Anal. Chem. 1989, 6 1 , 1 R - 1 3 R
Air Pollution Donald L. Fox Department of Environmental Sciences and Engineering, School of Public Health, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599-7400
This review is extracted from the literature from January 1987 to October 1988 and is an extension of literature previously discussed ( A I ) . The major source of information was Chemical Abstracts Selects: Pollution Monitoring. In addition journals related to air pollution and environmental chemistry were surveyed. This review reflects the increase in technical literature in non-English publications. The organization consists of two major divisions: gaseous methods, which have single letter designations before reference numbers; and aerosol and particulate methods, which have two letter designations before the reference numbers.
GASES Books and Reviews. Harrison and Perry edited a 2nd edition of the Handbook of Air Pollution Analysis (A2). Gaseous monitoring with tunable diode lasers was the subject of a book edited by Grisar et al. (A3). A Russian text on atmosphere and industrial emissions appeared ( A 4 ) . Two books were published on air sampling and analyses in industrial settings (A5, A6). The American Chemical Society published the collected papers of a symposium entitled Radon and Its Decay Products which included intercomparisons of various sampling and analytical techniques (A7). Kratochvil presented a review on the general principles of sampling (A8). Klochow reviewed all aspects of ambient air sampling including strategy, techniques, maintenance, and quality assurance considerations (A9). Other reviews on sampling included use of activated charcoal (AlO),application of passive samplers ( A l l , A l 2 ) , a comparison of active and passive sensors ( A I 3 ) , design and operation of automated sequential gas samplers ( A l 4 ) ,diffusive sampling for volatile compounds ( A l 5 ) ,and thermo-denuder and wet denuder air sampling systems ( A l 6 ) . Reviews of techniques for personal monitoring for inorganic compounds (AI 7 ) and organic compounds (A18) were presented by Saito and Shirai. Taylor published a review on calibration principles including sources of error and uncertainty ( A I 9 ) . Special calibration systems for reactive gases were reviewed by Dorko and Hughes (A20). Dimitriev et al. published a review of aldehyde monitoring methods (A2I). Hawthorne and Matthews reviewed models for estimating indoor formaldehyde source strengths (A22). Sampling and analysis methods for formic and acetic acid were reviewed by Puxbaum (A23). Rudolph et al. reviewed problems and solutions associated with measurement of hydrocarbons and halocarbons outside urban areas (A24). A review on determination of halocarbons and on their global distribution was presented by Kawamoto and Urano (A25). Person et al. reviewed air sampling and analysis for volatile hydrocarbons (A26). Monoterpene sampling was reviewed by Fuwa (A27). A general review of tropospheric NO, monitoring included detection requirements and measurement techniques (A28). Torvala reviewed the use of chemiluminescence and IR and visual-UV spectroscopy to measure NO, in air and flue gases (A29). Murano reviewed techniques to determine gaseous H N 0 3 and nitrate-containing particles (A30). Two reviews appeared on the use of epiphytic lichens as biomonitors for atmospheric SO2 (A31, A32). Sextro reviewed the origins of indoor radon to assist in predicting indoor Rn concentrations in air (A33). Instruments and methods for measuring radon and its decay products were reviewed by George (A34). A review of the recent developments for the use of lasers for remote sensing was presented by Wilkerson (A35). Megie (A36) and Richter et al. (A37) reviewed the use of resonance scattering and differential absorption laser techniques. Baev
reported on the use of intercavity laser spectroscopy to greatly enhance the sensitivity of differential absorption measurements (A38). The use of tunable diode laser absorption spectroscopy for NO, and HC1 measurements was presented by Fried and Sams (A39). Bicanic et al. reviewed the basic concepts and application of laser photoacoustic spectroscopy for monitoring gaseous pollutants (A40). Domnin reviewed optoacoustic techniques (A41). Reviews appeared on the use of lidar (A42, A43) and satellite sensors (A44). Smart reviewed the use electrodes for pollutant measurement (A45). Several reviews appeared on air-quality monitoring including reviews on requirements and techniques in the Federal Republic of Germany (A46, A47), in the Netherlands (A48), and in France (A49). Two other general reviews appeared (A50, A51). Several reviews focused on indoor air quality. Traynor covered sampling strategies and pollutant profile modeling (A52). Siefert also considered strategies (A53). Two reviews discussed the selection of instrumentation (A54, A55). Calibration. Denyszyn and Sassaman described the basic problems associated with the preparation mixtures of volatile organic compounds in the 10-150 ppb level ( B l ) . Wright et al. reported on two performance audits of calibration gas mixtures containing SO,, NO, CO, and C3Hs (B2). Mitchell discussed dynamic calibration systems (B3). Nan0 et al. described a dynamic gas generation system using permeation tubes and gas saturators (B4). Giese et al. used the saturation vapor pressure principle to develop a gas generation system (B5). A complex generation system with up to 12 different gas streams was developed by Grate et al. (B6). Allen et al. reported severe tailing of chromatographic peaks for several oxygenated compounds for samples from calibration cylinders when stainless steel gas sampling loops were used. They then compared sampling loops constructed of Al, Cu, Teflon, and stainless steel; A1 sampling loops resulted in a significant improvement (B7). Ozone. Smith and Rehmg reported on a program to intercompare a standard reference photometer, as a primary O3 standard and other O3 transfer standards ( C l ) . Fishman et al. described the use of satellite total ozone measurements to track a regional air pollution episode over the southeastern United States (C2). Tan et al. developed a XeCl excimer laser system for remote sensing of atmospheric O3 (C3). Du et al. found the use of triethanolamine (TEA) to adjust the pH of neutral buffered KI solution resulted in low ozone values. TEA-ozone reactions formed HCHO and other aldehydes ((24). Phenoxazine was found to have potential applications for an O3 visual monitor. A reaction product with exceptional stability is formed (C5). Balzer et al. described an automated tropospheric O3 monitoring station for use in remove sites (C6). Nitrogen Oxides. Nitrogen dioxide (NO,) in pressurized cylinders was used to generate mixtures of HNO2-NOZmixtures by the use of different coated annular denuders ( D I ) . Hemenway and Jakab described techniques to generate NO2 mixtures with an NOz permeation calibration system ( 0 2 ) . Controlled ozonization of NO was used to generate standard gas mixtures for calibration of chemiluminescent NO, analyzers ( 0 3 ) . Passive NO, and SO2samplers were evaluated with respect to accuracy, precision, influence of weather, and storability. NOz samplers performed over a wider range of conditions ( 0 4 ) . Yangisawa et al. in a study of NO, passive samplers reported Palmes tubes were more affected by changes in wind velocity than filter badges (D5). An investigation of Na2C03 as a coating for diffusion annular denuders was reported (D6). An
0003-2700/89/0361-1R$06.50/00 1989 American Chemical Society
