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Background: The lead concentration in plasma is correlated to that in whole blood with a two to fourfold variation. It has never been investigated if this variation is inter-individual.

Methods: Lead and hemoglobin were determined in blood and plasma from 13 lead workers with a history of relatively high blood-lead concentrations, sampled three times during 1 day. The variation in the distribution of lead between cells and plasma was studied, but not the variation in the lead concentrations as such.

Results: Blood hemoglobin decreased with rising plasma lead (0.9–3.0 µg/L). Regarding the distribution of lead, no effect of current exposure during the day or of recent meals appeared. As much as 84% of the overall variance of the distribution of lead between cells and plasma could be attributed to individual factors. After adjustment for erythrocyte volume fraction this decreased to 67%. Plasma samples with elevated hemoglobin concentrations (due to in vitro hemolysis) had somewhat elevated lead concentrations.

Conclusions: Plasma lead is not significantly altered by variation in a single day's exposure and, therefore, the choice of time of the day is not critical for sampling. However, plasma lead is negatively correlated to blood hemoglobin and mild hemolysis (not visible by the eye) in a sample may increase plasma lead with up to 30%. Finally, plasma provides lead exposure information that differs from whole blood, but it is not clear which one of these is the biomarker with the closest relation to exposure and/or effects.

Manual work involving vibrating power tools is associated with symptoms that include vascular, neurological and musculoskeletal disorders. This study examines the vibration exposure of welders to determine the change between 1987 and 2008. Vibration measurements on handheld tools were used to evaluate the acceleration and the daily exposure time was determined by subjective rating. From these data, the 8-hour equivalent vibration exposure A(8), has been calculated. During the period, the A(8) decreased from 3.9 m/s² to 1.9 m/s². It was concluded that this decrease is the result of fewer vibrating tools and a decrease in daily exposure time. Although the daily vibration exposure has decreased over the study time, for some welders the daily vibration exposure A(8) is still above the action value set by the EU directive on vibration. This means more effort should be spent to decrease vibration exposure.

OBJECTIVE: This study investigates different aspects of stress and sleep in medically examined individuals with varying severity of building-related symptoms (BRS).

METHODS: Three questionnaires were used to assess acute and long-term stress and sleep (Perceived Stress Scale; Shirom Melamed Burnout Questionnaire, and Karolinska Sleep Questionnaire).

RESULTS: Individuals with BRS, regardless of severity, did not differ in level of perceived stress (indicator of short-term stress). The indicators of long-term stress differed between the groups where an increased severity was associated with higher levels of burnout and sleep problems.

CONCLUSIONS: The study suggests an association between symptom severity and measures of long-term stress and sleep quality. This has implications for the treatment of persons affected by BRS, because not only the environment needs to be treated, but also the concurrent signs of distress, such as burnout or sleep problems.

The aim of this study was to investigate if there are differences in symptom ratings and plasma concentrations of oxylipins as a measure of acute inflammation between individuals with building-related symptoms (BRS) and referents during exposure to rooms where people experienced BRS and rooms where they did not experience BRS. Medically examined individuals with BRS and healthy, age and sex matched referents working in the same building were exposed for 60 min. Ratings of symptoms and collection of blood to measure oxylipins in plasma were performed before and after each exposure. Individuals with BRS reported more symptoms (mostly mucosal) than the referents in the problem rooms and there was a tendency towards a difference between the groups in concentration of metabolites from the cyclooxygenase pathway (COX). The mean reported intensity of symptoms among all participants was also found to be positively correlated with both COX and lipoxygenase (LOX-15) oxylipins in problem rooms.

A self-operated personal sampling technique called 'self assessment of exposure' (SAE) has been suggested as an easy method for collecting inhalation exposure data, as the workers themselves are performing the sampling. Employers and employees have raised the question of whether a different estimate of the air concentration is likely to be obtained depending on whether the sampler is fastened at the left or the right shoulder. In order to answer this question, the exposure to styrene vapour in two different small enterprises within the reinforced plastics industry was measured. Seven workers participated and the air sampling was performed by diffusive sampling. We observed no statistically significant difference in the determined air concentration of styrene between the left and right shoulder (P = 0.878). The results strongly indicate that the fastening of a sampler on the left or right shoulder does not produce a difference in the estimation of the inhalation exposure. SAE can thus be used to collect reliable exposure data of styrene vapour. The reliability of SAE will most certainly inspire occupational hygienists, physicians and other experts to involve the workers in repeated exposure measurements. Taking the exposure variability into account, repeated measurements are crucial when evaluating acute and chronic health effects following inhalation exposure to gases and vapours from chemical hazards.

