Scrubber

A micro-gas analysis system, μGAS, is proposed here for the continuous and highly sensitive on-site measurement of atmospheric trace gases. The μGAS presented here is comprised of a microchannel scrubber and a high-sensitivity small fluorescence detector. The key to the μGAS is the fabrication of a good gas permeable membrane on a shallow channel to allow for the efficient accumulation of the analyte into the absorbing solution. The channel is formed by micromachining, and a gas permeable membrane of any desired thickness is formed by spin-coating on a fluorosilane-treated substrate. In this work, polydimethylsiloxane was used for both the channel block and the gas permeable membrane, and were easily tightly bonded. The microchannel structure ensures a high sensitivity, and the sensitivity is inversely proportional to the membrane thickness. The device, including the air supply function, is set in only 30-mm-cube. The performance of the μGAS has been demonstrated as a H2S gas sensor. The μGAS consumes only 1ml of the reagent solution in 8h of operation with a detection limit of 1ppbv.

RESUMEN Debido a sus efectos nocivos, el abatimiento de las emisiones de contaminantes gaseosos adquiere una importancia cada día mayor. Con el objeto de disminuir la emisión de los mismos, se diseñó y construyó un tren de lavado de gases provenientes de un incinerador de residuos sólidos instalado en el Parque Industrial de la Provincia de San Juan, Argentina. Dicho tren de lavado está compuesto por un enfriador y un equipo lavador de gases, tipo spray. El enfriador cumple una doble función; por un lado enfría los gases hasta la temperatura necesaria para que se produzcan las reacciones de absorción de contaminantes en el lavador, y por otro, se produce una absorción parcial de gases ácidos (como: HCl, HF y SO 2 ) y eliminación parcial de cenizas volantes. La corriente gaseosa ingresa a la torre de lavado por la parte inferior de la columna mientras que una solución alcalina ingresa por la parte superior, siendo distribuida uniformemente por un banco de rociadores. La altura de la columna asegura la eliminación de los contaminantes gaseosos ácidos, hasta cumplir con las normativas vigentes. La solución alcalina usada es una solución de NaHCO 3 , debido a que las sales sódicas presentan mayor solubilidad, reactividad y rendimiento; además los productos de las reacciones presentan alta solubilidad facilitando su tratamiento posterior. Los resultados obtenidos en el monitoreo realizado por la Subsecretaría de Medio Ambiente dependiente del Gobierno Provincial indican un eficiente funcionamiento del equipo diseñado.

This paper will explore Amager Bakke, focusing first on the process by which the plant generates energy from waste combustion. This will provide the  context to then delve into the contaminant removal process, a discussion that will cover the relevance of the possible emissions, and by extension, the implications for the air quality in the surrounding communities. Subsequently, a more detailed walk-through of the hypothetical design of such a system will provide a more complete understanding of contaminant removal from the effluent waste stream (flue gas). This will include an analysis of the cost and implications of such a system. Finally, the paper will conclude with a review of the ethical principles surrounding waste-to-energy plants, including responsible parties, ethical dilemmas, and measures to prevent malpractice.

Scrubber dapat di definisikan sebagai alat pemisahan suatu partikel solid (debu) yang ada di gas atau udara dengan menggunakan cairan sebagai alat bantu. Air adalah cairan yang pada umumnya digunakan dalam proses scrubbing, meskipun dapat juga digunakan cairan lainnya (seperti : asam sulfat, dll). Pada umumnya, scrubber mampu menghasilkan partikel dengan ukuran 5 µ diameter.

Experimental studies on diesel fume scrubbing have been conducted in a down-flow type liquid-jet ejector-venturi scrubber. The fume particulates have been captured in the throat of the ejector-venturi by a mechanism involving inertial impaction and impingement. The effect of nozzle geometry and the motive fluid flow rates on the suction created and the volumetric fume aspiration rates have been analyzed, in order to select the optimum nozzle geometry. Using the optimum nozzle geometry the efficiency of fume collection has been experimentally investigated as function of various hydrodynamic parameters. A theoretical analysis has been performed to interpret the experimental findings and determination of nozzle loss coefficients.

