfur dioxide, a t least in London, and the results of a number of measurements are reported. A number of techniques were evaluated for the determination of sulfuric acid mist in the presence of large
amounts of sulfur dioxide (188, 244).
A method for differential determination of both sulfur oxides in flue gases was described (103). Several papers concerned the detailed analysis of mixtures of inorganic and organic sulfur compounds, using both chemical and gas chromatographic methods (3, 5, 151, 385). Hisatsune and his students made structural studies of the nitrogen oxides (164, 156, 156). Gill compared a number of techniques for the determination of nitrogen dioxide and nitric oxide in air (117). Two rapid field methods for the determination of nitrogen oxides were published. One involved the use of a detector tube (189), while the other utilized a dry sensitized paper (115). Haagen-Smit et al. adapted nondispersive infrared analyzers for the measurement of nitric oxide and sulfur dioxide in stack gases (156). Higher concentrations of nitrogen dioxide may also be determined by solution in aqueous base, and subsequent direct ultraviolet determination of the nitrite ion formed (21). A differential method for determining nitrite and nitrate in mixtures is based on the Griess technique of diazotization and coupling (199). Nitrite is determined initially. For nitrate determination, the initial nitrite is diazotized, and the diazonium ion is removed by ion exchange. Nitrate is then reduced to nitrite and determined as such. Hora and Webber called attention to a systematic error in the standard method for nitrate using phenoldisulfonic acid (160). A technique for nitrate involving the nitration of chromotropic acid was suggested by West and Lyles (377). The method is claimed to be more sensitive and less complicated than the phenoldisulfonic acid technique. 2,Ei-Xylenol was also suggested as a reagent for nitrate (143). The behavior of alkyl nitrites in the Griess reaction was studied by Altshuller and Schwab (17). These were found for the most part to react to about the same extent as nitrogen dioxide. Three methods were reported for the determination of nitroparaffins ( I S , 69, 111). A comprehensive bibliography of the occurrence and biological effects of fluorine compounds was published, which included a section on fluorine chemistry and fluoride analysis (60). Hall reported a n ingenious technique for the determination of microgram amounts of fluorine by gaseous diffusion (138). Adams and his coworkers reported on two distinctly different instruments for the continuous monitoring of atmospheric hydrogen fluoride concentrations (1, 2, 4). Atmospheric fluoride levels were determined by continuous colorimetry of a zirconium lake, while the instrument for source concentrations was based on the decolor-
lzation of the complex between ferrous salts and ferron. An electrometric instrument for inplant and source concentrations of fluoride was reported by Howard and Weber (161). An extensive annotated bibliography on ozone in the atmosphere, covering the literature of 100 years on the subject, was published by Xeteorological Abstracts and Bibliography (268, 269). Haagen-Smit summarized a number of years of experience with both the rubber-cracking technique for ozone (134) and the phenolphthalin reagent for oxidant (135). Ehmert discussed a simple coulometric technique for oxidant determination, using the potassium iodide reagent (96). A careful study was made of the reactivity of a number of oxidants other than ozone with potassium iodide (18). A continuously recording oxidant sensor, using coulometric detection, was evaluated for its specificity to ozone (374). Saltzman and Gilbert reported a technique which was claimed to be specific for ozone (286). The incoming air stream was mixed with approximately 1 p.p.m. of nitric oxide. After passage through a length of tubing sufficient to permit around 40 seconds of reaction time, the resulting nitrogen dioxide was determined. This time was insufficient for significant oxidation of nitric oxide by oxygen. KO negative interference could be detected from sulfur dioxide or hydrogen sulfide. Kogan determined both ozone and chlorine by the potassium iodide reagent, detecting the excess potassium iodide polarographically (191). So far as the stoichiometry of the ozone-potassium iodide reaction is concerned, the method is curious in that it apparently uses a strongly acidic reagent solution. Baloch reported a technique for the rapid determination of gaseous iodine in air (40). In the absence of interfering materials, boranes could be titrated coulometrically with iodine generated from potassium iodide solution (48). It seems likely that the results with this instrument would be significant only in industrial hygiene and source situations.