INTRODUCTION: Increased rates of leukaemia have been found among tanker crews. Occupational exposures to the leukomogen benzene during loading, unloading, and tank cleaning are possible causes. Studies on older types of tankers carrying gasoline with most handling being done manually have revealed important exposures to benzene. Our study explores benzene exposures on tankers with both automatic and manual systems. Correlations between benzene exposure and benzene in alveolar air (AlvBe), benzene in urine (UBe), and trans,trans-muconic acid (ttMA) in urine were investigated.

METHODS: Forty-three male seafarers (22 deck crewmembers and 21 not on deck) on five Swedish different product and chemical tankers transporting 95- or 98-octane gasoline were investigated between 1995 and 1998. The tankers used closed systems for the loading and unloading of gasoline but stripping and tank cleaning were done manually. Benzene in respiratory air was measured using personal passive dosimeters during a 4-h work shift. Samples for biomarker analyses were collected pre- and post-shift. Smoking did occur and crewmembers did not use any respiratory protection during work.

RESULTS: The average 4-h benzene exposure level for exposed was 0.45 mg m-3 and for non-exposed 0.02 mg m-3. Benzene exposure varied with type of work (range 0.02-143 mg m-3). AlvBe, UBe, and ttMA were significantly higher in post-shift samples among exposed and correlated with exposure level (r = 0.89, 0.74, and 0.57, respectively). Smoking did not change the level of significance among exposed.

DISCUSSION: Benzene in alveolar air, unmetabolized benzene, and ttMA in urine are potential biomarkers for occupational benzene exposure. Biomarkers were detectable in non-exposed, suggesting benzene exposure even for other work categories on board tankers. Work on tankers carrying gasoline with more or less closed handling of the cargo may still lead to significant benzene exposure for deck crewmembers, and even exceed the Swedish Occupational Exposure Limit (OEL; 8-h time-weighted average [TWA]) of 1.5 mg m-3.

Inomhusmiljön har en betydande inverkan på människors hälsa och välbefinnande. Man är idag överens om att dålig inomhusmiljö kan ge upphov till ohälsa, särskilt hos dem som redan har någon form av överkänslighet. Medicinsk forskning har dock inte kunnat påvisa någon enskild faktor i inomhusmiljön som orsak till ohälsan. Det finns indikationer på att organiska kemiska föreningar i inomhusluften har betydelse, men man kan idag inte peka ut några enskilda föreningar som orsak till hälsoproblemen. Man har även ställt sig frågan hur olika kemiska föreningar samverkar och om kombinationen av många ämnen tillsammans kan vara det som ger upphov till hälsoproblemen. Eftersom vi idag fortfarande har mycket begränsad kunskap om vad det är man blir sjuk av används istället försiktighetsprincipen. Det innebär att man strävar efter så låga koncentrationer av föroreningar som möjligt då man bygger nytt eller renoverar gammalt.

A new method for detecting hidden moisture damage was tested in a pilot study. Volatile organic compounds (VOCs) were sampled from within different building structures and the emission profiles were compared using principal component analysis (PCA). When all 60 samples were examined at the chemical group level (i.e. aldehydes, ketones, etc.), the samples separated into two major groups, representing concrete and wooden structures. Alcohols, terpenes, ketones, hydrocarbons, polyaromatic hydrocarbons (PAHs) and a group of unidentified compounds were more strongly associated with structures in which the predominant construction material was concrete, than in structures mainly made of wood. For the 20 samples from wooden structures, 8 chemical groups were more abundant in those sampled in moisture-damaged buildings than in those sampled in the building with no known damage. These were terpenes, phenols, ketones, aldehydes, alcohols, furans, PAH and carboxylic acids. Emissions from moisture-damaged concrete structures were higher than from wooden ones but more chemical groups were emitted from moisture-damaged wooden structures. The results indicate that sampling and analyses of VOCs inside building structures, and using PCA for data analysis, are useful for finding chemical fingerprints for moisture damages but more data are needed to substantiate this.

The aims of this study were to find important emissions patterns for different building structures and whether the same compounds also could be found in room air. VOCs were sampled both within different building structures and from air in the adjacent rooms. The emission profiles were compared using multivariate data analysis techniques and influential and significant chemical compounds were identified. Patterns typical for tar in concrete structures could be identified but the same pattern could not be seen in room air. When comparing wooden structures, most of the influential compounds found were regarded as particle board emissions. This pattern could also be seen in room air. The presence of the same chemical compounds in both building structures and room air could be partly from the structure but, because they were common indoor chemicals, they also have other sources that affect the indoor air.