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NO preconcentrator consisting of a N,N,N',N'-tetrametkyl-p-phenylenediamine dihydrochloride solution was developed. The NO2 was separated from the absorbing solution, reduced to NO, and determined by chemiluminescence. Other nitrogen species interference was 11 to 9-11 and the wavelength from 610 to 473 nm (014). 1Methylperimidine reaction with NOz formed stable colored products with the potential as a warning indicator (015). Punkkinen reported on an automated colorimetric method based on Saltzman reagent (016). KI- and starch-impregnated silica gel was used as NOz indicator tubes (017). Maeda and Munemori reported on a separation column to remove the interference of HzO in the determination of NOz by gas chromatography with electron capture detector (GC/ECD) (018). Burkhardt et al. developed a GC method with luminol-base chemiluminescence detection. Ambient air scrubbed by passage over FeS04 eliminated the need for compressed gas cylinders for carrier gas. Detection limits were 0.12 ppb for PAN and 0.2 ppb for NOz (019). Schiff et al. developed a portable NO2 instrument based on luminol chemiluminescence (020). A luminol based instrument for NO2 and O3 was developed (021). Kuts et al. reported on chemiluminescence NO, determination by reaction with O3 (022). Hoe11 et al. reported good correlation for an intercomparison of a laser-induced fluorescence system with two chemiluminescence instruments designed for airborne measurements in the 5-100 ppt range (023). Fehsenfeld et al. reported on an intercomparison of NO, NO, NO2 methods in the 0.4-10 ppb range (024). A chemiluminescence NO, analyzer was used to measure NO, from aircraft off the east coast of North America (025). Staehr used differential absorption lidar (DIAL) to measure vertical profiles of NO2 and SO2 (026). A DIAL system was developed to measure NO2 urban atmosphere (027). A tunable diode laser absorption spectrometer was developed to measure two gases simultaneously. The system measured NO, NOz, HN03, NH3, H20z,and HCHO (028). Schmidtke et al. described an automated diode laser spectrometer for monitoring NO, NO2, HN03, 03,and SO2 (029). Adams et al. proposed a new NO spectroscopic technique based on a Zeeman modulated radiometer (030). Photoacoustic spectroscopy (PAS) was used to measure NO2, HCHO, and MeHCO over several orders of magnitude (031). Venema et al. described the design of NO2 sensors based on surface acoustic waves as the detection method (032). Madronich intercompared nitrogen dioxide photodissociation and UV radiometers for determination of atmospheric values of the NO? photodissociation coefficient, J (033). Sickles and Michie evaluated the performance of sulfation and nitration plates and reported high sensitivity to wind speeds ( 0 3 4 ) . PAN, HNO "02. Meyrahn et al. described two procedures for cali!kation of an electron capture detector (ECD) for PAN: (1)photochemical generation of PAN in mixtures of Me2C0 and NOp in air and (2) first-order decay of PAN in glass storage vessels ( E l ) . Maeda et al. discussed the treatment of a Pyrex glass bottle with Cr207-H+304 to inhibit the decomposition of PAN (E2). Baunok used hexane cold traps to preconcentrate PAN samples for detection by GC (E3). Hering et al. reported on the overall results of a field comparison of 19 HNO measurement methods. Seventeen other papers accompanied this article detailing each method. Values by the various instrumental techniques varied as much as a factor of 4. Filter packs generally reported the higher concentrations and transition flow reactors, annular denuders, and tunable diode laser absorption methods gave lower concentrations (E4). Transition flow reactors were compared with tunable diode laser absorption for HN03 measurement (E5). 2R
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Durham et al. developed the transition-flow reactor for measurement of trace gases such as H N 0 3 (E6). Annular denuders have been developed for HN03/HN02 (E7, E8). Roberts and cc-workers reported a positive mterference in the measurement of HN03 by the tungsten oxide technique (339). Marinaro investigated the effect of water vapor on the tungsten oxide HN03 measurement technique (EIO). Papenbrock and Stuhl reported on the feasibility of detecting gaseous HN03 by ArF excimer laser irradiation ( E l l ) . Rogers developed a photofragmentation/laser-induced fluorescence detection system for atmospheric nitrous acid (E12). Bernegger et al. reported on a laboratory system based on laser-photoacoustic spectroscopy for HN03 (E13). Free Radicals. Sakugawa and Kaplan reported a comparison of cold trap method for collection of HzOzwith an impinger bubbling method. Higher values from the impinger method were attributed to H202formation from Ogorganic compound reactions occurring in the impinger (F1). Jacob and cc-workers also reported the cryogenic sampling technique an improvement over the impinger technique (F2). Murano reported on an HzOzfluorometric method with a detection limit of 0.8 ppb based on dimer formation by reaction with p-hydroxyphenylacetic acid (F3). Kolbe and Leskovar discussed the use of millimeter and submillimeter wave detection of Hz02 (F4). A stable orange-red chelate formed by the acid and vanareaction of Hz with pyridine-2,6-dicarboxylic date(V) in acid solution was the basis for a spectrophotometric Hz02method with a detection limit of 1 ppb (F5). Platt et al. described a laser long-path absorption method for hydroxyl radicals (F6). Hofzumahaus used laser induced fluorescence (LIF) to measure tropospheric OH (F7). Shirinzadah et al. investigated the pressure dependence of ozone interference with LIF detection of OH (F8). A double-pulse method UV laser spectrometer measured tropospheric OH (F9). Campbell et al. described potential radiochemical techniques for OH measurement (F10). Kleindienst et al. intercompared a luminol method, TDIR, and fluorescence from an enzymically produced complex to measure HzOz(F11). Maeda et al. used a luminol method based on chemical amplification to measure H 0 2 radicals (F12). Sulfur Dioxide. Farwell and co-workers reported on two low loss permeation tube techniques for generation of SO2, HzS, CS2, and CH3SH concentrations in the low to sub-ppb range ( G I , G2). Air-SO2 mixtures in cylinders were characterized as transfer standards in a large intercomparison of 29 continuous SO2 analyzers in eight EEC member countries (G3). Eickeler et al. studied the stability of SO2 test gases in aluminum cylinders with nitrogen and synthetic air as carrier gases ((24). Cadle and Mulawa reported a greatly increased retention of SO2 on nylon filters manufactured after May 1984 (G5). Dasgupta reported on nylon monofilament as a collection medium for a diffusion scrubber (G6). A computer-controlled thermodenuder system was developed for ambient SO2 measurements with a 0.1 pg/m3 SOzdetection limit (G7). Liaw investigated solids reagents for SO2, 03,and CO measurements (G8). Naus et al. developed a diffusional dosimeter for SO2 (G9). A passive device for the determination of long-term atmospheric SO2 concentrations was reported by Orr et ai. (G1O)with subsequent discussion ( G l l ) . Semicarbazide hydrochloride absorbing reagent efficiently collected SOz. Spectrophotometry a t 505 nm was used following complexation with p-aminoazobenzene and HCHO in acid solution (G12). Auramine was reported as a new complexing agent for the spectrophotometric determination of SO2 ((213). Spectrophotometry was used to determine SO2 after its preconcentration into formaldehyde solution in an aerodispersion system (G14). Two reports were published on a modified West-Gaeke SO2 method (G15, (216). Thornton and co-workers used cryogenic preconcentration to determine SOz at ppt levels. A Nafion perfluorinated membrane was used to dry the sampled air (G17). Yang and Guo used cold traps for SO2preconcentration for GC analysis ((218). Determination of low ppb SO2 by GC/FPD was reported (G19). An isotope-dilution GC MS method was used to measure ppt levels of SOz (G20). anaka and co-workers measured SO2with ion chromatography of filter extracts. The filters were impregnated with 1% NazC03-l % glycerol solution (G21).
