Annular Denuder Sampling Research Articles

Seasonal and Spatial Variations of Atmospheric Ammonia in the Urban and Suburban Environments of Seoul, Korea

Atmospheric ammonia is a significant pollutant throughout the year, necessitating standardized measurement and identification of emission factors. We performed a quantized evaluation of ammonia concentrations at various locations in and around Seoul, South Korea. The established testing methods of the Radiello Passive Sampler were used for ammonia sampling, and the method was validated using annular denuder sampling. Urban and suburban areas were studied to gain a deeper understanding of the factors responsible for ammonia pollution. This study aimed to establish the fluctuations in concentration over one year, by analyzing the seasonal and regional variation in ammonia concentration. Livestock and agricultural areas recorded the highest concentration of ammonia among all sites, with the highest concentration recorded in autumn. However, at most of the other studied sites, the highest and lowest ammonia concentrations were recorded during summer and winter, respectively. This study attempted to establish a correlation between ammonia concentration and temperature, as well as ammonia concentration and altitude.

Measurement of fine particulate matter water-soluble inorganic species and precursor gases in the Alberta Oil Sands Region using an improved semicontinuous monitor

The ambient ion monitor–ion chromatography (AIM-IC) system, which provides hourly measurements of the main chemical components of PM2.5 (particulate matter with an aerodynamic diameter <2.5 μm) and its precursor gases, was evaluated and deployed from May to July 2011 and April to December 2013 in the Athabasca Oil Sands Region (AOSR) of northeastern Alberta, Canada. The collection efficiencies for the gas-phase SO2 and HNO3 using the cellulose membrane were 96% and 100%, respectively, and the collection efficiency of NH3 using the nylon membrane was 100%. The AIM-IC was compared with a collocated annular denuder sampling system (ADSS) and a Federal Reference Method (FRM) Partisol PM2.5 sampler. The correlation coefficients of SO42− concentrations between the AIM-IC and ADSS and between the AIM-IC and the Partisol PM2.5 sampler were 0.98 and 0.95, respectively. The comparisons also showed no statistically significant difference between the measurement sets, suggesting that the AIM-IC measurements of the PM2.5 chemical composition are comparable to the ADSS and Partisol PM2.5 methods. NH3 concentration in the summer (mean ± standard deviation, 1.9 ± 0.7 µg m−3) was higher than in the winter (1.3 ± 0.9 µg m−3). HNO3 and NO3− concentrations were generally low in the AOSR, and especially in the winter months. NH4+ (0.94 ± 0.96 µg m−3) and SO42− (0.58 ± 0.93 µg m−3) were the major ionic species of PM2.5. Direct SO2 emissions from oil sands processing operations influenced ambient particulate NH4+ and SO42− values, with hourly concentrations of NH4+ and SO42− measured downwind (~30 km away from the stack) at 10 and 28 µg m−3. During the regional forest fire event in 2011, high concentrations of NO3−, NH4+, HNO3, NH3, and PM2.5 were observed and the corresponding maximum hourly concentrations were 31, 15, 9.6, 89, and >450 (the upper limit of PM2.5 measurement) µg m−3, suggesting the formation of NH4NO3.Implications: The AOSR in Canada is one of the most scrutinized industrial regions in the developed world due to the extent of oil extraction activities. Because of this, it is important to accurately assess the effect of these operations on regional air quality. In this study, we compare a new analytical approach, AIM-IC, with more standard analytical approaches to understand how local anthropogenic and nonanthropogenic sources (e.g., forest fires) impact regional air quality. With this approach, we also better characterize PM2.5 composition and its precursor gases to understand secondary aerosol formation mechanisms and to better identify possible control techniques if needed.

