Airborne Particulate Samples Research Articles

Isomer distribution of nitrotriphenylenes in airborne particles, diesel exhaust particles, and the products of gas-phase radical-initiated nitration of triphenylene

The formation of mutagenic nitro-polycyclic aromatic hydrocarbons (NPAHs) 1- and 2-nitrotriphenylene (1- and 2-NTP) via gas-phase OH or NO 3 radical-initiated reactions of triphenylene was demonstrated for the first time using a flow reaction system. In contrast with the results of conventional electrophilic nitration, 2-NTP was formed in larger yield than 1-NTP, but this is consistent with the mechanism proposed for gas-phase radical-initiated nitration of PAH. In diesel exhaust particle (DEP) samples, both 1- and 2-NTP were identified and their concentrations determined, as well as 1-nitropyrene (1-NP), which is a representative combustion-derived NPAH: the mean concentrations of 1-NTP, 2-NTP, and 1-NP were 4.7, 1.9, and 32 pmol mg DEP –1, respectively. The mean 2-NTP/1-NTP, 1-NTP/1-NP, and 2-NTP/1-NP ratios in samples of airborne particles collected in a residential area in Osaka, Japan, were>1.55,<0.25, and 0.37, respectively; these values are much higher than those of the DEP samples. This finding indicates that there is another source for airborne NTPs, especially 2-NTP, apart from diesel exhaust. These results strongly suggest that airborne NTPs originate from atmospheric processes such as radical-initiated reactions of triphenylene, and this has a significant influence on the atmospheric occurrence of NTPs.

ISO to Revise Two Cleanroom Standards

The Working Group is reviewing airborne particulate classification factors, sampling requirements, and other clauses as it develops new editions of ISO 14644-1 and 14644-2, targeted for publication in 2008.

Heavy coal combustion as the dominant source of particulate pollution in Taiyuan, China, corroborated by high concentrations of arsenic and selenium in PM10

Coal burning generates toxic elements, some of which are characteristic of coal combustion such as arsenic and selenium, besides conventional coal combustion products. Airborne particulate samples with aerodynamic diameter less than 10 μm (PM10) were collected in Taiyuan, China, and multi-element analyses were performed by inductively coupled plasma atomic emission spectrometry (ICP-AES) and inductively coupled plasma mass spectrometry (ICP-MS). Concentrations of arsenic and selenium from ambient air in Taiyuan (average 43 and 58 ng m−3, respectively) were relatively high compared to what is reported elsewhere. Arsenic and selenium were found to be highly correlated (r=0.997), indicating an overwhelmingly dominant source. Correlation between these two chalcophile elements and the lithophile element Al is high (r is 0.75 and 0.72 for As and Se, respectively). This prompted the hypothesis that the particles were from coal combustion. The enrichment of the trace elements could be explained by the volatilization–condensation mechanism during coal combustion process. Even higher correlations of arsenic and selenium with PM10 (r=0.90 and 0.88) give further support that airborne particulate pollution in Taiyuan is mainly a direct result of heavy coal consumption. This conclusion agrees with the results from our previous study of individual airborne particles in Taiyuan.

Microwave assisted sample preparation for determining water-soluble fraction of trace elements in urban airborne particulate matter: Evaluation of bioavailability

The feasibility of using two different microwave-based sample preparation methods was investigated to determine the total and water-soluble trace metal fraction in airborne particulate matter. The extraction techniques were then applied to urban particulate matter of different sizes in order to evaluate their bioavailability of associated trace metals. While a combination of HNO 3–HF–H 2O 2 was used for the total trace metal fraction of particulate matter, water was employed for the microwave-assisted extraction of water-soluble trace metal fractions. Inductively coupled plasma-mass spectrometry (ICP-MS) was used for the analysis of trace elements. The experimental protocol for the microwave assisted digestion was established using two different SRMs (1648, urban particulate matter and 1649a, urban dust). In the case of water-soluble trace metal fraction, the quantities extracted from the SRMs were compared between ultrasonic and microwave-assisted extractions, and there was a good agreement between the two extraction methods. Blanks values and limits of detection (LODs) for total and water-soluble trace metal concentrations were determined for three different filter substrates (Teflon, Zeflour, and Quartz). Subsequently, the proposed digestion method was evaluated for its extraction efficiency with these filter substrates. Finally, the real-world application of the proposed microwave-based sample preparation methods was demonstrated by analyzing trace elements in airborne particulate samples collected from different outdoor environments in Singapore. The solubility of 11 trace elements detected in the particulate samples is quantified.

