| 1. |
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| 2. |
- Bye, E., et al.
(author)
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Quantitative Determination of Airborne Respirable Non-Fibrous alpha-Silicon Carbide by X-ray Powder Diffractometry
- 2009
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In: Annals of Occupational Hygiene. - : Oxford University Press (OUP). - 0003-4878 .- 1475-3162. ; 53:4, s. 403-408
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Journal article (peer-reviewed)abstract
- Objectives: The purpose of the present investigation was to establish a method for the determination of airborne respirable non-fibrous silicon carbide (SiC). The main application is within the industrial production of SiC. Methods: Due to the complex airborne aerosol mixture of crystalline compounds in the SiC industry, X-ray powder diffractometry was selected as the most appropriate method. Without any international standard material for the respirable fraction of non-fibrous SiC, pure and suitable products from three SiC plants in Norway were selected. These products have a median particle diameter in the range 4.4-5.1 mu m. The method is based on thin sample technique, with the dust deposited on a polycarbonate filter. Absorption correction is done by standard procedures with the use of a silver filter, situated below the polycarbonate filter. Results: The diffraction line used for quantitative determination was selected carefully. This was done to avoid interferences from quartz, cristobalite, and graphite, which all are airborne components present in the atmosphere during the industrial process. The instrumental limit of detection for the method is 12 mu g. Conclusions: This method has been used to determine airborne non-fibrous SiC in a comprehensive ongoing project in the Norwegian SiC industry for further epidemiological studies. The method is fully applicable for compliance work.
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| 3. |
- Elihn, Karine, et al.
(author)
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Ultrafine particle characteristics in seven industrial plants.
- 2009
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In: Annals of Occupational Hygiene. - : Oxford University Press (OUP). - 0003-4878 .- 1475-3162. ; 53:5, s. 475-484
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Journal article (peer-reviewed)abstract
- Ultrafine particles are considered as a possible cause of some of the adverse health effects caused by airborne particles. In this study, the particle characteristics were measured in seven Swedish industrial plants, with a special focus on the ultrafine particle fraction. Number concentration, size distribution, surface area concentration, and mass concentration were measured at 10 different job activities, including fettling, laser cutting, welding, smelting, core making, moulding, concreting, grinding, sieving powders, and washing machine goods. A thorough particle characterization is necessary in workplaces since it is not clear yet which choice of ultrafine particle metric is the best to measure in relation to health effects. Job activities were given a different order of rank depending on what particle metric was measured. An especially high number concentration (130 x 10(3) cm(-3)) and percentage of ultrafine particles (96%) were found at fettling of aluminium, whereas the highest surface area concentration (up to 3800 mum(2) cm(-3)) as well as high PM10 (up to 1 mg m(-3)) and PM1 (up to 0.8 mg m(-3)) were found at welding and laser cutting of steel. The smallest geometric mean diameter (22 nm) was found at core making (geometric standard deviation: 1.9).
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| 4. |
- Gustavsson, Marcus, et al.
(author)
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Adsorption Efficiency of Respirator Filter Cartridges for Isocyanates
- 2010
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In: Annals of Occupational Hygiene. - : Oxford University Press (OUP). - 0003-4878 .- 1475-3162. ; 54:4, s. 377-390
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Journal article (peer-reviewed)abstract
- In some industries, the temperature and the humidity will vary greatly between different work places, such as outdoor work in arctic or tropical climates. There is therefore a need to test respirator filters at conditions that simulate conditions that are relevant for the industries that they are used in. Filter cartridges were exposed to controlled atmospheres of varying isocyanate concentration, air humidity, and temperature in an exposure chamber. For isocyanic acid (ICA) and methyl isocyanate (MIC), the exposure concentrations were between 100 and 200 p.p.b., monitored using a proton transfer reaction mass spectrometer. ICA and MIC were generated by continuous thermal degradation of urea and dimethylurea. The breakthrough was studied by collecting air samples at the outlet of the filter cartridges using impinger flasks or dry samplers with di-n-butylamine as derivatization reagent for isocyanates followed by liquid chromatography tandem mass spectrometry (LC-MS/MS) analysis. For hexamethylene diisocyanate (HDI) and isophorone diisocyanate (IPDI), the exposure concentrations were between 4 and 20 p.p.b. and were generated by wet membrane permeation. To reveal the profile of adsorption in different layers of the respirator filters, representative samples from each of the layers were hydrolyzed. The hydrolysis products hexamethylene diamine and isophorone diamine were determined after derivatization with pentafluoropropionic anhydride (PFPA) followed by LC-MS/MS analysis. The two filter types studied efficiently absorbed both ICA and MIC. There was no trend of impaired performance throughout 48-h exposure tests. Even when the filters were exposed to high concentrations (similar to 200 p.p.b.) of ICA and MIC for 96 h, the isocyanates were efficiently absorbed with only a limited breakthrough. The majority of the HDI and IPDI (> 90%) were absorbed in the top layers of the absorbant, but HDI and IPDI penetrated farther down into the respirator filters during 120 h of exposure as compared to 16 h exposure.