Field inter-comparison of eleven atmospheric ammonia measurement techniques

Abstract. Eleven instruments for the measurement of ambient concentrations of atmospheric ammonia gas (NH3), based on eight different measurement methods were inter-compared above an intensively managed agricultural field in late summer 2008 in Southern Scotland. To test the instruments over a wide range of concentrations, the field was fertilised with urea midway through the experiment, leading to an increase in the average concentration from 10 to 100 ppbv. The instruments deployed included three wet-chemistry systems, one with offline analysis (annular rotating batch denuder, RBD) and two with online-analysis (Annular Denuder sampling with online Analysis, AMANDA; AiRRmonia), two Quantum Cascade Laser Absorption Spectrometers (a large-cell dual system; DUAL-QCLAS, and a compact system; c-QCLAS), two photo-acoustic spectrometers (WaSul-Flux; Nitrolux-100), a Cavity Ring Down Spectrosmeter (CRDS), a Chemical Ionisation Mass Spectrometer (CIMS), an ion mobility spectrometer (IMS) and an Open-Path Fourier Transform Infra-Red (OP-FTIR) Spectrometer. The instruments were compared with each other and with the average concentration of all instruments. An overall good agreement of hourly average concentrations between the instruments (R2&gt;0.84), was observed for NH3 concentrations at the field of up to 120 ppbv with the slopes against the average ranging from 0.67 (DUAL-QCLAS) to 1.13 (AiRRmonia) with intercepts of −0.74 ppbv (RBD) to +2.69 ppbv (CIMS). More variability was found for performance for lower concentrations (&lt;10 ppbv). Here the main factors affecting measurement precision are (a) the inlet design, (b) the state of inlet filters (where applicable), and (c) the quality of gas-phase standards (where applicable). By reference to the fast (1 Hz) instruments deployed during the study, it was possible to characterize the response times of the slower instruments.

A Review on the Sampling and Analytical Methods for Ammonia in Air

The quantification of ammonia concentrations has received a lot of scientific attention. Numerous devices for the quantification of <TEX>$NH_3$</TEX> in the ambient air have been developed to provide more technical possibilities for research in abating <TEX>$NH_3$</TEX> emission from various source processes. For the proper quantification of <TEX>$NH_3$</TEX>, a number of sampling methods have been discussed by grouping them into different categories based on the principle of functioning. In general, active samplers employ pumps to draw air in, while passive samplers are exposed to air over a certain period of time to obtain integrated signature of <TEX>$NH_3$</TEX>. In case of the former, impingers and absorption flasks can be employed simultaneously with suitable absorbents to capture <TEX>$NH_3$</TEX> passing through them. The methods of analysis include both in-situ and laboratory determination. In the laboratory, colorimetric or ion chromatographic methods are generally used for its quantification. In the field, a number of real time analyzers have been proven to be useful. These real time analyzers can be grouped according to their principle of operation. These analyzers may use the principle of spectroscopy (e.g. DOAS), photoacousticics (e.g. photoacoustic monitor) or Chemiluminescence (<TEX>$NO_x$</TEX> analyzer). The automated annular denuder sampling system with on-line analyzer is also suitable for continuous monitoring of ammonia in air.

Sampling Time Effect on 2,4‐Toluene Diisocyanate Concentration by using Different Samplers

In order to understand the sampling time effect on the 2,4‐TDI (Toluene diisocyanate) concentrations, laboratory and field tests were conducted in this study. An ADS (annular denuder sampler) and two OFFCs (open face filter holders) with different filters were tested for 1 to 120 minutes in the laboratory using 2,4‐TDI gas. In the field study, the standard sampling method, the dual filter the triple filter and annular denuder systems were used at two workplaces to study the change of 2,4‐TDI concentrations with sampling time from 15 to 60 minutes. The test results in both laboratory and field studies show that the sampling time influences the sampled TDI concentration considerably which may be due to reaction of TDI with water vapor and polyo in the sampling process. It is evident that as sampling time increases the TDI concentration decreases very significantly.

Gas‐aerosol partitioning of semi volatile carbonyls in polluted atmosphere in Hachioji, Tokyo

Gaseous and particulate semi volatile carbonyls have been measured in urban air using an annular denuder sampling system. Three dicarbonyls, five aliphatic aldehydes and two hydroxy carbonyls were observed. Concentrations of other biogenic and anthropogenic volatile organic compounds (VOCs), SO2, CO, NO2 and particle concentration were also measured. Estimated gas‐aerosol equilibrium constants for the carbonyls showed an inverse correlation with the concentrations of anthropogenic pollutants such as benzene, isopentane and SO2. This suggests that the increase in the fraction of non‐polar anthropogenic particles in the atmosphere could change the average property of the ambient aerosols and drive the gas particle equilibrium of the carbonyls to the gas phase. This trend is uncommon in remote forest air. In this study, we examined the factors controlling the equilibrium in the polluted atmosphere and show that there is a difference in gas‐aerosol partition between polluted and clean air.