The new external beam facility for environmental studies at the Tandetron accelerator of LABEC

At the new 3MV Tandetron accelerator of the LABEC laboratory of INFN in Florence, an external beam facility fully dedicated to measurements of elemental composition of atmospheric aerosol has been installed. The experimental set-up hitherto used for this kind of applications has been upgraded with the introduction of a silicon drift detector and of a beam current monitor system based on the backscattering of protons on the extraction window. The new facility will be presented, together with some methodological results obtained so far for the analysis of airborne particulate matter samples collected on quartz fiber filters.

A review of workplace aerosol sampling procedures and their relevance to the assessment of beryllium exposures

Standardized conventions governing the fractions of airborne particles that can penetrate the human head airways, the thoracic airways and the alveolar spaces have been internationally (although not universally) adopted. Several agencies involved in setting limit values for occupational exposure concentrations have taken these conventions into account when considering the appropriate standard for specific chemicals, in order to ensure the standards are biologically relevant. A convention is selected based on the characteristic health effects, and forms the basis of measurement against the limiting concentration value. In order to assess exposure for comparison to this metric or any other purposes, it is necessary to choose a sampler whose performance matches the convention, and protocols have been developed and used to test sampler performance. Several aerosol sampling devices are available, nominally at least, for each of the conventions. Some considerations important to the sampling of airborne particles containing beryllium with regard to the sampling conventions, the test protocols and sampler performance are discussed.

Effect of chemical composition on the induction of DNA damage by urban airborne particulate matter

Airborne particulate matter (PM) contains a large number of genotoxic substances capable of endangering human health. In the present study, we have investigated the ability of chemically characterized water-soluble and organic-soluble fractions of two particle sizes (PM2.5 and PM10) from different regions of Mexico City to induce DNA damage in a human lung epithelial cell line. We also evaluated associations between the physicochemical parameters of the PM and its genotoxicity. The airborne particulate samples were collected from four regions of the city; a HiVol air sampler was used to collect PM10 on glass fiber filters and a tapered element oscillating system coupled to an automatic cartridge collection unit was used to collect PM2.5 on teflon filters. PM mass was determined by gravimetric analysis of the filters. Filters containing PM2.5 and one section of each PM10 filter were agitated either with deionized water to extract water-soluble compound, or with dichloromethane to prepare organic-soluble compounds. The chemical composition of the extracts was determined by ion and gas chromatography and atomic adsorption spectroscopy. A549 human type II alveolar epithelial cells were exposed to different concentrations of the PM2.5 and PM10 extracts, and alkaline single cell gel electrophoresis or the Comet assay was performed to measure DNA damage and repair. These analyses indicated that soluble transition metals and the organic-soluble PM fractions are crucial factors in the DNA damage induced by PM. PM composition was more important than PM mass for producing genotoxicity. The results of this study showed that the constituents of the water-soluble PM extract are more likely to induce DNA damage than the organic compounds.

Gross alpha, gross beta activities and gamma emitting radionuclides composition of airborne particulate samples in an oceanic island

Gross alpha, gross beta activities and gamma emitting radionuclides composition of airborne particulate samples in an oceanic island

Geochemical and size variations in inhalable UK airborne particles: the limitations of mass measurements

Current European Union legislation limits acceptable levels of inhalable particulate matter &lt;10 μm based only on measurements of mass (currently 50 μg m 3 of PM 10 per day), without considering particle shape, size or chemistry. However, SEM and inductively coupled plasma mass spectrometry data on airborne particle samples from five UK sites (Port Talbot, London, Sheffield, Birmingham and the Lizard, Cornwall) show huge variations in PM 2.5 /PM 10 ratios and particle chemistry, irrespective of mass. Local geology, as well illustrated by the abundance of silicate particles of ophiolitic derivation from the Lizard, can be an important factor in particle variation. Thus a consideration of mass alone provides inadequate information about an airborne dust sample and any potential health effects linked to that sample.