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Donald L. Fox Is Rofesl~nIn me Depa~men1 of Environmml Scbnm and Engineering and Asscchte Dean of me School of Public HaaHh. Univmny of Nom? Carolina at Chapel Hill He received h k W.D. degree In chemism tram Arizona Stale Unluersny. HIS research and teaching interests Include alrnaspherlc photochemical processes including anvlronmentaily acceptable *as to chlorotlwocarbms and halons. He k a member of the American Chemical S e Cbty.
Rios e t al. described the amperometric determination of SOzin air samples in a closed-loop flow injection system (G22). Opehar et al. employed pneumatoamperometric methods to measure SOz in air with a detection limit of 0.3 pph (G23). Cvijin e t al. demonstrated pulsed UV photoacoustic spectroscopy could measure SOz in purified air at ppb levels ((24). Kunugi et al. described a method of compensation of excitation light intensity in pulsed UV fluorescenceSOz detection (G25). Wolfbeis et al. explored a fiber-optic fluorosensor for SOzthat utilized SOz as an efficient quencher (G26). A mobile remote SOz sensing system hased on differential absorption lidar was described (G27).Dohi et al. developed a compact SO, gas sensor based on a tunable PhSnTe diode laser (CZS). Field intercomparison studies were reported for acid decomposition methods (G29)and SO, monitoring (G30). Kuster and Goldan measured lasses of gaseous sulfur compounds to Teflon enclosure walls (G31). Maffiolo et al. reported on the development of short response time SOz analyzers for airborne applications (G32). Other Sulfur Compounds. A potential new sampling device for atmospheric hydrogen sulfide was developed by LaRue et al. The samplersensor is a spiral channel lined with an absorbent filter pretreated with a Cd(I1) salt (HI, H2). Farwell et al. reported the performance of a silver nitrate filter/fluoresceine Hg(Ac0.j method for measuring pph-ppt concentrations of HzS. Other sulfur gases showed no interference (H3). However, Cooper and Saltzman found COS generated S" on the silver nitrate impregnated filters (H4). Lewin et al. described a GC/MS method for determining COS. Molecular Sieve 5A had the best trapping and recovery properties (HS). CSz was trapped by triethanolamine, then reacted with Ni acetate solution followed by extraction in BuOH. The complex was determined by spectrophotometry (H6).Cathodic stripping voltammetry was used to determine CS, after reaction with pentamethylenecarhamoditbioic acid ( H n . Mori and co-workers investigated UV spectrophotometry to determine CSz in air. The photoactive Ni(I1)-Et xanthate complex was extracted in chloroform (HS). Halocarbons. Kowalski et al. described the preparation of standard reference materials for 19 halogenated hydrocarbons. The technique involved preparation of dilute mixtures of the halocarbons in MeOH. This liquid mixture was used to prepare the gas mixture in a chamber ( J I ) . Organic halogen compounds were absorbed on activated c h a r d . The absorbed halocarbons were eluted with hexane and analyzed by GC-ECD (52). Kuho collected halocarbons on Tenax GC followed hy GC-ECD (53). Methods for halocarbons involving trapping on an adsorbent, thermodesorption, cryofocusing, and GC-ECD were investigated hy Frank and Frank (J4)and No et al. (J5). 8hIoro compounds, hromoalkanes and bromoalkenes, and nonhalohenzenes were investigated with class modeling pattern recognition of autocorrelation transformed mass spectra (J6). Oda et al. used GC/MS to determine pph levels of C1CHCCIz, C,CI4, and l,l,Z,Z-tetrachloroethane(J7). HX. Zankel et al. reported improvements in the douhletape sampler metbod for HF. They eliminated large errors due to uptake hy the stainless steel intake by replacing it with one made of Teflon ( K l ) . Okuma et al. described the use of ion exchange chromatography for determination of fluoride and Chloride in ambient air (KZ). Stan et al. described complexation methods for
colorimetrically determining fluorine and chlorine in air samples (K3). Dimmock and Marshall developed a diffusion denuder method to collect HCI. Analysis by a Cl--selective electrode followed washing the sample from the tube ( K 4 ) . An automated system for HF, HCI, F, and F- based on ion-specific electrodes was developed hy Dbannarajan and Brouwers (K5). Radovskaya et al. used F--selective electrodes to determine gaseous fluorine compounds in air (K6). Fernando measured HCI by monitoring sensitized fluorescence following intracavity excitation by a HCI chemical laser (K7). Remote measurements of HCI were made with a DF laser differential absorption and scattering lidar (KB). Total atmospheric column HCI was determined from high resolution ground-based infrared solar spectra ( K 9 ) . Ammonia. Tanaka et al. investigated two NH3 collection methods-a H,P04-glycerol impregnated filter and an oxalic acid in EtOH coated diffusion denuder. Both methods have approx. 95% collection efficiency with a detection limit of 0.13 pg/m3 (sample volume 4.8 m3) ( L l ) . Ishii and Aoki used an aqueous solution of diethylene glycol and H,BO, in a diffusion sampling system to continuously monitor NH, (L2). Pranitis and Meyerhoff developed a membrane-electrode-based detector sensitive to gas-phase NH3 concentrations surrounding a sniffer tube (L3). Atmospheric NH, and particulate ammonium were collected on a filter pack. Each were determined by the fluorescence of a NHlf o-phthalaldehyde moiety (L4). Hawley et al. reported on remote NH, detection by a DIAL system and on in situ detection by a tunable diode laser system (L5). Spetz et al. investigated the potential for metal oxide semiconductor (MOS) capacitors to measure NH, gas (L6). Ahdullaev et al. investigated a Si planar n-p-n transistor as a sensor for NH, (L7). Carbon Monoxide. Nouh developed a stochastic method to calculate the sampling time required for CO determination (MI). A Ag-gelatin complex was suitable for determination of CO. The complex formed an intensely colored product upon reaction with CO. (M2). Huang reported on a CO method involving reduction to CH, over a Ni catalyst followed by FID (M3). Wiesemann and Diehl developed a laser-based system to remotely monitor CO (M4, M5). Astakhov e t al. described the performance of the FGLT 02-1 diode laser system for CO measurements (M6). Hoell et al. compared a laser differential absorption method and two grah sample/GC methods for CO. Good agreement was reported with correlations in the range of 0.85-0.98 for respective pairs of instruments (M7). Aldehydes. Wang and Ren used solid sorbent GDX 401 for sampling HCHO. Samples were stable a t room temperature for up to 5 days ( N l ) . Molecular sieves ( X 1 3 ) were reported as efficient solid sorbents for crotonaldehyde with no losses for tubes stored at -15" for 1 week (N2). Acetaldehyde was preconcentrated on Porasil A and then analyzed by gas chromatography (N3). Ciccioli et al. used traps fded with Carbopack B coated with 2,4-DNPH and H,PO, to collect aldehydes and carbonyl compounds. AcH, HCHO, propionaldehyde, and MezCO were determined by HPLC after extraction with MeCN (N4). Wang and Zhou reported a DNPH/HPLC technique for formaldehyde (NS).An annular denuder coated with 2,4DNPH collected C,-C, aldehydes. Analysis was completed hv HPLC with UV or voltammetric detection (N6). Georghiou et al. investigated the storage stability of formaldehvdt sulutions containing pararosaniline reagent ( N 7 J . A colurimetric method for HCHO was hased on the determination of excess HS03- (NB). Sinitsyna et al. reported a colorimetric method for formaldehyde based on l-benzyl-2hydrazine benzimidazole hydrogen chloride (N9).Pal and Das used a Ag-gelatin complex to determine trace amounts of HCHO spectrophotometrically (NIO). A spectrophotometric formaldehyde method based on an acytylactone adduct was reported by Popler and Skutilova ( N I I ) . Lavus et al. developed a fluorometric method hased on the reaction of HCHO with NAD to produce the coenzyme (NADH). The detection limit was 120 ppt (N12). Yuan et al. developed a differential pulse polarography method for HCHO in air ( N I 3 ) . Stewart and co-workers compared the performance of two formaldehyde passive dosimeters (N14). ANALYTICAL CHEMISTRY. VOL. 61, NO. 12, JUNE 15, 1989