Measurement of phase-distributed nitrophenols in Rome ambient air

Atmospheric nitrophenols (NPs) were determined both in the gas and particle phases by combining the annular denuder sampling technique with GC–MS analysis. The phase distribution of six mono-NPs identified in air sampled in downtown Rome was assessed. 4-NP, 3-methyl-4-NP and 2,6-dimethyl-4-NP were found for more than 75% in the particle phase, whilst 2-NP, 4-methyl-2-NP and 5-methyl-2-NP predominated in the gas phase. Concentration levels lower than 20 ng m −3 were observed for all NPs, among which 4-NP (17.8 ± 5.6 ng m −3) and 2-NP (10.4 ± 4.2 ng m −3) were the most abundant congeners in the two phases, respectively.

Evaluation of an annular denuder tubes for atmospheric PAH partitioning studies—1: evaluation of the trapping efficiency of gaseous PAHS

This paper is an evaluation of the gas phase collection efficiency of a commercially available annular denuder sampler used to collect gas and particle phase semivolatile organic compounds. Laboratory and field experiments were carried out to determine the gas phase collection efficiency using naphthalene as reference compound. Laboratory tests were performed to study the influence of environmental conditions (temperature, relative humidity and gas phase concentration) and sampling conditions (sampling flow rate, and sampling duration) on the collection efficiency. During laboratory experiments, the collection efficiency of the gas phase was measured using a dynamic gas generator. It was above 90% for a range of experimental conditions covering: temperature from 9°C to 39°C, relative humidity from 30% to 90%, sampling duration up to 14 h, flow rate of 1 and 2 m3 h−1 and quantity of gaseous naphthalene considerably higher than the one usually collected during atmospheric sampling.

Variation on the atmospheric concentrations of biogenic carbonyl compounds and their removal processes in the northern forest at Moshiri, Hokkaido Island in Japan

Biogenic aldehydes, hydroxycarbonyls, and dicarbonyls in gas and particle phases were collected with an annular denuder sampling system (ADSS) in a Quercus crispula and Picea glehnii mast mixed forest. Eighty samples were collected from 22 to 29 August 2002. The size distributions of aerosols were also observed concurrently with a scanning mobility particle sizer (SMPS). The gaseous concentrations of these carbonyl compounds ranged from the detection limit (approximately 1 pptv) to 154 pptv (630 ng m−3, 4‐oxopentanal), and the particulate concentrations ranged from the detection limit (approximately 3 ng m−3) to 200 ng m−3 (4‐oxopentanal). Although the production processes of these compounds are different from each other, the temporal variations of the gaseous concentrations were quite similar. In addition, the variation was also similar to that of the ambient temperature. Furthermore, gas‐to‐particle conversion was suggested to be an important removal process of these compounds. We could evaluate the importance of the gas‐to‐particle conversion as a removal process of the gaseous species by an ADSS measurement. In addition, the results of our experiment indicated that the conversion includes two processes. The first is an adsorption onto the aerosols which have already existed in the atmosphere. The next is dissolution into the water phases in the aerosols. The latter process was particular to water soluble compounds. The measurement allowed us to identify the most likely removal processes of biogenic semivolatile organic compounds (SOCs). In this study, we discuss about these processes of semivolatile and biogenic carbonyls in the forest atmosphere.