Analysis of Organic Gases and Vapors. A number of methods were suggested for the determination of total organic vapors in air. Vendt and Lebedeva developed a new oxidation catalyst which would permit t h e gravimetric determination of all such organics as carbon dioxide (367). Another similar technique utilized a nondispersive carbon dioxide analyzer as the detecting device (282). The possibility of concentrating atmospheric organics and analyzing them by dispersive infrared techniques was summarized by Feldstein and coworkers (102). Infrared instruments, both dispersive and nondispersive, are
frequently calibrated by evacuating the gas cells and filling them to a small partial pressure with the test substance. Altshuller and Wartburg showed that serious errors can be introduced unless an inert gas is added to bring the mixture to a t least a substantial fraction of atmospheric pressure, due to pressure broadening phenomena (22). It was suggested that a reasonablr estimate of total pollution might be made by draming a dried air sample through a small adsorption tube filled with activated carbon a t reduced temperature, then desorbing the pollutants directly into a thermal conductivity cell n i t h helium (379). The dcvelopment of more sensitive detectors makes the concentration step unnecessary. Andreatch and Feinland determined total gaseous organics directly by passing the sample stream into a flame ionization detector (30). X a y measured higher hydrocarbon concentrations by optical interferometry, achieving a lower limit of approximately 10 p.p.m. (229). Successful mass spectrometric hydrocarbon-type analysis of automotive exhaust gases is reported by Coulson, who achieved a differential analysis by removing the olefins with mercuric perchlorate (76). Sen gave a new theoretical treatment to vapor phase chromatographic column behavior (326). He derived equations governing column performance in such a form as to permit exact duplication of retention times and plate numbers from one column to the next. Two different systems were reported for the concentration of gaseous pollutants and their subsequent chromatographic separation (101, 378). A system specifically suited to the determination of methane in air was reported (202). Heaton and Wentworth improved the sPnsitivity of the gas chromatograph for hydrocarbons by following the analytical column with a catalytic furnace and a nondiypersive carbon dioxide analyzer (147). Since response was now proportional to carbon number, the technique made the instrument particularly sensitive to higher molecular weight hydrocarbons, which are in general present in lower concentrations. A rather complete gas chromatographic analysis of the individual hydrocarbons in automotive exhaust by Hurn and Davis showed the effect of fuel composition on the relative concentration of the exhaust hydrocarbons (166). The light hydrocarbons are not particularly amenable to analysis by ordinary chemical techniques. However, Urone showed that the ultraviolet spectra of certain olefin-metal complexes might provide a technique for olefin analysis (364). Altshuller and his coworkers developed several techniques suitable for the determination of olefins
of four or more carbon atoms (19, 20) and of certain diolefins (14). Hughes and Gorden reported a method for the determination of acetylene using small tubes of silica gel (162). With care, a lower limit of as little as 1 p.p.b. can be achieved. A detailed evaluation was presented of the chroniotropic acid method for the determination of formaldehyde (16). Sandler and Strom reported a gas chromatographic column materid capable of separating formaldehy(1e from water vapor (288). It was demonstrated that 4-hexylresorcinol is a specific reagent for the determination of acrolein at extremely low concentrxtions (70). Formaldehyde catalysis of the oxidation of p-phenylenediamiiie by hydrogen peroxide was made the basis of the simple technique involving saiiipling on silica gel (163). Sawieki and Hauser reported the use of 2-hydrazinobenzothiazole as a reagent for the dctection and determination of aldehydes (300). This reagent could also be u w l on silica gel tubes. Sawicki and his coworkers reportcd several other techniques for the identification of carbonyl compounds. Thcse included spot tests for glyoxal, pyruvaldehyde, and certain aromatic aldehydes (29, 52, Soja, 305b) and tests for a number of aliphatic ketones (291, 303, 339). Sedivec explored the determination of esters as the corresponding ferric hydroxamates (326). A substantial number of ox?