Atmospheric Particulate Samples Research Articles

Source characterisation of fine urban particles by multivariate analysis of trace metals speciation

A series of 41 samples of atmospheric particles below 0.61 μm were collected at 12 sites in a Mediterranean city. Meteorological data were related to analytical data. Direct observation technique was used to support the results. Total content and chemical form concentrations for 11 metals were determined, the chemical forms being determined through a specific speciation scheme for fine particles. All sampling sites were differentiated according to the level of metallic pollution. These levels were 40% higher on weekdays than at weekends. Organic-sulphidic chemical form levels of Cd, Pb, Mn and Ti were highest on weekdays. Sources from the sampling sites were influenced by local emissions more than by transferred pollution. Various sources were identified by a sequential principal component analysis as the resuspended soil particles, oil combustion, emissions from foundries and traffic.

A new method for the simultaneous determination of PAH and metals in samples of atmospheric particulate matter

A method for the analysis of polycyclic aromatic hydrocarbons (PAH) and metals in the same filter portion employed for atmospheric particulate samples collection is proposed in this study. Two standard reference materials, SRM 1648 and SRM 1649a, were extracted by microwave-assisted extraction with hexane/acetone (1:1) and the solid residue was acid digested for the determination of levels of metals. It is demonstrated that there were no significant losses of the metal load during the PAH extraction process. Finally, the devised methodology was applied to actual atmospheric particulate samples.

Determination of aliphatic and polycyclic aromatic hydrocarbons in atmospheric particulate samples of A Coruña City (Spain).

The hydrocarbon composition of atmospheric particulate matter from A Coruña city (Northwest Spain) has been studied. TSP (total suspended particulate) and PM10 (particulate matter with aerodynamic diameter < 10 microm) samples were taken over 7 and 4 months at two stations located in residential and industrial sectors of A Coruña city, respectively. The levels of hydrocarbons found in atmospheric particulate samples of A Coruña city are higher than the ones found in other cities over the world. Ratios between the analysed compounds and their sources were established. Both anthropogenic and biogenic origins were found.

Speciation of hexavalent chromium in atmospheric particulate samples by selective extraction and ion chromatographic determination

The predominant use of chromium in industry unfortunately causes environmental concern. In this respect, elaboration and improvement of the extraction process of hexavalent chromium (Cr(VI)) in atmospheric particulate matter followed by quantitative determination using an ion chromatographic method was performed. The detection of Cr(VI) is based on colorimetric absorbance measurement at 520 nm by variable UV/VIS detector. The elution process was performed by complex formation of Cr(VI) with pyridine-2-6-dicarboxylic acid (PDCA) followed by post-column derivatization reaction of the effluent with 1,5 diphenyl carbohydrazide (DPC). Improvement in selective extraction of Cr(VI) was carried out using carbonate/bicarbonate mixture in phosphate buffer/magnesium sulfate solution. Performance characteristics of the improved method, including limits of detection, precision and recovery of the spiked air sample were also investigated. Interference effects arise because of the presence of various reducing species, such as Cr(III) and Fe(II), but the extraction process developed their performance.

Concentration and clean-up of trace hydrocarbons from atmospheric particulate matter

The aim of this work is to establish the best conditions for concentration and purification steps in the trace analysis of aliphatic and polycyclic aromatic hydrocarbons (PAH) from atmospheric particulate matter by gas chromatography-flame ionisation detection (GC-FID) and high performance liquid chromatography with ultraviolet and fluorescence detection (HPLC-UV-FL). The best results for the more volatile compound were obtained with a combination of rotary evaporation and a stream of nitrogen (near to 100% for aliphatic hydrocarbons and from 70 to 105% for PAH). Two types of solid phase extraction (SPE)cartridges (Supelclean tm LC-Silica SPE tubes and Sep-Pak® Plus silica cartridges) and glass column were examined for the purification and fractionation step. Blank chromatograms of both types of cartridges analysed by GC-FID made this study difficult, because a PSS (programmed split-splitless) injector was employed thereby increasing the sensitivity. This problem was not observed in the HPLC-UV-FL blank chromatograms of these cartridges. Glass columns filled with silica and alumina were chosen because no interference was found in the GC-FID blank chromatograms and the best recoveries in the fractionation of both aliphatic hydrocarbons and PAH were achieved. This is especially important when aliphatic hydrocarbons concentrations are lower than 1 μg mL−1. Finally, the selected conditions were applied to the analysis of hydrocarbons in real atmospheric particulate samples.