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Hydrocarbon Sampling/Solid Sorbents. Isidorov and Gordillo Perez described the collection of hydrocarbons with sampling tubes containing mixed adsorbers with detection by GC. They reported detection limits for a 10-L sample of 1, 0.05-0.005, and 2-5 pg/m3 for aromatics, halomethanes, and carbonyls ( P I ) . Collection of organic solvents on activated charcoal was investigated by two groups. Cocheo et al. looked a t 34 solvents (P2) and Ashida et al. determined CS2 desorption efficiencies for 19 solvents (P3). Hydrocarbon losses in gas sampling bags were investigated for Me2C0, CO, C H6, 1,3-butadiene, 1-butene, MeOH, and 1,1,2-trichloroethy!ene (P4). Mazur and co-workers found a large variability in the performance of two continuous bandtype monitors for toluene diisocyanate (TDI) (P5). Rando et al. added an electronic microcircuit controller to convert a continuous tape monitor for TDI into a sequential sampler (P6). Aikin and co-workers used evacuated spheres to collect methane and other light hydrocarbon grab samples from a balloon platform (P7).Merrifield described a 6-L capacity stainless steel evacuated canister system to collect volatile organic compounds over a time period up to 24 h (P8). DeRoos et al. evaluated a high-volume air sampler for PCDDs and PCDFs. Polyurethane foam (PUF) and silica gel were used as absorbent materials (P9). Murphy and Fahey have presented an improved analytical solution to model the loss of gases to the wall of diffusion tubes in laminar flow (P10). McMurry and Stolzenburg discussed the theory for penetration of "sticky" gaseous molecules through diffusion tubes and the impact on measurements of mass accommodation coefficients (P11). The passive sampling technique for organic vapors endorsed by Shields and Weschler for long term monitoring (several weeks) (P12). Gentry and Walsh reported on the performance of a diffusive sampler and short-term stain tube for personal monitoring (P13). Coyne et al. evaluated a new desorption technique for air sampling sorbent tubes which involves removal of the sorbent from the tube for desorption (P14).Kollar et al. discussed passive dosimeters and their comparison with standard methods for gas sampling (2'15). Spicer et al. conducted an intercomparison of sampling techniques for toxic organic compounds in indoor air including sampling canisters, high and low rate passive sampling, and distributive air volume sampling (P16). The effects of fluctuating concentrations of pollutants on the performance of passive dosimeters were investigated by Popler and Skutilova (PI 7). Kuroda reported on round-robin tests among 30 institutions of charcoal tube samplers for organic solvent vapors (P18). McClenny and Paur reported on the development of continuous samplers including stainless steel canisters, Tenax tubes, filter packs, and annular denuder systems (PI9). Otson et al. evaluated sampling systems for aromatic amines consisting of glass fiber and Ag membrane filters followed by different combinations of sorbent tubes. Tenax was the best sorbent because of poor and inconsistent recoveries from silica gel and limited capacity of XAD-2 (P20). The advantages of supercritical fluid extraction from Tenax were reported by Wright e t al. (P21) and Raymer et al. (P22). Boynton and co-workers described a volatile organic sampler for unattended ambient monitoring in New York (P23). Two studies compared the performance of Tenax solid sorbent with stainless steel canisters for sampling volatile organic compounds (P24,P25). Schmidbauer and Oehme (P25)reported both techniques were suitable for very low ppt concentration of C,Ha and PhMe. Wjniender et al. constructed a low volume automated, sequential sampler for remote monitoring of organic atmospheric pollutants (P26). Figge et al. tested the performance of 26 solid sorbents with 29 organic compounds. Specific retention volumes and breakthrough volumes were reported (P27). James et al. compared Tenax GC and Spherocarb as solid sorbents for sampling volatile organic compounds from hazardous waste incineration (P28). Cummins et al. developed a sampling technique for ethylene oxide in the work place involving a HBr-coated charcoal tube (P29). Pannier reported the performance characteristics of activated charcoal dosimeters in sampling C2Cl+,PhMe, CsHII, C7H16, EtoAc, and C6H6 (P30). Cucco described an experimental protocol to determine the adsorption-desorption efficiency of air sampling traps. The method involves the 4R
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volatilization of a known volume of a liquid organic compound (P31). Coppi et al. described methods to determine safe sampling volumes for Porapak Q, Chromosorb 101,102, and 103 (P32). Verkoelen and Nielen reported substantial losses of organic vapors from open glass and stainless steel Tenax absorption tubes (P33). Zhu and co-workers described a passive sampler for collection of organic compounds (P34). McClenny et al. reported on the use of stainless steel canisters for organic sampling operated in vacuum mode or under positive pressure (P35). Selection criteria for diffusive sampler adsorbent/analyte combinations were developed based on physical dimensions of the sampler and diffusion coefficients (P36). Gonzalez and Levine described vapor phase spiking with analyte for desorption efficiency studies (P37). Cassinelli and co-workers developed an elaborate evaluation protocol for passive monitors. Factors considered include recovery, capacity, reverse diffusion, storage stability, accuracy and precision, shelf life, behavior in the field, and the effects of concentration, exposure time, face velocity, humidity, interferences, orientation, and temperature (P38). Matsumura categorized the quality of adsorbents with respect to specific surface area and pore size distribution derived from nitrogen adsorption isotherms (P39). Tourres and Matyjasik reported on the influence of humidity and presence of other volatile compounds on the adsorption capacity of C6H6on activated charcoal (P40). Hydrocarbons/Gas Chromatography. Nan0 and Borroni described a permeation tube system for generation of gas chromatography (GC) standards ( Q I ) . Pleil et al. reported on the improvements of Nafion tube dryers for sample preparation prior to GC analysis (Q2). Headspace gas chromatography was used to determine ethylene oxide (Q3) and volatile chlorinated hydrocarbons (Q4).
