Anal. Chem. 1997, 69, 1R-13R
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 Review Contents Gases Books and Reviews Ozone Radicals and Peroxides Ammonia Oxides of Nitrogen H2S and SO2 Carbon Monoxide Sampling Solid Sorbents Aldehydes Hydrocarbons: Gas Chromatography Spectroscopy Aerosols Books and Reviews Particulate Carbon Polycyclic Aromatic Hydrocarbons Multielement Analysis Asbestos Single-Particle Analysis Lidar Calibration/Standard Reference Materials Single-Stage/Multistage Collection Particle Sizing Bioaerosols Acknowledgment Literature Cited
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This review is extracted from the literature from January 1995 to December 1996 and is an extension of literature previously discussed (A1). The major source of information was Chemical Abstracts Selects: Pollution Monitoring and Air Pollution (Books and Reviews). The organization consists of two major divisions: gaseous methods, which have single-letter designations before reference numbers, and aerosol and particulate methods, which have twoletter designations before reference numbers. Areas that are included are listed in the table of contents. The classification and subclassification scheme is not necessarily technique or pollutant specific. An example occurs in the ozone section (B). This section contains articles that are primarily about ozone techniques. However other articles refer to ozone in sampling and spectroscopy sections. Please read other sections which might contain information of interest. GASES Books and Reviews. Lee authored a guide to the U.S. EPA requirements for sampling, analysis, and monitoring methods (A2). Several proceedings appeared reporting advances in application of spectroscopy to air quality measurements. Grosar et al. (A3) edited a volume on monitoring of gaseous pollutants by tunable diode lasers. Three proceedings volumes appeared from the 1995 S0003-2700(97)00004-8 CCC: $14.00
© 1997 American Chemical Society
scientific meeting in Munich on air toxics and water monitoring (A4), lidar and atmospheric sensing (A5), and air pollution and visibility measurements (A6). Romano edited a proceedings on optical remote sensing for environmental and process monitoring (A7). Several specific contributions in these proceedings are referenced in other sections of this review. The proceedings of a specialty conference on regional photochemical measurements and modeling was edited by Parrish et al. (A8). Baldasano et al. (A9) edited a volume on air pollution control and monitoring. The Japanese Standards Association published a handbook on environmental measurements (A10). Ure and Davidson (A11) edited a text on chemical speciation in the environment. A book on environmental analysis and ecotoxicology was edited by Holler et al. (A12). A number of reviews appeared in the last two years on monitoring, sampling, organic analysis, radicals, spectroscopy, and other topics. A review of the calibration and monitoring methods for the Global Environmental Monitoring System (GEMS) appeared (A13). The performance of real-time air monitoring equipment for use at Superfund sites was reviewed (A14). Khopkar discussed air pollution monitoring in India including sampling, laboratory techniques, and instrumentation development (A15). Szczurek reviewed the components of automatic systems for air pollution measurements (A16). Crill et al. (A17) presented an extensive review of standard analytical methods for measuring trace gases in the environment including standardization, sampling, carbon gases, N gases, and reduced S gas analysis. The trends in the development of novel on-line and in situ measuring techniques such as optical remotesensing devices were reviewed by Broeker and Gaertner (A18). Devices for determining toxic substances at workplaces were discussed (A19). Laird discussed atmospheric analyses, gaseous analytical techniques and sampling, and aerosol techniques in a recent review (A20). The principles, types, and application of passive samplers were reviewed by two groups (A21, A22). Slanina and Wyers (A23) reviewed the use of automatic denuder systems including thermodenuders, wet denuders, automated systems, and measurement of dry deposition. Neglia (A24) reviewed the equipment and techniques available for personal sampling. Aircraft-based sampling strategies and techniques were reviewed by Wilson and Fahey (A25). Wortham et al. (A26) reviewed methods of sampling, preservation, and analysis of acetic and formic acids in the atmosphere. Nishikawa and Yasuhara (A27) reviewed the derivatization techniques used for the analysis of volatile aldehydes in air samples including pentafluorobenzyloxime derivatives, thazolidine derivatives and 2,4-dinitrophenylhydrazine (DNPH) derivatives. Suzuki (A28) reviewed sampling, pretreatment, and analysis methods for determining organic pollutants in air. Cecinato et al. (A29) reviewed speciation of C4-14 hydrocarbons including sampling and analysis of polar and nonpolar compounds. Kern Analytical Chemistry, Vol. 69, No. 12, June 15, 1997 1R
(A30) reviewed the determination of volatile air pollutants by gas chromatography (GC), ion trap mass spectrometry (MS), flame ionization detection (FID), and photoionization detection (PID). Tominaga (A31) reviewed analytical methods for monitoring trace chlorofluorocarbons. Luxenhofer et al. (A32) reviewed techniques for separation, detection, and occurrence of (C2-C8)alkyl and phenylalkyl nitrates. Jonsson et al. (A33) reviewed the use of GC for determining cyclic organic acid anhydrides. Techniques for the direct measurement of atmospheric radicals were reviewed by Hirokawa and Akimoto (A34). Crosley (A35) reviewed methods for local detection of OH in the atmosphere with particular emphasis on laser-induced fluorescence (LIF). Ehhalt et al. (A36) reviewed the measurement of OH with longpath UV absorption methods. de Korte et al. (A37) reviewed developments in thermometer bolometers which may permit the observation of OH in the atmosphere. Kolb et al. (A38) reviewed recent advances in spectroscopic instrumentation for measuring stable gases in the natural environment. Simonds et al. (A39) reviewed optical remote sensing with spectroscopic methods. Other reviews of optical remote sensing appeared (A40-A43). Pfab (A44) reviewed LIF and ionization spectroscopy of gas-phase species. Plane and Smith (A45) reviewed