Design of digital filters for frequency weightings (A and C) required for risk assessments of workers exposed to noise

Many workers are exposed to noise in their industrial environment. Excessive noise exposure can cause health problems and therefore it is important that the worker’s noise exposure is assessed. This may require measurement by an equipment manufacturer or the employer. Human exposure to noise may be measured using microphones; however, weighting filters are required to correlate the physical noise sound pressure level measurements to the human’s response to an auditory stimulus. IEC 61672-1 and ANSI S1.43 describe suitable weighting filters, but do not explain how to implement them for digitally recorded sound pressure level data. By using the bilinear transform, it is possible to transform the analogue equations given in the standards into digital filters. This paper describes the implementation of the weighting filters as digital IIR (Infinite Impulse Response) filters and provides all the necessary formulae to directly calculate the filter coefficients for any sampling frequency. Thus, the filters in the standards can be implemented in any numerical processing software (such as a spreadsheet or programming language running on a PC, mobile device or embedded system)

The development of an intervention programme to reduce whole-body vibration exposure at work induced by a change in behaviour: a study protocol

<p>Abstract</p> <p>Background</p> <p>Whole body vibration (WBV) exposure at work is common and studies found evidence that this exposure might cause low back pain (LBP). A recent review concluded there is a lack of evidence of effective strategies to reduce WBV exposure. Most research in this field is focussed on the technical implications, although changing behaviour towards WBV exposure might be promising as well. Therefore, we developed an intervention programme to reduce WBV exposure in a population of drivers with the emphasis on a change in behaviour of driver and employer. The hypothesis is that an effective reduction in WBV exposure, in time, will lead to a reduction in LBP as WBV exposure is a proxy for an increased risk of LBP.</p> <p>Methods/Design</p> <p>The intervention programme was developed specifically for the drivers of vibrating vehicles and their employers. The intervention programme will be based on the most important determinants of WBV exposure as track conditions, driving speed, quality of the seat, etc. By increasing knowledge and skills towards changing these determinants, the attitude, social influence and self-efficacy (ASE) of both drivers and employers will be affected having an effect on the level of exposure. We used the well-known ASE model to develop an intervention programme aiming at a change or the intention to change behaviour towards WBV exposure. The developed programme consists of: individual health surveillance, an information brochure, an informative presentation and a report of the performed field measurements.</p> <p>Discussion</p> <p>The study protocol described is advantageous as the intervention program actively tries to change behaviour towards WBV exposure. The near future will show if this intervention program is effective by showing a decrease in WBV exposure.</p

The prevalence of musculoskeletal diseases among casual dock workers Prevalecía de enfermedades musculoesqueléticos entre trabajadores portuarios apulsos Prevalência de doenças musculoesqueléticas entre trabalhadores portuários avulsos

This study identified the prevalence of work-related musculoskeletal disorders among casual dockworkers. This is a retrospective and quantitative study, the data sources of which included the medical files of dockworkers from 2000 to 2009. Data were collected in a medical service for dockworkers using a previously developed form; descriptive quantitative analysis was performed. Ethical aspects were complied with. A total of 15.8% of the diagnoses identified among male workers referred to musculoskeletal disorders. Individuals older than 52 years of age and with more than 21 years working in the field predominated. The most frequent musculoskeletal diseases included low back pain (38.8%), tendinitis (19.7%), and neck pain (12.5%). These diseases can be prevented through health interventions, confirming the importance of developing clinical support in nursing in order to improve the quality of life of dockworkers.<br>Este estudio tuvo como objetivo identificar la prevalecía de enfermedades osteomusculares relacionadas al trabajo entre trabajadores portuarios sin registro. Estudio cuantitativo, retrospectivo. La fuente de datos las tablas de atención medica de los trabajadores portuarios sin registro en el período de 2000 a 2009. La colecta de datos fue realizada en un Servicio de Medicina del Trabajo Portuario a partir de un formulario predeterminado. Se procedió en el análisis cuantitativo descriptivo de los datos. Los aspectos éticos fueran respetados. Se identificó 15,8% diagnósticos de enfermedades osteomusculares, entre trabajadores del sexo masculino. Predominaran individuos con más de 52 años de edad y con tiempo de actuación laboral superior a 21 años. Las principales enfermedades fueran de lumbalgia (38,8%), tendinitis (19,7%) y cervicalgía (12,5%). Las enfermedades osteomusculares mas prevalentes fueran las lumbalgías, tendinitis y cervicalgías, las cuales pueden prevenirse por medio de acciones interventoras y evaluativas en salud, ratificando la importancia de construir subsidios clínicos en enfermería que colaboren para la cualidad de vida del trabajador portuario.<br>O objetivo deste estudo foi identificar a prevalência de doenças musculoesqueléticas relacionadas ao trabalho, entre trabalhadores portuários avulsos. É estudo quantitativo, retrospectivo. A fonte de dados constituiu-se de fichas de atendimento médico dos trabalhadores portuários avulsos, no período de 2000 a 2009. A coleta de dados foi realizada em um serviço de medicina do trabalho portuário, a partir de formulário pré-determinado. Procedeu-se à análise quantitativa descritiva. Aspectos éticos foram respeitados. Identificaram-se 15,8% de diagnósticos de doenças osteomusculares, entre trabalhadores do sexo masculino. Predominaram indivíduos com mais de 52 anos de idade e com tempo de atuação laboral superior a 21 anos. As doenças osteomusculares prevalentes foram lombalgias (38,8%), tendinites (19,7%) e cervicalgias (12,5%), que podem ser prevenidas por meio de ações interventoras em saúde, ratificando a importante construção de subsídios clínicos em enfermagem para a qualidade do trabalho portuário