| 11. |
- Arshadi, Mehrdad, et al.
(författare)
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Emission of Volatile Aldehydes and Ketones from Wood Pellets under Controlled Conditions
- 2009
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Ingår i: Annals of Occupational Hygiene. - : Oxford University Press (OUP). - 0003-4878 .- 1475-3162. ; 53, s. 797-805
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Tidskriftsartikel (refereegranskat)abstract
- Different qualities of biofuel pellets were made from pine and spruce sawdust according to an industrial experimental design. The fatty/resin acid compositions were determined by gas chromatography-mass spectrometry for both newly produced pellets and those after 2 and 4 weeks of storage. The aldehydes/ketones compositions were determined by high performance liquid chromatography at 0, 2, and 4 weeks. The designs were analyzed for the response variables: total fatty/resin acids and total aldehydes/ketones. The design showed a strong correlation between the pine fraction in the pellets and the fatty/resin acid content but the influence decreased over storage time. The amount of fatty/resin acids decreased similar to 40% during 4 weeks. The influence of drying temperature on the aldehyde/ketone emission of fresh pellets was also shown. The amounts of emitted aldehydes/ketones generally decreased by 45% during storage as a consequence of fatty/resin acid oxidation. The matrices of individual concentrations were subjected to multivariate data analysis. This showed clustering of the different experimental runs and demonstrated the important mechanism of fatty/resin acid conversion.
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| 12. |
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| 13. |
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| 14. |
- Blanco, Luis E., et al.
(författare)
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The determinants of dermal exposure ranking method (DERM) : A pesticide exposure assessment approach for developing countries
- 2008
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Ingår i: Annals of Occupational Hygiene. - : Oxford University Press (OUP). - 0003-4878 .- 1475-3162. ; 52:6, s. 535-544
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Tidskriftsartikel (refereegranskat)abstract
- A new method for assessment of dermal exposure to pesticides in subsistence farmers by use of determinants of dermal exposure is described. The method, called the determinants of dermal exposure ranking method (DERM), is a combination of checklists and expert rating assessment. Thus, determinants are listed in a form, which is used to check their presence and to assess them using a simple algorithm based on two factors, the type of transport process (T value) and the area of body surface exposed (A value). In addition, the type of clothing worn during applications is included as a protection factor. We applied the DERM to real pesticide applications, characterizing dermal exposure and comparing DERM estimates with earlier developed semiquantitative visual scores based on fluorescent tracer, the total visual score (TVS) and contaminated body area (CBA). DERM showed a very good level of agreement with both the TVS (r = 0.69, P = 0.000) and the CBA (r = 0.67, P = 0.000). DERM allowed identification of the determinants that had the highest effect on exposure and the farmers with the highest exposure. In conclusion, DERM provided information on the determinants responsible for dermal exposure in a group of subsistence farmers. This can be useful to design monitoring and preventive programs, define priorities for intervention and prioritize and select most adequate measurement strategies. DERM promises to be a low-cost easy-to-use method to assess dermal exposure to pesticides in developing country conditions.
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| 15. |
- Burström, Lage, 1954-, et al.
(författare)
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Vibrotactile perception and effects of short-term exposure to hand-arm vibration
- 2009
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Ingår i: The Annals of Occupational Hygiene. - : Oxford University Press (OUP). - 1475-3162 .- 0003-4878. ; 53:5, s. 539-47
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Tidskriftsartikel (refereegranskat)abstract
- This study clarifies whether the established frequency weighting procedure for evaluating exposure to hand-transmitted vibration can effectively evaluate the temporary changes in vibrotactile perception thresholds due to pre-exposure to vibration. In addition, this study investigates the relationship between changes of the vibrotactile perception thresholds and the normalized energy-equivalent frequency-weighted acceleration. The fingers of 10 healthy subjects, five male and five female, were exposed to vibration under 16 conditions with a combination of different frequencies, intensities, and exposure times. The vibration frequencies were 31.5 and 125 Hz and exposure lasted between 2 and 16 min. According to International Organization for Standardization (ISO) 5349-1, the energy-equivalent frequency-weighted acceleration for the experimental time of 16 min is 2.5 or 5.0 m s(-2) root-mean-square, corresponding to a 8-h equivalent acceleration, A(8), of approximately 0.5 and 0.9 m s(-2), respectively. A measure of the vibrotactile perception thresholds was conducted before the different exposures to vibration. Immediately after the vibration exposure, the acute effect was measured continuously on the exposed index finger for the first 75 s, followed by 30 s of measures every minute for a maximum of 10 min. If the subject's thresholds had not recovered, the measures continued for a maximum of 30 min with measurements taken every 5 min. Pre-exposure to vibration significantly influenced vibrotactile thresholds. This study concludes that the influence on the thresholds depends on the frequency of the vibration stimuli. Increased equivalent frequency-weighted acceleration resulted in a significant change in threshold, but the thresholds were unaffected when changes in the vibration magnitude were expressed as the frequency-weighted acceleration or the unweighted acceleration. Moreover, the frequency of the pre-vibration exposure significantly influenced (up to 25 min after exposure) recovery time of the vibrotactile thresholds. This study shows that the frequency weighting procedure in ISO 5349-1 is unable to predict the produced acute changes in the vibrotactile perception. Moreover, the results imply that the calculation of the 'energy-equivalent' frequency-weighted acceleration does not reflect the acute changes of the vibration perception thresholds due to pre-exposure to vibration. Furthermore, when testing for the vibrotactile thresholds, exposure to vibration on the day of a test might influence the results. Until further knowledge is obtained, the previous practice of 3 h avoidance of vibration exposure before assessment is recommended.