atmospheric monitoring by differential optical absorption spectroscopy (DOAS). Two reviews of tunable diode laser absorption spectroscopy (TDLAS) reviewed the properties and operation of tunable diode lasers (A46, A47). Werle and Muecke (A48) reviewed the frequency-modulation technique with tunable diode lasers to conduct in situ trace gas analysis. Kolb et al. (A49) reviewed mid-IR TDLAS techniques for rear-time air analysis. Milinkovic (A50) reviewed ion mobility spectrometry including basic principles and potential applications. Charles and Feinberg (A51) reviewed the applications of mass spectrometry for environmental research including analysis of air quality samples. Ricco (A52) reviewed surface acoustic wave (SAW) chemical sensors including response fundamentals, design, selectivity and sensitivity, and materials. Fehsenfeld (A53) reviewed techniques for measurement of chemically reactive trace gases at ambient concentrations including NOx, CO, NH3, S-containing compounds, and O3. Lynch (A54) reviewed approaches and techniques for measurement of worker exposure to airborne hazards. Ozone. Geyh et al. (B1) developed an active personal ozone sampler using a hollow tube diffusion denuder coated with a nitrite reagent. Manning et al. (B2) compared the performance of Ogawa passive ozone samplers with a collocated UV photometric meter and found good agreement for 7-day sampling periods in a rural location. Scheeren et al. (B3) developed and tested a passive measurement method for ozone based on the reaction of ozone with indigo carmine. Reaction products are detected spectrophotometrically after exposure. Bukreev et al. (B4) described a lidar system to measure O3 concentrations at altitudes of 0.3-0.5 km by a differential absorption method. A mobile three-wavelength UV differential absorption lidar (DIAL) system was developed for ground-based ozone measurements (B5). Martina et al. (B6) presented intercomparisons of O3, NO2, NO, and SO2 measurements by DOAS and conventional monitoring techniques. The results were in good agreement when conditions were conducive to good vertical and horizontal mixing. 2R
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Krueger (B7) described the total O3 mapping spectrometer (TOMS) technique used by on-board satellite monitoring of the atmosphere. Pougatchev et al. (B8) reported infrared measurements of the O3 vertical distribution above Kitt Peak. These measurements showed good agreement with the TOMS satellite total columns for the same location and dates at Kitt Peak. Delahaique et al. (B9) described the use of atmospheric heterodyne laser spectroscopy to measure O3 in the atmosphere. The use of a 18O12C18O laser eliminates atmospheric CO2 absorption. Puckrin et al. (B10) described an O3 remote monitoring method based on thermal emission spectroscopy. A ground-based FT-IR system measured the thermal radiation from ozone against the cold background blackbody emission of clouds. Malicet et al. (B11) measured the absolute absorption cross sections of O3 at five temperatures in the UV wavelength region. Penrose et al. (B12) investigated the ability of miniature amperometric gas sensors to detect O3 in air at concentrations as low as 5 ppb. Radicals and Peroxides. Schultz et al. (C1) developed and tested a radical source that generates HO2 at atmospheric concentrations in the pptv range. Brune et al. (C2) reported the in situ measurement of OH and HO2 by laser-induced fluorescence (LIF) at low pressure. Mount and Harder (C3) reported on the use of long-path spectral absorption to measure OH and ancillary trace gases in the atmosphere. Cantrell et al. (C4) used chemical amplification to measure peroxy radicals at the Mauna Loa Observatory. Campos and Kok (C5) evaluated Horibe traps for the cryogenic collection of hydrogen peroxide and methyl hydroperoxide. They reported on the effect of interferences of O3, ethylene, and SO2. Possanzini and Di Palo (C6) determined atmospheric H2O2 by the titanium method which consists of collection on a Ti(IV)H2SO4-coated filter. The Ti peroxy complex is extracted and analyzed spectrophotometrically after having added 4-(2-pyridylazo)resorcinol. Ammonia. Sommer et al. (D1) developed a passive flux sampler coated with oxalic acid for measuring ammonia volatilization. Yamanouchi et al. (D2) tested detector tubes for measuring NH3. Jaeschke et al. (D3) used an active wet denuder to collect NH3 in an HCl solution with subsequent ion chromatographic (IC) detection. Mennen et al. (D4) conducted an intercomparison of six automatic ammonia monitorssthree denuder-based systems, DOAS, photoacoustic spectrometry (PAS), and a chemiluminescence NO monitor with an ammonia converter. Field tests were used to address operational and technical performance and environmental chamber tests determined functional parameters such as range, precision, and detection limits. Harren et al. (D5) reported on improvements to a CO2 laserbased spectrometer which permitted ammonia measurements with subsecond response times. Oxides of Nitrogen. Becker et al. (E1) have measured the IR absorption spectra and line strengths of HNO2 with a tunable diode laser spectrometer. Several studies appeared on passive sampling of NO2 in home indoor air, workplaces, and outdoors. Passive samplers often use coated surfaces to collect the NO2, which is subsequently extracted and detected with ion chromatography. De’ Murari et al. (E2) described N02 passive sampling for indoor air. Moriske