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| 5. |
- Gylestam, Daniel, 1979-, et al.
(author)
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Dry Sampling of Gas-Phase Isocyanates and Isocyanate Aerosols from Thermal Degradation of Polyurethane
- 2014
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In: Annals of Occupational Hygiene. - : Oxford University Press (OUP). - 0003-4878 .- 1475-3162. ; 58:1, s. 28-49
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Journal article (peer-reviewed)abstract
- The performance of a dry sampler, with an impregnated denuder in series with a glass fibre filter, using di-n-butylamine (DBA) for airborne isocyanates (200ml min−1) is investigated and compared with an impinger flask with a glass fibre filter in series (1 l min−1). An exposure chamber containing 1,6-hexamethylene diisocyanate (HDI), isophorone diisocyanate (IPDI), and 2,4- and 2,6-toluene diisocyanate (TDI) in the concentration range of 5–205 μg m−3 [0.7–33 p.p.b.; relative humidity (RH) 50%], generated by gas- and liquid-phase permeation, was used for the investigation. The precision for the dry sampling for five series with eight samplers were in the range of 2.0–6.1% with an average of 3.8%. During 120-min sampling (n = 4), no breakthrough was observed when analysing samplers in series. Sixty-four exposed samplers were analysed after storage for 0, 7, 14, and 21 days. No breakdown of isocyanate derivatives was observed. Twenty-eight samplers in groups of eight were collecting isocyanates during 0.5–32h. Virtually linear relationships were obtained with regard to sampling time and collected isocyanates with correlation coefficients in the range of 0.998–0.999 with the intercept close to the origin. Pre- or post-exposure to ambient air did not affect the result. Dry sampling (n = 48) with impinger-filter sampling (n = 48) of thermal decomposition product of polyurethane polymers, at RH 20, 40, 60, and 90%, was compared for 11 isocyanate compounds. The ratio between the different isocyanates collected with dry samplers and impinger-filter samplers was in the range of 0.80–1.14 for RH = 20%, 0.8–1.25 for RH = 40%, 0.76–1.4 for RH = 60%, and 0.72–3.7 for RH = 90%. Taking into account experimental errors, it seems clear that isocyanic acid DBA derivatives are found at higher levels in the dry samples compared with impinger-filter samplers at elevated humidity. The dry sampling using DBA as the reagent enables easy and robust sampling without the need of field extraction.
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| 6. |
- Gylestam, Daniel, 1979-, et al.
(author)
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Sampling of Respirable Isocyanate Particles
- 2014
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In: Annals of Occupational Hygiene. - : Oxford University Press (OUP). - 0003-4878 .- 1475-3162. ; 58:3, s. 340-354
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Journal article (peer-reviewed)abstract
- An advanced design of a denuder impactor (DI) sampler has been developed for characterization of possible airborne isocyanate exposure in different particle size fractions. The sampler is equipped with 12 different parallel denuder tubes, 4 impaction stages with the cut-off values (d50) of: 9.5, 4, 2.5 and 1 µm, and an end filter that collects particles < 1 µm. All collecting parts were impregnated with di-n-butylamine DBA as the reagent in a mixture with acetic acid. The performance of the DI sampler was studied on a standard atmosphere containing gas and particulate isocyanates. The isocyanate atmosphere was generated by liquid permeation of 2,4-, 2,6-Toluene Diisocyanate (TDI), 1,6-Hexamethylene Diisocyanate (HDI) and Isophorone Diisocyanate (IPDI). 4,4’-Methylene Diphenyl Diisocyanate (MDI) particles were generated by heating of technical MDI and condensing the mixture of gas and particle-borne MDI in an atmosphere containing mixed salt particles. The study was performed in a 0.85 m3 environmental chamber with stainless steel walls. With the advancement of the DI sampler it is now possible to collect isocyanate particle samples for up to 320min. The performance of the DI sampler is essentially unaffected by the humidity. The DI sampler and the ASSET™ EZ4-NCO sampler (Sigma-Aldrich/Supelco, Bellefonte, PA, USA) gave similar results. Sample losses within the DI sampler are low. In the environmental chamber it was observed that the particle distribution may be affected by the humidity and ageing. A scanning mobility particle sizer (SMPS) was used to separate a flow of selected fractions containing MDI particles from mixed MDI and salt particles. The particle-size distribution had a maximum at about 300nm, but later in the environmental chamber 1 µm dominated. The distribution was very different as compared to with only NaCl or MDI present. The biological relevance for studying isocyanate nano particles is significant as these have the possibility to reach the lower airways where allergic reactions may occur. SMPS and isocyanate air sampling can be used for the investigation of isocyanate nano particles.