Lunsford and Gagnon reported on GC column maintenance technique in the determination of 1,3-butadiene. A backflushable polar precolumn removed vinylidene chloride (85). Phenolic compounds were determined by GC after preconcentration (Q6). Matsuka et al. developed a single column temperature program GC technique for C2-CIOhydrocarbons involving on-column cryofocusing and GC reinjection (Q7). Acrylonitrile was determined by GC after collection in KMn04 solution and bromination (Q8). Airborne isocyanates were determined by headspace GC (89).Maeda et al. developed techniques for GC determination of ppb levels of atmospheric alcohols based on their reaction with NO2 to form alkyl nitrates (810). Hydrocarbons (Cz-cG) were determined with temperature programmed gas chromatography on an A1203-coated fused silica column with flame ionization detection (FID) (811). Benzene in the 2-600 ppb range was determined by GC/FID after collection in a passive sampler (812). Zhang used carbon molecular TDX-01 as adsorbent for c&, benzene derivatives and GC/FID for analysis (Q13). Lindskog and co-workers developed a GC/FID method for methyl chloride collected on activated charcoal (Q14). Vashchun et al. reported high sensitivity with respect to organic compounds sensed by a hermetically sealed photoionization detector (Q15). Berkeley evaluated a portable photoionization GC for measurement of C6H6,PhMe, bromoand chlorobenzene, o-xylene, and 9 halo-methanes, -ethanes, and -ethylenes (Q16). Jerpe and Davis developed a portable photoionization GC with a detection l i i i t of 20 pg for benzene (Q17). Lee et al. found a flame ionization detector was less affected by high humidity that a photoionization detector in a study of additive detector response for multicomponent organic mixtures (818). Muller and Riedel used an electron-capture detector (ECD) and a flame ionization detector (FID) to measure hydrocarbons by headspace chromatography (Q19). Acrolein was determined by GC-ECD after formation of the brominated o-methyloxime derivative (Q20). Part per billion levels of toluene diisocyanate were determined by GC-ECD with a detection limit of 0.6 ppb (Q21). Yang and Chen described a capillary gas chromatography/mass spectrometry (GC/MS) technique with splitless sample injection for determining C1-Cll hydrocarbons (Q22). Merrill used GC/MS to develop screening methods to sample indoor air pollution sources (Q23). A collection and analysis system for organic trace gases was based on solid sorbent
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sampling and detection by GC/MS (Q24). Shepson et al. described a VOC sampling method consisting of cryogenic trapping followed by revolatilization and transfer to a Tenax cartridge assembly. Samples were then returned to the lab for analysis by GC/MS (925).Qiao et al. described a capillary column GC/MS system for VOCs (Q26). Oda and Ichikawa measured low molecular carboxylic acids by GC/MS with a ran e of detection limits 0.3-2.8 ppb (Q27). Priority pollutant anatysis in Norway consisted of adsorption on activated charcoal and XAD-2 and analysis by GC/MS (Q28). Hodgson and co-workers described VOC method involving solid sorbent sampling, thermal desorption, on-column cryogenic focusing, and GC/MS (829). Bis(chloromethy1) ether was determined to >0.1 ppb by GC/MS (Q30). Smith et al. described sampling and GC/MS analytical methods for dioxins in air (Q31). Fujii and Kitai developed a very selective method for trimethylamine based on gas chromatography - - - and thermal ion mass spectrometry (432). Hvdrocarbons /Non-GC. Toluene diisocvanate (TDI) was coU&ted on glass' fiber filters impregnated with 1;(2-methoxypheny1)piperazine. Urea derivatives were determined with HPLC (RI-R3). Dalene and co-workers collected TDI in alkaline EtOH. Urethane derivatives were formed and analyzed by HPLC. Electrochemical detection was found to be an order of magnitude more sensitive than W detection (R4). Pukkila et al. used HPLC/UV to determine 2-phenyl-2imidazoline in air (R5). Low concentrations of aliphatic amines were analyzed after collection with silica gel tubes. rn-Toluoyl derivatives were measured with HPLC/UV (R6). Low ppb levels of C1 and C2 acids and aldehydes were determined by ion chromatography (R7). Brocco et al. used a filter pack to collect organic and inorganic acid species in air. Water extracts were analyzed by ion chromatography (RB). Cryogenic sampling was used to collect aniline; subsequent analysis was conducted by liquid chromatography with electrochemical detection (R9). Pietrucha and Lalevic presented the characteristics of a palladium-MNOS capacitor as a sensor for CzH4and CHI (RIO). Loper and co-workers described the application of CO laser photoacoustic spectroscopy to monitoring of hydrazine-tased rocket fuels ( R I I ) . Wang et al. used a synchronous fluorescence spectrometer to measure phenol with a detection limit of 0.5 ppb (R12). Tandem mass spectrometry was applied to the measurement of nitroaromatic species by Glish et al. (RI3) and to atmospheric ions by Eisele (R14). A total organic carbon monitoring system was evaluated by Jayanty et al. (R15). Other Spectroscopy. Tomm and co-workers described a lead salt diode laser system for gas monitoring ( S I ) . Fortunato and co-workers used interference spectroscopy to monitor SO2, NO, NO2, HC1, Os,HF, H2S, and CO ( 8 2 ) . Sugimoto discussed the application of the Hadamard transform spectrometer to long-path adsorption measurements (S3). Vasilenko et al. discussed several methods to conduct remote sensing of power-plant plumes ( S 4 ) . Griffith and co-workers developed a matrix isolation technique with FT-IR spectroscopy to measure N20, CFCl,, CF2C12,COS, CS2,SO2,and PAN with detection limits in the 10-50 ppt range ( S 5 ) . Otagawa and Stetter described principles for selection of a chemical concentration modulation sensor (S6). Other. Bettis and coworkers applied physical and mathematical models to the release and expansion of heavy gas and particulate clouds ( T I ) . Havens developed a computer program to predict the dispersion of dense gases (2'2). Puzak and McElory outlined the U S . Environmental Protection Agency's role in quality assurance for ambient air measurements including standardized monitoring methods, monitoring guidance and technical assistance, and assessments of monitoring data (T3). In the Federal Republic of Germany, the technical and organizational structure to ensure the quality of air monitoring network results was described by Pfeffer and Dobrick (2'4) and the results of round-robin testing for quality assurance were reported by Mann (73). Zaromb and Beasley presented a mathematical treatment for the calibration of permeation absorbers (2'6). Computer-controlled mass flow meters were the basis of a gas blending
device to prepare standards ( T 7 ) . Hughes and many coinvestigators reported the results of an international comparison of reference gases (2'8). Restelli described the use of the ambient C02and N20 concentration as an in situ calibration standard for IR tunable diode laser absorption spectrometers (2'9). A HCN permeation device was described for standard gas preparation (TIO). Standard protocols for sampling indoor air were presented (2'11, 2'12). Che et al. developed a set of models to optimize the site selection for air pollution monitoring stations (273). Bell and De Brou described the instrumentation and application of mobile air monitoring units (2'14). Langstaff and co-workers described an air monitoring site selection process that emphasized data collection for population exposure assessments (T15).