A common approach when investigating indoor air problems is sampling volatile organic compounds (VOCs) in the air within rooms. The chemical composition of indoor air is complex and there are many sources of the chemicals present. Measurements of emissions from building materials are commonly collected only from surface materials when estimating the effects of building structures on indoor air quality. The potential for exposure from sources in hidden spaces such as wall cavities is poorly understood and little information exists on the toxic potential of chemical releases resulting from the moisture-related degradation of building materials. While their impact on health is often unclear, VOCs can be used to indicate technical problems in buildings. Sampling the air inside building structures should exclude emissions from other sources, leaving only those from the construction materials. The aims of this study were to find important emissions profiles in different types of building structures and to determine whether the same profiles were also present in indoor air. The emissions profiles for different building structures were compared using multivariate data analysis techniques, and influential and significant chemical compounds were identified. Emissions profiles typical for PVC flooring, polystyrene insulations and wood preservatives were identified. The specific profiles found in the structures could not be found in indoor air, although small amounts of individual compounds were sometimes found. The combination of sampling inside building structures and data analysis using multivariate methods gave us more information about materials and VOCs present in building structures than could have been obtained using traditional indoor air measurements. This method therefore facilitates technical investigations in problem buildings and aids in locating and removing emission sources with suspected effects on occupant health.

Exposure to air pollution is of great concern for public health although studies on the associations between exposure estimates and personal exposure are limited and somewhat inconsistent. The aim of this study was to quantify the associations between personal nitrogen oxides (NOx), ozone (O3) and particulate matter (PM10) exposure levels and ambient levels, and the impact of climate and time spent outdoors in two cities in Sweden. Subjects (n = 65) from two Swedish cities participated in the study. The study protocol included personal exposure measurements at three occasions, or waves. Personal exposure measurements were performed for NOx and O3 for 24 h and PM10 for 24 h, and the participants kept an activity diary. Stationary monitoring stations provided hourly data of NOx, O3 and PM, as well as data on air temperature and relative humidity. Data were analysed using mixed linear models with the subject-id as a random effect and stationary exposure and covariates as fixed effects. Personal exposure levels of NOx, O3 and PM10 were significantly associated with levels measured at air pollution monitoring stations. The associations persisted after adjusting for temperature, relative humidity, city and wave, but the modelled estimates were slightly attenuated from 2.4% (95% CI 1.8–2.9) to 2.0% (0.97–2.94%) for NOx, from 3.7% (95% CI 3.1–4.4) to 2.1% (95% CI 1.1–2.9%) for O3 and from 2.6% (95% 0.9–4.2%) to 1.3% (95% CI − 1.5–4.0) for PM10. After adding covariates, the degree of explanation offered by the model (coefficient of determination, or R2) did not change for NOx (0.64 to 0.63) but increased from 0.46 to 0.63 for O3, and from 0.38 to 0.43 for PM10. Personal exposure to NOx, O3 and PM has moderate to good association with levels measured at urban background sites. The results indicate that stationary measurements are valid as measure of exposure in environmental health risk assessments, especially if they can be refined using activity diaries and meteorological data. Approximately 50–70% of the variation of the personal exposure was explained by the stationary measurement, implying occurrence of misclassification in studies using more crude exposure metrics, potentially leading to underestimates of the effects of exposure to ambient air pollution.

Production of wood pellets is a relatively new and expanding industry in which the exposure profiles differ from those in other wood-processing industries like carpentries and sawmills where there are lower levels of wood dust. Sixty-eight personal exposure measurements of wood dust (inhalable and total dust) and resin acids were collected for 44 participants at four production plants located in Sweden. Results were used to estimate within- and between-worker variability and to identify uniformly exposed groups and determinants of exposure. In addition, overexposure, whether the risk of the long-term mean exposure of a randomly selected worker exceeding the occupational exposure limit is acceptably low, was calculated as well as the underestimation of the exposure-response relationship (attenuation). Greater variability in exposure between work shifts than between workers was observed with the within-worker variation accounting for 57-99% of the total variance in the individual-based model. Several uniformly exposed groups were detected but were mostly associated with a between-worker variation of zero which is an underestimation of the between-worker variation but an indication of uniformly exposed groups. Cleaning was identified as a work task that increases exposure slightly; so reducing workers' exposure during this operation is advisable. The levels of wood dust were high and were found to pose unacceptable risks of overexposure at all plants for inhalable dust and at three out of four plants for total dust. These findings show that exposure to dust needs to be reduced in this industry. For resin acids, the exposure was classed as acceptable at all plants. According to an individual-based model constructed from the data, the level of attenuation was high, and thus there would be substantial bias in derived dose-response relationships.

Background. To investigate the dermal uptake of 4,4'-diphenylmethane diisocyanate (4,4'-MDI), a study was performed in which 2 female volunteers were exposed to 10 and 25 mg, respectively, of 4,4'-MDI by applying 2.0% 4,4'-MDI in petrolatum over areas where the surface concentration corresponded to 800 µg/cm(2) . Ten days later, they developed eczematous dermatitis at the area of application.

Objectives. To investigate whether the dermal application caused active sensitization to 4,4'-MDI.

Methods. Chemical analysis of the 4,4'-MDI preparation used in the application and the amount of 4,4'-MDI not absorbed by the skin was performed with liquid chromatography-mass spectrometry. The volunteers were tested with serial dilutions of 4,4'-MDI and the potentially cross-reacting substances 4,4'-diaminodiphenylmethane (4,4'-MDA), p-phenylenediamine (PPD), and dicyclohexylmethane-4,4'-diisocyanate (DMDI).