Massive quantities of sulfite-rich flue gas desulfurization (FGD) scrubber sludge have been generated by coal burning power plants. Utilization of the sulfite-rich sludge for preparing a-calcium sulfate hemihydrate (a-HH), an important kind of cementitious material, is of particular interest to electric utilities and environmental preservation. In the experiment, calcium sulfite hemihydrate was directly transformed to a-HH without the occurrence of calcium sulfate dihydrate (DH). The transformation was performed in a concentrated CaCl 2 solution containing Mg 2+ and Mn 2+ at 95°C, atmospheric pressure and low pH. The oxidation of calcium sulfite and the subsequent crystallization of a-HH constitute the whole conversion, during which the oxidation turns out to be the rate controlling step. Solid solution comprised of calcium sulfite hemihydrate and calcium sulfate was found to coexist with a-HH in the suspension. Calcium sulfate increases and calcium sulfite decreases spontaneously until the solid solution disappears. Thus, it is a potential alternative to utilize sulfite-rich FGD scrubber sludge for the direct preparation of a-HH.

Experimental studies on diesel fume scrubbing have been conducted in a down-flow type liquid-jet ejector-venturi scrubber. The fume particulates have been captured in the throat of the ejector-venturi by a mechanism involving inertial impaction and impingement. The effect of nozzle geometry and the motive fluid flow rates on the suction created and the volumetric fume aspiration rates have been analyzed, in order to select the optimum nozzle geometry. Using the optimum nozzle geometry the efficiency of fume collection has been experimentally investigated as function of various hydrodynamic parameters. A theoretical analysis has been performed to interpret the experimental findings and determination of nozzle loss coefficients.

Biogas production is one of the most promising pathways toward fully utilizing green energy within a circular economy. The anaerobic digestion process is the industry standard technology for biogas production due to its lowered energy consumption and its reliance on microbiology. Even in such an environmental-friendly process, liquid digestate is still produced from the remains of digested bio-feedstock and will require treatment. With unsuitable treatment procedure for liquid digestate, the mass of bio-feedstock can potentially escape the circular supply chain within the economy. This paper recommends the implementation of evaporator systems to provide a sustainable liquid digestate treating mechanism within the economy. Studied evaporator systems are represented by vacuum evaporation in combination with ammonia scrubber, stripping and reverse osmosis. Nevertheless, complex multi-dimensional decisions should be made by stakeholders before implementing such systems. Our work utilizes a novel techno-economics model to study the techno-economics robustness in implementing recent state-of-art vacuum evaporation systems with exploitation of waste heat from combined heat and power (CHP) units in biogas plants (BGP). To take into the account the stochasticity of the real world and robustness of the analysis, we used the Monte-Carlo simulation technique to generate more than 20,000 of different possibilities for the implementation of the evaporation system. Favourable decision pathways are then selected using a novel methodology which utilizes the artificial neural network and a hyper-optimized decision tree classifier. Two pathways that give the highest probability of providing a fast payback period are identified. Descriptive statistics are also used to analyse the distributions of decision parameters that lead to success in implementing the evaporator system. The results highlighted that integration of evaporation system are favourable when transport costs and incentives for CHP units are large and while feed-in tariffs for electricity production and specific investment costs are low. The result of this work is expected to pave the way for BGP stakeholders and decision makers in implementing liquid digestate treating technologies within the currently existing infrastructure.

This study investigated a gas chromatographic (GC) method to assess the destruction or removal efficiency (DRE) of local scrubbers on five perfluorocompounds (PFCs), i.e., SF 6 , NF 3 , CF 4 , C 2 F 6 , and C 3 F 8 , which are very potent greenhouse gases used in a semiconductor fabrication plant. Air samples taken at inlets and outlets of local scrubbers were analyzed by a self-constructed multi-column GC system equipped with thermal conductivity detection. Three packed columns were integrated into the heart-cut GC system to allow simultaneous analysis of the five target PFCs. The Porapak Q pre-column performs rough separation and cuts eluent groups to two analytical columns for optimal separation. The Molecular Sieve -5A column separated NF 3 , CF 4 , and C 3 F 8 and the second Porapak Q separated SF 6 and C 2 F 6 . Linearity was greater than 0.995 (R 2 ) for the five PFCs, and the reproducibility was about 4% (relative standard deviation) for NF 3 , and better than 0.5% for the other four PFCs.