High abundance of gaseous and particulate 4-oxopentanal in the forestal atmosphere

Atmospheric concentrations of 4-oxopentanal (4-OPA) in both gas and particulate phase were measured at the experimental forest, 200 km north of Sapporo, Japan, from August 13 to 15, 2001. 4-OPA was collected using an annular denuder sampling system and measured with a gas chromatography employing benzylhydroxyl oxime derivatization. Its gas phase concentrations ranged from 180 ng m −3 (44 pptv) to 1570 ng m −3 (384 pptv), whereas those in the particulate phase were from below the detection limit (25 ng m −3) to 207 ng m −3. The particulate 4-OPA accounted for 28% (particle/(gas + particle)) of the total concentration as the maximum at 06:00 on August 15th (average: 10%). The particulate concentrations of 4-OPA were found to be comparable to those of pinonic acid, indicating that 4-OPA is also an important constituent of organic aerosols in the forestal atmosphere. Here, we report, for the first time, the concentrations of 4-OPA in both gas and particulate phase and its diurnal variations in the forestal atmosphere.

Spatial distributions of oxygenated organic compounds (dicarboxylic acids, fatty acids, and levoglucosan) in marine aerosols over the western Pacific and off the coast of East Asia: Continental outflow of organic aerosols during the ACE‐Asia campaign

Aerosol sampling for major oxygenated organic compounds (dicarboxylic acids, fatty acids, and levoglucosan) was conducted from 15 March to 19 April 2001 on board the National Oceanic and Atmospheric Administration R/V Ronald H. Brown over the western North Pacific, the East China Sea, and the Sea of Japan, as part of the Asian Pacific Regional Aerosol Characterization Experiment (ACE‐Asia) campaign. During the cruise, aerosol particles were collected on quartz fiber filters using a high‐volume air sampler. Diacids were also collected using an annular denuder sampling system to assess their gas‐particle partitioning. Concentrations of total diacids, total fatty acids, and levoglucosan were found to be higher off the coasts of East Asia than in the remote Pacific. Contributions of these organic compounds to total organic carbon and total organic matter (OM) were calculated to be 9.8 ± 2.3% and 19.0 ± 4.8%, respectively, assuming OM to be organic carbon × 1.6. Diacid concentrations were highly correlated with nss‐SO42− and NO3−, which originate from anthropogenic sources over East Asia. The temporal variations and chain‐length distributions of fatty acids suggest that atmospheric transport of terrestrial organic materials is important off the coast of the continent. C2 − C5 diacids were present predominantly in the particulate phase. The relative abundances of C2 − C5 diacids stayed almost unchanged throughout the cruise, suggesting that deposition is more important than chemical decomposition as a sink of diacids and that they are relatively stable end products in the atmosphere.

Evaluation of the Performance of Annular Denuder Samplers

Two annular denuder samplers were evaluated for the determination of atmospheric nitric acid, SO 2 , and fine particulate sulfate and nitrate. One, the University Research Glassware (URG) sampler, used an elutriator-impactor to remove coarse particles prior to sampling the aerosol through the denuder sections for the removal of acid gases. The second, the Rupprecht and Patashnick (R&P) ChemSpec, removes the acid gases in diffusion denuder sections and then removes coarse particles prior to the collection of fine particles. Possible sampling artifacts examined included the removal of HNO 3 (g) by the inlet of the URG sampler before the collection of this gas-phase species by the diffusion denuder, resulting in the underestimation of HNO 3 (g) and the deposition of some coarse particles in the R&P denuders prior to the removal of these larger particles, and the collection of fine particles on a filter, resulting in the overestimation of HNO 3 (g) and SO 2 (g). Samples were collected in Riverside, CA, Bakers...

High-Volume Diffusion Denuder Sampler for the Routine Monitoring of Fine Particulate Matter: II. Field Evaluation of the PC-BOSS

The high-volume Brigham Young University organic sampling system with a particle concentrator (PC-BOSS) has been field evaluated for the determination of airborne fine particulate matter including semivolatile chemical species during 3 intensive sampling programs in 1997: Tennessee Valley Authority (TVA), Lawrence County, TN; Riverside, CA; and Provo, UT. The PC-BOSS precision was tested using 2 collocated PC-BOSS samplers. In addition, the PC-BOSS results were compared with results from a prototype PM 2.5 U.S. EPA federal reference method (FRM sampler), a filter pack sampler (quartz and charcoal sorbent filters), the BIG BOSS, an annular denuder sampler, and the ChemSpec sampler for the determination of major fine particulate species. Fine particulate mass, sulfate, nitrate, and organic carbonaceous material (OC) determined by 2 PC-BOSS samplers agreed within - 10%. Possibly due to absorption of SO 2 by a quartz filter, the sulfate concentrations determined by the filter pack sampler and the BIG BOSS wer...