Results. Patch test results suggested that the volunteers were actively sensitized to 4,4'-MDI following the dermal uptake study, as they reacted positively to 4,4'-MDA, a marker for 4,4'-MDI allergy. No positive reactions were seen to PPD or DMDI. Chemical investigation confirmed that the correct concentration had been used for the dermal uptake study, and showed that about 70% of the applied 4,4'-MDI was not absorbed.

Conclusions. A dermal uptake study with 4,4'-MDI in 2.0% pet. with an occlusion time of 8 hr induced active sensitization to 4,4'-MDI and subsequently to 4,4'-MDA.

Very little is known about the dermal uptake of isocyanates, and dermal exposure to isocyanates has been discussed as a factor involved in the induction of respiratory diseases. To investigate the dermal uptake of diphenylmethane-4,4'-diisocyanate (4,4'-MDI). Four volunteers were dermally exposed to 10, 25, 49 and 50 mg 4,4'-MDI, respectively, for eight hours. The exposed areas were tape stripped. Urine and blood were biologically monitored for 48 hours. Tape strips, plasma, and urine were analysed by liquid chromatography-mass spectrometry. In total, 35-70% of the applied dose of 4,4'-MDI was absorbed by the skin. Very low fractions of applied dose were found in the tape strips. The 4,4'-MDA concentration in plasma and urine was low, but peaked in urine at 10-14 hours and plasma at 8-32 hours after exposure. 4,4'-MDI is readily absorbed by human skin. Only small fractions of 4,4'-MDI remain as such in the superficial skin layers. The amounts found in blood and urine were only small fractions of the total applied doses which indicates that very small amounts of 4,4'-MDI penetrate the skin and reach the blood stream. The dermal uptake and distribution of 4,4'-MDI is much slower compared to that associated with airway uptake. Our data strongly indicate that formation of 4,4'-MDA from 4,4'-MDI upon reacting with water in the skin can only occur to a very limited extent.

When assessing occupational exposures, repeated measurements are in most cases required. Repeated measurements are more resource intensive than a single measurement, so careful planning of the measurement strategy is necessary to assure that resources are spent wisely. The optimal strategy depends on the objectives of the measurements. Here, two different models of random effects analysis of variance (ANOVA) are proposed for the optimization of measurement strategies by the minimization of the variance of the estimated log-transformed arithmetic mean value of a worker group, i.e. the strategies are optimized for precise estimation of that value. The first model is a one-way random effects ANOVA model. For that model it is shown that the best precision in the estimated mean value is always obtained by including as many workers as possible in the sample while restricting the number of replicates to two or at most three regardless of the size of the variance components. The second model introduces the ‘shared temporal variation’ which accounts for those random temporal fluctuations of the exposure that the workers have in common. It is shown for that model that the optimal sample allocation depends on the relative sizes of the between-worker component and the shared temporal component, so that if the between-worker component is larger than the shared temporal component more workers should be included in the sample and vice versa. The results are illustrated graphically with an example from the reinforced plastics industry. If there exists a shared temporal variation at a workplace, that variability needs to be accounted for in the sampling design and the more complex model is recommended.

Methyl methacrylate (MMA) is a commonly used chemical in dental work that can cause dermatitis. Nineteen dental technicians participated in a field study in which potential dermal exposure to MMA and exposure determinants, including glove use and MMA vapour in the breathing zone, were repeatedly monitored during three consecutive days. Using patches placed on various parts of their hands we observed that the fingers and palms of the dental technicians were exposed to MMA, and their forefingers were significantly more exposed than their ring fingers; this is based on pooled data for both left and right hands (p = 0.04). The exposure variability was greater between workers than within worker (i.e. day-to-day variability), but the between worker variability was to some extent explained by a model which included the tested determinants. Neither the amount of MMA vapours in the breathing zone nor glove use was consistently correlated with the dermal exposure. Thus, the effects of glove use and the distribution of exposure to MMA on the hands in working environments needs to be further investigated.