The result of pumping air containing 56 ppb NO 2 through a terpene-spiked adsorbent (90-130 ng, 90-100 ml min À1 ), Tenax TA, for 20 min (1.8-2.0 l) was that 8% of a-pinene, 7% of b-pinene, 21% of D 3 -carene and 5% of limonene were oxidised. In similar experiments with air containing 56 ppb O 3 , 3% of a-pinene, 4% of b-pinene, 10% of D 3 -carene and 38% of limonene were oxidised. Sampling a mixture of a terpene and NO 2 using Tenax TA can give unwanted overestimation of the amount of reaction products from the terpene-NO 2 reaction or underestimation of the original terpene levels. A scrubber was needed to reduce the problems caused by interfering reactions on the adsorbent of NO 2 and to reduce discrimination of reactive compounds due to their relatively fast decay on the adsorbent. Several chemicals have been tested for their ability of removing NO 2 and our objective was to develop a well functioning, reusable, easy to handle, easy manufactured NO 2 scrubber. The result of the experiments was a scrubber consisting of two glass fibre filters coated with Na 2 SO 3 assembled in a dust collector. The recovery of the terpenes through the scrubber varied between 75% and 97% at 15-75% relative humidity, and the scrubber is a one-use scrubber due to memory effects. The Na 2 SO 3 scrubber could be stored in room air for at least one month without loosing the capacity of removing NO 2 . r

This investigation was to test different blends of tertiary amine; triethanolamine (TEA) into primary amine; Monoethanolamine (MEA) used to capture CO2 in packed bed scrubber with recycle stream. Four different operating parameters: Amine Combination (A), Dilution Water (B), Liquid Flow rate (C), and Gas Flow rate (D) were varied to study the behavior of the system. Moreover, Taguchi method was employed to establish the order of importance of different parameters in the process. A 4 factor and 3 level was chosen for the study and it was explored using L9 (3 4) orthogonal array design. According to 3-level design 0%, 20% and 30% were chosen for A, 10%, 20% and 30% for B

Debido a sus efectos nocivos, el abatimiento de las emisiones de contaminantes gaseosos adquiere una importancia cada día mayor. Con el objeto de disminuir la emisión de los mismos, se diseñó y construyó un tren de lavado de gases provenientes de un incinerador de residuos sólidos instalado en el Parque Industrial de la Provincia de San Juan, Argentina. Dicho tren de lavado está compuesto por un enfriador y un equipo lavador de gases, tipo spray. El enfriador cumple una doble función; por un lado enfría los gases hasta la temperatura necesaria para que se produzcan las reacciones de absorción de contaminantes en el lavador, y por otro, se produce una absorción parcial de gases ácidos (como: HCl, HF y SO 2 ) y eliminación parcial de cenizas volantes. La corriente gaseosa ingresa a la torre de lavado por la parte inferior de la columna mientras que una solución alcalina ingresa por la parte superior, siendo distribuida uniformemente por un banco de rociadores. La altura de la columna asegura la eliminación de los contaminantes gaseosos ácidos, hasta cumplir con las normativas vigentes. La solución alcalina usada es una solución de NaHCO 3 , debido a que las sales sódicas presentan mayor solubilidad, reactividad y rendimiento; además los productos de las reacciones presentan alta solubilidad facilitando su tratamiento posterior. Los resultados obtenidos en el monitoreo realizado por la Subsecretaría de Medio Ambiente dependiente del Gobierno Provincial indican un eficiente funcionamiento del equipo diseñado. Palabras claves: Incineración, enfriamiento, lavador de gases, absorción de SO 2 , control de polución de aire.

The main part of this paper is an industrial case study. It deals with an application of a heat pump in energy systems for biomass gasification in a wood processing plant. Process Integration methodology is applied to deal with complex design interactions as many streams requiring heating and cooling are involved in the energy recovery. A refrigeration cycle maintains low temperature in the scrubber where the production gas (or synthesis gassyngas) is cooled and undesirable contaminants are removed before the syngas is introduced into the engine. In addition to electricity generation, a large amount of waste heat is available in the biomass gasification system studied in the paper, and its appropriate heat integration with utility systems within a plant allows the available heat to be efficiently utilized for the site. The conceptual understanding gained from the case study provides systematic design guidelines for further process development and industrial implementation in practice

Massive quantities of sulfite-rich flue gas desulfurization (FGD) scrubber sludge have been generated by coal burning power plants. Utilization of the sulfite-rich sludge for preparing a-calcium sulfate hemihydrate (a-HH), an important kind of cementitious material, is of particular interest to electric utilities and environmental preservation. In the experiment, calcium sulfite hemihydrate was directly transformed to a-HH without the occurrence of calcium sulfate dihydrate (DH). The transformation was performed in a concentrated CaCl 2 solution containing Mg 2+ and Mn 2+ at 95°C, atmospheric pressure and low pH. The oxidation of calcium sulfite and the subsequent crystallization of a-HH constitute the whole conversion, during which the oxidation turns out to be the rate controlling step. Solid solution comprised of calcium sulfite hemihydrate and calcium sulfate was found to coexist with a-HH in the suspension. Calcium sulfate increases and calcium sulfite decreases spontaneously until the solid solution disappears. Thus, it is a potential alternative to utilize sulfite-rich FGD scrubber sludge for the direct preparation of a-HH.