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| 16. |
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| 17. |
- Bye, E., et al.
(författare)
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Quantitative Determination of Airborne Respirable Non-Fibrous alpha-Silicon Carbide by X-ray Powder Diffractometry
- 2009
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Ingår i: Annals of Occupational Hygiene. - : Oxford University Press (OUP). - 0003-4878 .- 1475-3162. ; 53:4, s. 403-408
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Tidskriftsartikel (refereegranskat)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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| 18. |
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| 19. |
- Bylund, Sonya H, et al.
(författare)
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A descriptive study of women injured by hand-arm vibration
- 2002
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Ingår i: Annals of Occupational Hygiene. - 0003-4878 .- 1475-3162. ; 46:3, s. 299-307
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Tidskriftsartikel (refereegranskat)abstract
- The aim of this study was to describe the symptoms and the prognosis of vibration injuries in women. The investigation was based on a study of 374 women who had reported an injury due to hand-arm vibration to the Social Insurance Office or had received financial compensation from the Swedish Labor Market Insurance scheme during 1988-1997. Information on, for example, self-rated health symptoms and vibration exposure was collected by means of a questionnaire. On average, the first symptoms started after 7 yr of exposure and the first visit to a doctor took place after 11 yr. Neurological symptoms developed after a shorter period of exposure compared to vascular symptoms, 6.8 and 9.2 yr, respectively. The prevalence of numbness at the time of reporting the injury was 91% and the prevalence of white fingers was reported by 54%. The occupational group with the highest prevalence of vibration injuries was dental technicians. Two thirds of the women had stopped using vibrating machines in their work. Among the women who suffered from white fingers when they reported the injury, 50% declared impairment or no improvement of the symptoms. One woman in five was retired and the same number of women had retrained due to the occupational injury.
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| 20. |
- Coenen, Pieter, et al.
(författare)
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Bias and power in group-based epidemiologic studies of low-back pain exposure and outcome : effects of study size and exposure measurement efforts
- 2015
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Ingår i: Annals of Occupational Hygiene. - : Oxford University Press (OUP). - 0003-4878 .- 1475-3162. ; 59:4, s. 439-454
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Tidskriftsartikel (refereegranskat)abstract
- Objectives: Exposure-outcome studies, for instance on work-related low-back pain (LBP), often classify workers into groups for which exposures are estimated from measurements on a sample of workers within or outside the specific study. The present study investigated the influence on bias and power in exposure-outcome associations of the sizes of the total study population and the sample used to estimate exposures.Methods: At baseline, lifting, trunk flexion, and trunk rotation were observed for 371 of 1131 workers allocated to 19 a-priori defined occupational groups. LBP (dichotomous) was reported by all workers during three years of follow-up. All three exposures were associated with LBP in this parent study (p<0.01).All 21 combinations of n=10,20,30 workers per group with an outcome, and k=1,2,3,5,10,15,20 workers actually being observed were investigated using bootstrapping, repeating each combination 10,000 times. Odds ratios (OR) with p-values were determined for each of these virtual studies. Average OR and statistical power (p<0.05 and p<0.01) was determined from the bootstrap distributions at each (n,k) combination.Results: For lifting and flexed trunk, studies including n≥20 workers, with k≥5 observed, led to an almost unbiased OR and a power >0.80 (p-level 0.05). A similar performance required n≥30 workers for rotated trunk. Small numbers of observed workers (k) resulted in biased OR, while power was, in general, more sensitive to the total number of workers (n).Conclusions: In epidemiologic studies using a group-based exposure assessment strategy, statistical performance may be sufficient if outcome is obtained from a reasonably large number of workers, even if exposure is estimated from only few workers per group.
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