OBJECTIVES: Although corticosteroids have been used for over 50 years as anti-inflammatory and anti-proliferative agents, few studies have examined their exposure levels and health effects on workers employed in the corticosteroid manufacturing industry. The aims of the study reported here were to develop a tape-stripping technique for monitoring budesonide (a corticosteroid used in inhalators for treating respiratory diseases) and to apply the method in a pilot study to estimate the potential dermal exposure to budesonide among workers at a pharmaceutical formulation site. METHODS: The tape-stripping method was evaluated by applying 0.5 and 2.07 microg of budesonide dissolved in ethanol on tape strips. The same amounts were also applied on a cleaned glass plate and human skin of volunteers, which were then stripped by series of tapes immediately, and 30 min later, the amounts collected by the tapes were measured. Finally, the technique was used to study the exposure of budesonide among eight employees at a pharmaceutical industry site. Three exposure sites were tested: the tip of the forefinger, palm of the hand and ventral part of the lower arm. Five consecutive tape strips per sampling site were used in both the recovery studies and the field study. RESULTS: The mean overall recoveries from spiked tapes and the glass plate were 96 and 81%, respectively, while for human skin the corresponding figure was 38%, (for applications of 2.07 microg; no detectable amounts were recovered from human skin after 0.5 microg applications). The recovered amount was found on two consecutive tapes after 0 min, but only on the first tape strip after 30 min. The inter-individual variability was 4-fold. In the field, quantifiable amounts were found for four of eight employees and a concentration gradient was detected along the two or three consecutive tape strips. The tip of the forefinger and the palm of the hand were the most highly exposed sites to budesonide. CONCLUSIONS: A tape-stripping method can be used to determine potential dermal exposure to budesonide. The results also indicate that budesonide is taken up by the skin of operators who are exposed to the substance at their workplace.

OBJECTIVES: Occupational assessments of chemical exposure are often inadequate because of difficulties in obtaining sufficient numbers of measurements by trained professionals (experts). The objective of this study was to determine whether workers can provide unbiased data via self-assessments of exposure facilitated by the use of simple passive monitors for personal sampling.

METHODS: Untrained workers obtained personal measurements of their exposures to gaseous contaminants (terpenes in sawmills and styrene in reinforced plastics factories) with passive monitors and written instructions. To study the validity of the self-assessments, an occupational hygienist performed exposure measurements on the same occupational groups after the workers had obtained two or more measurements independently. The potential bias of the self-assessments was evaluated by comparing the self-assessments with the expert assessments in mixed-effects statistical models.

RESULTS: A total of 153 terpene (97 self and 56 expert) and 216 styrene (159 self and 57 expert) measurements were obtained from four sawmills and six reinforced plastics factories, respectively. No significant differences in the geometric mean exposures were observed between the self-assessments and the expert assessments in 3 of 4 sawmills and 5 of 6 reinforced plastics factories (P > 0.10). The potential bias of the self-assessments of exposure ranged from less than 0.1% to 102% and was less than 17% in 9 of the 10 groups investigated.

CONCLUSIONS: The results indicate that untrained, unsupervised workers are able to collect consistently unbiased exposure data by employing currently available passive monitors.

Diisocyanates are a group of chemically reactive agents, which are used in the production of coatings, adhesives, polyurethane foams, and parts for the automotive industry and as curing agents for cores in the foundry industry. Dermal and inhalation exposure to methylene bisphenyl isocyanate (MDI) is associated with respiratory sensitization and occupational asthma. However, limited research has been performed on the quantitative evaluation of dermal and inhalation exposure to MDI in occupationally exposed workers. The objective of this research was to quantify dermal and inhalation exposure levels in iron foundry workers. Workers involved in mechanized moulding and mechanized production of cores were monitored: 12 core makers, 2 core-sand preparers, and 5 core installers. Personal breathing-zone levels of MDI were measured using impregnated filter sampling. Dermal exposure to MDI was measured using a tape-strip technique. Three or five consecutive tape-strip samples were collected from five exposed skin areas (right and left forefingers, left and right wrists, and forehead). The average personal air concentration was 0.55 microg m(-3), 50-fold lower than the Swedish occupational exposure limit of 30 microg m(-3). The core makers had an average exposure of 0.77 microg m(-3), which was not significantly different from core installers' and core-sand preparers' average exposure of 0.16 microg m(-3) (P = 0.059). Three core makers had a 10-fold higher inhalation exposure than the other core makers. The core makers' mean dermal exposure at different skin sites varied from 0.13 to 0.34 microg while the two other groups' exposure ranged from 0.006 to 0.062 microg. No significant difference was observed in the MDI levels between the skin sites in a pairwise comparison, except for left forefinger compared to left and right wrist (P < 0.05). In addition, quantifiable but decreasing levels of MDI were observed in the consecutive tape strip per site indicating MDI penetration into the skin. This study indicates that exposure to MDI can be quantified on workers' skin even if air levels are close to unquantifiable. Thus, the potential for uncured MDI to deposit on and penetrate into the skin is demonstrated. Therefore, dermal exposure along with inhalation exposure to MDI should be measured in the occupational settings where MDI is present in order to shed light on their roles in the development of occupational isocyanate asthma.

Background: There are numerous factors including physical, biomechanical, and individual that influence exposure to hand-transmitted vibration (HTV) and cause variability in the exposure measurements. Knowledge of exposure variability and determinants of exposure could be used to improve working conditions. We performed a quasi-experimental study, where operators performed routine work tasks in order to obtain estimates of the variance components and to evaluate the effect of determinants, such as machine–wheel combinations and individual operator characteristics.