Effect of Semivolatile Material on PM 2.5 Measurement by the PM 2.5 Federal Reference Method Sampler at Bakersfield, California

The chemical composition of fine particulate material was determined for samples collected in Bakersfield, CA, during February-March, 1998 using several diffusion denuder samplers, including the PC-BOSS, which measures both semivolatile fine particulate nitrate and organic material. An average of 56% of the fine particulate carbonaceous material was lost from the filters of the Particle Concentrator-Brigham Young University Organic Sampling System (PC-BOSS). A comparable amount of fine particulate semivolatile organic material was also lost from collected particles with single filter samplers, such as the PM 2.5 Federal Reference Method. The fraction of nitrate lost from collected particles was a function of temperature and humidity, with the biggest effect being due to temperature. The fraction of nitrate lost was comparable for conventional annular denuder samplers and the PM 2.5 FRM, averaging 33%. The nitrate loss from particles for the PC-BOSS was smaller, averaging 11%, possibly due to the concentration of particulate material prior to collection with this sampler. The loss of nitrate and semivolatile organic material during sample collection resulted in the PM 2.5 FRM sampler giving PM 2.5 mass that was an average of 30% (7.3 w g/m 3 ) lower than the true value and different from the true value from negligible to 20 w g/m 3 .

Field evaluation of a mobile high-capacity particle size classifier (HCPSC) for separate collection of coarse, fine and ultrafine particles

This paper presents results from a field evaluation of a mobile high-capacity particle size classifier (HCPSC) which samples at 850 l min −1 and classifies ambient particles in three size groups: coarse, fine (or accumulation) and ultrafine modes. Particles in coarse and fine modes are collected by impaction on a small, uncoated surface area (14 cm 2) and can be extracted with a small amount of solvent for toxicological tests and chemical characterization. Particle bounce is eliminated by using cavity-type impaction substrate configurations. Polyurethane foam is used as the impaction substrate material. Ultrafine particles are collected on 20×25 cm quartz or Teflon filters TM (PTFE). The performance of the HCPSC was evaluated in a field study conducted in the Netherlands from May to August 1999. Field tests showed that mass, chloride, nitrate and sulfate concentrations in the coarse mode (2.5–10 μm) measured by means of the HCPSC and a collocated Micro-Orifice Uniform Deposited Impactor (MOUDI) were in very good agreement (within 10% or less). Comparison between fine mode PM concentrations obtained with the HCPSC and MOUDI indicated that approximately 10–15% of fine mode particles are carried over to the ultrafine mode due to imperfect collection efficiency characteristics of rectangular geometry impactors (HCPSC) compared to round nozzle impactors (MOUDI). Comparisons between the PM-2.5 nitrate concentrations obtained with the HCPSC and MOUDI and those with a collocated Harvard/EPA Annular Denuder Sampler (HEADS) yielded average nitrate sampling efficiencies of about 80 and 70% for HCPSC and MOUDI, respectively. Nitrate losses from Teflon filters during this study were on the average higher than 50%.

Indoor/Outdoor Relationships for Ambient PM2.5 and Associated Pollutants: Epidemiological Implications in Lindon, Utah

ABSTRACT Outdoor and indoor fine particulate species were measured at the Lindon Elementary School in Lindon, Utah, to determine which components of ambient fine particles have strong indoor and outdoor concentration correlations. PM25 mass concentrations were measured using tapered element oscillating microbalance (TEOM)7 monitors and by gravimetric analysis of Teflon filter samples. Gas-phase HNO3, sulfur dioxide, particulate nitrate, strong acid, and particulate sulfate were measured using annular denuder samplers. Soot was measured using quartz filters in filter packs. Total particulate number was measured with a condensation nucleus counter (CNC). Total par-ticulate number and fine particulate sulfate and soot were correlated for ambient and indoor measurements. Indoor PM 2.5 mass showed a low correlation with outdoor PM 2.5 mass because of the influence of coarse material from student activities on indoor PM2.5. Fine particle acidity and the potentiation of biological oxidative mechanisms by iron were not correlated indoors and outdoors.

