Ing-Marie Andersson

Contaminant dispersion in the vicinity of a worker in a uniform velocity field

The transportation of gaseous contaminant from a low and moderate low impulse (momentum<1 m s(-1)) source to the breathing zone was studied in a uniform air stream flow. Results of the effects of the direction and the velocity of principal air flow, convection due to a human body, arm movement of a human being and the type of source on the concentration profiles are presented. Three important results were obtained. Firstly, for a given low and moderate impulse low impulse contaminant source in the near field of a worker, his/her orientation relative to the principal air flow direction is the most important factor in reducing occupational exposure, with an air velocity of about 0.3 m s(-1). Secondly, the effect of convection resulting from body heat on air flow was lower than expected. Thirdly, arm movements influence contaminant dispersion, and should be included when models assessing exposure are developed. The present data can also be used to validate existing computational fluid dynamic (CFD) models.

Swedish Entrepreneurs' Use of Occupational Health Services:

Small-scale enterprises are less often covered by occupational health services and have insufficient awareness about health and risks in the work environment. This study investigated how Swedish entrepreneurs in small-scale enterprises use occupational health services. The study used a questionnaire sent in two waves, 5 years apart. At baseline, 496 entrepreneurs responded, and 251 participated 5 years later. The questionnaire included items about affiliation with and use of occupational health services, physical and psychosocial work environments, work environment management, sources of work environment information, and membership in professional networks. Only 3% of entrepreneurs without employees and 19% of entrepreneurs with employees were affiliated with an occupational health service. Entrepreneurs affiliated with occupational health services were more active in work environment management and gathering information about the work environment. The occupational health services most used were health examinations, health care, and ergonomic risk assessments. Affiliation with occupational health services was 6% at both measurements, 4% at baseline, and 10% 5 years later.

Extent of the Reverse Flow Wake Region Produced by a Body in a Uniform Flow Field

A reverse flow is created in front of an object placed in a uniform air stream that originates from behind the object. Gaseous contaminants may then be transported into the breathing zone of a worker from sources located within the reverse flow region. This should be taken into consideration when local ventilation systems are designed. The objective of this study was to characterize the reverse flow zone created in front of a worker in a uniform flow of air,using both experimental data and numerical simulation. Experiments were carried out by moving a point contaminant source on a table placed in front of the worker, and by measuring the contaminant concentration at nose level in front of the worker. The experimentally estimated length of the reverse flow region was smallest (0.5-1.0 m) with a nominal freestream velocity of 0.1 m/s, and similar (1.1-1.4 m) with nominal freestream velocities of 0.3 and 0.5 m/s.

Research Note: Video exposure monitoring for transfer of knowledge in chemical hazards to small enterprises

Abstract Despite the development of effective control technology, occupational exposure to silica and wood dust is a significant important problem for many small enterprises in wood working and quarrying industries. Tens of millions of workers’ occupations involve hazardous silica dust exposure and within the European Union alone, about 3.6 million workers are exposed to inhalable wood dust. The present study used the visualisation method PIMEX for transfer of knowledge in how health risks may be reduced. Typical work situations observed to cause high dust exposures were recorded. The results demonstrate that appropriate use of generally available technology and knowledge can significantly reduce worker exposure. The PIMEX-video monitoring method is a useful tool in knowledge transfer and also is seen to improve worker’s as well as manager’s motivation to use available knowledge. Case studies of the application of the technology have been made available on Internet. Visualised presentations using the PIMEX recordings are seen to be more effective compared to the more traditional training materials.

Work environment investments: outcomes from three cases

Work environment investments are important in order to create a healthy and safe workplace. This article presents findings from a seven-step interventions process aimed at examining and following-up work environment investments in small and medium-sized enterprises (SMEs), with a particular focus on air contaminants. Three different cases were analyzed and included in the study: (a) an educational center for welding; (b) a paint station in furniture manufacturing; (c) a joinery in furniture manufacturing. The results show that the work environment investments were highly appreciated by the employees and managers, but at the same time the investment could be optimized through markedly decreased exposure levels for the worker. Factors such as follow-ups of the investment, education and training in how to use the equipment, worker involvement in the process and leadership engagement are important in order to optimize work environment investments.

Short-term Variation in Occupational Exposure to Air Contaminants

Many industrial workers are exposed to air contaminants. A significant proportion of this exposure is found to occur as short peaks, a fact that has received limited attention in the literature. The present study focuses on short-term variation in air contaminant exposure measured at the level of seconds, linking exposure peaks to typical work situations in selected Swedish industries. The video exposure monitoring method was used to characterize this variation. Ten different videos were analyzed, from recordings varying in length between 15 and 34 minutes. Cumulative exposure for sampling intervals ranked from high to low, relative to the total exposure was calculated as a function of time. Measures of exposure variation included geometric standard deviation and maximum exposure divided by arithmetic mean. The results show that the characteristics of the variation differ between industrial situations. Samples from the stone, wood, and pharmaceutical industries generated the highest variation, implying that exposure peaks of short duration explain a large proportion of the total exposure. It can be concluded that video monitoring of exposure, combined with calculation of exposure variation as percentage of time accounting for given percentages of exposure, can help to reduce exposure to air contaminants in industrial situations by introducing more targeted control measures.

What pupils in vocational schools learn about risk at work

Negative health effects because of poor work environment is more common among young workers compared to older. One explanation might be that younger ones have a low awareness of risk, a lack of safety training, and inadequate introductions to the work. A study has been made focusing on the pupils in vocational schools knowledge and experiences about potential work environment risks in their future work. Questionnaires were distributed to 239 pupils in ten Swedish upper secondary schools’ graduating classes in four vocational programs focusing on basic knowledge about health risks at work as well as the work environment legislation. The programs were the Industrial Technology Program, the Restaurant Management and Food Program, the Transport Program, and the Handicraft Program (in which students specialize in wood). The results from the questionnaires were followed up with focus group discussions. The results showed that the pupils in general had limited knowledge that employers must, by law, conduct risk analyses and prevent risks. It was common that they mentioned themselves as the main responsible to work safe and was not clear about the employers’ duty to arrange for safe work. Pupils in all programs mentioned acute risk as the biggest risk at work. It was concluded that a systematic approach to pupils’ training in work environment is lacking. The results indicates a clear gap between what knowledge the pupils are offered and what’s intended by laws as well as state-of-the-art in occupational health risk research.