Methods: Two pre-defined simulated work tasks were performed by 11 operators: removal of a weld puddle of mild steel and cutting of a square steel pipe. In both tasks, four angle grinders were used, two running on compressed air and two electrically driven. Two brands of both grinding and cutting wheels were used. Each operator performed both tasks twice in a random order with each grinder and wheel and the time to complete each task was recorded. Vibration emission values were collected and the wheel wear was measured as loss of weight. Operators’ characteristics collected were as follows: age, body height and weight, length and volume of their hands, maximum hand grip force, and length of work experience with grinding machines (years). The tasks were also performed by one operator who used four machines of the same brand. Mixed and random effects models were used in the statistical evaluation.

Results: The statistical evaluation was performed for grinding and cutting separately and we used a measure referring to the sum of the 1-s r.m.s. average frequency-weighted acceleration over time for completing the work task (a _sa). Within each work task, there was a significant effect as a result of the determinants ‘the machine used’, ‘wheel wear’, and ‘time taken to complete the task’. For cutting, ‘the brand of wheel’ used also had a significant effect. More than 90% of the inherent variability in the data was explained by the determinants. The two electrically powered machines had a mean a _sa that was 2.6 times higher than the two air-driven machines. For cutting, the effect of the brand of wheel on a _sa was ~0.1 times. The a _sa increased both with increasing wheel wear and with time taken to complete the work task. However, there were also a number of interaction effects which, to a minor extent, modified the a _sa. Only a minor part (1%) of the total variability was attributed to the operator: for cutting, the volume of the hands, maximum grip force, and body weight were significant, while for grinding, it was the maximum grip force. There was no clear difference in a _sa between the four copies of the same brand of each machine.

Conclusions: By including determinants that were attributed to the brand of both machine and wheel used as well as the time taken to complete the work task, we were able to explain >90% of the variability. The dominating determinant was the brand of the machine. Little variability was found between operators, indicating that the overall effect as due to the operator was small.

OBJECTIVES: To quantify variance components of hand-arm vibration exposure from data collected in a laboratory study of four different angle grinders.

METHODS: Four different angle grinders were sent to seven laboratories for grinding tests by three operators at each laboratory. Vibration in both the throttle and support handles was measured. For one grinder, the experimental set-up was repeated and two measurements were collected for that specific grinder.

RESULTS: At least one-third of the estimated variability is attributable to the wheel and less than one-third to the operator. In repeated experiments, between-occasion, operator and wheel factors explained 4, 29 and 17% of the total variability, respectively.

CONCLUSIONS: Since measured vibrations in the support and throttle handles are significantly differed, measurements should be taken at both locations. Factors influencing vibration variability include the presence/absence of an auto balance unit, wheel and operator, but other factors remain to be elucidated.

Background: Measurements of exposure to vibrations from hand-held tools are often conducted on a single occasion. However, repeated measurements may be crucial for estimating the actual dose with good precision. In addition, knowledge of determinants of exposure could be used to improve working conditions. The aim of this study was to assess hand–arm vibration (HAV) exposure during different grinding operations, in order to obtain estimates of the variance components and to evaluate the effect of work postures.

Methods: Ten experienced operators used two compressed air-driven angle grinders of the same make in a simulated work task at a workplace. One part of the study consisted of using a grinder while assuming two different working postures: at a standard work bench (low) and on a wall with arms elevated and the work area adjusted to each operator’s height (high). The workers repeated the task three times. In another part of the study, investigating the wheel wear, for each grinder, the operators used two new grinding wheels and with each wheel the operator performed two consecutive 1-min grinding tasks. Both grinding tasks were conducted on weld puddles of mild steel on a piece of mild steel. Measurements were taken according to ISO-standard 5349 [the equivalent hand–arm-weighted acceleration (m s⁻²) averaged over 1 min]. Mixed- and random-effects models were used to investigate the influence of the fixed variables and to estimate variance components.

Results: The equivalent hand–arm-weighted acceleration assessed when the task was performed on the bench and at the wall was 3.2 and 3.3 m s⁻², respectively. In the mixed-effects model, work posture was not a significant variable. The variables ‘operator’ and ‘grinder’ together explained only 12% of the exposure variability and ‘grinding wheel’ explained 47%; the residual variability of 41% remained unexplained. When the effect of grinding wheel wear was investigated in the random-effects model, 37% of the variability was associated with the wheel while minimal variability was associated with the operator or the grinder and 37% was unexplained. The interaction effect of grinder and operator explained 18% of the variability. In the wheel wear test, the equivalent hand–arm-weighted accelerations for Grinder 1 during the first and second grinding minutes were 3.4 and 2.9 m s⁻², respectively, and for Grinder 2, they were 3.1 and 2.9 m s⁻², respectively. For Grinder 1, the equivalent hand–arm-weighted acceleration during the first grinding minute was significantly higher (P = 0.04) than during the second minute.

