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961.
Otto Hänninen Juhani Ruuskanen Jari Oksanen 《Environmental monitoring and assessment》1993,28(3):215-220
The abundance of epiphytic green algae has been observed to correlate strongly with air quality in several studies. In contrast to lichens, the abundance of green algae is difficult to measure accurately by visual observation. A new method based on photography and digital image processing was developed to estimate the chlorophyll content of algae growing on the bark of pine. Calibration data for the method was collected from polluted areas by spectrophotometric analysis of chlorophyll density. 相似文献
962.
Henriks-Eckerman ML Välimaa J Rosenberg C Peltonen K Engström K 《Journal of environmental monitoring : JEM》2002,4(5):717-721
The thermal degradation products of polyurethanes (PURs) and exposure to isocyanates were studied by stationary and personal measurements in five different occupational environments. Isocyanates were collected on glass fibre filters impregnated with 1-(2-methoxyphenyl)piperazine (2MP) and in impingers containing n-dibutylamine (DBA) in toluene. connected to a glass fibre postfilter. The derivatives formed were analysed by liquid chromatography: 2MP derivatives with UV and electrochemical detection and DBA derivatives with mass spectrometric detection. The release of aldehydes and other volatile organic compounds into the air was also studied. In a comparison of the two sampling methods, the 2MP method yielded about 20% lower concentrations for 4,4'-methylenediphenyl diisocyanate (MDI) than did the DBA method. In car repair shops, the median concentration of diisocyanates (given as NCO groups) in the breathing zone was 1.1 microg NCO m(-3) during grinding and 0.3 microg NCO m(-3) during welding, with highest concentrations of 1.7 and 16 pg NCO m(-3), respectively. High concentrations of MDI, up to 25 and 19 microg NCO m(-3), respectively, were also measured in the breathing zone during welding of district heating pipes and turning of a PUR-coated metal cylinder. During installation of PUR-coated floor covering, small amounts of aliphatic diisocyanates were detected in the air. A small-molecular monoisocyanate, methyl isocyanate, and isocyanic acid were detected only during welding and turning operations. The diisocyanate concentrations were in general higher near the emission source than in the workers' breathing zone. A sampling strategy to evaluate the risk of exposure to isocyanates is presented. 相似文献
963.
Schnelle-Kreis J Jänsch T Wolf K Gebefügi I Kettrup A 《Journal of environmental monitoring : JEM》1999,1(4):357-360
An investigation of the variability in the size distribution of particle adsorbed polycyclic aromatic hydrocarbons (PAHs) on an inner city sampling site showed differences depending on the wind direction. Particle size distributions of PAHs from outdoor air sampling were measured in Munich from 1994 to 1997. The sampling site is located northeast of a crossing with heavy traffic and southwest of a large inner city park. Depending on the wind direction, three different size distributions of particle adsorbed PAHs were observed. The maximum PAH concentration on very small particles (geometric mean diameter 75 nm) was observed with wind from west to southwest coming directly from the crossing area or the roads with heavy traffic. The maximum PAH concentration on particles with geometric mean diameter of 260 nm was found on days with wind from the built-up area north of the sampling site. On particles with geometric mean diameter of 920 nm the maximum PAH concentration was found on days with main wind directions from northeast to east. On these days the wind is blowing from the direction of the city park nearby. The distribution of particle adsorbed PAHs within different particle size classes is substantially influenced by the distance of the sampling site from strong sources of PAH loaded particulate matter. 相似文献
964.
During 24 h, water samples were taken for determination of a number of key parameters in a water system containing high concentrations of FeII at circumneutral pH. None of the major constituents (Ca, Mg, Na, K and sulfate) showed diurnal variations, while dissolved oxygen and pH increased during the night. This increase could entirely be explained by the decrease in water temperature. However, the concentration of FeII slightly increased at constant concentration of total Fe during the night, opposite to earlier observations in other systems where the presence of FeII was shown to be controlled by photoreduction. Nocturnal peaks of FeII have also been observed in other systems with high iron concentrations, however, at acidic pH, but without obvious explanation. The mechanisms for this process therefore need further investigation. 相似文献
965.