et al. (E3, E4) reported on laboratory and field testing of passive Palmes samplers. Ross (E5) compared passive Palmes samplers to continuous NO2 analyzers for home indoor air monitoring. Sasaki et al. (E6) developed a simple NO2 sampler and collected samples at various locations in a street canyon surrounded by concrete buildings. Krochmal and Gorski (E7) improved a passive sampler to reduce the effect of wind velocity changes. De Santis et al. (E8) determined NO2 and PAN in ambient air by collection with a carbon-coated annular diffusion denuder and subsequent analysis by IC. Hedrick et al. (E9) conducted an NO2 intercomparison study of chemiluminescent NO/NOx analyzer, chemiluminescent NO2 analyzer using luminol solution, and an electrochemical NO2 analyzer. Pastel and Sausa (E10) reported the use of (2 + 2) resonanceenhanced multiphoton ionization and photoacoustic spectroscopy to detect NO and NO2. Peng et al. (E11) developed a laser-based procedure, using simple ionization chambers to detect NO2 in air to a few ppb. Toriumi et al. (E12) described a tunable blue laser differential absorption lidar system for NO2 monitoring in the blue region (453 nm). Mihalcea et al. (E13) used two single-mode diode lasers to record high-resolution absorption spectra of NO2 near 670.2 and 394.5 nm over a range of temperatures and pressures. Sausa et al. (E14) detected NO, NO2, HNO3, and CH3NO2 with laser-induced photofragmentation/photoionization spectrometry. Coquart et al. (E15) reported new values for the absorption cross sections of NO2 at low temperatures in the 400-500 nm region. Schultz et al. (E16) describe a chemical actinometer for calibration of photoelectric detectors for measurement of NO2. de Agapito and Santos (E17) compared theory and experimental data for the interaction of NO2 with degenerate nanocrystalline tin dioxide thin films. Krognes et al. (E18) reported on an interlaboratory calibration of PAN with liquid standards. Watanabe et al. (E19) described methods of sampling, transporting, and analyzing for PAN in field studies at remote sites and by aircraft. They reported a PAN limit of detection of 2 ppt for a 500 mL sample. Schrimpf et al (E20) modified a GC method to determine PAN with instrumentation mounted on aircraft. Lu and Lin (E21) presented a theoretical evaluation of measurement artifact for sampling nitric acid gas by an annular denuder system. The model considered deviation from the state of gas-particle equilibrium and diffusional deposition of NH4NO3containing aerosols. H2S and SO2. Shooter et al. (F1) adapted the silver nitrate/ fluorescein mercuric acetate fluorometric method to passive sampling for measurement of atmospheric hydrogen sulfide. Samplers were tested in indoor and outdoor locations. Xia et al. (F2) characterized a fluorometric method for H2S with fluorescein. Eroglu et al. (F3) developed a solid surface luminescence H2S technique which uses a filter coated with cadmium chloride. Cadmium sulfide crystals are the luminescent species. Yoo et al. (F4) reported on SnO2 thin-film sensors for H2S. Krochmal and Kalina (F5) used a passive sampler to collect SO2 and NO2 in outdoor locations. Leaderer et al. (F6) developed and evaluated a passive sampler for SO2 and HNO2. Humidity, sampling time, and concentration effects were investigated.
Velasquez et al. (F7) determined SO2 concentrations in an urban area with IC. Rambaldi et al. (F8) developed a new lidar system based on UV-tunable solid state lasers and reported its use for SO2 and O3. Conner (F9) described the use of DOAS for field measurements of SO2, NO2, and O3 including calibration procedures and comparisons with point monitors. Watanabe and Ikeda (F10) described the instantaneous measurement of SO2 by electrical conductivity. Murashov et al. (F11) investigated the use of alkoxycyclophosphazenes as sorption coating in piezoelectric quartz resonators for detection of SO2. Carbon Monoxide. Klemm et al. (G1) described an aircraftmounted CO monitoring method which reacts CO with HgO forming Hg followed by atomic absorption spectrometric (AAS) detection. Long and Sun (G2) reported the indirect measurement of CO by reaction with nickel with AAS detection. Turnidge and Simpson (G3) detected CO down to 500 pptv using IR excitation of CO dissolved in liquid Ar solution with LIF detection. Baldacchini et al. (G4) measured CO with tunable diode lasers at 2077 cm-1 over a path of 104 m. Jiang et al. (G5) determined CO in the atmosphere by catalytic (with Ni catalyst) conversion of CO into CH4 and FID detection. Sampling. Kennedy et al. (H1) presented guidelines for air sampling and analytical method development and evaluation. Chan and Hwang (H2) described a statistical approach to quantify the spatial representativeness for the air measurements of an urban fixed-site ambient air monitoring station. Doerr et al. (H3) described a computer-controlled modular system which permits automatic directional sampling of air pollutants. Several studies reported on various aspects of denuder sampling. Lu et al. (H4) developed a mathematical model to predict the performance of an annular denuder system accounting for gas diffusion, aerosol diffusion, and evaporation. Fan et al. (H5) presented a study of gas collection efficiency and entrance flow effects for an annular denuder. Hori and Tanaka (H6) investigated the effect of face velocity on the performance of diffusive samplers. Feigley et al. (H7) investigated the performance characteristics of diffusive samplers in the laboratory and in simulated use conditions and recommended careful attention to ensuring mass-transfer resistance conditions are appropriate when used in the field. Bemgard et al. (H8) used two theoretical methods based on the Gormley-Kennedy equation to predict breakthrough times for denuder samplers and VOCs. Cocheo et al. (H9) developed a new diffusive sampler with a radial diffusive path geometry which affords high uptake rates. KozdronZabiegala et al. (H10) studied the permeation of VOCs through polyethylene films to passive samplers. Sioutas et al. (H11) conducted laboratory and field evaluations of a glass honeycomb denuder/filter pack sampler to measure gases and particles. Kelly and Holdren (H12) reviewed the literature to determine which of the 189 hazardous air pollutants (HAP) in the U.S. Clean Air Act were candidates for using canisters for sample storage. Brymer et al. (H13) experimentally tested the accuracy, precision, and storage stability results for 194 VOCs generated in humidified ambient air and collected in SUMMA polished canisters. A total of 168 of 194 compounds studied appear to be amenable to the canister technique. Whitaker et al. (H14) developed and tested a whole-air sampler for measurement of personal exposure to VOCs based on a 1-L canister. Analytical Chemistry, Vol. 69, No. 12, June 15, 1997