-genatcd species have been identified in automotive exhaust by a combination of gas chromatographic and chemical techniques (165). Other species of occasional interest for which ne17 methods were reported include halogenated hydrocarbons (59) and toluenediisocyanates (285) I
CALIBRATION TECHNIQUES
The production of properly ch,iracterized test atmospheres is as important to the analytical chemistry of air pollution as to toxicology or to corrosion studies. I t may be necessary to produce a known gas concentration, a known aerosol concentration, or an aerosol of known particle size. Whcre a very high degree of accuracy is required, there are probably no pmfectly general techniques in any of thcw areas. The previously cited review of chambers for animal exposure (107) sets forth a number of the problcms encountered in the generalized pro. duction of test atmospheres. Dautrebande and his coworkers described two new generators for submic. o n aerosols (82). Both utilizcd thc principle of obligatory liquid fi1tr:ition. Atomization and drying of a vcry clilutc suspension of phagc or virus \vas sugVOL. 33, NO. 5, APRIL 1961
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gested as a technique for producing uniform particles in the millimicron aize range (343). Less uniform particles in the same range were produced by Walkenhorst by the rapid oxidation of tungsten to tungsten oxide (371). Toward the other end of the aerosol particle size range, Gordieyeff suggested the use of glass microspheres as inhalation tracers (127). The same material was also used in the previously mentioned work of Hage as an atmospheric tracer to evaluate adhesive foil as a sampling device (137). In this case, the glass microspheres were coated with a fluorescent dye. Of interest both in the preparation of knoan test atmospheres and in the evaluation of sampling devices is a tabulation of vapor pressures of organic compounds for pressures less than 1 mm. of mercury, compiled by Hughes and Lias (164). The use of gaseous diffusion as a means of producing known vapor concentrations for instrument calibration was described by Gordon et ul. (128), while Altshuller and Cohen developed an improved diffusion cell which permitted calculation of the resulting Concentration from first principles (12). Two papers discussed other types of dynamic systems for producing known vapor concentrations (65, 313). Kusnetz and his coworkers described techniques specifically intended for the calibration and evaluation of gas rfrti cting tubes (198), and Kusnetz suggcoted the use of a soap bubble flowmeter for checking the air flow through the tube (197). A simple integrated test chamber for duplication of conditions conducive to photochemical smog has been designed (56). The chamber itself was an air-supported toroid of polyethylene film. 3 smaller static test chamber for testing air samplers was designed and evaluated in detail by McCaldin and Hendrickson (219). One of the primary design criteria was the use of inexpensive construction materials, permitting it to be used more widely than a more elaborate and expensive design. By way of contrast, a highly controlled environmental test facility for the study of auto exhaust photolysis was described by Rose and Brandt (279). This integrated facility comprised an automobile, a dynamometer, an air purification system, a n irradiation chamber, and a complex of monitoring equipment. ATMOSPHERIC REACTIONS
Several reviews of atmospheric chemistry in general have already been cited. While the bulk of research in the chemistry of polluted atmospheres has been concerned with the auto exhaust problem, work has been done in other areas. Yaffe and Cadle studied the 8R
