Sätt och apparat för provtagning av reaktiva föreningar i en aerosol

Submikrona partiklar som innehåller reaktiva föreningar i en provaerosol uppsamlas för kemisk bestämning av partiklarna, utan oönskade förändringar i den kemiska sammansättningen hos partiklarna. En känd reagensvätska levereras till ett poröst material i fluidkommunikation med provaerosolen, och reagensvätskan bringas att förångas till en ånga med tillhanddahållna uppvärmningsorgan. Reagensångan blandas med provaerosolen till en resulterande aerosolblandning, vilken överförs till en kondensationsenhet där reagensångan kondenserar på partiklarna hos aerosolen varigenom en kemisk reaktion orsakas mellan reagensen och de reaktiva föreningarna hos partiklarna. Ett stabilt derivat erhålles, vilket uppsamlas med en partikeluppsamlingsanordning för efterföljande analys

Measurement report: Black carbon properties and concentrations in southern Sweden urban and rural air – the importance of long-range transport

Soot, or black carbon (BC), aerosol is a major climate forcer with severe health effects. The impacts depend strongly on particle number concentration, size and mixing state. This work reports on two field campaigns at nearby urban and rural sites, 65 km apart, in southern Sweden during late summer 2018. BC was measured using a single-particle soot photometer (SP2) and Aethalometers (AE33). Differences in BC concentrations between the sites are driven primarily by local traffic emissions. Equivalent and refractory BC mass concentrations at the urban site were on average a factor 2.2 and 2.5, with peaks during rush hour up to a factor ∼4, higher than the rural background levels. The number fraction of particles containing a soot core was significantly higher in the city. BC particles at the urban site were on average smaller by mass and had less coating owing to fresh traffic emissions. The organic components of the fresh traffic plumes were similar in mass spectral signature to hydrocarbon-like organic aerosol (HOA), commonly associated with traffic. Despite the intense local traffic (∼ 30 000 vehicles passing per day), PM1, including organic aerosol, was dominated by aged continental air masses even at the curbside site. The fraction of thickly coated particles at the urban site was highly correlated with the mass concentrations of all measured chemical species of PM1, consistent with aged, internally mixed aerosol. Trajectory analysis for the whole year showed that air masses arriving at the rural site from eastern Europe contained approximately double the amount of BC compared to air masses from western Europe. Furthermore, the largest regional emissions of BC transported to the rural site, from the Malmö–Copenhagen urban area, are discernible above background levels only when precipitation events are excluded. We show that continental Europe and not the Malmö–Copenhagen region is the major contributor to the background BC mass concentrations in southern Sweden.</p

Long-term exposure to transportation noise and risk of incident stroke:A pooled study of nine scandinavian cohorts

BACKGROUND: Transportation noise is increasingly acknowledged as a cardiovascular risk factor, but the evidence base for an association with stroke is sparse. OBJECTIVE: We aimed to investigate the association between transportation noise and stroke incidence in a large Scandinavian population. METHODS: We harmonized and pooled data from nine Scandinavian cohorts (seven Swedish, two Danish), totaling 135,951 participants. We identified residential address history and estimated road, railway, and aircraft noise for all addresses. Information on stroke incidence was acquired through link-age to national patient and mortality registries. We analyzed data using Cox proportional hazards models, including socioeconomic and lifestyle con-founders, and air pollution. RESULTS: During follow-up (median = 19:5 y), 11,056 stroke cases were identified. Road traffic noise (Lden ) was associated with risk of stroke, with a hazard ratio (HR) of 1.06 [95% confidence interval (CI): 1.03, 1.08] per 10-dB higher 5-y mean time-weighted exposure in analyses adjusted for indi-vidual-and area-level socioeconomic covariates. The association was approximately linear and persisted after adjustment for air pollution [particulate matter (PM) with an aerodynamic diameter of ≤2:5 lm (PM2:5 ) and NO2 ]. Stroke was associated with moderate levels of 5-y aircraft noise exposure (40–50 vs. ≤40 dB) (HR = 1:12; 95% CI: 0.99, 1.27), but not with higher exposure (≥50 dB, HR = 0:94; 95% CI: 0.79, 1.11). Railway noise was not associated with stroke. DISCUSSION: In this pooled study, road traffic noise was associated with a higher risk of stroke. This finding supports road traffic noise as an important cardiovascular risk factor that should be included when estimating the burden of disease due to traffic noise. https://doi.org/10.1289/EHP8949