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Wang et al. (H15) investigated the stability of VOCs in Tedlar bags and found the type of fittings were an important factor in losses. Groves and Zellers (H16) investigated organic vapor losses to condensed water vapor in Tedlar bags used for exhaledbreath sampling. Wang et al. (H17) reported a method for sampling and analyzing VOCs in breathing air by repeated exhalation to the same bag. Koppmann et al. (H18) found very small degradation of light non-methane hydrocarbons by ozone during cryogenic preconcentration. Monn and Hangartner (H19) used passive diffusion samplers to measure aromatic VOCs in ambient air. Risse et al. (H20) investigated active diffusive sampling for aromatics as a function of length and humidity. Harper et al. (H21) evaluated diffusive samplers for gasoline oxygenates such as MBTE in air. Lioy et al. (H22) field tested passive and active samplers for MTBE associated with automobile use activities. Tang et al. (H23) developed a multipurpose sampling loop for analysis of nanogram per cubic meter quantities of sulfur compounds by GC-SCD. Smith (J24) evaluated a closed cycle cooler for preconcentration of VOCs for GC analysis. Solid Sorbents. Bourdin et al. (J1) investigated the masstransfer kinetics of solid sorbents using the thermal frequency response method. Helmig and Vierling (J2) determined the water adsorption capacity of six sorbents using a gravimetric technique. They made recommendations to minimized the amount of water trapped during sampling periods. Supercritical fluid extraction (SFE) is a technique for removal of VOCs from collection media. A paper appeared on the stability and cleanliness of various sorbents under SFE conditions (J3). Lin et al. (J4) reported improvements in supercritical CO2 extraction efficiencies for chlorinated hydrocarbons with addition of a methanol modifier. Matsumura (J5) reported on the selection of desorbing solvents for 46 kinds of organic compounds from active carbon. Comes et al. (J6) reported on the absorption behavior of odorous VOCs while sampling with solid sorbents. Herber and Meisch (J7) investigated the application of static headspace GC as an alternative to extraction of volatile halocarbons from activated carbon traps. Rudenko et al. (J8) presented the retention volumes of 40 VOCs on four sorbents. Stanetzek et al. (J9) investigated seven materials for suitability for sampling polar and nonpolar lowvolatility compounds, polar high-melting compounds, nonpolar high-melting compounds, polar high-volatility compounds, and nonpolar high-volatility compounds. Prado et al. (J10) evaluated sorbents for diffusive monitoring using benzene and n-hexane as test compounds. Martinez Vidal et al. (J11) studied the desorption of five pesticides from six different solid sorbents. Baya and Siskos (J12) evaluated Anasorb CMS and Tenax TA for sampling VOCs indoor and outdoor air by breakthrough measurements. Jaouen et al. (J13) described a dynamic gas generator used to investigate solid sorbent performance. Calogirou et al. (J14) investigated the decomposition of terpenes by ozone during sampling on Tenax. Aldehydes. Levin et al. (K1) reported on the preparation of certified reference materials for the monitoring of aldehydes in air by DNPH including solid hydrazones of formaldehyde, acetaldehyde, acrolein, acetone, and glutaraldehyde. Pengelly et al. (K2) investigated differences in composition of formaldehyde 4R
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atmospheres generated from different source materials and the impact on diffusive sampling. Lindahl et al. (K3) presented a validation study of a diffusive sampler for the determination of acetaldehyde in air. Grosjean and Grosjean investigated the performance of DNPHcoated C18 cartridges for sampling C1-C9 carbonyls in air (K4), the effect of dry vs humid air on carbonyl collection efficiency (K5) and liquid chromatographic properties of C1-C10 carbonyls (K6). Trapp and De Serves (K7) compared formaldehyde monitoring with the DNPH with UV/Vis detection and a porous membrane diffusion scrubber with fluorescent detection. Both methods were found to be suitable for field experiments in the low-ppbv formaldehyde range. Groemping and Cammann (K8) reported the field evaluation and automation of a DNPH with HPLC/UV detection for aldehydes and ketones in air. Lehmpuhl and Birks (K9) used 2,4,6-trichlorophenylhydrazine (TCPH) as the derivatizing reagent for atmospheric aldehydes and ketones. The higher volatility of TCPH permits the use of gas chromatography with electron capture detection. Rodriguez et al. (K10) investigated two kinetic methods based on the stopped-flow technique to determine formaldehyde in air: (1) reaction with 3-methyl-2-benzothiazolone hydrazone (MBTH) followed by photometric detection and (2) reaction with acetylacetone followed by fluorometric detection. They reported these methods to be sensitive, rapid, and reproducible. Audige et al. (K11) reported the use of a DOAS system with a diode array detector to monitor formaldehyde. Kern et al. (K12) used TDLAS to measure formaldehyde in urban polluted air. Mackay et al. (K13) used TDLAS to measure formaldehyde and H2O2 in background air at Mauna Loa Observatory with a detection limit of 25 pptv. Muecke et al. (K14) used TDLAS to evaluate a less specific enzymic measurement technique for formaldehyde. Hoshika et al. (K15) reported the use of atmospheric pressure ionization mass spectrometry to measure acetone in the 0.010.1 ppmv range. Hydrocarbons: Gas Chromatography. Berkley et al. (L1) reported on field tests of portable GC instruments for ambient VOC measurements. Tang et al. (L2) evaluated a portable GC with a Tenax preconcentration unit. Several papers appeared reporting VOC measurements with GC systems with cryogenic preconcentration. Giarrocco et al. (L3) continuously monitored C2-C10 VOCs in air using cryogenic trapping with capillary-GC/FID analysis. Selia (L4) reported on C2-C12 monitoring with sampling via SUMMA stainless steel canisters, cryogenic preconcentration, and capillary GC. Igari (L5) collected light non-methane hydrocarbons (NMHC) in liquid N2 trap with subsequent purging of O2 with He. The NMHC in the trap were volatilized into a GC for analysis. C2-C9 hydrocarbons were cryogenically trapped and then analyzed by automatic GC (L6, L7). Mowrer et al. (L8) used GC/FID to analyze 7-day diffusive samples of C6-C9 VOCs collected in urban air. Thermal desorption GC techniques were reported for vinyl chloride (L9) and chlorobenzene (L10). Oliver et al. (L11) described an automated GC/MS system to collect and analyze both nonpolar and polar VOCs in ambient air. The system is designed for monitoring subsets of the 97 VOCs among the 189 HAPs listed in the Clean Air Amendments of 1990.
