Filter Pack Sampling Research Articles

Long term trends of wet deposition and atmospheric concentrations of nitrogen and sulfur compounds at EMEP site in Armenia

This paper presents the trends of gaseous nitric acid, nitrogen dioxide, sulfur dioxide, ammonia and nitrate, ammonium, sulfate ions in atmospheric air, and nitrate, ammonium and sulfate ions in wet deposition over 2008–2018 in Armenia. Atmospheric nitrogen and sulfur concentrations were monitored by data obtained from filter pack samplers and glass sinter filters at background monitoring station of Armenia (Amberd), which is designated as EMEP (European Monitoring and Evaluation Programme) station. Laboratory analyses were performed by ion chromatography system and UV spectrophotometer. MAKESENS programme was used for detecting and estimating trends in the time series of annual average values of atmospheric concentrations. Long term trends of atmospheric concentrations of nitrogen and sulfur compounds at the Amberd air quality monitoring station were calculated and discussed for the investigated decade. The trends significance levels for all parameters are calculated. It is identified that there are no significant trends for all explored paramenters, except reduced sulfur in aerosols. Possible emission and deposition changes of nitrogen and sulfur compounds in Armenia were explored in order to identify possible transboundary air pollution and its main sources. Deposition data was estimated by EMEP MSC-W model calculations. Investigation of transboundary fluxes of nitrogen and sulfur compounds displays main receptor areas and contributors. Analysis of seasonality in atmospheric pollutants shows strong seasonal behaviour of the measured parameters in wet deposition - higher concentrations during summertime compared with the wintertime. Atmospheric concentrations of nitrate and ammonium ions are lower during summertime compared with the wintertime, while ammonia has low concentrations during wintertime. Atmospheric nitric acid, sulfate ion, sulfur dioxide and nitrogen dioxide revel no significant seasonality.

NO2 and HONO concentrations measured with filter pack sampling and high HONO/NO2 ratio in Ho Chi Minh city, Vietnam

Nitrogen dioxide and nitrous acid (HONO) in the atmosphere were simultaneously measured with a filter pack (FP) method in Ho Chi Minh City, Vietnam (HCM), in 2017 and 2018. To collect NO2 effectively, the absorption performance of NO2 by the FP method with a triethanolamine (TEA)-impregnated filter was improved. After HNO3 and HONO in the sample air were collected by NaCl and Na2CO3 impregnated filters, respectively, at 2.0 or 4.0 dm3 min−1, NO2 was collected. The air flow was divided into two lines after the HNO3 and HONO filter pack, and one line was used for collecting NO2. With a 0.1 dm3 min−1 flow rate and 20 wt% TEA in the impregnating solution, the collection efficiency of NO2 was almost 100%. The present method was applied for the measurement of HONO and NO2 in HCM in August 2017 and 2018. The average concentrations (29–48 h average) of NO2 and HONO were 17.1 ± 5.7 ppb (average ± 1 standard deviation) and 2.2 ± 0.6 ppb, respectively. The average HONO/NO2 ratio of 13.4 ± 3.5% was significantly higher by a considerable margin than reported values in the literature.

Selective Collection of Particulate Ammonium for Nitrogen Isotopic Characterization Using a Denuder-Filter Pack Sampling Device.

Nitrogen stable isotope analysis (δ15N) of particulate ammonium (NH4+) may provide additional constraints on this critical component of fine particulate matter; however, no previous collection method has been verified for its ability to accurately and precisely characterize δ15N(NH4+). This is a critical point due to the difficulty of quantitative NH4+ collection and possible sampling artifacts. Here, we report on δ15N(NH4+) precision using an established denuder-filter pack combination with two filter configurations including (1) a nylon filter plus an acid-impregnated cellulose filter and (2) an acid-impregnated glass fiber filter for NH4+ collection in both laboratory-controlled environments and ambient air samples. Laboratory NH4+ were generated from the nebulization of ammonium salt solutions and collected using a filter pack sampling train for off-line concentration and isotopic measurement. Quantitative collection of NH4+ was achieved using both filter configurations in both laboratory and field collections. Laboratory experiments indicate a δ15N(NH4+) precision of ±0.9‰ (1σ; n = 24) and ±0.6‰ ( n = 9) for the nylon plus citric acid impregnated cellulose filter and for the citric acid impregnated glass fiber filter, respectively. Field sample reproducibility was assessed from 24 h collected side-by-side samples and indicated δ15N(NH4+) to be reproducible within 1.1‰, consistent with the laboratory findings. This work represents the first established method for speciated NH4+ collection for isotopic analysis with important implications for furthering our understanding of its atmospheric dynamics.