ANALYTICAL CHEMISTRY
kin1 tic behavior of submicron sodium chloride and titanium dioxide aerosols (386). Members of the samc group reported on studies of aerosol-gas reactions which convert sodium chloride to hydrogen chloride (273), and sulfuric acid to ammonium sulfate (272). Johnstone continued his work on the oxidation of sulfur dioxide to sulfuric acid (176). The photochemical production of large numbers of atmospheric condensation nuclei in nucleus-free air was noted by Verzar and Evans (368). They suggested that the causative agent might be hydrogen sulfide, which was photochemically oxidized to sulfate. They calculated that a concentration of hydrogen sulfide of the order of one part in 10’5 would be sufficient to explain the observed effect. It w:is discovered that sulfur dioxide reacts photochemically with paraffinic hydrocarbons to produce a n aerosol (174). The studies were carried on a t modprate to high concentrations of both species, both in inert atmospheres and in air. I’he nature of the resulting products is still under study. In general, the photolysis of mixtures of nitrogen oxides and olefins produce most of the manifestations of the Los Angeles smog except the smog aerosol. However, the addition of traces of sulfur dioxide results in the immediate formation of such a n aerosol (260, 266. 3201. On the basis of such information, Renzetti and Doyle computed that the automobiles of Los Sngeles are responsible for the production of about 11 tons of particulate matter per day in the atmosphere (267). Altshuller and Cohen studied the thermal reaction products of nitrogen oxides with olefins, using infrared spectrophotometry as the principal analytical tool (16). This necessitated the evaluation of nitrogen dioxide-resista n t window materials for their cells (11). Saltzman and Gilbert followed the reaction of ozone and 1-hexene, using analytical techniques which differentiated ozone from organic oxidants (287). Some general observations on auto exhaust composition were made by Stephens and coworkers ( 3 4 2 ) . Several papers were published based on work performed in the auto exhaust facility a t the Stanford Research Institute. Although a number of analyses were performed, the critical measure employed was the intensity of eye irritation produced by the synthetic smog (321, 322, 323). The relationship of eye irritation potential to fuel composition was noted, the half life of the lachrimator was determined, and similar studies using pure species were performed. General status reports on the work were made by Ford and Schuck (105) and by Faith and Renzetti (99). Gas chromatography was
employed in a study of catalysts of the oxidation of exhaust gases, performed by the U. S. Bureau of Mines (341). Several promising catalysts were reported. The corrosion of structural material is another aspect of atmopsheric chemistry which has received some attention. Yocom reviewed the current state of knowledge of the deterioration of materials in polluted atmospheres (387). The specific case of the corrosion of ferrous metals was reviewed by Larrabee (201). The possible effects of various dusts in promoting corrosion was studied by Barton (42). The role of sulfur dioxide in metal corrosion was studied in pure synthetic systems (289). Temperature, humidity, sulfur dioxide concentration, and duration of exposure were all varied. It was stated that a number of metals exhibit critical humidities below which no corrosion occurs under these conditions. Principles and procedures for the design and interpretation of atmospheric corrosion tests were summarized by Copson in an extensive review (75). Lodge and Havlik suggested the use of evaporated metal films as corrosion indicators (21Sa).
FIELD STUDIES