Helmig et al. (L12) used a fully automated GC/MS system to measure 65 VOCs in background air at the Mauna Loa Observatory. Suzuki (L13) determined 26 halogenated VOCs in air by thermal desorption and cold trap GC/MS. Furukawa et al. (L14) determined 1,2-dichloroethane and other compounds in the atmosphere with GC/MS. Orko et al. (L15) described the use of a GC/MS system to chemically identify odorous gases simultaneously with olfactory sensing. Kotsuka and Suzuki (L16) used GC/MS to analyze derivatives of nitrated phenols. In a laboratory evaluation, Simpson et al. (L17) showed GC/ ion mobility spectrometry to be very sensitive for monitoring vinyl chloride and other chlorinated hydrocarbons in ambient air. Amagai et al. (L18) described a simple analytical method for nine volatile organohalogen compounds using a passive sampler and capillary GC with electron capture detection (ECD). Sugama et al. (L19) used GC/ECD to measure low boiling point organic chlorine compounds and CFCs which were collected on activated carbon columns. Elkins et al. (L20) adapted an GC/ECD for use aboard aircraft. CFCs and other halocarbons could be sampled every 360 s. Zapevalov et al. (L21) reported measurements of triethylamine with GC and a selective surface ionization detector. Aromatic amines were determined as their N-dimethylthiophosphoryl derivatives by GC/FPD (L22). Gritsun et al. (L23) reported calibration and measurement techniques for methyl iodide and halocarbons in the atmosphere with capillary-GC. Lagomarsino (L24) discussed an improved capillary-GC technique for determining perfluorocarbon tracers in the atmosphere. Fung et al. (L25) developed and tested a method to measure oxygenated hydrocarbons at ppb levels. The method involves sorbent sampling, extraction, and analysis with two-dimensional GC using intermediate cryogenic trapping and detection with an oxygen-specific detector. Spectroscopy. Camy-Peyret et al. (M1) presented the results of an intercomparison of eight different long-path UV/Vis DOAS instruments measuring NO2, O3, and SO2 concentrations in moderately polluted air. Todd (M2) evaluated the accuracy of an open-path FT-IR spectrometer using an exposure chamber. Russwurm et al. (M3) investigated the quality assurance aspects of FT-IR data using a short cell and high concentrations of gases including the stability of instrument response and the measurement accuracy. Theriault et al. (M4) investigated retrieval methods associated with FT-IR systems. Wu et al. (M5) described field testing an FT-IR spectrometer in a complex source environment. Milton et al. (M6) described approaches for calibration of openpath optical instrumentation that include the calibration of a DIAL measurement system using a cell in which a stable flow of the target gas is maintained. Langford (M7) reported a method to correct analog-to-digital converter nonlinearities in DIAL systems. Petrin et al. (M8) reported on atmospheric effects on CO2 DIAL sensitivity. Robinson et al. (M9) presented a mobile DIAL system, which operates in the UV, visible, and IR spectral regions. Petrov et al. (M10) described developments in the availability of tunable infrared laser sources and their potential application to trace gas measurements. Kita et al. (M11) described the principles and applications of TDLAS for measurement of NO2, HCl, CH4, NH3, H2S, and HF.
The feasibility of intracavity diode laser spectrometry for in situ detection of atmospheric trace gases was presented by Gurlit et al. (M12). Photoacoustic spectroscopy was used to measure pollutant gases (M13, M14). Gordon et al. (M15) reported the use of ion trap MS for direct sampling and analysis of VOCs in air. Pagotto and Sewell (M16) applied subatmospheric negative-pressure ion mass spectrometry for monitoring trace levels of SF6, and C1-C2 CFCs. Meng et al. (M17) monitored indoor ambient atmospheres for VOCs using an ion mobility analyzer array with selective chemical ionization. Leonhardt et al. (M18) determined aromatics with an ion mobility spectrometer using photoionization. AEROSOLS Books and Reviews. Articles in this section are presented in the following order: general reviews, sampling, composition analysis, fibers, and microorganisms. Considerable attention has been directed at single-particle analysis during the last two year period. A new book entitled Airborne Particulate Matter was edited by Kouimtzia and Samara includes several aspects of aerosol characterization (AA1). Jambers et al. (AA2) described the application of several microanalysis techniques to characterize individual environmental particles. Laaksonen et al. (AA3) presented an extensive review of particle nucleation processes including new theories which incorporate information about molecular interactions in a more appropriate manner. Techniques used to count and size particles were reviewed by Hollander (AA4). He also discussed particle size statistics, mobility, and relaxation time sizing and inversion methods. Lilienfeld (AA5) described the development and application of nephelometry to the continuous monitoring of ambient fine particulate matter. Wallace (AA6) presented substantive review of concentrations, sources and measurements of particles in the indoor environment. Sampling of airborne particulate matter was reviewed by Hollaender (AA7). The use of diffusive samplers to assess community air pollution problems was discussed by Brown (AA8). Chemical characterization of aerosols can occur while the particle remains suspended or after collection on a filter medium or impaction surface. Johnston and Wexler (AA9) described recent advances in the development and application of mass spectrometry for on-line, real-time analysis of single aerosol particles including detection, sizing, and laser desorption/ionization. A review of nuclear methods such as neutron activation analysis (NAA), X-ray fluorescence (XRF), and particle-induced X-ray emission (PIXE) and energy-dispersive X-ray fluorescence (EDXRF) described their application for elemental analysis of collected aerosol samples (AA10). The application of PIXE analysis techniques to characterize urban aerosols was reviewed (AA11, AA12). Orlic (AA13) reviewed the application of nuclear microscopy techniques such as electron microprobe and laser microanalysis of single particles. Ise (AA14) reviewed the use of radiological techniques such as β-ray absorption to characterize suspended particulate matter. Samara (AA15) presented a discussion of complexity of determining the organic fraction of particulate matter and the current methodology available for accomplishing the analyses. Analytical Chemistry, Vol. 69, No. 12, June 15, 1997