Analysis of inorganic mercury species associated with airborne particulate matter/aerosols: method development.

This paper describes a method for speciation of Hg associated with airborne particulate matter. This method uses a mini-sampler for sample collection and analysis, thermal desorption for separating Hg species, and inductively coupled plasma mass spectrometry (ICP-MS) for identification and quantification of Hg. Coal fly ash spiked with different Hg compounds (e.g. Hg0, HgCl2, HgO, and HgS) was used for qualitative calibration. A standard reference material with a certified value for Hg concentration was used to evaluate the method. When the temperature of the furnace was programmed at a linear rate of increase of 50 degrees min(-1), different Hg compounds could clearly be separated. Three airborne particulate matter samples were collected in parallel in Toronto, ON, Canada and analyzed using this method. Reproducible results were obtained and Hg0, HgCl2, HgO, and HgS species from these samples were detected.

Determination of 1-hydroxypyrene in children urine using column-switching liquid chromatography and fluorescence detection

This study developed an acid hydrolysis method instead of using enzyme extraction, equipped with column-switching system for the pretreatment of samples, in the determination of 1-hydroxypyrene in the urine from children and pyrene in airborne particulates. We collected both types of samples from areas near a petrochemical industry and rural areas as reference. Samples were first treated with acid hydrolysis and followed by solvent extraction prior to being injected into the separation system for the determination with high performance liquid chromatography and fluorescence. A column-switching system was on-line with a C 18 separation column to remove matrix interference and obtain a stable baseline of the chromatogram. The eluent used to separate the 1-hydroxypyrene was 60% (v/v) aqueous acetonitrile solution. A fluorescence detector was used to monitor 1-hydroxypyrene at λ ex =348 nm and λ em =388 nm , and pyrene at λ ex =331 nm and λ em =390 nm . Both calibration graphs were linear with very good correlation coefficients ( r>0.999) and the detection limits were ca. 2 pg (5 ng/l). Results showed that there was a significant association between 1-hydroxypyrene levels in urine specimens and pyrene levels in airborne particulate samples ( r=0.68, P<0.05). The average levels of pyrene in the particulates (0.18 versus 0.09 ng/m 3) and of 1-hydroxypyrene in urine specimens (155.9 versus 110.2 ng/g creatinine) were higher for the petrochemical area than for the rural area. This method is stable and sensitive for measuring polycyclic aromatic hydrocarbons in environmental samples.

Characteristics of lead isotope ratios and elemental concentrations in PM10 fraction of airborne particulate matter in Shanghai after the phase-out of leaded gasoline

Abstract The stable lead (Pb) isotope ratios and the concentrations of 23 elements, including heavy metals and toxic elements, were measured in the PM10 airborne particle samples collected at seven monitoring sites in Shanghai, China, to evaluate the current elemental compositions and local airborne Pb isotope ratio characteristics. Some source-related samples, such as cement, coal and oil combustion dust, metallurgic dust, vehicle exhaust particles derived from leaded gasoline and unleaded gasoline, and polluted soils were analyzed for their Pb content and isotope ratio and compared to those observed in PM10 samples. Airborne Pb concentration ranged from 167 to 854 ng/m3 in the seven monitored sites with an average of 515 ng/m3 in Shanghai, indicating that a high concentration of Pb remains in the air after the phasing out of leaded gasoline. Lead isotopic compositions in airborne particles (207Pb/206Pb, 0.8608±0.0018; 208Pb/206Pb, 2.105±0.005) are clearly distinct from the vehicle exhaust particles (207Pb/206Pb, 0.8854±0.0075; 208Pb/206Pb, 2.145±0.006), suggesting that the automotive lead is not currently the major component of Pb in the air. By using a binary mixing equation, a source apportionment based on 207Pb/206Pb ratios, indicates that the contribution from automotive emission to the airborne Pb is around 20%. The Pb isotope ratios obtained in the source-related samples confirmed that the major emission sources are metallurgic dust, coal combustion, and cement.