AEROSOLS Books and Reviews. Spurny edited a volume on methods to characterize the physical and chemical properties of individual airborne particles ( A A I ) . A USSR reference to the Soviet literature on harmful substances in the environment was published (AA2). Stevens presented a review of collection and analysis methods for aerosol particles including the application of X-ray fluorescence (XRF),neutron activation analysis (NAA), ion exchange chromatography, X-ray diffraction, optical microscopy, and scanning electron microscopy (SEM) (AA3). Mukai and Furuya discussed methods of chemical analysis for airborne particles (AA4). Pui and Lui reviewed advances in instrumentation for atmospheric aerosols including filter samplers, cascade impactors, condensation nucleus counters, quartz-crystal microbalance sensors, vibrating mass sensors, and electrical aerosol analyzers (AA5). The difficulties of sampling for airborne polycyclic aromatic hydrocarbons (PAH) were reviewed by Leinster and Evans including collection media, reactions during sampling, losses, and extraction for analysis (AA6). Fradkin discussed sampling of microbiological contaminants such as fungi, bacteria, virus, and protozoa (AA7). Burge and Solomon reviewed sampling and analysis techniques for biological aerosols (AA8). McLaren discussed the applications of inductively coupled plasma-atomic emission spectroscopy (ICP/AES) for analysis of airborne particulate matter (AA9). Schroeder et al. reviewed sampling and analysis methodology for trace metals associated with airborne particles (AA10). Annegarn et al. reviewed time-sequence sampling devices and nuclear analysis techniques (AAI I ) . Stoeppler discussed recent progress in determination of cadmium with atomic spectroscopy, polarography, and total reflection X-ray fluorescence (AA12). A review of analytical techniques for mercury was published (AA13). Van Cauwenberghe discussed sampling size distribution, reactivity and analysis of organic aerosol constituents (AA14). Reviews appeared on techniques for measuring elemental carbon and organic carbon in aerosols (AA15, AA16). Sampling methods for PAHs were presented (AA17, AA18). Greenberg and Darack discussed atmospheric reactions for PAHs (AA19). Cox and Linton reviewed the application of X-ray photoelectron spectroscopy to particle analysis including instrumentation, speciation of N and S, and depth profiling (AA20). Several articles appeared on measurement methods for asbestos fibers including various microscopy techniques (AA2I-AA24). Milford and Davidson reviewed the size distributions of particulate sulfate and nitrate in the atmosphere (AA25). Potockova et al. reviewed methods for sampling and size fractionation of atmospheric aerosols (AA26). Watson and co-workers discussed the PMIo measurement process and analysis techniques (AA27,AA28). Bitter reviewed airborne dust monitoring consistent with Federal Republic of Germany guidelines and regulations (AA29). Manns discussed the application of automated radiometric (P-particle) monitors in total suspended particulate monitoring (AA30). Mathai and Tombach presented an assessment of the interrelationship of atmospheric visibility and aerosol measurements (AA31) Thurston and Lioy reviewed receptor modeling, aerosol transport, and source apportionment and made recommendations on how to treat transported aerosols ANALYTICAL CHEMISTRY, VOL. 61, NO. 12, JUNE 15, 1989
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in receptor models (AA32). Jaenicke reviewed atmospheric aerosol modeling (AA33). Sulfur/Nitrogen Speciation. John and co-workers presented measurement methods and reported results for dry acid deposition in California ( B B l ) . Tamaki et al. compared the results of a jar-type filtered acid deposition sampler and an automated wet/dry sampler over a 3-year period (BB2). Hicks and co-workers described the application of inferential methods for measuring dry deposition (BB3). Michelis described an automatic collection system for acid precipitation (BB4). Jaffrezo and co-workers developed a precipitation sampling system that excludes dry deposition and provides for separation of successive rain events (BB5). Verzhbitskaya described factors to be considered when sampling for sulfates (BB6). Chan et al. found artifact sulfate formation on nylon filters to be quite variable (BB7). Koutrakis et al. developed improved handling techniques for acidic aerosol samples (BB8). A continuous sulfuric acid and sulfate monitor was based on a thermodiffusion denuder and a flame photometric detector (FPD). The detection limits were 0.1 pg/m3 for HzSO, and 1.0 pg m3 for S04z-(BBlO). After collection on Teflon filters, sul uric acid particles were extracted and methylated with diazomethane and then analyzed by GC-FID (BB11). Glabisz et al. extracted water-soluble sulfates for analysis by colorimetric techniques (BB12). Ion chromatography was used by Yamanaka et al. to analyze sulfuric acid samples which were extracted with benzaldehyde from Teflon filters (BB13). Ferrer and Perez determined NO3- and SO4- with ion chromatography (BB14). Russell and Cass used ambient measurements of aerosol nitrate and nitric acid to verify predictive mathematical models (BB15). Durham and co-workers conducted a performance evaluation of a nitric acid-nitrate aerosol diffusion denuder comparing field results with predictions based on the Gormley-Kennedy equation (BBl6). White and Macias used a filter pack of Nylon followed by Teflon to sample for fine-particle nitrate and gaseous nitric acid at rural sites in the western U.S. (BB17). Particulate Carbon. Gunderson and Anderson discussed collection methods for separating airborne vapor and particulate matter and used aniline as an example ( C C l ) . Lane et al. developed a gas and particle sampler for semivolatile chlorinated organic compounds which consisted of a gas removing section based on diffusion followed by filters with backup adsorption cartridges for any material volatilized from the filters ( 0 2 2 ) . Foreman and Bidleman developed an experimental system to investigate the partitioning of semivolatile organic compounds on filters ( 