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Spokes and Jickells (AA16) have reviewed techniques to conduct metal speciation. Kaneko et al. (AA17) reviewed the application of ion-pair reversed-phase partition HPLC for determination of vanadium in aerosols. Sioutas and Koutrakis (AA18) characterized methods for measuring atmospheric acidic particles and gases. They discussed the shortcomings of using filters, the advantages and disadvantages of diffusion denuders, and the use of conventional impactors. Spruny and Moehlmann (AA19) reviewed direct-reading instruments for measure fibers with a length of 2-300 µm and a diameter of 2-20 µm. Madsen et al. (AA20) presented a review covering analytical methods for the qualitative and quantitative determination of crystalline silica in air. Aerosol characterization has developed to include mass, interaction with light, size, metallic, organic, acid components, single-particle analysis and, more recently, microbiological characteristics of aerosols. Two extensive reviews appeared (AA21, AA22) describing the distribution of microorganisms in the outdoor and indoor environments. Valerio (AA23) reviewed specific problems associated with urban polycyclic aromatic hydrocarbon (PAH) sampling, analysis, and data interpretation. Xu et al. (AA24) reviewed the use of GC and HPLC for analysis of PAHs and nitro-PAHs. Particulate Carbon. Carbon can be present in several forms in airborne particulate matter as inorganic carbonates, as elemental carbon such as graphite, and as organic compounds. Several techniques have been developed to distinguish between the latter twoselemental and organic carbonsby using differential volatility and/or pyrolysis techniques. Smith and O’Dowd (BB1) described a high-temperature volatility system based around an optical particle counter and an aethalometer for the direct observation of soot carbon concentrations. The temperature ranges from near ambient to 1000 °C. Nezu (BB2) determined elemental and organic carbon in atmospheric particulate matter by GC-pyrolysis and used the results to assess diesel exhaust pollution and secondary organic aerosol formation. Chan et al. (BB3) modified the Walkley-Black method, a traditional technique used to determine the organic content of soils, to determine the organic and elemental carbon content of urban aerosols collected on glass fiber filters. Petzold and Niessner (BB4) developed a discontinuous coulometric method to determine elemental carbon. They used a combination of solvent extraction and thermal desorption to separate the organic and elemental carbon fractions. They (BB5) also presented a photoacoustic sensing method to monitor black carbon in situ with a detection limit of 0.5 µg/m3. Yordanov et al. (BB6) described the application of EPR spectroscopy the estimation of carbonaceous content of aerosols in urban air samples. Polycyclic Aromatic Hydrocarbons. Articles on PAHs are in the aerosol sections because these compounds are predominantly present in the condensed phase in the atmosphere. Tyagi (CC1) discussed the methodological aspects of measuring PAHs in the urban atmosphere. He discussed different collection media, methods to relate size and composition, the problems of sample collection and cleanup, techniques to quantitative separate various compounds and fractions, and the instrumentation to measure specific PAH components. Doerr et al. (CC2) described a wind directional sampling system for monitoring PCDD/F levels. Menichini and Monfredini (CC3) reported the results of a field comparison of “total suspended particles” 6R
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and “PM10” samplers in collection of PAHs. The PM10 sampler concentrations were on average 73%-93% of those provided by the high-volume TSP sampler. Hawthorne et al. (CC4) reported on the use of polyurethane foam (PUF) and quartz fiber filters to determine the vapor-phase and particulate-phase fractions of pesticides and PCB concentrations in rural air. Watanabe (CC5) investigated the stability and recovery characteristics associated with the use of silica gel columns to sample 38 pesticides. Kiss et al. (CC6) used Sep-Pak C18 cartridges to determine PAHs in precipitation. The role of cartridge preconditioning, addition of organic modifiers, flow rate, concentration, drying, and different organic extraction solvents was investigated. Butterfield et al. (CC7) described the use of solid β-cyclodextrin as a collection medium for extracting PAHs from air. Measurement of PAHs generally involves collection of vaporand/or particle-phase samples, followed by extraction and partitioning or fractionation; then most often a chromatographic separation occurs with fluorescence or mass spectrometry used as the detection system. Xu et al. (CC8) studied the chromatographic behavior of 130 polychorinated biphenyl (PCB) congeners to develop routine environmental analytical methods. GC/MS techniques were used to measure PAHs in the studies which follow. These studies differed in the sample preparation phase. Allen et al. (CC9) used a microorifice impactor to sizesegregate PAHs with molecular weights between 178 and 302. They reported on distribution differences in urban and rural samples. Garcia et al. (CC10) used Carbosphere activated carbon to collect and analyze for nonortho- and monoortho-PCBs. Kawata et al. (CC11) used quartz fiber filters and activated carbon fiber filters to determine pesticides in air. Matz et al. (CC12) used a thermodesorbable silicone-coated glass fiber filter to collect PCBs in air. The use of short GC columns permitted a rapid determination (∼10 min) of a sum parameter for PCBs. Three articles reported the use of quartz fiber filters for collection of PAHs (CC13-CC15). Two research groups investigated the gas-phase and condensed-phase characteristics of PAHs. Dai et al. (CC16) used glass fiber filters for condensed-phase sampling and Tenax-GC for gas-phase sampling. Eskinja et al. (CC17) used glass fiber filters for condensed-phase sampling and XAD-2 for gas-phase sampling. Hachimi et al. (CC18) characterized nitro-PAHs by using a combination of laser microprobe mass analysis, Fourier transform mass spectrometry, and GC/tandem mass spectrometry. Agnesod et al. (CC19) compared off-line sampling and analysis techniques and an automatic photoelectric aerosol sensor to determine PAHs in airborne particulate matter. Comparison of the results showed a satisfactory linearity. Giam et al. (CC20) reported on the use of an ion mobility spectrometer to monitor “priority pollutants” including PAHs. They presented response results for several PAHs, PCBs and pesticides. Campiglia and Vo-Dinh (CC21) developed a fiber-optic sensor for PAHs based on laser-induced room-temperature phosphorimetry. A pulsed nitrogen laser was used to excite phosphorescence emission from compounds on filter paper substrates. Shpol’skii spectroscopy, a high-resolution cryogenic molecular luminescence technique, has been evaluated for identification of PAHs. Two groups presented data on specific vibrationally resolved spectra for PAHs (CC22, CC23).