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| 7. |
- Lidén, Göran, et al.
(author)
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A headset-mounted mini sampler for measuring exposure to welding aerosol in the breathing zone.
- 2009
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In: Annals of Occupational Hygiene. - : Oxford University Press (OUP). - 0003-4878 .- 1475-3162. ; 53:2, s. 99-116
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Journal article (peer-reviewed)abstract
- There is a need for a small personal aerosol sampler for measuring occupational exposure to airborne particles in the breathing zone. Existing aerosol samplers are too large to be mounted inside modern welder's protective equipment without disturbing the worker. A headset-mounted mini sampler has been developed to fill this gap with focus on manganese exposure. This mini sampler is easy to use and can be mounted inside modern, slimline welder's face shield. The mini sampler is based on a commercially available 13-mm filter holder that has been modified to incorporate an inlet nozzle made of aluminium. The nominal flow rate of the mini sampler is 0.75 l min(-1). The mini sampler is to be worn mounted on a headset, modified from professional microphone headsets. Several aspects related to using the mini sampler have been tested by personal and static sampling at five workplaces and in the laboratory. Four headset models were tested for their suitability as a sampler holder, of which three models were accepted by the welders. The sampling bias of the mini sampler versus the IOM sampler and the open-face 25-mm filter holder, respectively, depends on the size distribution of the sampled aerosol. At the lowest encountered mass concentration ratio of the open-face 25-mm filter holder to the IOM sampler (0.65), the sampling bias of the mini sampler versus the IOM sampler is approximately -26% and versus the open-face 25-mm filter holder is approximately +12%. For manganese, the negative root mean square (RMS) sampling bias of the mini sampler versus the IOM sampler is -0.046 and versus the open-face 25-mm filter holder is non-significant. Both these biases are statistically non-significant. The mini sampler can therefore be employed for determining welders' occupational exposure to manganese. The pressure drop across the filter can become excessive due to the small filtration area. Compared to the Casella Apex pump, the SKC AirChek2000 pump was generally found to be able to keep its flow rate constant within +/-5% at higher concentrations and for longer sampling times. Our results indicate that the inhalable fraction of the welding aerosol mass at the visited plants only consisted of 25-55% welding fume particles (agglomerates of coagulated particles generated by nucleation/condensation). The rest of the mass is made up of particles from spattering and grinding. More than 65% of manganese is generally found in the fume particles. The weighing precision of 13-mm filters is 2.2 microg. The RMS sample loss due to transport when loaded samples are shipped by mail in padded envelopes is 6 microg. Both figures are very low in comparison to the mass expected to be collected by personal sampling, generally exceeding 200 microg. The headset-mounted mini sampler is user-friendly, easy to adjust individually, does not disturb the welder during sampling and allows sampling inside personal protective equipment. The headset mounting arrangement improves personal sampling as it maintains the sampler close to the nose/mouth during the whole sampling period. This study shows that the developed headset-mounted mini sampler is suitable for assessing exposure to manganese in welding aerosol.
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| 8. |
- Lidén, Göran, et al.
(author)
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Experimental investigation of the concept of a 'breathing zone' using a mannequin exposed to a point source of inertial/sedimenting particles emitted with momentum
- 2010
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In: Annals of Occupational Hygiene. - Oxford : Oxford University Press. - 0003-4878 .- 1475-3162. ; 54:1, s. 100-116
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Journal article (peer-reviewed)abstract
- An inhaling mannequin, CALTOOL, was used in a specially ventilated room to compare the concentrations inhaled with those sampled by samplers mounted across the breathing zone. The CALTOOL is made from metal sheets and consists of a cylindrical torso (42 x 24 x 54 cm) with a circular cylinder as head. A circular nozzle simulates the mouth. This nozzle is part of a cassette that holds a filter. The inhalation rate is not periodic but kept constant at nominally 20 l min(-1). The CALTOOL was placed in a horizontal air stream ( approximately 10 cm s(-1)) either facing or back to the wind. In front of the lower chest of the CALTOOL, a particle source was mounted which emitted particles with a momentum directed upwards at an angle of 45 degrees towards the CALTOOL. Five monodisperse aluminium oxide powders were used as test aerosols. The mass median aerodynamic diameters of the test aerosols ranged approximately 10 to 95 mum. Six conically shaped aerosol samplers were mounted horizontally and over the breathing zone of the CALTOOL, one on each shoulder, three across the upper torso, and one at the lower torso centre. Four to six runs per test aerosol and CALTOOL orientation in the airflow were conducted. The samples were analysed gravimetrically. The concentration ratio aerosol sampler to the CALTOOL cassette was determined for the investigated mounting positions. The results showed that when the CALTOOL was exposed to particles emitted with momentum from a point source in front of the lower chest, the variation in concentration over the breathing zone was large. The ratio of the concentration sampled by an aerosol sampler mounted somewhere within the breathing zone to the CALTOOL cassette concentration, would, for specific particle sizes, easily differ by a factor of 3, but may extend up to 10-100, depending on the particular conditions. The basic concept of a breathing zone consisting of a hemisphere of radius 25-30 cm is therefore not well suited for workers handling a point source emitting large particles. For such sampling situations, it is suggested that the radius of the breathing zone is reduced to 10 cm, which may be achieved by a head-mounted sampler.