Trans-boundary and in-country transport of air pollutants observed in Kobe, Japan by high frequent filter pack sampling method

The seasonal intensive sampling of gases and particulate matter in ambient air was conducted at the site established in urban area of Japan to study the seasonal difference of the temporal variation of gases and particulate matter concentrations in urban atmosphere as well as to illustrate the different transport regimes that impacts air pollutants. The sample was collected by the four-stage filter-pack method with 6-h interval for one week in four seasons (spring, summer, autumn and winter). The trans-boundary transport of air pollutants with high concentration was characteristically observed in the spring sampling. On the other hand, we could successfully detect the in-country transports of air pollutants in the summer sampling. Four-season’s intensive survey considered, we could show the characteristic transport of air pollutants to provide the episodic high concentration for ambient air in the urban area of Japan, and successfully illustrate the seasonal-dependent transport regimes to impact on air pollutants.

Multi-component gas emission measurements of the active lava lake of Nyiragongo, DR Congo

Between 2007 and 2011 four measurement campaigns (June 2007, July 2010, June 2011, and December 2011) were carried out at the crater rim of Nyiragongo volcano, DR Congo. Nyiragongo is one of the most active volcanoes in Africa. The ground-based remote sensing technique Multi-Axis Differential Optical Absorption Spectroscopy (MAX-DOAS), which uses scattered sunlight, the in-situ Multi-Component Gas Analyzer System (Multi-GAS) and alkaline impregnated filter were simultaneously applied during all field trips. The bromine monoxide to sulfur dioxide (BrO/SO2) and carbon dioxide to sulfur dioxide (CO2/SO2) molar ratios were determined, among other ratios. During the different field trips variations of the level of the lava lake up to several tens of meters were observed during intervals of the order of minutes up to days and also between the years. The measured gas ratios presented covariations with the lava lake level changes. BrO/SO2 ratios and CO2/SO2 ratios showed similar behavior. Annual CO2/SO2 and BrO/SO2 average values are generally positively correlated. In June 2011 increased BrO/SO2 as well as increased CO2/SO2 ratios have been observed before a sudden decrease of the lava lake.Overall the Cl/S ratio, determined by filter-pack sampling, shows an increasing trend with time, which is accompanied by a decreasing sulfur dioxide flux, the later measured nearly continuously by automated MAX-DOAS instruments since 2004.Mean gas emission fluxes of CO2, Cl and ‘minimum-BrO’ fluxes are calculated using their ratio to SO2. The first two show an increase with time, in contrast to the SO2 fluxes.A simple conceptual model is proposed which can explain in particular the June 2011 data, but as well our entire data set. The proposed model takes up the idea of convective magma cells inside the conduit and the possible temporary interruption of part of the cycling. We propose than two alternatives to explain the observed gas emission variation: 1. It is assumed that the diffuse and fumarolic degassing could have significant influence on measured gas composition. The measured gas composition might rather represent a gas mixture of plume, diffuse and fumarolic degassing than only representing the volcanic plume. 2. It is proposed that the interruption of the convection has taken place in the upper part of the conduit and deep degassing of CO2 and bromine initially continues while mixing already with gas emissions from an ageing source, which is characterized by an already diminishing sulfur content. These complex process but as well as the gas mixing of different sources, could explain general features of our dataset, but can unfortunately neither be confirmed nor disproven by the data available today.