Direct sampling of atmospheric aerosol particles during Arctic Airborne Measurement Program (AAMP 98)

Direct sampling of atmospheric aerosol particles during Arctic Airborne Measurement Program (AAMP 98)

Problems in the Extraction of Polycyclic Aromatic Hydrocarbons from Diesel Particulate Matter

In this work, a comparison between Soxhlet, ultrasonic, and microwave-assisted extraction (MAE) (using hexane:acetone 1:1) of polycyclic aromatic hydrocarbons (PAHs) from SRM 1650 diesel particulate matter was made. As good recoveries were not obtained for the higher molecular weight compounds, MAE with toluene and dichloromethane was also tested. Achieved recoveries were compared with the results obtained in the same assays made with SRM 1648 urban particulate matter and real atmospheric particulate samples. In order to explain the difficulty of the extraction of PAHs from SRM 1650 in comparison to SRM 1648 and real atmospheric particulate samples, elemental analysis, X-ray diffraction, and particle analysis using scanning electron microscopy coupled to an automatic computer imaging system were also made. It is important to notice that SRM 1650 shows a high percentage of carbon and differences in the morphology of the particles between SRM 1650 and SRM 1648 were observed.

Catalytic oxidation of CS2 over atmospheric particles and oxide catalysts

The catalytic oxidization of CS 2 over atmospheric particles and some oxide catalysts was explored through FT-IR, MS and a fixed-bed stainless steel reactor. The results show that atmospheric particles and some oxide catalysts exhibited considerable oxidizing activities for CS 2 at ambient temperature. The reaction products are mainly COS and elemental sulfur, even CO 2 on some catalysts. Among the catalysts, CaO has the strongest catalytic activity for oxidizing CS 2 . Fe 2 O 3 is weaker than CaO. The catalytic activity for Al 2 O 3 reduces considerably compared with the former two catalysts, and SiO 2 the weakest. Atmospheric particle samples’ catalytic activity is between Fe 2 O 3 ’s and Al 2 O 3 ’s. The atmospheric particle sample collected mainly consists of Ca(Al 2 Si 2 O 8 )·4H 2 O, which is also the main component of cement. COS, the main product, is formed by the catalytic oxidization of CS 2 with adsorbed “molecular” oxygen over the catalysts’ surfaces. The concentration of adsorbed oxygen over catalysts’ surfaces may be the key factor contributed to the oxidizing activity. It is indicated that CS 2 could be catalytically oxidized over atmospheric particles, which induced that this reaction may be another important source of atmospheric COS from CS 2 .

Atmospheric dust aerosol over the Tibetan Plateau

Cascade impactor and bulk samples of atmospheric aerosol particles were collected at three sites on the Tibetan Plateau: Udaoliang (September 1993 to May 1994) and Lhasa and Gongga (May 1998). The average dust concentration at these groundbased sites was 82 μg m−3; this is lower than the lowest average concentration observed over the nine major Chinese deserts (arithmetic mean value of 270 μg m−3), and it also is lower than that over the Loess Plateau (170 μg m−3). The elemental mass‐particle size distributions for several major dust‐derived elements (Al, Ca, Fe, K, Mn, Si, and Ti) were approximately lognormal, but those for Al, Fe, and Ti differed from Ca, K, and Si. Dry deposition velocities calculated from the observed size distributions and a two‐layer deposition model averaged 2.7 cm−1 for Al, Fe, and Ti. For Ca, K, and Si, which appear to be more strongly affected by local Tibetan sources, the average calculated dry deposition velocity was 4.3 cm s−1. Wet deposition fluxes estimated from scavenging ratios indicate that less than 10% of the total deposition on the Tibetan Plateau is attributable to wet removal during the 9 months for which data are available. The yearly mean dust deposition rate (local plus remote and dry plus wet) is estimated to be of the order of ∼100 g m−2 yr−1, which is lower than that onto the Chinese desert regions (320 g m−2 yr−1) or the Loess Plateau (250 g m−2 yr−1), suggesting that the sources upwind of China, and the Tibetan Plateau itself, are not major sources for Asian dust.