Characteristic of Size-Classified Airborne Particulates in Kobe, Japan

Airborne particulate samples were collected and fractionated into five sizes (diameter of 7.0 μm) with a high volume cascade impactor. The size distribution of airborne particulates was bimodal, having two peaks, coarse (> 7.0 μm) and fine (< 1.1 μm), which accounted for approximately 29% and 42%, respectively. Inhalable particulates accounted for approximately 50% of the total. The mass percentages of these extracts were also similar to airborne particulate concentrations. Eight authentic polycyclic aromatic hydrocarbons (PAHs; fluoranthene, pyrene, benz[a]anthracene, benzo[e]pyrene, benzo[b]fluoranthene, benzo[k] fluoranthene, benzo[a]pyrene, benzo[ghi]pelyrene) were detected in airborne particulates. The concentration of PAHs was dependent on size, with the following order: airborne particulates larger than 7.0 < 3.3-7.0 < 2.0-3.3 < 1.1-2.0 < smaller than 1.1 μm. Almost all of the PAHs detected existed in fine airborne particulates smaller than 1.1 μm. Ionic species in size-classified airborne particulate were also investigated. NH4+, SO42- and K+ existed in the fine particulates, whereas NO3-, Cl- and Na+ existed in the coarse particulates. It is likely that SO42- and NO3- were generated from the combustion of fossil fuel and air, and Na+ and Cl- from sea salt. Since NO3- was generated from atmospheric NO2, these concentrations were related to each other. The sampling site is located near a highway, so the results suggested that the main source of most fine particulates was car exhaust, especially diesel exhaust.

POLYCYCLIC AROMATIC HYDROCARBON CONCENTRATIONS OF AIRBORNE PARTICLES IN URBAN AIR OVER THE PAST TWENTY YEARS

To estimate human exposure to hazardous chemicals, it is important to measure the annual trends regarding the concentrations of these compounds in the environment. Airborne particulate samples were collected over the past 20 years (1980–2001) from ambient air using a quartz fiber filter with the help of a high-volume air sampler placed on the top of the National Institute of the Public Health building, Minato-ku, Tokyo, Japan. In the present study, portions of these filter samples were analyzed to investigate the trends regarding the concentration of PAHs in urban air over the sampling period. The concentrations of various PAHs per unit air volume were determined. The concentrations of seven PAHs decreased within the sampling periods, especially in the late 1980s, and slowly decreased from the middle 1990s. The concentrations of seven PAHs were higher in autumn and winter than in the spring and summer.

The application and development of k0-standardization method of neutron activation analysis at Dalat research reactor

In recent years the k0-NAA method has been applied and developed at the 500 kW Dalat research reactor, which includes (1) the establishment of a PC database of k0-NAA-related nuclear parameters, e.g., radionuclide produced, half-lives, k0-factors, Q0, r, Eg, etc; the access to the database is able by a k0-NAA software or by manual; (2) the detection efficiency calibration of gamma spectrometers used in k0-NAA, (3) the determination of reactor neutron spectrum parameters such as a and f factors and neutron fluxes in the irradiation channels, and (4) the validation of the developed k0-NAA procedure by analysing some SRMs, namely Coal Fly Ash (NIST-1633b), Bovine Liver (NIST-1577b) and IAEA-Soil7. The analytical results showed the deviations between experimental and certified values were mostly less than 15% with most Z-scores lower than 2. The k0-NAA procedure established at the Dalat research reactor has been regarded as a reliable standardization method of NAA and as available for practical applications, in particularly for airborne particulate and crude oil samples.

Characterization of African dust transported to Puerto Rico by individual particle and size segregated bulk analysis