High emission rate of sulfuric acid from Bezymianny volcano, Kamchatka

AbstractHigh concentrations of primary sulfuric acid (H2SO4) in fumarolic gases and high emission rate of sulfuric acid aerosol in the plume were measured at Bezymianny volcano, an active dome‐growing andesitic volcano in central Kamchatka. Using direct sampling, filter pack sampling, and differential optical absorption spectroscopy measurements, we estimated an average emission of H2SO4 at 243 ± 75 t/d in addition to an average SO2 emission of 212 ± 65 t/d. The fumarolic gases of Bezymianny correspond to arc gases released by several magma bodies at different stages of degassing and contain 25–92% of entrained air. H2SO4 accounts for 6–87 mol% of the total sulfur content, 42.8 mol% on average, and SO2 is the rest. The high H2SO4 in Bezymianny fumaroles can be explained by catalytic oxidation of SO2 inside the volcanic dome. Because sulfate aerosol is impossible to measure remotely, the total sulfur content in a plume containing significant H2SO4 may be seriously underestimated.

Properties of Indoor Particles Collected in Japanese Homes

Due to the heightened ambient PM 2.5 levels, the whole citizen of Japan, especially dwellers in Fukuoka Prefecture, start to make attention to the particulate matter (PM) of indoor environments. This study was aimed to thoroughly estimate the characteristics of indoor PM collected in five Japanese homes located in Fukuoka Prefecture. Simultaneous indoor measurements of PM were intensively made at five homes using filter-pack samplers, particle counters, and PM 2.5 monitors for a day in springtime, 2012. Major ionic and carbonaceous components were also analyzed. The time series fluctuation of PM number concentration was gradually decreased by 6 AM and then it was rapidly increased by 8 AM in all indoor sites. The maximum level of PM 2.5 was measured at the morning time (8 AM-9 AM) when the resident’s behavior was fast and strenuous. The Indoor/Outdoor (I/O) ratio for the giant PM larger than 5.0 μm was 1.16. It was possible to identify PM types and estimate the resident’s behavior through the comparison the theoretically calculated and the measured retention times for several types of PM in an indoor site. The theoretically reconstructed mass concentration of PM 2.0-0.3 suggested that the portion of PM 2.5 in indoor was quietly occupied by PM 0.3 or the PM inherently originated from indoor environment.

Airborne filter pack measurements of S and Cl in the plume of Redoubt Volcano, Alaska February–May 2009

Filter pack data from six airborne campaigns at Redoubt Volcano, Alaska are reported here. These measurements provide a rare constraint on Cl output from an andesitic eruption at high emission rate (>104t d−1 SO2). Four S/Cl ratios measured during a period of lava dome growth indicate a depth of last magma equilibration of 2–5km. The S/Cl ratios in combination with COSPEC SO2 emission rate measurements indicate HCl emission rates of 1500–3600t d−1 during dome growth. SO2 and HCl emission rates at Redoubt Volcano correlate with each other and were low prior to the eruption, high during the eruption, and low after the eruption. S/Cl ratios measured by filter pack at andesitic volcanoes have a small range of variance, with no clear trends seen for eruptive versus passive activity. The very few S/Cl ratio measurements by filter pack at andesitic volcanoes are not as predictive of future volcanic activity as has been demonstrated for basaltic volcanoes. This may be because there are so few of these measurements. We have demonstrated it is possible to collect these samples by air between explosions during lava dome-building eruptions. We recommend more filter pack sampling be performed at andesitic volcanoes to determine the technique's utility for volcano monitoring. Filter pack data has been demonstrated to be useful for calculating the depth of magma equilibration at volcanoes including Redoubt Volcano.

An Orchestrated Attempt to Determine the Chemical Properties of Asian Dust Particles by PIXE and XRF Techniques

An orchestrated attempt was made to analyze samples of bulk and individual particulate matters (PM) collected at the Gosan ground-based station on the west coast of Jeju, Korea. A two-stage filter pack sampler was operated to collect particles in both large (＞1.2 ㎛) and small size fractions (＜1.2 ㎛) between the Asian dust (hereafter called “AD”) storm event and non-Asian dust period. Elemental components in bulk and individual particles were determined by PIXE and synchrotron XRF analysis systems, respectively. To assess the transport pathways of air parcels and to determine the spatial distribution of PM, the backward trajectories of the Meteorological Data Explorer (Center for Global Environmental Research, 2010) and the NOAA’s HYSPLIT dispersiontrajectory models were applied. In line with general expectations, Si and other crustal elements in large size particles showed considerably higher mass loading on AD days in comparison with non-AD days. Computation of the crustal enrichment factors [(Z/Si)particle/(Z/Si)desert sand] of elements in large size particles (＞1.2 ㎛) allowed us to estimate the source profile and chemical aging of AD particles as well as to classify the soil-origin elements. On the basis of a single particle analysis, individual AD particles are classified into three distinct groups (neutralized mineral particles, S-rich mineral particles, and imperfectly neutralized particles).