Conclusions: Work posture during grinding operations does not appear to affect the level of HAV. Grinding wheels explained much of the variability in this study, but almost 40% of the variance remained unexplained. The considerable variability in the equivalent hand–arm-weighted acceleration has an impact on the risk assessment at both the group and the individual level.

The objective of this study was to examine workers’ mental interpretation models developed in response to occupational chemical exposure. The study was performed in six companies within the reinforced plastics industry in northern Sweden, in which styrene was used; 32 workers participated in the study. Each worker performed between four and seven exposure measurements. Before receiving each result of the second to seventh measurements, the workers were asked to predict the level of their next exposure measurement. Their predictions were evaluated with respect to two judgmental principles: coherence (that the predictions are based on logical decision rules, that is, the mean value of the prior exposure levels); and correspondence (the predictions have high empirical accuracy) by calculating the mean absolute percent forcast error (MAPE). The coherence principle was tested by comparing each of the workers’ predictions with the mean, median, and last exposure level (last value) of the prior measurements. The correspondence principle was tested by comparing the worker’s prediction with the outcome of the measurement. The coherence principle was found to be the best descriptor of the workers’ predictions and the median model had the best fit. The mean model had a similar but significantly poorer fit (MAPE values of 29 and 31, respectively). The correspondence model had a poor fit with a MAPE of 54. The workers’ predictions were generally lower than their average exposures. We conclude that the workers’ interpretation model can be best described by a coherence model rather than by a correspondence model.

OBJECTIVES: The aim was to investigate how workers interpret and act upon results from self-assessment of exposure (SAE). METHODS: Workers in four sawmills in Sweden were supplied with diffusive samplers for measurement of terpenes. Workers received both oral and written instructions about terpenes, their medical effects and how to handle the samplers. Responsibility for sampling was left to the individual worker; written feedback about terpene levels was provided after each measurement. The number of measurements was registered. The workers and supervisors were interviewed about their attitudes, perceived control of their work environment, need for preventive actions and future surveillance of the workplace. RESULTS: In total, 28 workers performed 100 terpene measurements. At one sawmill, there was a significant association between exposure levels and the number of measurements performed by each worker (rho = 0.79, P = 0.03). Contrary to instructions, supervisors played an important role in spontaneous organization of the measurements at each mill. Four measurements revealed terpene concentrations that exceeded the occupational exposure limits, and one preventive action was taken as a consequence of high levels. Seventy percent of the workers could not identify any reason for more measurements. Only 15% considered the measurements as their 'own' project, and the rest stated that they participated in order to satisfy the researchers. CONCLUSIONS: Previous studies have shown that workers can perform valid measurements, both select a day and technically perform measurements. This study indicates that this ability is not sufficient to ensure that measurements will be done or that implementing measurements will result in preventive actions. Workers need additional support to take preventive actions and use SAE for ongoing surveillance.

Exposure to whole-body vibration (WBV) may cause health problems, e.g. lumbago. The risk will depend on intensity and duration. Exposure to WBV in vehicles varies due to several factors as the vehicle type, the terrain condition, the driver, the speed etc. To estimate the health risk, the measurement strategy has to consider this variation. Furthermore, to understand the importance of different preventive strategies, the cause of the variation has to be known. The objective of this study was to describe variation in exposure to seated WBV during occupational operation of forwarder vehicles and to investigate sources for variation. WBV was measured in 10 various terrain types for seven forwarders operated by 11 drivers. For each driver there were between four and 35 measurements. The measurement periods varied between 0.2 and 34 min. The vibration total value (a_v) and total vibration dose value (VDV_t) were determined. Results showed that WBV exposure varied considerably and that this variation could result in different conclusions regarding health risk assessments. The highest magnitudes were achieved during travelling activities. During travelling empty, variations in a_v were significantly dependent upon forwarder model and terrain type. No significant predictor for variation in VDV_t was however found for travelling empty. During travelling loaded the forwarder model and operator were the most important predictors for variation in a_v. Variation in VDV_t was also dependent on the forwarder model during travelling loaded.

Objectives: In an occupational environment, passive sampling could be an alternative to active sampling with pumps for sampling of dust. One passive sampler is the University of North Carolina passive aerosol sampler (UNC sampler). It is often analysed by microscopic imaging. Promising results have been shown for particles above 2.5 µm, but indicate large underestimations for PM_2.5. The aim of this study was to evaluate, and possibly improve, the UNC sampler for stationary sampling in a working environment.

Methods: Sampling was carried out at 8-h intervals during 24 h in four locations in an open pit mine with UNC samplers, respirable cyclones, PM₁₀ and PM_2.5 impactors, and an aerodynamic particle sizer (APS). The wind was minimal. For quantification, two modifications of the UNC sampler analysis model, UNC sampler with hybrid model and UNC sampler with area factor, were compared with the original one, UNC sampler with mesh factor derived from wind tunnel experiments. The effect of increased resolution for the microscopic imaging was examined.