Application of programmed-temperature split/splitless injection to the trace analysis of aliphatic hydrocarbons by gas chromatography

The dependence of the programmed-temperature solvent split sampling technique using a PSS (programmed-split/splitless) injection mode on different variables affecting the introduction of large sample volumes for a mixture of alkanes in capillary GC was evaluated. Apart from the studies found in the literature on different factors such as speed of injection, presence of adsorbent in the liner, internal diameter of the liner, initial and final injector temperature, split flow-rate and initial split time, affecting the chromatographic signal of different compounds, others were studied whose influence has not been considered until now. They include length of the microsyringe needle, adsorbent distribution in the liner, injection volume on analyte discrimination, speed of injector heating, time which the column stays at the initial temperature and time that the injector stays at the final temperature. Once finalised, the study of the PSS injection mode was compared with the conventional mode of gas chromatography splitless injection, and found that the proposed method increases sensitivity in GC trace analysis. Finally, the application of both injection modes in the determination of aliphatic hydrocarbons was tested in an atmospheric particulate sample.

Beryllium concentrations in ambient air and its source identification. A case study.

Beryllium concentrations in atmospheric particulate and soil samples in and around a Beryllium Processing Facility (BPF) have been measured. The mean air concentration level of beryllium in and around the fence line of the BPF is 0.48 +/- 0.43 ng m(-3) (n = 397) and is mostly influenced by diurnal and seasonal changes. The observed air concentration levels were well below the prescribed ambient air quality (AAQ) standard of 10 ng m(-3). The soil concentration levels of beryllium in the study area were found to be in the range of 1.42-2.75 microg g(-1). The mass median aerodynamic diameter (MMAD) of beryllium aerosols in ambient air was found to be 6.9 microm. Source identification using the Enrichment Factor (EF) approach indicates soil as the predominant contributory source for air concentrations at the site.

Determination of barium, chromium, cadmium, manganese, lead and zinc in atmospheric particulate matter by inductively coupled plasma atomic emission spectrometry (ICP-AES)

The present paper has shown that the Q concept, as proposed by P.W.J.M. Boumans, J.J.A.M. Vrakking, Spectrochim. Acta Part B 43 (1988) 69, can be used as a basic methodology in the determination of Ba, Cr, Cd, Mn, Pb and Zn in pairs of atmospheric particles by inductively coupled plasma atomic emission spectrometry (ICP-AES). The data base of Q values for line interference [ Q Ij (λ a )] and Q values for wing background interference [ Q WJ (Δλ a )] were obtained in our former work [N. Daskalova, Iv. Boevski, Spectral interferences in the determination of trace elements in environmental materials by inductively coupled plasma atomic emission spectrometry, Spectrochim. Acta Part B 54 (1999) 1099–1122]. The samples of atmospheric particles were collected by the Bergerhoff method. The ICP-AES determination was performed after sample digestion with aqua regia. Q values were used for the calculation of both the total interfering signal under the analysis lines and the true detection limits, depending on the matrix constituents in the different samples. Comparative data for the concentration of analytes were obtained by flame atomic absorption spectrometry (FAAS) and direct current arc atomic emission spectrographic method (dc arc-AES).

Numerical analysis of the airflow hydrodynamics near the inlet to a shrouded probe for sampling of atmospheric aerosol particles at high velocities

Numerical analysis of the airflow hydrodynamics near the inlet to a shrouded probe for sampling of atmospheric aerosol particles at high velocities

Zinc Is the Toxic Factor in the Lung Response to an Atmospheric Particulate Sample