The link between anthropogenic emissions of carbon dioxide, increasing atmospheric CO 2 levels, and concomitantly increasing global temperatures is established and accepted. The use of aqueous ammonia, to capture CO 2 and produce an inexpensive nitrogen fertilizer, ammonium bicarbonate (ABC), is believed to be a feasible approach to CO 2 sequestration. Due to the varying concentrations of reactants and varying reaction conditions, different ammonia-carbon compounds may be produced. ABC is the ideal product for maximizing NH 3 utilization in CO 2 capture; therefore, identification and quantification of ABC in the reaction products is mandatory. Various analytical techniques were used to distinguish and quantify the ABC. Fourier transform infrared spectroscopy can only be used to distinguish ammonium carbamate, and. X-ray diffraction can be used to qualitatively distinguish ABC from the other possible products of the CO 2 capture reaction. Carbon-hydrogen-nitrogen elemental analysis and near-infrared (NIR) spectroscopy were used to quantify ABC, with both techniques giving (5% agreement for ABC concentrations for 8 of 13 samples from a benchscale aqueous ammonia CO 2 scrubbing system. An additional 3 of the 13 samples were within (12%. Results indicate that NIR will be an ideal tool for real-time, online measurements of ABC in a full-scale aqueous ammonia CO 2 scrubber. The ABC in 11 samples from the bench-scale scrubber at Western Kentucky University was determined by these techniques and assessed to have very good quality as a fertilizer in accordance with GB-3559-92, the Agricultural Ammonium Bicarbonate National Standard of China.

Partitioning of PCDD/F congeners between vapor/solid phases and removal and destruction efficiencies achieved with selective catalytic reduction (SCR) system for PCDD/Fs at an existing municipal waste incinerator (MWI) and metal smelting plant (MSP) in Taiwan are evaluated via stack sampling and analysis. The MWI investigated is equipped with electrostatic precipitators (EP, operating temperature: 230°C), wet scrubbers (WS, operating temperature: 70°C) and SCR (operating temperature: 220°C) as major air pollution control devices (APCDs). PCDD/F concentration measured at stack gas of the MWI investigated is 0.728 ng-TEQ/Nm 3. The removal efficiency of WS + SCR system for PCDD/Fs reaches 93% in the MWI investigated. The MSP investigated is equipped with EP (operating temperature: 240°C) and SCR (operating temperature: 290°C) as APCDs. The flue gas sampling results also indicate that PCDD/ F concentration treated with SCR is 1.35 ng-TEQ/Nm 3. The SCR system adopted in MSP can remove 52.3% PCDD/Fs from flue gases (SCR operating temperature: 290°C, Gas flow rate: 660 kN m 3 /h). In addition, the distributions of PCDD/F congeners observed in the flue gases of the MWI and MSP investigated are significantly different. This study also indicates that the PCDD/F congeners measured in the flue gases of those two facilities are mostly distributed in vapor phase prior to the SCR system and shift to solid phase (vapor-phase PCDD/Fs are effectively decomposed) after being treated with catalyst. Besides, the results also indicate that with SCR highly chlorinated PCDD/F congeners can be transformed to lowly chlorinated PCDD/F congeners probably by dechlorination, while the removal efficiencies of vapor-phase PCDD/Fs increase with increasing chlorination.