The applicability of a low resolution (8 cm-1) Fourier transform infrared (FTIR) gas analyser with an absorption path length of 3 m was evaluated for the on-line monitoring of organic solvent mixture emissions in a flexographic ink manufacturing plant. The on-line monitoring revealed that the highest variations of solvent concentrations, up to three decades, occurred in the exhaust air. The FTIR analyser with a dynamic range of four decades covers well the concentration ranges typically found in the exhaust air and in the workroom air of ink manufacturing plants. The average emission rate of solvent mixture based on a sampling period of two days was 1.8 kg h-1 consisting of mainly ethanol (70%), ethyl acetate (15%) and propan-2-ol (11%). The detection limits of the analyser for the solvent compounds ranged from 0.3 to 4.3 mg m-3 and the measurement uncertainty was less than 10% in the concentration range of 8-15,000 mg m-3. These characteristics make the apparatus appropriate for most industrial hygiene applications. An FTIR spectrophotometer, equipped with an multipoint sampling unit, facilitates rapid identification of solvent components, real-time display of concentration data relevant to workroom air and environment monitoring as well as process control. Furthermore, the on-line concentration information enabled a rapid selection of representative sampling locations. The spectrophotometer is transportable, rugged and relatively simple to calibrate even in a hostile industrial environment. 相似文献
966.
Air concentrations and urinary metabolites of polycyclic aromatic hydrocarbons among paving and remixing workers 总被引:1,自引:0,他引:1
Väänänen V Hämeilä M Kontsas H Peltonen K Heikkilä P 《Journal of environmental monitoring : JEM》2003,5(5):739-746
The exposure of paving workers to polycyclic aromatic hydrocarbons (PAH) during stone mastic asphalt (SMA) paving and remixing was evaluated. The effects on the workers' PAH exposure were also evaluated during the use of an industrial by-product, coal fly ash (CFA), instead of limestone as the filler in the SMA. The PAH exposure was measured by personal air sampling and by analysing the levels of urinary naphthols, phenanthrols and 1-hydroxypyrene (1-OHP) in the workers' pre- and post-shift urine samples. The respiratory PAH exposure of the paving workers (geometric mean (GM) 5.7 microg m(-3)) was about ten-fold that of the traffic controllers (GM 0.43 microg m(-3)). The levels of PAH metabolites were significantly higher (p < 0.05) in the post-shift urine samples than in the pre-shift urine samples, and the levels of metabolites in the post-shift urine of paving workers were significantly higher than in that of the controls (p < 0.01). Urinary 1-naphthol correlated well with the airborne concentrations of the two- to three-ring PAHs (r = 0.544, p = 0.003) and naphthalene (r = 0.655, p < 0.001), when non-smoking paving workers were tested. A good correlation was observed between urinary 1-OHP and the airborne concentrations of the four- to six-ring PAHs (r = 0.524, p = 0.003) as well as total PAHs (r = 0.575, p = 0.001). The concentrations of 1-OHP and phenanthrols in the urine of the pavers were significantly higher (p < 0.01) during remixing than during SMA paving. The CFA in the asphalt had no effect on the airborne PAH exposure or on the concentrations of the PAH metabolites in the paving workers' urine. 相似文献
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968.
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970.
Objective: Drowsy driving is a profound road safety issue. In patients with excessive daytime sleepiness (EDS), the Maintenance of Wakefulness Test (MWT) is commonly used to evaluate driving ability. However, there is little evidence that MWT predicts driving performance, and several sleep latency cutoffs have been suggested.Methods: Based on a retrospective chart analysis of patients with an MWT and a driving ability assessment between January 2006 and November 2014, we identified 63 studies in 60 patients. The driving ability assessment judged the patients as qualified or disqualified for commercial driving. MWT latencies to 3?s of alpha activity, 3?s of drowsiness (microsleep), and sleep onset were compared between qualified and disqualified patients and their validity to identify driving qualification was evaluated.Results: Disqualified patients had shorter alpha, microsleep, and sleep latencies, but the latency distributions were widely overlapping. MWT accuracy to predict driving performance was poor: two thirds of short sleep latencies were false positives. Adding information from alpha and microsleep latencies added little extra accuracy.Conclusions: MWT results correlate poorly with driving performance in a 2-h test irrespective of sleep latency cutoff or added alpha/microsleep latency data. Better diagnostic tools are needed to evaluate driving performance in patients with EDS. 相似文献