Throughout the period covered by this review, a large number of reports appeared conce,ning measured or expected concentrations of pollutants in specific areas or situations. Many of these were paper stridies involving no analysis on the spol whatever. Others were the result of largc capitalizations for monitoring equipment. What follows is not intended to be ~ x haustive, but rather to be a sampling of those studies having some substantial analytical component. Altshuler reviewed the natural sources of substances which, when found in population centers, are considered to be pollutants (10). Some determinations of the natural levels of nitrous oxide were made by Birkeland and Shaw (45). Lodge reported some inferences from chloride-sulfate ratios found in the atmosphere and in precipitation the world over (211). The concentrations of a number of pollutant species in the air in mid-Pacific were also measured (214). Two papers related to a series of measurements made at remote California coastal sites (141, 169). Even the most remote of these still experienced identifiable effects due to urban pollution. Taylor reviewed air monitoring throughout the State of California (346). Tebbens has reported the results obtained with an automatic smoke sampler a t a single site in Berkeley, Calif. (346, 347). The instrument has
been in operation for an excess of five years. Thomas and St. John operated a recorder for oxides of nitrogen in hlenlo Park, Calif., for a number of months and reported their findings (352). An exhaustive inventory was made of nitrogen oxide emissions from stationary sources in Los Angeles County (215). So far as suri’eys from the United States outside California are concerned, some results were reported on the joint Detroit-Windsor air pollution study (184). Cholak et al. discussed a long term study of sulfur dioxide and particulate matter in Cincinnati, Ohio (67). High ozone concentrations occur in the vicinity of metropolitan Washington, sometimes reaching high enough values to cause fleck injury to tobacco grown in the area (373). Lead and carbon monoxide wcre measured and related to traffic density in an unnamed city in the Sortheastern United States (51). A number of chemical species were measured in precipitation water collected the country over (180). Cholak, among others, reviewed current information on airborne fluoride (65). Lodge and coworkers measured the carbon-14 content of various fractions of particulate matter from St. Louis and Los Angeles, and related this to the rclntive contribution of fossil and contemporaneous organic matter to pollution (212). 4 survey of the 3,4benzpyrene content of the air of about 140 American communities was reported by Sawicki et al. (296). Two publications appeared relating to the findings of the National Air Sampling Ketwork (62, 389). I n Canada, in addition to the previously cited Detroit-JT7indsor study, a series of intensive measurements was made of contamination in a railway tunnel in Ottawa (183, 236, 265). Several exploratory surveys were made of pollution in Mexico City, and a close relationship was found between carbon dioxide concentration and atmospheric turbidity (37, 370). In Great Britain, Cummings and Redfearn surveyed sulfur dioxide concentrations near power stations (79), Results were reported on a %year program of measurement of smoke and sulfur dioxide in Sheffield (254). A smaller study was made in Bolton (384). The accidental release of radioactive iodine as a result of the reactor incident a t Windscale was used by Bolin as a n opportunity for some studies on the exchange of iodine between the atmosphere, the land, the biosphere, and the sea (46). Gorham summarized data on atmospheric tar concentrations throughout Great Britain and compared them with lung cancer data (199). There was also a report on polynuclear hydrocarbon concentrations from 23
sites in England and Wales (72). The results of a preliminary survey in Christchurch, New Zealand, were also reported (383). In Germany, particulate loadings n-ere surveyed in Hamburg (93) and in Leipzig (255). Effenberger studied the carbon monoxide hazard to customs officials a t the German borders (95). hlrose measuredatmospheric reductants, principally sulfur dioxide, in Wahnsdorf, and correlated the results with meteorological parameters (237). Techniques for reducing pollution mcasurenients to punched cards w r e summarized by Zewe et al. (388). Several studies mere reported of pollution in Milan, Italy (119, 120, 130, 369). Dustfall \vas measured by 49 gages located in Oslo, Korway (205). A general survey was made of pollution in Kiev, U.S.S.R. (35’7) and 3,4-benzpyrrne was determined sgstematically in the snow of Kalinin (87). Dust concentration has been measured over a long period of time in Egypt (97). Data are included on a severe dust storm. Sulfur dioxide concentrations mere measured in Keihin, Japan (1SI). METEOROLOGY