The use of high-sulfur coal for power generation in the United States requires the removal of sulfur dioxide (SO 2) produced during burning in order to meet clean air regulations. If SO 2 is removed from the flue gas using a wet scrubber without forced air oxidation, much of the S product created will be sulfite (SO 3 2-). Plants only take up S in the form of sulfate (SO 4 2-), and SO 3 2is toxic to plants and may cause damage to plant roots. For agricultural uses, SO 3 2in flue gas desulfurization (FGD) products must oxidize to SO 4 2in soils before crops are planted. However, there is little information about the oxidation of SO 3 2in FGD product to SO 4 2under field conditions. An FGD-CaSO 3 obtained from American Electric Power Company was applied at rates of 0, 1.12 and 3.36 Mg ha-1 to the surface of an agricultural soil (Wooster silt loam, Oxyaquic Fragiudalf). The SO 4 2in the surface soil (0-10 cm) was analyzed on days 3, 7, 17, 45, and 61. The distribution of SO 4 2and Ca in the 0-90 cm soil layer was also determined on day 61. Results indicated that SO 3 2in the FGD-CaSO 3 rapidly oxidized to SO 4 2on the field surface during the first week and much of SO 4 2and Ca moved downward into the 0-50 cm soil layer during the experimental period of two months. It is safe for plants if FGD-CaSO 3 is applied to the field surface one month before planting. However, application too long before planting might cause some of the S and Ca for plant uptake to be lost due to leaching or other soil processes.

The paper reports on global release and mass partitioning in the flux of residues of PCDD/Fs, evaluated with dedicated field campaigns at a municipal solid waste incineration plant during normal and transient operation. Results are compared with those obtained in other installations equipped with furnaces, energy recovery options and flue gas treatment technologies representative of most of the European incineration plants currently in operation. Levels of the pollutants of interest were determined in all the solid, liquid and gaseous residues produced by every single facility, and the results analysed in terms of the effects arising from the fed waste and the configuration of the plant. PCDD/Fs total release between 1.5 and 45 lg I-TEQ per ton of burned waste was evaluated, with lower values resulting from the adoption of catalytic conversion process for flue gas treatment. Most of the mass flux emitted is associated with solid residues deriving from activated carbon PCCD/F dry removal options, with significant contributions also from fly ash produced by particulate removal devices located immediately downstream the boiler and from scrubber blowdowns treatment sludge. During transient operating conditions the dioxin total release may increase by 50% with comparison to steady-state functioning.

It is a well-known fact that the Marine Environment Protection Committee (MEPC) confirmed that the sulfur content in marine fuel should be at least 0.5% by January 1, 2020. Thus, shipowners have two options: to install air treatment devices on their ships or use fuel with low sulfur content.
So what is better - the installation of scrubber systems or the use of LS fuel (with 0.5% sulfur content)?

Nowadays, a great effort has been applied into the research of pollution control devices in order to reduce the effect of gaseous emissions to the atmosphere. Amongst the various methods, the venturi scrubber is one of the most efficient processes used for removing dust particles. In this study, droplet dispersion in a large scale circular venturi scrubber, operating horizontally, was examined both theoretically and experimentally. A venturi scrubber was built consisting of a converging section 230 mm long, a throat of 300 mm in length and a diverging section 740 mm in length. The gas velocity at the throat was 34 to 70 m/s, and the liquid flow rate was set between 0.013 and 0.075 kg/s. The water is injected just upstream of the venturi and subsequently atomized into droplets of different sizes due to the influence of the turbulent gas stream. Several empirical probability distribution functions have been used to describe the spray distribution. The Rosin-Rammler function, one of the most common distributions, is suited to describe the droplet population. This is handled at each step along the venturi as a distribution of 16 size classes, whose characteristics are based on experimental data. Comparisons between the experimental data and the calculated droplet size are presented.

Hydrogen sulfide (H 2 S) is currently removed from gaseous effluents by chemical scrubbing using water. Chlorine is a top-grade oxidant, reacting with H 2 S with a fast kinetic rate and enhancing its mass transfer rate. To design, optimize and scale-up scrubbers, knowledge of the reaction kinetics and mechanism is requested. This study investigates the H 2 S oxidation rate by reactive absorption in a mechanically agitated gas-liquid reactor. Mass transfer (gas and liquid sides mass transfer coefficients) and hydrodynamic (interfacial area) performances of the gas-liquid reactor were measured using appropriated physical or chemical absorption methods. The accuracy of these parameters was checked by modeling the H 2 S absorption in water without oxidant. A sensitivity analysis confirmed the robustness of the model. Finally, reactive absorption of H 2 S in chlorine solution for acidic or circumneutral pH allowed to investigate the kinetics of reaction. The overall oxidation mechanism could be described assuming that H 2 S is oxidized irreversibly by both hypochlorite anion ClO-(k = 6.75 10 6 L mol-1 s-1) and hypochlorous acid ClOH (k = 1.62 10 5 L mol-1 s-1).