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| 9. |
- Lidén, Göran
(author)
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The European Commission Tries to Define Nanomaterials
- 2011
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In: Annals of Occupational Hygiene. - : Oxford University Press (OUP). - 0003-4878 .- 1475-3162. ; 55:1, s. 1-5
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Journal article (peer-reviewed)abstract
- In 2010, the European Commission held a short consultation on a proposed definition for nanomaterials, to be used in European Union legislation and programmes. This was in response to a European Parliament resolution, and the definition followed a proposal by one of the Commission's scientific committees. The definition has three parts: on size distribution, size of internal structural elements, and surface area; a material caught by any of these parts meets the definition. There are a number of problems. The definition seems to be written with engineered nanomaterials in mind but as written applies to non-supplied materials, such as smokes. The structural element component seems to capture items such as sunscreen and tennis rackets, which include nanomaterials. Use of the definition will require some international standards, which have yet to be written and which will involve some difficult decisions. It is understandable why there are both size and surface area requirements, but they are not wholly consistent. The Commission plans a further consultation in 2012, but it might be better to delay this until after the standardisation work.
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| 10. |
- Riddar, Jakob B., 1981-, et al.
(author)
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A novel sampler for alkanolamines and a new method for determination using hydrophilic interaction liquid chromatography tandem mass spectrometry
- 2014
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In: Annals of Occupational Hygiene. - 0003-4878 .- 1475-3162.
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Journal article (peer-reviewed)abstract
- A novel sampler for determination of airborne alkanolamines is presented using hydrophilic interaction liquid chromatography (HILIC) with tandem mass spectrometry (MSMS). The sampler consisted of a denuder comprising a polypropylene tube (length = 7 cm, ID = 0.8 cm) with an inner wall coated with a glass fibre filter and internal glass fibre filter strip folded into a ‘V’ to increase the denuder surface coupled in series with a 13 mm glass fibre filter. Sulphuric acid was used for impregnation of all the filters.Electrospray ionisation and multiple-reaction monitoring (MRM) of the protonated molecular ions and corresponding deuterium-labelled internal standards resulted in selective quantifications with linear correlation coefficients > 0.992, instrumental precision (n = 16) of < 6 % and detection limits of 5.1 – 48 pg for ethanol amine (EA), n-propanol amine (NPA), isopropanol amine (IPA), dimethylethanol amine (DMEA), diethanol amine (DEA), diethylethanol amine (DEEA), methyldiethanol amine (MDEA), diisopropanol amine (DIPA) and triethanolamine (TEA).The performance of the sampler was investigated by sampling a standard atmosphere of EA, IPA, DMEA, DEEA and MDEA (0.03-6.1 mg m-3) in an exposure chamber (0.3 m3). The air concentrations of the amines were generated by liquid phase membrane permeation.The extraction recovery for spiked samplers (10 μg) was in the range 93-106 %. The precision when sampling three series of ten samplers each was in the range 2.1-4.8 %. No breakthrough was observed from the sampler when sampling during 60 min using four sets of two samplers in sequence at a flow rate of 0.2 L min-1. A minor breakthrough was observed for DEEA and DMEA at 0.8 L min-1 and the collection efficiencies were > 99.4 %. The distribution of the alkanolamines in the sampler was studied by dissection of the denuders (into eight parts) for two different flow rates (0.2 and 1.1 L min-1). The first parts of the denuder collected the highest amount of alkanolamines, which then declined throughout the remaining parts. It was observed that the denuder was too short to collect all the gas phase alkanolamines and the presence of the end filter was necessary for efficient collection. No effect was observed on the collection efficiency when samplers were stored for up to 45 days prior sampling. No degradation of the alkanolamines on the sampler was observed when exposed samplers were stored for up to 45 days. When sampling DMEA and DEEA, over a period of 0.5 - 8 h (n = 6), linear relationships were obtained with correlation coefficients > 0.998. Using sampling flow rates of 0.05 - 0.8 L min−1, linear relationships were obtained with correlation coefficients > 0.974. Pre- or post-exposure to ambient air for up to 10 h at 25 °C or 50 °C did not affect the sampler performance.
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