The atmospheric dust sample EHC-93 is known to induce lung cell injury and inflammation in which the toxicity has been attributed to a soluble component, possibly metal ions. To determine whether any specific metal is responsible for the pulmonary reactivity, various metal salts, at the concentration of metal present in the soluble fraction of EHC dust, have now been instilled into mouse lung. After 3 days, only a solution containing all metals tested and that of a zinc salt alone induced an increase in inflammatory cells and protein in lung lavage fluid. These two solutions also increased DNA synthesis in lung cells at this time, indicating a reparative response. Other solutions containing metals such as Cu, Fe, Al, Pb, Mg, or Ni induced no changes in the preceding measurements at the EHC dose level of metal. In a more extensive 28-day study, zinc salts induced rapid focal necrosis of Type 1 alveolar epithelial cells followed by inflammation and elevation of protein levels in lavage fluid over a 2-week period. Following the injury, epithelial cell proliferation increased and focal fibrosis was seen at 4 weeks. A solution containing all the other metals tested without the zinc component induced only minimal lung effects. When a zinc salt was administered at a 10× dose, the pulmonary changes were greatly enhanced, and after 4 weeks fibrosis could be measured biochemically. The results indicate that the acute toxicity associated with EHC atmospheric dust is most likely the result of the level of soluble zinc in this particulate sample. This suggests that a high soluble metal content of atmospheric dust, in this case the zinc level, may be a crucial factor in determining pulmonary cell reactivity to inhaled particulates.

Radionuclides in aerosol samples collected after the criticality accident in the JCO uranium conversion facility

Aerosol samples originating from the JCO criticality accident were collected around JCO for measurements by γ-ray spectrometry with a high-purity germanium (HPGe) detector and high-purity germanium low-energy photon detector (LOAX). Fission products were not detected in four samples of atmospheric particles from three sites. A trace amount of 131 I was detected in a sample collected on activated carbon with a quartz fiber filter. The concentration of 131 I corrected to the termination time of the criticality accident was (43±10)×10 −6 Bq m −3.

Microwave assisted extraction of polycyclic aromatic hydrocarbons from atmospheric particulate samples

For several years, microwave assisted extraction (MAE) was applied to extract organic compounds such as polycyclic aromatic hydrocarbons (PAHs), polychlorinated biphenyls, etc., from soils, sediments and standard reference materials. Very few authors applied this methodology for the extraction of PAHs from atmospheric particulate matter. In the present study, MAE of polycyclic aromatic hydrocarbons with hexane/acetone (1:1) from real atmospheric particulate samples was investigated and the effect of microwave energy and irradiation time studied. The yields of extracted compounds obtained by microwave irradiation were compared with those obtained using traditional Soxhlet extraction. MAE was evaluated using spiked real atmospheric particulate samples and two standard reference materials. Analytical determinations of PAHs were carried out by high performance liquid chromatography (HPLC) with ultraviolet and fluorescence detection. The best recoveries were achieved with a microwave energy of 400 W and an irradiation time of 20 min.

The changing nature of the 206Pb/207Pb isotopic ratio of lead in rainwater, atmospheric particulates, pine needles and leaded petrol in Scotland, 1982-1998.

The inductively coupled plasma-mass spectrometry (ICP-MS)-determined 206Pb/207Pb ratio of 145 samples of rainwater collected at 25 locations around Scotland during December 1997 and January 1998 and at three longterm monitoring stations in the northeast, central belt and southeast of the country from November 1997 to December 1998 averaged 1.144+/-0.017 (1 s). This represents a significant increase from the mean value of 1.120+/-0.016 recorded for the long-term sites in 1989 1991, only partly attributable to a concomitant increase in the 206Pb/207Pb ratio of leaded petrol from 1.075+/-0.013 to 1.088+/-0.007. The rainwater 206Pb/207Pb data for the late 1990s also contrast markedly with the lower 206Pb/207Pb ratios found for pine needle and atmospheric particulate samples from Scotland (e.g. Glasgow: 1.085+/-0.012 in 1985-1986, 1.099+/-0.007 in 1991-1992), England and Western Europe in this study for the period 1982-1992 when emissions of lead to the atmosphere from petrol-engined vehicles in the UK were approximately 2-9 times higher. The observed change in the lead isotopic signature of rainwater predominantly reflects the impact of measures, such as the introduction and growing uptake of unleaded petrol, to reduce car exhaust emissions of lead to the atmosphere in the UK. Based on the rainwater data, source apportionment calculations suggest a general decline in the contribution of leaded petrol to atmospheric lead in Scotland from 53-61% in 1989-1991 to 32-45% in 1997-1998, with a corresponding decline in the urban environment from 84-86% to 48-58%.