Gui and Berdahl (CC24) reported on a rapid field technique for PCBs based on a chemiluminescence immunoassays. Multielement Analysis. Several articles reported various extraction or digestion techniques for sample preparation. Wang et al. (DD1, DD2) investigated closed-vessel acid digestion methods to extract aerosols collected on glass fiber filters in preparation for analysis by inductively coupled plasma-atomic emission spectroscopy (ICP-AES) and AAS. Mateu et al. (DD3) investigated various combinations of filter media, extraction, and analysis techniques to determine inorganic species (heavy metals, light metals, anions, ammonium ion). Hlavay et al. (DD4) applied a three-stage sequential leaching procedure to identify the distribution of aerosol trace elements into environmentally mobile, carbonate and oxide associated, and environmentally immobile fractions. Atomic absorption spectrometry is a versatile method for multielemental analysis. Almeida and Lima (DD5) described a method for Cd, Cr, Cu, Ni, and Pb trapped on cellulose acetate filters. Electrothermal atomization AAS was used for the direct analysis of filter samples. Dong et al. (DD6) used AAS for a combination of metals in airborne particulate samples. Lee et al. (DD7) evaluated an impaction-graphite furnace AAS system to determine metals in aerosols. Zeeman AAS with absorption pulse restoration was used to measure Cd, Cu, Mn, and Pb in atmospheric aerosols (DD8). AAS techniques were used to measure Se (DD9), Pb (DD10), and Hg (DD11). Kimbrough et al. (DD12) reported on use of ICP-AES to analyze for 16 toxic elements (As, Ag, Ba, Be, Cd, Co, Cr, Cu, Mo, Ni, Pb, Sb, Se Tl, V, Zn) from acid digestion extracts of glass fiber filters. Baldwin et al. (DD13) determined the presence of 19 metals in airborne aerosols with ICP-AES. Tilch et al. (DD14) used a combination of laser-excited atomic fluorescence spectroscopy and ICP-mass spectrometry to determine Pb, Pd, and Tl in aerosol samples. Proton-induced X-ray emission spectroscopy has become a widely used analytical method to determine a number of elements in aerosol samples. Waetjen and Cave (DD15) reported the development of a complete procedure for calibration and quality control in PIXE analysis. They are developing a standard reference material (SRM) for use with PIXE analysis of aerosol samples. Cahill (DD16) discussed the application of PIXE spectrometry for compositional analysis of atmospheric aerosols including complementary techniques, nature of atmospheric aerosols, and particle removal rates for atmospheric aerosols. Swietlicki et al. (DD17) describe the possible evolution of PIXE spectroscopy in combination with ion beam analytical techniques to provide for an almost complete characterization of the atmospheric aerosol. Hietel et al. (DD18) have developed a dual-energy technique for rapid PIXE analysis of aerosol samples covering elements with atomic numbers down to Z ) 13. Nejedly et al. (DD19) reported on an intercomparison of four multielement methods for rural aerosol samples including PIXE, proton elastic scattering analysis (PESA), EDXRF, and IC. Schiavuta (DD20) applied PIXE to the analysis of samples associated with the air-sea interface. In order to obtain time resolution for aerosol composition, samplers have been developed that can deposit aerosol particles at different locations on the collection surface. These samplers are referred to as streakers. PIXE has sufficient sensitivity to be able to analyze a small quantity of deposited aerosol. Annegarn
et al. (DD21) described the modification of a streaker sampler for sampling from aircraft platforms. PIXE multielement analysis has been applied to aerosol characterization in Milan (DD22, DD23), Hungary (DD24), and with cascade impactor sampling in Vienna (DD25). Mentes et al. (DD26) describes the combination of ion beam thermography with PIXE, PESA, pNRA, and cPESA to obtain elemental analysis of aerosol samples. The ion beam gradually heats the sample to 600 °C, vaporizing chemical compounds at specific temperatures. Nakamura (DD27) used neutron activation analysis (NAA) to investigate the collection efficiency of volatile heavy metal compounds. Beigalski et al. (DD28) applied short-lived NAA to aerosol samples utilizing a loss-free counting system. Boix et al. (DD29) used SEM/EDX to analyze atmospheric aerosol samples collected in a coastal area subject to emissions from urban and industrial activities. Schaefer et al. (DD30) compared two different approaches to calibrate an EDXRF spectrometer using standards obtained from an aerosol generator or liquid droplets. Leenanupan and Srichom (DD31) described the use of EDXRF along with determination of enrichment factors and quality assurance and detection limits. Ando et al. (DD32) describe preparation of standard reference materials for XRF systems used for aerosol analysis. Haupt et al. (DD33) described the results of XRF calibration materials prepared on membrane and quartz filters. Applications using XRF to conduct multielement analysis appeared (DD34, DD35). Santos et al. (DD36) reported on the use of X-ray diffraction to characterize crystalline species present in atmospheric particulate matter. Esteve et al. (DD37) used X-ray diffraction to analyze cascade impactor samples. Schelles et al. (DD38) described the use of dc glow discharge mass spectrometry to analyze particles collected on a single-orifice impactor stage. Asbestos. Schlecht et al. (EE1) evaluated phase contrast microscopic asbestos fiber-counting performance over a 20-year Proficiency Analysis Testing (PAT) program. Skogstad et al. (EE2) described the preparation of 10 replicate filter samples with asbestos fibers using an exposure chamber. Turner and Steel (EE3) described the development of a high-precision set of counting rules for counting asbestos collected on filters. Olcerst (EE4) developed a statistical approach to determine the analytical limit of detection which demonstrates the importance of collecting and analyzing a sufficient number of field blanks. Kohyama and Kurimori (EE5) developed a sample preparation method for measuring airborne asbestos by optical or electron microscopy that utilizes one membrane filter. McIntosh and Searl (EE6) reported on the importance of fiber orientation and inclination when using scanning electron microscopy (SEM) to size fibers. Transmission electron microscopy (TEM) is also used to assess airborne asbestos fibers. Kauffer et al. (EE7) evaluated the conditions where direct and indirect sample preparation were appropriate and how the use of ultrasonics effects the sample. Sahle and Laszlo (EE8) also compared the direct and indirect sample-transfer methods and preferred the direct method. Kauffer et al. (EE9) propose a new sampling head, based on the collection of the thoracic fraction, for collection of asbestos fibers. Single-Particle Analysis. Sha et al. (FF1) described three different methods for preparing samples of single particles for analysis by nuclear microprobe. Maynard (FF2) developed a Analytical Chemistry, Vol. 69, No. 12, June 15, 1997