Sulfur-rich geothermal emissions elevate acid aerosol levels in metropolitan Taipei

Several studies have demonstrated that millions of people globally are potentially exposed to volcanic gases. Hydrogen sulfide is a typical gas in volcanic and geothermal areas. The gas is toxic at high concentrations that predominantly affects the nervous, cardiovascular, and respiratory systems. The WHO air quality guideline for hydrogen sulfide is 150 μg m −3 (105 ppb). The northwest part of Taipei is surrounded by sulfur-rich geothermal and hot springs. Active fumaroles and bubbling springs around the geothermal area emit acidic gases. In combination with automobile emissions, the pollution of acid aerosols is characteristic of the metropolis. This study considered sulfur-rich geothermal, suburban and downtown locations of this metropolis to evaluate geothermally emitted acid aerosol and H 2S pollution. Acid aerosols were collected using a honeycomb denuder filter pack sampling system (HDS), and then analyzed by ion chromatography (IC). Results indicated that long-term geothermal emissions, automobile emissions and photochemical reactions have led to significant variations in air pollution among regions of metropolitan Taipei. The highest H 2S concentration was 1705 ppb in the geothermal area with low traffic density and the mean concentration was 404.06 ppb, which was higher than WHO guideline and might cause eye irritation. The SO 2 concentrations were relatively low (mean concentration was 3.9 ppb) in this area. It may partially result from the chemical reduction reaction in the geothermal emission, which converted the SO 2 gas into SO 4 2− and H 2S. Consequently, very high sulfate concentrations (mean concentration higher than 25.0 μg m −3) were also observed in the area. The geothermal areas also emitted relatively high levels of aerosol acidity, Cl −, F −, PO 4 3−, and N-containing aerosols. As a result, concentrations of HNO 3, NO 2 −, PO 4 3−, and SO 4 2− in metropolitan Taipei are significantly higher than those in other urban areas considered in other studies. These results provide evidence that geothermal emissions represent a significant source of acid aerosols in metropolitan Taipei. Therefore, in this metropolitan area, the combined health effects of air pollutants from automobiles and geothermal emissions should be particular concern.

Exposure of acid aerosol for schoolchildren in metropolitan Taipei

Metropolitan Taipei, which is located in the subtropical area, is characterized by high population and automobile densities. For convenience, most primary schools are located near major roads. This study explores the exposure of acid aerosols for schoolchildren in areas in Taipei with different traffic densities. Acid aerosols were collected by using a honeycomb denuder filter pack sampling system (HDS). Experimental results indicated that the air pollutants were significantly correlated with traffic densities. The ambient air NO 2, SO 2, HNO 3, NO 3 −, SO 4 2−, and aerosol acidity concentrations were 31.3 ppb, 4.7 ppb, 1.3 ppb, 1.9 μg m −3, 18.5 μg m −3, and 49.5 nmol m −3 in high traffic density areas, and 6.1 ppb, 1.8 ppb, 0.9 ppb, 0.7 μg m −3, 8.8 μg m −3 and 14.7 nmol m −3 in low traffic density areas. The exposure levels of acid aerosols for schoolchildren would be higher than the measurements because the sampling height was 5 m above the ground. The SO 2 levels were low (0.13–8.03 ppb) in the metropolitan Taipei. However, the SO 4 2− concentrations were relatively high, and might be attributed to natural emissions of sulfur-rich geothermal sources. The seasonal variations of acid aerosol concentrations were also observed. The high levels of acidic particles in spring time may be attributed to the Asian dust storm and low height of the mixture layer. We conclude that automobile contributed not only the primary pollutants but also the secondary acid aerosols through the photochemical reaction. Schoolchildren were exposed to twice the acid aerosol concentrations in high traffic density areas compared to those in low traffic density areas. The incidence of allergic rhinitis of schoolchildren in the high traffic density areas was the highest in spring time. Accompanied by high temperature variation and high levels of air pollution in spring, the health risk of schoolchildren had been observed.