On the Determination of Reactive Compounds in Aerosols

Many sources of airborne contaminants have always been present in various work environments. With the development of thermosetting plastic systems, the use of reactive chemical compounds was greatly increased and thus also the risk of exposure to reactive and potentially hazardous compounds. Exposure can occur in many situations, not only at the workplace where the raw materials are handled. The finished products may emit unreacted or excess compounds, like in furniture made of particleboard with phenol-formaldehyde resin that may emit formaldehyde for a long time. Another emission source can arise when some thermosetting plastics like polyurethane and phenol-formaldehyde-urea resins are heated, intentionally or by accident. Many different types of isocyanates in a complex mixture are released at such occasions. In an effort to characterise those emissions in more detail, a new analytical method for the derivatisation and analysis of isocyanates was developed. The new derivatisation reagent, di-n-butylamine, was found to be suitable for the determination of many types of isocyanates even when complicated mixtures of air pollutants were present in the work environment. However, it was found that the used standard sampler, the midget impinger, had almost negligible collection efficiency for particles with an aerodynamic diameter smaller than 1.5 µm. In the work operations where polyurethane products were heated and decomposed, leading to the emission of isocyanate-containing aerosols, the particles were found to be mainly in the sub-micron range and thus not collected by the impinger sampler. In car repair shops, very high concentrations of airborne isocyanates found to be emitted at common work operations as welding and cutting in polyurethane painted vehicles. As an initial solution, a glass-fibre filter was connected in series after the impinger to collect the particles that otherwise would have escaped sampling. The relatively volatile reagent dibutylamine proved to be well suited for this sampling technique as the reagent evaporates from the sampling liquid and impregnates particles collected on the filter. In air samples taken with this method in car repair shops, very high concentrations of isocyanates were found to be emitted during operations such as welding and cutting in vehicles. In order to avoid undesirable reactions that can take place between the studied compound and other compounds present in the work environment, it is desirable to supply the reagent at the earliest possible moment in the sampling process. The ideal might be to supply the reagent to the sample even before collection. Using the aerosol particles as condensation nuclei for a condensing reagent vapour, this can be done. A new method to supply a large excess of liquid reagent to particles in an aerosol before collection of the particles was presented. This new type of sampler may become useful in the investigation of the actual chemical composition of reactive air contaminants at workplaces

Levels of N-methyl-2-pyrrolidone (NMP) and its metabolites in plasma and urine from volunteers after experimental exposure to NMP in dry and humid air.

Department of Occupational and Environmental Medicine, Institute of Laboratory Medicine, Lund University Hospital, S-221 85 Lund, Sweden. The aim of this study was to investigate if the uptake of N-methyl-2-pyrrolidone (NMP), a widely used industrial chemical, increases after exposure to NMP in humid air compared to dry air. NMP has been described to be an airway irritant and a developmentally toxic compound. Six male volunteers were exposed to NMP, three at the time, for 8h in an exposure chamber. They were each exposed on four different occasions to air levels of 0 and 20mg NMP/m(3) in dry and humid air. Blood and urine were sampled before, during and up to 5 days after the end of the 8-h exposure. Plasma and urine were analysed for NMP and its metabolites, using liquid chromatography-tandem mass spectrometry. There was no statistically significant increase in the total cumulated excretion of NMP and its metabolites in urine after exposure in humid air as compared to dry air. Furthermore, there were no differences in the levels of peak concentrations in either plasma or urine. Also, no differences were found in AUC between the exposures. However, there were large individual differences, especially for the exposure in humid air. A not previously identified metabolite in human, 2-pyrrolidone (2-P), was identified. The results do not support a significantly higher absorption of NMP at exposure in humid air as compared to dry air. However, the large individual differences support the use of biological monitoring for assessment of NMP exposure. In addition, 2-P was confirmed to be an NMP metabolite in humans. This may be of importance for the developmental toxicity of NMP since 2-P have been described to be a reproductively toxic substance

Characteristics of Particle Emissions at Paint Manufacturing

The handling of pigments and powders in paint manufacturing cause emissions of airborne particles. A great variety of substances occur. Previous studies (Bohgard et al., 1994) of simulations of pouring of pigments, which occur in small scale weighing procedures, showed typically bimodal size distribution including a sub-micron and a super-micron mode.The objective of the study was to get detailed knowledge on the relation between different source processes (depending on production technology, equipment and the manual handling routines) and aerosol characteristics.Super-micron particles were continuously measured with a time-of-flight instrument (Aerodynamic Particle Sizer, APS TSI Inc.) and sub-micron particles with an electric mobility spectrometer (Scanning Mobility Particle Sizer, SMPS TSI Inc.). In addition filter sampling techniques for standardised work-place sampling (so-called total dust filter cassettes, a cyclone sampler for respirable dust and IOM-samplers for inhalable dust) have been used for idealised exposure/area measurements using a rotating mannequin as a carrier of these samplers. The filters were analysed gravimetrically and with Particle Induced X-ray Emission Analysis. The aerosols were measured during manufacturing of batches of paint. Sources and source mechanisms, as pouring pigments from bags, disposal of packages, mixing of powders and pigments and suspected re-suspension sources, were documented simultaneously with the performance of the measurements.Figure 1 shows examples of size distributions obtained with the APS and SMPS. The size distributions have essentially bimodal shapes with median diameters of 0.05 -0.4 [mu ]m and of 2-5 [mu ]m respectively. Rapid variation in concentration occurs.Preliminary results show that several sources occur. Irregular activities and events as disposal of package material, cleaning, leakage from conveyor tubes and re-suspension due to wind velocities from open gates and moving vehicles significantly contribute to the particle concentrations.Filter sampling with the samplers mounted on a mannequin torso, rotating 360 degrees forth and back, is advantageous by giving idealised measures on exposure. Samplers mounted on equal horizontal level will have equal sampling location integrated over time. Furthermore, the sampling procedure emulate sampling in accordance with sampling conventions. Inlet characteristics of samplers mounted on a body differ from characteristics of free-hanging samplers (Vincent, 1989). Higher estimated mass concentrations were obtained with the IOM-samplers for inhalable dust than with the 37 mm open-face [ldquo ]total dust[rdquo ] cassettes.Figure omitte