0 2 3 ) . McDow investigated how sampling procedures can affect organic aerosol measurement (CC4). Dangler et al. used Fourier transform IR (FTIR) spectroscopy to identify function groups in size segregated atmospheric organic aerosols (CC5). Gordon et al. determined functional groups in organic aerosol samples by extraction, chromatography, and diffuse reflectance FTIR (CC6). Lane and Jenkins reported on the use of microwave desorption of organic compounds from particulate matter (CC7). Mazurek et al. used computer-assisted, high-resolution gas chromatography (HRGC) for the analysis of extractable organic matter (CC8). The use of simultaneous ultrasonic extraction and silylation improved recoveries during the determination of organic acids, alcohol, and phenols from airborne particulate matter (CC9). Yokouchi et al. measured y-lactones (CgI5) in atmospheric aerosols (CClO). Several investigators reported on methods to determine organic carbon and elemental carbon based on thermal oxidation in different temperature ranges with inert and oxidizing atmospheres (CCll-CC14). Lin and Friedlander cautioned that glass fiber filters contain chemical compounds which catalyze the oxidation of elemental carbon at lower temperatures than would normally be expected (CC15). Sakai and Kadowaki used a C-H-N analyzer to determine elemental carbon in dust samples (CClS). Currie and co-workers reported on the combined use of carbon-14 accelerator mass spectrometry and laser microprobe mass spectrometry to identify the source of carbonaceous aerosols ( 0 2 1 7 ) . Polycyclic Aromatic Hydrocarbons (PAHs). De Raat et al. investigated the use of polyurethane foam (PUF) for
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sampling of PAHs. PUF must be throughly rinsed and the extraction solvent carefully selected to minimize mutagenicity interference (001).Hunt and Pangaro concluded the combined use of PUF and glass fiber filters (GFF) for PAH sampling was more accurate than GFF alone because the more volatile PAHs were collected on the PUF cartridge ( 0 0 2 ) . A PUF-Tenax sandwich cartridge was developed to quantitively collect dichlorobenzenes from 30-165 m3 ambient air (003). Chuang et al. compared the sampling efficiency for a variety of PAHs on XAD-2 and PUF ( 0 0 4 ) . Knecht and co-workew evaluated XAD-2, PUF, silica gel, and Polygosil as collection media for 20 PAHs. The latter two were not suitable as a PAH adsorbent (005). Otson et al. discussed the limitations of various PAH sampling methods caused by the degree of volatility associated with the PAH (DD6). Chuang et al. found XAD-4 compared very well with XAD-2 in collection efficiencies for PAHs (007).Jacob and co-workers reported the reevaporation of lower boiling point PAHs collected on GFF (008). Raymer and Pellizzari reported on the use of supercritical COzto desorb PAHs from Tenax-GC (009). Rappe et al. used a GFF followed by XAD-2 to sample for ambient levels of polychlorinated dibenzodioxins ( 0 0 1 0 ) . Quartz fiber filters followed by PUF were used to collect woodsmoke by Hornig et al. ( 0 0 1 1 ) . Knecht et al. investigated reevaporation of PAHs from glass fiber filters as a function of flow rate and recommended a solid sorbent backup for GFFs ( 0 0 1 2 ) . Lindskog and co-workers found no difference in the chemical reaction of PAHs and NOz on GFF and Teflon-coated GFFs ( 0 0 1 3 ) . Wu and Niki investigated the kinetics of surface-absorbed PAHs and NO2 ( 0 0 1 4 ) . Arey et al. investigated the formation of nitroarenes during high volume sampling (0015). Lindskog et al. reported PAH oxidation losses with NOz on XAD-2 and to a lesser amount on PUF ( 0 0 1 6 ) . Davis and co-workers developed a trap to remove O3 prior to high volume sampling of PAHs (0017 ) . Coutant et al. found no evidence of PAH-ozone reactions on filter surfaces under normal ambient sampling conditions ( 0 0 1 8 ) . Butler and co-workers developed on integrated chemical class/ bioassay system to investigate the identity and mutagenicity of atmospheric constituents (0019). Bioassay fractionation schemes were reported for hydroxy-nitro-PAHs and nitro-PAHs ( 0 0 2 0 , 0 0 2 1 ) . Kopczynski a plied multidimensional gas chromatography to nitrated PA& ( 0 0 2 2 ) . Benzo[a]pyrene collected on GFFs was determined by automated thermal desorption gas chromatography ( 0 0 2 3 ) . Azaarenes were determined by Nielsen et al. ( 0 0 2 4 ) and Sueta et al. ( 0 0 2 5 ) . Semipreparative HPLC and GC/MS were used to measure PAHs ( 0 0 2 6 , 0 0 2 7 ) . Vogt and co-workers used high-resolution GC/MS and pattern recognition analysis to investigate airborne and soil samples of PAHs near a major industrial source ( 0 0 2 8 ) . Negative ion chemical ionization mass spectrometry combined with gas chromatography was used to determine halogenated PAHs (0029),mononitropyrenes ( 0 0 3 0 ) ,BaP (00311, and PAHs and alkylated-PAHs ( 0 0 3 2 ) . High-performance liquid chromatography (HPLC) with spectrofluorometric detection was used to determine PAHs ( 0 0 3 3 - 0 0 3 5 ) , aza heterocyclic hydrocarbons ( 0 0 3 6 ) ,azarenes ( 0 0 3 7 ) ,and nitroarenes (0038).Yodoriyama et al. used TLC to determine PAHs ( 0 0 3 9 ) . MacCrehan et al. used liquid chromatography (LC) with electrochemical and fluorescence detection to determine nitro-PAHs ( 0 0 4 0 ) . Draisci and co-workers reported on small bore LC for analysis of PAHs (DD41). Kirsch and Winefordner studied the use of electrothermal vaporization and laser-induced fluorescence as screening tools for PAHs (0042). Verdun et al. applied laser microprobe mass analysis (LAMMA) microscopy to PAH detection ( 0 0 4 3 ) . Synchronous luminescence was used for screening PAHs ( 0 0 4 4 ) . BaP was determined with synchronous fluorescence spectrophotometry by Lei (0045)and low-temperature spectrofluorometry by Shiozaki et al. (0046). Vo Dinh et al. developed a PAH personal dosimeter with room temperature phosphorescence ( 0 0 4 7 ) . Niessner reported on in situ photoemission from PAHs (0048).Lee et al. ( 0 0 4 9 ) and Wang et al. (0050) described a UV screening method for PAHs. Shpol’skii spectrometry was used to measure PAHs ( 0 0 5 1 , 0052).