Debido a sus efectos nocivos, el abatimiento de las emisiones de contaminantes gaseosos adquiere una importancia cada día mayor. Con el objeto de disminuir la emisión de los mismos, se diseñó y construyó un tren de lavado de gases provenientes de un incinerador de residuos sólidos instalado en el Parque Industrial de la Provincia de San Juan, Argentina. Dicho tren de lavado está compuesto por un enfriador y un equipo lavador de gases, tipo spray. El enfriador cumple una doble función; por un lado enfría los gases hasta la temperatura necesaria para que se produzcan las reacciones de absorción de contaminantes en el lavador, y por otro, se produce una absorción parcial de gases ácidos (como: HCl, HF y SO 2 ) y eliminación parcial de cenizas volantes. La corriente gaseosa ingresa a la torre de lavado por la parte inferior de la columna mientras que una solución alcalina ingresa por la parte superior, siendo distribuida uniformemente por un banco de rociadores. La altura de la columna asegura la eliminación de los contaminantes gaseosos ácidos, hasta cumplir con las normativas vigentes. La solución alcalina usada es una solución de NaHCO 3 , debido a que las sales sódicas presentan mayor solubilidad, reactividad y rendimiento; además los productos de las reacciones presentan alta solubilidad facilitando su tratamiento posterior. Los resultados obtenidos en el monitoreo realizado por la Subsecretaría de Medio Ambiente dependiente del Gobierno Provincial indican un eficiente funcionamiento del equipo diseñado. Palabras claves: Incineración, enfriamiento, lavador de gases, absorción de SO 2 , control de polución de aire.

h i g h l i g h t s 2 Mesh pads in scrubber using Natural gas and N 2 /Exxsol at 20, 50 and 85 bars. Pressure drop, separation efficiency, separated droplet size and flooding point. Re-entrainment affects separation efficiencies at high pressures. Droplets deposit via inertial impaction for the N 2 /Exxsol fluid systems. Droplets deposit by direct interception for Natural gas systems.

A diffusion scrubber based automated instrument measures HONO utilizing ion chromatography and UV detection with time resolutions of 7-15 min and a detection limit of ca. 20 pptv. The thermodynamic equilibrium of NH3(g) and HONO(g) over NH4N02(s) can be described by In (pHONO, atm) =-8018 f 84/T + 16.81 f 0.30 and provides a convenient and reliable source for HONO(g) free from major contamination with NO,. Ambient measurement data for Lubbock, TX, are presented. Persistent daytime concentrations of HONO in the 100-500 pptv range, weekday morning peak concentrations up to 1 ppbv following peak traffic hours, and typical nighttime peak concentrations between 1 and 2 ppbv are observed. Nitrous acid plays an uniquely important role in atmospheric chemistry. It is efficiently photolyzed by near-UV radiation during daytime with a near-unity quantum yield at 368 nm to produce NO and 'OH (I) and is unequivocally a major daytime source of 'OH. The exact extent to which nitrous acid and nitrites account for acidic deposition is unknown; however, there are some reports that in areas with high traffic density [HONO(g)] can far exceed total nitrate (2). Formation mechanisms of HONO are not well-characterized at this time; nighttime formation schemes invoke the reaction of NO, 'OH, and a third body. Other sources include direct vehicular emission and heterogeneous hydrolytic reactions involving NO and NO2 (ref 3 and citations therein). Despite the importance of HONO, relatively few reported measurements exist. Since its unequivocal detection is ambient air a decade ago by long-path differential optical absorption spectroscopy (DOAS; see, e.g., ref 4), this technique has been responsible for much of the extant HONO data (refs 5-7 and citations therein). Rodgers and Davis (8) described the limitations of the DOAS approach and proposed a sensitive method involving the photofragmentation of HONO and laser-induced fluorescence of the excited NO thus formed. Routine utility of this technique is deterred by the sizable instrument cost. Alkaline adsorbent coated diffusion denuders provide an affordable alternative for HONO measurement; this was pioneered by Ferm and Sjodin (9) and since utilized by others, typically in the annular denuder format (see, e.g., refs 10-12). Ambient data on HONO concentrations obtained by this technique have been reported (12-14), and at least in once case (12), the nighttime results have been shown to agree with DOAS measurements. These measurements can, however, be subject to error from artifact production of NO2-from other atmospheric N compounds mediated by an alkaline denuder surface (14,15) or from the 0,-induced oxidative loss of the collected NOf (16). Also, the technique is labor-intensive, is difficultly automated, and provides relatively poor temporal resolution. Although one automated approach based on serial tungstic acid and potassium iron oxide coated denuders has been reported for the determination of HN02, HNO,, NO, and