Acid aerosols in the Pittsburgh Metropolitan area

This article presents data on ambient concentrations of selected acidic aerosols at four existing monitoring sites in the Pittsburgh PA metropolitan area. The data were collected by staff of the Allegheny County Health Department, Division of Air Quality during the summer and fall of 1993. The sampling protocol was focused on obtaining 24 h-average ammonia, ammonium, acidic sulfates, and particle strong acids data on a 2 to 3 day cycle. The data were obtained using Harvard University School of Public Health's “Short-HEADS” annular denuder sampling train. The Pittsburgh area is of interest because it is downwind of a major regional source of sulfur and nitrogen emissions from coal-burning power plants: the Ohio River Valley. The data presented here indicate that ground-level concentrations of acidic aerosols in Pittsburgh are highly correlated spatially and that many pollutants are higher on days when ground-level wind direction vectors indicate that wind is coming from the southwest rather than from the Pittsburgh source area itself. The monitoring site that is most upwind of the Pittsburgh source area – South Fayette – has particle strong acid levels about twice those of sites closer in to the Pittsburgh central business district.

Long term measurements of the land–atmosphere exchange of ammonia over moorland

Measurements of the exchange of ammonia between the atmosphere and moorland vegetation using micrometeorological methods at a site in southern Scotland are reported. The median concentration of continuous measurements over seven months of the log-normally distributed ammonia data at the site is 0.45 μg NH 3 m -3 with a geometric standard deviation of 3.4. The measurements made using a continuous wet annular denuder sampling system with a separate denuder at three heights above the surface provided satisfactory fluxes by the aerodynamic flux-gradient method for over 70% of the time between January and August 1995. The site which consists of unimproved moorland vegetation represented an efficient sink for ammonia during the winter months with deposition velocities ( V d) in the range 15 to 30 mm s -1 and canopy resistances ( R c) close to zero. The monthly median V d declined with time from 25 mm s -1 in February to 5 mm s -1 in August as the result of a steady increase of the canopy resistance in the dry, warmer, summer conditions to typically 100 s m -1 during the daytime. The canopy compensation point increased from zero during winter months to about 0.2 μg m -3 in August and short periods of NH 3 emission were observed whenever ambient concentration fell below 0.2 μg m -3 during the summer. The annual input of gaseous NH 3 to this moorland surface is approximately 2 kg N ha -1, and is similar to the input of NH + 4-N in wet deposition.

Development of an annular denuder sampling system for the determination of lower aliphatic aldehydes and amines in stack gas.

Development of an annular denuder sampling system for the determination of lower aliphatic aldehydes and amines in stack gas.

Sampling artifacts in the determination of particulate sulfate and SO2(g) in the desert Southwest using filter pack samplers

Particles collected in the desert Southwest on Teflon filters using an annular denuder sampling system absorb SO 2 (g) in a subsequential exposure to SO 2 (g) in the laboratory if the concentration of fine particulate sulfate measured with a filter pack sampling system is greater than the concentration of sulfate measured with the annular denuder sampling system. If the concentrations of sulfate determined using the two sampling systems agreed, no absorption of SO 2 (g) by the denuder-collected particles occurs. These results show that SO 2 (g) may be collected by Southwest desert fine particles during sampling, resulting in measured concentrations of fine particulate sulfate that are higher than the correct concentrations. The magnitude of this filter pack sampling artifact, 0.1-0.4 μg SO 4 2- /m 3 , is small. However, the artifact is important relative to the concentration of particulate sulfate present in the desert Southwest, typically 0.5-2 μg SO 4 2- /m 3 . The magnitude of the filter pack sulfate sampling artifact is not related to either the atmospheric particulate sulfate or SO 2 (g) concentrations.