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Chuang and co-workers investigated the presence of PAHs in indoor particulate samples ( 0 0 5 3 , 0 0 5 4 ) . Kamens et al. identified cyclopentafused isomers of BaP in woodsmoke (0055). PAH surveys were reported for a remote site in the Mediterranean Sea ( 0 0 5 6 ) and in the USSR (0057). Asbestos. Baron and Deye developed procedures for preparation of replicate asbestos aerosol samples for Calibration standards (EE1). Ogden et al. addressed the issue of within-laboratory quality control of asbestos counting by recommending a stock of permanently mounted reference slides (EE2). Cherrie and co-workers compared optical and electron microscopy for evaluation of different asbestos types (EE3). Phanprasit et al. compared a fibrous aerosol monitor and the optical fiber count technique. They concluded the monitor could not be a substitute for standard counting methods (EE4). Another study compared asbestos evaluation methods by considering the effects of asbestos type, mounting medium, graticule type, and counting rules (EE5). Willey investigated orientation in a magnetic field as a tool to distinguish respirable asbestos and nonasbestos fibers (EE6). Baron was able to lessen the electrostatic effects in sampling asbestos by using a conductive sampler (EE7). Johnston and co-workers investigated the effect of electrostatic charge on the aspiration efficiencies of airborne dust samplers (EE8). DeWaele used laser microprobe mass analysis to characterize asbestos fiber surfaces (EE9). Atomic Absorption Spectroscopy. Alkyllead was analyzed by using gas chromatography and atomic absorption spectroscopy (GC/AAS) by several investigators (FF1-FF4). Roeyset and Thomassen used electrothermal AAS to measure alkyllead (FF5). Electrothermal atomization atomic absorption spectroscopy was used to determine mercury collected on a single stage impaction system (FF6). Moura and coworkers introduced disks cut from filters directly into the graphite furnace to determine Pb by AAS (FF7). Other inGestigators used graphite furnace AAS to determine AsH3 (FF8). As. Sb. Se (FF9). Pb. Cd. Ni. Cu. Mn (FFlO). Cd (FFly),and Ni(COj4 (FFlZ).' ' ' ' Bloom and Fitzgerald used low-temperature GC with cold-vapor atomic fluorescence for alkyl mercury (FF13). Flameless AA was used to determine SOz, Fe, Pb, Cu (FF14), and Be (FF15) from dust samples. Metals determined by hydride generation and AAS include Sn (FF16),Sn, Sb, Bi (FF17),and As (FF18). Schothorst et al. developed techniques to prepare filter samples and collected airborne dust for analysis by solid sampling direct Zeeman atomic absorption spectroscopy (FF19). X-Ray Techniques. Doi et al. described the use of X-ray fluorescence (XRF) spectroscopy to determine Mn, Fe, Ni, Cu, Zn, and Cr (GGI). The preparation of thin-fiim standards of lead and zinc for X-ray fluorescence spectroscopy was described (GG2). Tanaka et al. described XRF for Mn, Fe, Ni, Cu, Zn, and P from membrane and quartz fiber filters (GG3). Set0 and Kubo determined Pb, Zn, Ni, Fe, Mn, Cr, and V with XRF (GG4). Losno et al. described optimal conditions for application of XRF to atmospheric aerosols (GG5). Doern and Wotton used the complementary techniques of XRF and scanning electron microscopy to determine airborne lead particulate matter (GG6). Nakamura described the determination of CaS04 and CaC03 in airborne dusts by X-ray powder diffractometry (CG7). Total reflection X-ray fluorescence was used to determine s, C1, K, and Ca in aerosol samples (GG8). Maenhaut et al. discussed the accuracy and artifacts associated with the use of proton-induced X-ra emission (PIXE) spectroscopy for marine aerosol samples (JG9). Tang et al. described the effects of thickness difference between the blank and the sample substrate in PIXE analysis of aerosols (CGlO). Annegarn investigated the application of time series analysis to PIXE aerosol measurements ( G G I l ) . PIXE analysis of many samples was used to study the sources of respirable particles in Belgium (GG12). Feeney and coworkers developed a solar-powered PIXE aerosol sampler for unattended operation (GG13). A time sequential sampler coupled with PIXE spectroscopy was used to analyze atmospheric aerosols (GG14). Martinsson developed a system that used particle elastic scattering analysis (PESA) for C, I
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N, and 0 and PIXE for elements heavier than Si (GG15). Tang and co-workers described improvements in the target chamber for PIXE which improved the sample handling (GG16). Cahill combined PIXE and PESA to determine the hydrogen-sulfur correlation in aerosol samples (GG17). Other Spectroscopy. The application of a portable ion chromatograph for field measurements of fog water and atmospheric aerosols was described ( H H l ) . Leasure investigated ion mobility spectroscopy ("2). Kvietkus presented a method for the diffusive separation and sampling of gaseous and aerosol Hg with analysis by atomic A speciation sampling train containing fluorescence ("3). a series of selective sorbents was used to sample mercury for Roizenblat subsequent analysis by atomic fluorescence ("4). et al. described a colorimetric method for Sn (HH5). HexaChen valent chromium was determined by calorimetry ("6). et al. used an indirect spectrophotometric method to determine free silica in dust samples ("7). Mercury was determined coulometrically by using the iodine-azide reaction induced by sodium diethyldithioZreck and Horak discussed a mathematical carbamate ("8). model on the interaction of atmospheric aerosols and lidar techniques (HH9). Ancellet and Menzies studied atmospheric correlation-time measurements and coherent Doppler lidar (HHlO). Hollaender et al. described the use of laser Doppler anemometry to measure particle fluxes in dry deposition ( H H l l ) . Clarke and co-workers investigated measurement techniques for determining aerosol light absorption coefficients ("1 2). Tsonis used satellite imagery to infer the o tical depth of the pollutant layer and the ground aerosol SO4Pconcentration during clear sky conditions (HH13). Tsanev et al. used laser radar to study aerosol spatial distributions ("14). Sheridan used electron microscopy to study individual particles from the arctic haze aerosol (HH15). Scanning electron microscopy (SEM) was used by several authors to investigate the properties of individual aerosol particles (HH26-HH18). Inductively coupled plasma atomic emission spectroscopy was used to simultaneously determine major, minor, and trace Neutron activation elements in airborne particles ("19). analysis was used to determine 27 trace elements in aerosol samples from around the world (HH20). Gordon et al. -used diffuse reflectance Fourier-transform infrared spectroscopy to characterize organic functional groups in fine particles ("21). Electrochemical Methods. Wang and Zhang described potentiometric stripping analysis for Bi using a HC1-KSCNmethyl violet system (JJ1). Scholz et al. converted Hg(I1) to mercury metal. A gold-plated electrode and differential pulse stripping voltammetry were used for analysis (JJ2). Mercury was also determined by computerized flow constant-current stripping analysis (JJ3). Mu and Zhang determined vanadium compounds with catalytic polarography. Samples were collected on an NaOH impregnated polychloroethylene membrane filter (JJ4). Nickel oxide was analyzed by using dc polarography to measure oxygen released by dissolving Ni,O, in HC1 (JJ5). Particle Size Fractionation. Niessner et al. developed an aerosol preseparator for denuder sampling with an effective cut-off diameter of approximately 2.3 pm (KK1). Chen et al. reported on the design and performance of a virtual impactor with low wall losses (