A combination of size-resolved particle samplers and XRF microprobe technique for single particle study

It is important to understand the properties of individual airborne particulates that are determined by the processes of various physicochemical reactions occurring in their generation, transformation, and transport. This study describes the application of the X-ray fluorescence (XRF) microprobe technique to the analysis of size-resolved individual particles as well as the results of an experimental study on the comparison of three different particle collection instruments for single particle analysis: a two-stage filter pack, a low pressure Andersen impactor (LPAI), and a micro-orifice uniform deposit impactor (MOUDI). Though LPAI and MOUDI are relatively suitable for multisize-segregated particles sampling compared with the two-stage filter pack sampler, they can easily form particle clusters and finally these particle clusters impede single particle analysis. Even though more particle mass can be collected without overloading on the substrate using MOUDI, by stage rotating, particles are still deposited and form clusters on the concentric circles. When particles are forming a spot (or other shapes of particle cluster), single particle analysis using the XRF micro-beam technique is restricted to individual particles deposited at the edge of the spot. Thus, the sampling duration time depending on the sampler stage should be adjusted for single particle study.

Atmospheric Acidic Pollutants at Mt. Tsukuba, Japan, Determined Using a Portable Filter Pack Sampler

Abstract We measured the concentrations of atmospheric acidic pollutants at Mt. Tsukuba using a newly developed portable filter pack sampler. The results were analyzed to characterize the distribution and origin of pollutants, and were compared with measurements from Tsukuba City and from other mountainous areas in Japan.

Simultaneous determination of atmospheric sulfur and nitrogen oxides using a battery-operated portable filter pack sampler

We developed a method to analyze atmospheric SO(x) (particulate SO(4)(2-)+ gaseous SO(2)) and NO(x) (NO + NO(2)) simultaneously using a battery-operated portable filter pack sampler. NO(x) determination using a filter pack method is new. SO(x) and NO(x) were collected on a Na(2)CO(3) filter and PTIO (2-phenyl-4,4,5,5-tetramethylimidazoline-3-oxide-1-oxyl) + TEA (triethanolamine) filters (6 piled sheets), respectively. Aqueous solutions were then used to extract pollutants trapped by the filters and the resulting extracts were pre-cleaned (e.g. elimination of PTIO) and analyzed for sulfate and nitrite by ion chromatography. Recoveries of SO(2) and NO(x) from standard pollutant gases and consistency of the field data with those from other instrumental methods were examined to evaluate our method. SO(x) and NO(x) could be analyzed accurately with determination limits of 0.2 ppbv and 1.0 ppbv (as daily average concentrations), respectively. The sampler can determine SO(x) and NO(x) concentrations at mountainous or remote sites without needing an electric power supply.

Inter-particle and gas-particle interactions in sampling artifacts of PM in filter-based samplers