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thermophoretic precipitator for SEM analysis of ultrafine aerosol particles. The deposits on the support girds gave discrete deposits suitable for single-particle analysis. Sakamoto et al. (FF3) combined electron microprobe analysis with secondary ion mass spectrometry to obtain average composition as well as the compositional distribution with depth. Anderson et al. (FF4) used INAA and electron microprobe analysis to characterize marine aerosols. Van Malderen et al. (FF5) used X-ray microprobe techniques to determine Cr, Pb, and Zn in marine aerosols. An energy-dispersive x-ray spectrometer linked to a transmission electron microscope was used to analyze single particles (FF6). McMurry et al. (FF7) used a tandem differential mobility analyzer to separate particles by size and hygroscopicity. Particles collected by a specially designed impactor were then analyzed with a scanning TEM equipped with an EDAX detector. Hara et al. (FF8) used laser microprobe mass spectrometry (LAMMS) to measure the composition of individual aerosol particles collected in the Antarctic. Tourmann et al. (FF9) used laser desorption/ionization in combination with mass spectrometry to investigate the toxicological and environmental relevance of single-particle analyses. Yang et al. (FF10) described how two fiber-optic-based particle detectors mounted above an ion trap mass spectrometer can be used to analyze individual airborne particles. Bentz and co-workers (FF11, FF12) used plasma-based secondary neutral mass spectrometry (SNMS) to perform a depthresolved elemental analysis of aerosol particles. SNMS was used for analysis in which sample material is eroded layerwise by ion bombardment. Kievit et al. (FF13) described an instrument to count and size particles by optical methods and a time-of-flight mass spectrometer (TOF-MS) to analyze single particles. Bentz et al. (FF14) used a TOF secondary ion MS instrument to analyze individual particles collected in a rural area in Europe. Laser desorption/ionization TOF-MS was applied to individual particles by Noble and Prather (FF15) and Wexler and co-workers (FF16-FF18). The use of ICPMS for individual airborne particle analysis was reported (FF19, FF20). Lidar. Moosmuller and Wilkerson (GG1) developed a lidar method for the quantitative measurement of atmospheric backscatter ratio profiles. Their techniques help disentangle to aerosol and molecular contributions to lidar returns. Balin and Rasenkov (GG2) described a scanning single-frequency aerosol lidar which can be used to monitor the spatiotemporal distribution of aerosol plumes. Chaikovsky et al. (GG3) reported the use of lidar to monitor industrial plumes. Pershin (GG4) developed and tested a relatively simple eye-safe compact GaAlAs lidar for in/out door detecting of aerosol/dust pollution layers and measuring its range and height. Calibration/Standard Reference Materials. Esche and Groff (HH1) described a proficiency analytical testing program where standard samples for metals, fibers, and/or solvents are provided to laboratories to establish the analytical performance. Stankiewicz et al. (HH2) reported on the preparation of environmental thin-layer reference materials of urban particulate matter on filter media. Scalera (HH3) described the U.S. Environmental Protection Agency’s lead laboratory accreditation program to assure that laboratories are capable of determining Pb in paint chips, dust, and soil samples. Binstock et al. (HH4) described the preparation and evaluation of Pb-contaminated dust method evaluation materi8R
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als. Peters and Hurley (HH5) described the American Industrial Hygiene Association’s environmental lead laboratory accreditation program. Chein and Lundgren (HH6) designed, fabricated, and tested an aerosol generator capable of generating a narrow sizedistribution aerosol with high mass concentrations. Aerosols generated from a sodium chloride solution were found to have a mass median aerodynamic diameter in the range from about 1 to 10 µm and geometric standard deviation varying from 1.18 to 1.46. Horodecki and Fissan (HH7) compared three methods to calibrate tapered element oscillating microbalances for determining particle mass concentrations in gases. Single-Stage/Multistage Collection. Gartz et al. (JJ1) presented a theoretical model for calculation of losses of aerosol particles in air sampling tubes with turbulent flow. Muyshondt et al. (JJ2) measured particle deposition in contraction fittings. The aerosol particle deposition in the contraction fitting was also modeled numerically, and the results show good agreement with the experimental data. Romay et al. (JJ3) investigated the effects of probe electrification on the efficiency of the sampling of particles from air moving at relatively high wind speeds. Endo et al. (JJ4) studied the effect of charging and neutralization on the mobility distribution of nanometer-sized particles. Szulikowski and Kateusz (JJ5, JJ6) developed a particle sampler with automatic adjustment of isokinetic conditions. Vinzents (JJ7) described a passive sampler for personal particle sampling which uses sticky foil surfaces. Mage (JJ8) developed an empirical relationship among the British smoke measurement, coefficient of haze, and total suspended particulate mass. Moseholm et al. (JJ9) compared the performance of the former Soviet Union airborne dust sampler with the U.S. high-volume (TSP) sampler. Maenhaut et al. (JJ10) described the modification of a PM10 sampler that permits collection of two size fractions: “coarse” (2-10 µm) and “fine” (