Allergens in Paved Road Dust and Airborne Particles

Paved road dust present on the surface of streets in Southern California consists of a complex mixture of soil dust, deposited motor vehicle exhaust particles, tire dust, brake lining wear dust, plant fragments, and other biological materials. The research presented here shows that allergens from at least 20 different source materials are found in the paved road dust. These include pollens and pollen fragments, animal dander, and molds. When paved road dust is resuspended into the atmosphere by passing vehicle traffic, allergen concentrations in the air are increased above the levels that would prevail without the vehicle traffic. Using immunological assays that measure the proteins extracted from environmental samples that bind to IgE antibodies present in the blood serum of allergenic patients, it is possible to measure the allergen concentrations present in paved road dust and in airborne particle samples. Total protein contributions to monthly average airborne TSP and PM_(10) concentrations are found to be in the range from 1 to 5.8 μg m^(-3), potentially accounting for a significant fraction of the airborne particulate organic material that has not been identified to date by GC/MS techniques. Results show that up to 5−12% of the allergenicity of atmospheric total suspended particulate matter samples at Long Beach and Rubidoux, CA, is attributable to paved road dust emissions. In an industrial area of urban central Los Angeles where there is less proximity to vegetation and domestic activities, the paved road dust contribution to airborne allergen concentrations is lower, accounting for approximately 0.5% of the total allergenic activity of the atmospheric particle samples. In conclusion, paved road dust when entrained into the atmosphere by passing traffic is a source of allergen exposure for the general population and could be more important in areas with more abundant vegetation or with closer proximity of populations to major highways than is the case for the Southern California air monitoring sites studied here.

Pulmonary Toxicity of an Atmospheric Particulate Sample Is Due to the Soluble Fraction

Adverse health effects have been associated with the inhalation of a variety of atmospheric particles. The potential toxicity of a recently collected urban air particulate sample (EHC-93, mean diameter < 1 μm) was assessed after instilling 1 mg to mouse lung. A soluble fraction (15% of total) and an insoluble fraction of the original dust were also instilled at 1 and 0.15 mg doses and the lung reaction was followed for up to 8 weeks. The complete dust sample induced an inflammatory response in the first week with increased cell numbers and protein levels in lavage fluid. There was also ultrastructural evidence of epithelial necrosis followed by increased thymidine labeling during repair. The insoluble fraction induced only mild inflammation with no evidence of cell injury or repair at either dose. The soluble fraction produced similar early inflammatory changes but also produced the greatest lung injury. Type 1 cell necrosis was observed, followed by increased tritiated thymidine uptake mainly by Type 2 epithelial cells. This was found after 0.15 mg soluble fraction and was greatly increased in the 1.0 mg group, which subsequently developed fibrosis. The results indicate that while all particle samples induce some inflammation, the lung toxicity produced by the total dust sample EHC-93 can be accounted for by the reaction to its 15% soluble component. This suggests that the pulmonary response and cell injury following exposure to this urban dust is related to soluble material, probably metal ions, rather than to the number or composition of the insoluble particles.

Atmospheric particulate absorption and black carbon measurement

It is convenient to measure the optical attenuation A of the combination of a layer of atmospheric particulate matter and the quartz fiber filter on which it has been collected. The problem of relating A to the absorption and scattering coefficients k and s of the particulate matter itself is treated as a problem in diffuse reflectance spectroscopy using the KubelkaMunk theory. The results show that although, in general, A is a nonlinear function strongly dependent on both s and k, for a limited range of s and sample thickness d, A can be a practically linear function of k. Fortunately, this range includes that common to atmospheric particulate samples. Furthermore, it is shown that if the filter's reflectance is sufficiently high, A can be nearly independent of s. This is in agreement with experimental and, for the limiting case when the substrate filter reflectance is unity, theoretical results obtained by other researchers. Use of such measurements of A as a means of determining the black carbon mass loading C on a filter is also investigated. It is shown that when the black carbon mass fraction f(c) is high, as it is for samples collected in large urban areas, A is a predictable and practically linear function of C. However, when f(c) is low, as it is for many rural locations, then the slope of the function A(C) is strongly dependent on f(c), leading to possible overestimates of C. This problem can be alleviated by making the measurement of A at near-infrared wavelengths rather than in the visible spectrum.