Despite the recent rapid development of real-time measurements of chemical compositions in atmospheric aerosols, filter-based aerosol sampling for an extended period of time with post-sampling chemical analysis is still very common. The collected particles interact with both the in-coming gas and each other. These interactions lead to sampling artifacts. This paper investigates the role of aerosol ionic composition, inter-particle and gas-particle interactions in the sampling artifacts of PM 2.5 at high relative humidity. This is achieved by comparing PM 2.5 samples collected with and without a denuder/filter pack system at urban and suburban sites in Hong Kong. The samples collected with a denuder/filter pack were used to estimate the artifact-free ambient gas and particulate concentrations. Because of the prevailing high relative humidity (>70%RH) in HK, the collected particles were expected to have deliquesced and form an internal mixture, according to thermodynamic predictions. It was found that an ambient molar particulate [NH 4 + ]/[SO 4 2− ] ratio of 1.5 is a critical condition to the sampling artifact characteristics of PM 2.5 . The urban samples were all ammonium rich (AR; [NH 4 + ]/[SO 4 2− ] greater than 1.5) and were characterized by a high nitrate concentration and low strong-acidity. They had a significant strong acidity loss of 73%, roughly half of which was due to the neutralization of acidity by ammonia. The suburban samples were all ammonium poor (AP; [NH 4 + ]/[SO 4 2− ] less than or equal to 1.5) and were characterized by a low nitrate concentration and high strong-acidity. Sampling artifacts of the acidity, ammonium and sulfate were not important in the AP samples. In both the AR and AP samples, the individual evaporation of HNO 3 and HCl were the primary reactions for the artifacts of nitrate and chloride while the concomitant evaporation of HNO 3 and HCl with NH 3 was insignificant. In general, the extents of the sampling artifacts of nitrate and chloride increased with increasing gas-to-particulate concentration ratio of these two species. A methodology to estimate the artifact-free ambient concentrations of nitrate and chloride from measurements of filter pack samplers (without any denuders) for deliquesced particles is proposed.

A case study of the single and size-resolved particles in roadway tunnel in Seoul, Korea

Abstract Particle sampling was conducted at the center of Buk-Ak tunnel, which is one of heavily polluted tunnels in Seoul, in October 2000. The sampling equipments consist of a 2-stage filter pack sampler and an Andersen impactor sampler. Micro-particle induced X-ray emission (PIXE) was applied to determine the elemental composition of individual particles (>1.2 μm). The thermal/optical reflectance (TOR ® ) method was also employed in analyzing of EC and OC. Mass concentrations of fine and coarse particles are 177 and 40 μg m −3 , respectively. The most important contributor to particle mass concentration in the present study is carbonaceous components. Most of the individual particles are found to be internally mixed with soil-derived and trace elemental components.

Measurement of organic and elemental carbon associated with PM2.5 during Pacific 2001 study using an integrated organic gas and particle sampler

Abstract In order to investigate the characteristics of carbonaceous components in fine particles in the Lower Fraser Valley of British Columbia, PM2.5 samples were collected twice a day for selected days in August 2001 for the measurement of particle-bound organic and elemental carbon (OC and EC). A denuder-based integrated organic gas and particle sampler (IOGAPS) was employed to minimize sampling artifacts often encountered during filter pack (FP) sampling. During IOGAPS sampling, the gas phase chemicals are removed by an XAD-coated denuder prior to the collection of particles by a quartz filter. The evaporation of the semivolatile organic carbon from the particle-laden filter is quantified by the backup XAD sorbent impregnated filters. A FP sampler was used for a comparison study. OC and EC were measured from filter punches by a thermal and optical transmittance aerosol carbon analyzer. There was no significant difference between the average IOGAPS-EC (0.50 μg C m−3) and FP-EC (0.32 μg C m−3), indicating that the particle loss during the transit in the denuder tube was negligible. The average OC determined by the IOGAPS was 2.80 μg C m−3, about 28% lower than that determined by the FP (3.59 μg C m−3), suggesting that the positive artifacts dominated during the FP sampling. The OC and EC concentrations in Vancouver were comparable with those at other background sites such as Kosan in Korea, but lower than those observed at typical urban sites such as Toronto and Seattle.

Field intercomparison of filter pack and impactor sampling for aerosol nitrate, ammonium, and sulphate at coastal and inland sites