As part of the Puerto Rico Dust Experiment (PRIDE), airborne and surface dust particle samples from Africa were collected and subjected to bulk elemental and single‐particle analysis. Airborne samples were collected on polycarbonate filters at various altitudes and underwent single‐particle scanning electron microscopy with energy dispersive analysis with X‐rays (EDAX) to derive elemental ratios of key soil elements. Particle chemistry was related to size and morphological characteristics. At the principle surface site, particles were collected on a Davis Rotating Drum (DRUM) cascade impactor strips in eight stages from 0.1 to 12 μm at 4 hour time resolution. These samples were subjected to X‐ray florescence (XRF) to determine bulk elemental composition from Al through Zn. The elemental data showed good correlation between the DRUM and the aircraft samples. Cluster analysis of single‐particle data resulted in 63 statistically significant clusters. Several clusters can be easily related to their parent mineralogical species. However, as dust particles are to a large extent aggregates, most clusters are based on a continuum of varied mineralogical species and cannot be easily categorized. With 60,500 total particles counted from the airborne filters, a statistically significant number of large particles could be analyzed. Estimated mean surface area modal diameter is ∼5 μm, with an average aspect ratio of 1.9. An apparent change in source region is seen in the morphological data and non alumino‐silicate minerals but is not seen in the aluminum to silicon ratio. We suspect homogenization during long‐range transport.

Recent developments in receptor modeling

AbstractReceptor modeling is the application of data analysis methods to elicit information on the sources of air pollutants. Typically, it employs methods of solving the mixture resolution problem using chemical composition data for airborne particulate matter samples. In such cases, the outcome is the identification of the pollution source types and estimates of the contribution of each source type to the observed concentrations. It can also involve efforts to identify the locations of the sources through the use of ensembles of air parcel back trajectories. In recent years, there have been improvements in the factor analysis methods that are applied in receptor modeling as well as easier application of trajectory methods. These developments are reviewed. Copyright © 2003 John Wiley &amp; Sons, Ltd.

Study of air pollutants in Hong Kong using energy dispersive X-ray fluorescence

Airborne particulate samples were collected from various reference sites in Hong Kong and the energy dispersive X-ray fluorescence (EDXRF) intensities for 19 chemical elements were recorded. Principal component analysis (PCA) was employed so that the variances of these 19 original variables were captured by a few new indices called principal components or PCs. Data points for similar sources were automatically grouped together in a plot of the first three PCs (PC plot). Data for the monitoring site Mong Kok were located within the area defined by vehicular emissions. As such, the main air pollutant at this site was concluded to originate from vehicular emissions. A fraction of data for the Causeway Bay monitoring site also fell into this same identified area, so the main air pollutant could also be vehicular emissions. Some of the data located either on or outside the border can be explained in terms of meteorology.

Calibration of an alpha-beta moving filter particulates monitor

Sampling and detection of airborne particulates is a dynamical process and depends on the detailed characteristics of monitoring instruments. A clear understanding of the impact of these details is essential for superior designs and optimized conditions of operation. Therefore, the new moving filter particulates monitor BAI 9128-ENV for environmental monitoring of airborne activity was carefully calibrated by injection of known activity concentrations. These experiments were conducted at the NRG calibration facilities in Petten, the Netherlands. The instrument's calibration factor and its dynamic behavior were determined from these measurements. Different techniques for the compensation of natural activities were applied and investigated. Detection limits in the presence of radon were determined.

Exposure assessment to mycotoxins in workplaces: aflatoxins and ochratoxin A occurrence in airborne dusts and human sera

In order to evaluate the possible presence of mycotoxins in airborne particulates, a micro-method by HPLC was performed for aflatoxins and ochratoxin A (OA) in dust samples. A total of 44 samples of airborne particulates were collected in three different workplaces in Tuscany (central Italy), where three of the most susceptible foodstuffs (cocoa, coffee and spices) are processed. Air samples were obtained through both area and personal samplings collected during the entire workshift. Whenever possible, workers’ sera were collected in order to check the biomarker of exposure for OA. Dust samples were contaminated at different levels, ranging from less than the limit of detection to 0.080 ng for aflatoxins and to 5.481 ng for OA. The wide range of toxin levels could be related to different causes, such as the distance between the worker and the stocked raw materials, the worker's job, the exposure time and the amount of particulate matter sampled. Airborne levels of OA, and aflatoxins B 1, B 2, G 1 and G 2 were in the range 0.001–8.304, <0.002–0.038, <0.002–0.029, <0.002–0.036 and <0.014–0.131 ng/m 3, respectively. OA levels in workers’ sera showed much higher results (0.94–3.28 ng OA/ml) than the mean level found in the Italian population, showing that inhalation in the workplace can be considered a route of exposure additional to the consumption of contaminated foodstuffs.