Factors affecting the movement of air bearing pollutants can hartii.- be neglected in the study of :ttLnospheric pollution. A full s u r q of mrteorological papers relating to the overall problem of atniosph(,ric contamination is beyond the scope of this review; however, a few papers have been selected as exemplifying the literature of the field. Meade discussed techniques for the calculation for ground lcvcl concentrations from an isolated, elevated source of pollution (232). Pay-to-day changes of ozone concentrations over the British Isles were studied by Martin and Brewer, who attempted to interpret them on synoptic grounds (228). Sheppard reviewed the effect of pollution in reducing both solar and terrestrial radiation (329). McCormick discussed meteorological instruments suitable for air pollution surveys (22f). The use of uranine dye as a tracer for large scale air movements was proposed by Robinson (275). Smoke density, determined by the AIS1 Smoke Sampler was related to meteorological parameters by Narkee (227). More general interrelationships between meteorology and air pollution were discussed for the Detroit-Windsor area ( Y O ) , and for Cincinnati (328). The complexity of applying meteorological considerations to town planning for minimum air pollution are discussed by Rlunn (239), who points out that, despite the impossibility of a total solution of the problern on meteorological grounds, consideration of climato-
logical factors is still very necessary. Some grounds for decisions in the light of present knowledge are presented. LITERATURE CITED
(1) Adams, D. F., ANAL. CHEM.32, 1312 (1960). (2) Adams, D. F., Koppe, R. K., Zbid., 31, 1249 (1959). (3) Adams, D. F., Koppe, R. K., T a p p i 42, 601 (1959). (4) Adams, I>. F., Koppe, R. K.. Dana, H. J.. J . A i r Pollution Control Assoc. 9, 160 (1959). (5) Adams, D. F., Koppe, R. K., Jungroth, D. M., Tu p i 43,602 (1960). (6) Air Pollution Zontrol Association, J . A i r Pollution Control Assoc. 5 , 176 (1955). (7) Ale’aeeva, hI. V., Elfimova, E. V., Gigiena i Sanit. 23, 71 (1958); U. S. Joint Publ. Research Service, No. L-741-N. (8) Alekseeva, ST. V.,Ryazanov, V. A , ! eds., “Determination of iltmospheric Pollutanta,” Medgiz, Moscow, 1959. (9) Alperin, B.. Courbon, P., Plateau, J., Tissandier, G., J . Inst. Fuel 33, 399 (1960). (10) Altshuller, A. P.,Tellus 10, 479 (1958). (11) Altshiiller, A . P., Cohen, I. R., AKAL.CHmi. 31,628 (1959). (121 Zbid., 32,802 (1960). (13) Zbid., p. 881. (14) Ibid., p. 1813. (15) A41tshuller,A. P., Cohen, I. It.. Ind. Eng. Chern. 51, 776 (1959). (16) Altshuller, A. P.,Miller, U. I)., Sleva, S. F., Division of Water and FT‘aste Chemistry, 138th Meeting, ACS, TYew York, Tu’. Y.! Pept. 11-16, 1000. (17) Altshuller, A. P.,Schwab, C. SI., h A L . CHEM. 31, 314 (1959). (18) Altshuller, A. P., Sclimb, C. &I., Bare, M., Ihid., 31, 1987 (1959). (LO) Altshuller, A . P., Pleva, S.F., Division of Water and Waste Chemistry, 138th Meet,ine. ACS. New York. X. Y.. Sept. 11-16, g 6 0 . ‘ (20) Altshuller, A. P., Sleva, S. F., Wartburg, A. F., Ax.4~.CHEM.32,946 (1960). (21) Altshuller, A. P., Wartburg, A . F., Ibzd., 32, 174 (1980). (22) Altshuller, A. P., Wartburg, -4. F., Pittsburgh Conference on Applied Spectroscopy, Feb. 29-March 4,1960; A p p l . Spectroscopy, in press. (23) Amdur, M. O., Inlern. J . A i r Pollulzon 1, 170 (1959). (24) .4merican Industrial HygFne Assoc., “Air Pollution Manual. 1. Evaluation,’, Detroit, Mich., 1960. (25) American Petroleum Inst., “Air Pollution. An Ahnotated Bibliography,,’ New York, N. Y., 1960. (26) Am. SOC.Testing Materials, Philadelphia, Pa., ASTM Spec. Tech. Publ. No. 250, 1959. (27) Am. SOC. Testing Materials, Philadelphia, Pa., ASTM Committee D-22, 1959.