An intercomparison has been performed on the coarse (>2.5 μm) and fine fraction (<2.5 μm) mass concentrations of particulate nitrate, ammonium, and sulphate determined simultaneously by filter pack and MOUDI samplers. Five intensive field campaigns have been carried out in summer and winter seasons, both at coastal sites (Mace Head, Ireland, and Tenerife, Spain) and at an inland site (University of Birmingham, West Midlands, UK). Comparison between particle sulphate measurements shows that sulphate measurements are the same with both filter pack and MOUDI, independent of sampling site or season. For both nitrate and ammonium, the MOUDI results are observed to be usually less than those from the filter pack, especially in the case of polluted air masses. During periods when the measured concentration products [NH 3][HNO 3] are low (<0.1 ppbv 2), the ammonium concentrations obtained with the two samplers are matched very well with each other, but for nitrate, the filter pack system provides 15% higher mass concentrations than the MOUDI which are attributable to different inlet efficiencies. During more polluted periods, however, when there are high levels of gaseous ammonia and nitric acid in the atmosphere (with the measured concentration products [NH 3][HNO 3]>0.1 ppbv 2), significantly negative sampling artefacts are observed for both nitrate and ammonium concentrations obtained with the impactor relative to the filter pack. Nevertheless, it is shown that both filter pack and MOUDI are capable of collecting ammonium nitrate from polluted air masses although the absolute efficiency is unknown. From the measurements obtained with the MOUDI in summertime at both coastal and inland sites, it is observed that about 64% of collected particle nitrate is present in the coarse (>2.5 μm) mode; but in wintertime, only about 29% of particle nitrate is found to reside in the coarse particles collected at the inland site. The lower efficiency of the MOUDI for ammonium nitrate relative to the Teflon filter is in marked contrast to the reported higher efficiency of the Berner impactor than the Teflon filter for sampling nitrate from polluted air.

Assessment of wintertime atmospheric pollutants in an urban area of Kansai, Japan

Abstract An intensive measurement of particulate matter and gaseous materials was made to assess the characteristics of wintertime atmospheric pollutants in an urban area of Kansai, Japan. Sampling was performed by a combination of filter pack sampler and low-pressure Andersen impactor (LPAI). Particle-induced X-ray Emission (PIXE) and Thermal/Optical Reflectance (TOR®) methods were employed in analyzing element and carbon, respectively. The concentrations of SO2, NOx, and PM2.5 monitored during our intensive measurement show a strong time serial variation. PM2.5 levels are higher in the daytime with an average level of 21.3 μg m−3. Most of the peaks for NOx were regularly found in the morning throughout the campaign duration. The number concentration of particles larger than 0.3 μm appears dominated by the ultrafine particles ranged between 0.3 and 0.5 μm. The size distribution of elemental concentration as a function of water solubility was investigated. Organic carbon (OC) concentration shows the strong size distribution with the main peak formed in a range of 0.29–0.67 μm, while elemental carbon (EC) is principally enriched in a range of 0.12–0.29 μm ultra fine fraction. TC (OC+EC) fraction accounts for 42.5% and 26.2% of the mass concentration in fine particle fraction ( 1.17 μm), respectively. The simulated backward aerosol dispersion with the surface wind roses for three events of high PM2.5 mass concentration indicates that aerosol dispersions might be originated from the emission sources of Osaka and Shiga. Also the possibility of long-range transportation of fine particulate matter from the domestic areas of Japan, Taiwan, and Pacific Ocean was still raised. The result of factor analysis indicates that automobile exhaust, fossil fuel combustion, refuse incineration, iron industry, and soil originated particles contribute the major portion of PM2.5 in our sampling area.

Properties of individual Asian dust storm particles collected at Kosan, Korea during ACE-Asia

Abstract For the purpose of studying the properties of individual Asian dust storm particles, an intensive field measurement took place at the Kosan ground-based station located on the west coast of Cheju Island, Korea during ACE-Asia campaign. A 2-stage filter pack sampler was employed in the size-resolved (coarse and fine fractions) particle sampling. The trace elements of individual coarse particles (>1.2 μm) were analyzed by the X-ray microprobe analysis system equipped at SPring-8. The result of statistical analysis suggested that individual particles collected in Asian dust storm event could be classified into four groups: sea-salt-rich particles, crustal-rich particles, crustal/sea-salt/sulfur-rich particles, and crustal/sea-salt-rich particles. Moreover, according to the XRF elemental maps and elemental masks replayed corresponding to individual particles, particles could be categorized into two groups, namely internally mixed particles and externally mixed particles. A small part of the CaCO 3 in Asian dust storm particles would be converted to CaSO 4 through the chemical reaction between CaCO 3 and H 2 SO 4 during long-range transport. By means of XANES method, the major chemical state of Fe in Fe-rich particles was found to be Fe 3+ . Several minor trace heavy metals were probably affected by the air masses passed directly over the industrial areas of China.