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(29) iinderson, T., Dahlstrom, H., Sci. Tools 5 , 9 (1958). (30) Andreatch, A. J., Feinland, R., ANAL. CHEM.32, 1021 (1960). (31) Arnold, W. N., Intern. J . A i r Pollution 2, 167 (1959). (32) Ashford, J. R., Brit. J . A p p l . Phys. 11, 13 (1960). (33) Ayer, H. E., Saltzman, B. E., Am. I n d . Hyg. Assoc. J. 20, 337 (1959). (34) Badger, G. M., Kimber, R. W. L., Spotswood, T. M., Nature 187, 663 (1960). VOL. 33, NO. 5, APRIL 1961
9R
(35) Badzioch, S., Brit. J. Appl. Phys. 10, 26 (1959). (36) Badzioch, S., J. Inst. Fuel 33, 106 (1960). (37) Baez, A. P., Zng. quim. (Mezico City) 4, 22 (1959). (38) Bagnold, R. A., Intern. J . Air Pollution 2, 357 (1960). (39) Baker, R. A., Doerr, R. C., Ibid., 2, 142 (1959). (40) Baloch, L., Acta Physiol. Acad. Sn’. Hung. 14, 11 (1958). (41) Barber, E. D., Fox, F. T., Lodge, J. P., Jr., Marshall, L. M., J. Chromutog. 2, 615 (1959). (42) Barton, W., Werkstoffe u . Korrosion 9, 547 (1958). (43) Bieberdorf, F. W., Bull. T m e y Botan. Club 85, 197 (1958). (44) Binek, B., Staub 20, 184 (1960). (45) Birkeland, J. W., Shaw, J. H., J . Opt. SOC.Am. 49, 637 (1959). (46) Bolin, B., Intern. J. Air Pollution 2, 127 (1959). (47) Borrmann, H., Feingerate Tech. 8, 501 (1959). (48) Braman, R. S., DeFord, D. D., Johnston, T. N., Kuhns, L. J., ANAL. CHEM.32, 1258 (1960). (49) Brash, M. P., A p p l . Spectroscopy 14 (No. 2), 43 (1960). (50) Breitling, K., Staub 20,364 (1960). (51) Brief, R. S. Jones, A. R., Yoder, J. D.. J . Air hollution Control Assoc. 10, 384 (1960). (52). Broomhead, G., Hodkinson, J. R., Simons, V., Staub 20, 144 (1960). 153) Brown, E. iY.I. J., Boyer, IV. K., Proc. 52nd Annual Meeting, Air Pollution Control Assoc., Los Angeles, Calif., June 21-26, 1959. (154) Hisatsune, I. C., Scientific Rept. S o . 1, Contract No. AF19-(604)2255; Research Grant S-63, Public Health Service (AFCRC-TN-59-453) 1959, Kansas State University, Manhattan, Iian., 60 pp., 1959. (155) Hisatsune, I. C., Devlin, J. P., J . Chem. Phys. 31, 1130 (1959). (156) Hisatsune, I. C., Fitzsimmons, R . V.,Spectrochirnica Acta 10, 206 (1959). 1571 Hoffmann, D., Wynder, E. L., ASAL.CIIEJI.32, 295 (1960). 158) Holm-Jensen, I., A n a l . Chim. Acta 23, 13 (1960). 159) Holzworth, G. C., J . Neteorol. 16,68 ( 19.59). 160) Hora, F. B., \Vebber, P. J , Analyst 85, 567 (19tiO). 161) IIonard, 0 . H., Weber, C. W., -4. .IT. .4. Arch. I n d . Health 19, 355 11- O,i,O) .,- (162) Hrighrs, E. E., Gorden, R., Jr., ASAL.CHESI. 31, 94 (1959). (163) Hughes, E. E., Lias, S. G., ANAL. Crmr. 32, 707 (1960j. (164) Hughes, E. E., Lias, S. G., Sational Bureau of Standards, Washington, D. C., Kept. No. 6435, 1959. (16.5: Hughes, K. J., Hurn, R. W.,J . :1ir Poiiution Control Assoc. 10, 367 \
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(202) Lawrey, D. AI. CT., Cerato, C. C., A N A L . CHEM.31, 1011 (1959). (203) Lent, H., J . Inst. Fuel 32, 485 (1959). (204) Linch, A . L., Charsha, H. C., d / n . Znd. Hyg. Assoc. J . 21, 325 (1960). (205) Lindberg, W.,K:ttvig, H., Sard. Hyg. Tidskr. 40, Nos. 5-6, 89 (1959). (206) Lindsey, A. J., -4nal. Chim. : I d a . 20, 175 (1959). (207) Lippmann, AI., dirctr. Inti. Hyg. Assoc. J . 20, 406 (1959). (208) Lippmann, RI., Christofano, E. E., Graveson, R. T., Ibid., 20, 212 (195!?). (209) Lodge, J. P , J r . , Subil: 2 , 5 8 (1959). (210) Lodge, J. P., Jr., ed., Atmospheric Chemistry of Chlorine arid Sulfur Compounds,” Geophysical Monograph Yo, 3, Publ. 652, Americm Geophysical Union YAS/XRC‘, 129 pp., W‘avc’rly Press, Baltimore, Sld., 1959. (211) Lodge, J;( P., Jr., in Hellnut iyeickmnnn, ed. Physics of Precipitation,” Geophysical Monograph S Q ,5 , Publ. S o . 746, American Geophysical Union, SAd/NRC, p. 252, IVavrrly Press, Baltimore, &Id,,1960. (213) Lodge, J. P., Jr., Bicn, G , S., Suess, H. E., Intern. J . i l i r Poiiiction 2 , 309 (1960). (213) Lodge, J. P., Jr., Ferguson, J.! Huvlik B., - 1 s ~ ~ CIIEII. . 32, 12Ub il!iliOi.
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!(lit;, ,IOIIC,F,C’. .i.,J . .lir Pollutiori Corzt i e l :lssoc. 8, 2G8 (1958). (1771 Jii{i:tj J., llcdenhach, Ii., A r c h . f ~ ’ l d O , C ~//Lo.