Results: Use of the area factor and a higher resolution eliminated the underestimation for PM₁₀ and PM_2.5. The model with area factor had the overall lowest deviation versus the impactor and the cyclone. The intraclass correlation (ICC) showed that the UNC sampler had a higher precision and better ability to distinguish between different exposure levels compared to the cyclone (ICC: 0.51 versus 0.24), but lower precision compared to the impactor (PM₁₀: 0.79 versus 0.99; PM_2.5: 0.30 versus 0.45). The particle size distributions as calculated from the different UNC sampler analysis models were visually compared with the distributions determined by APS. The distributions were obviously different when the UNC sampler with mesh factor was used but came to a reasonable agreement when the area factor was used.

Conclusions: High resolution combined with a factor based on area only, results in no underestimation of small particles compared to impactors and cyclones and a better agreement with the APS’s particle size distributions. The UNC sampler had lower precision than the impactors, but higher than the respirable cyclone. The UNC sampler with area factor could be used for PM_2.5, PM₁₀ and respirable fraction measurements in this working environment without wind.

The aim of this study was to make a preliminary evaluation of the University of North Carolina passive aerosol sampler (UNC sampler) for personal air sampling of particles. Nine personal air samplings of respirable fraction were conducted in an open-pit mine, with pairwise UNC samplers and a respirable cyclone mounted on the chest of workers. UNC samples were analyzed with scanning electron microscopy (SEM) and to some extent energy dispersive X-ray spectroscopy (EDS). Respirable cyclone filter samples were weighed. Correlations and particle elemental compositions were described. Microscopic imaging of the collection surface showed that the particles were heterogeneously deposited across the surface of the UNC sampler. Collected particles were shaped as gravel particles and the resulting particle size distribution in air showed a peak at ca. 3 µm aerodynamic diameter, similarly to what has previously been reported from the same mine. The elemental composition indicated mineral origin. All correlations between the airborne mass concentrations from UNC samplers and respirable cyclones (Pearson = 0.54 and Spearman = 0.43) and between pairs of parallel UNC samplers (Pearson = 0.55 and Spearman = 0.67) were weak. The UNC sampler mass concentrations were approximately 30 times higher than those measured with the respirable cyclone. In conclusion, the UNC sampler, when used for personal sampling in a mine, provides a reasonable particle size distribution and the deposited particles appeared to be of mineral origin and not from textile or skin but the approximately 30-fold overestimation of mass concentrations when comparing with respirable cyclone sampling indicates that further improvements are necessary. Positioning of the sampler may be critical and moving the UNC sampler from the chest to e.g. the top of a helmet might be an improvement. Grounding of the sampler in order to avoid static electricity might also be useful. The UNC sampler should continue to be researched for personal sampling, as passive sampling might become a useful alternative to more laborious sampling techniques.

The University of North Carolina passive aerosol sampler (UNC sampler) could be an alternative when measuring occupational dust exposure, but the time required for microscopic imaging of the sampler needs to be reduced to make it more attractive. The aims of this study were to 1) characterise the effect on precision when reducing imaging, in order to shorten analysis time and 2) assess if the position of the images makes a difference. Eighty-eight samplers were deployed in different locations of an open pit mine. Sixty images were captured for each UNC sampler, covering 51% of its collection surface, using scanning electron microscopy. Bootstrapped samples were generated with different image combinations, to assess the within-sampler coefficient of variation (CV_ws) for different numbers of images. In addition, the particle concentration relative to the distance from the centre of the sampler was studied. Reducing the number of images collected from the UNC sampler led to up to 8.3% CV_ws for ten images when calculating respirable fraction. As the overall CV has previously been assessed to 36%, the additional contribution becomes minimal, increasing the overall CV to 37%. The mean concentrations of the images were modestly related to distance from the centre of the sampler. The CV_ws changed from 8.26% to 8.13% for ten images when applying rules for the image collection based on distance. Thus, the benefit of these rules on the precision is small and the images can therefore be chosen at random. In conclusion, reducing the number of images analysed from 60 to 10, corresponding to a reduction of the imaged sampling area from 51% to 8.5%, results in a negligible loss in precision for respirable fraction dust measurements in occupational environments.

Objectives: Dust is generally sampled on a filter using air pumps, but passive sampling could be a cost-effective alternative. One promising passive sampler is the University of North Carolina passive aerosol sampler (UNC sampler). The aim of this study is to characterize and compare the UNC sampler’s performance with PM₁₀ and PM_2.5 impactors in a working environment.

Methods: Area sampling was carried out at different mining locations using UNC samplers in parallel with PM_2.5 and PM₁₀ impactors. Two different collection surfaces, polycarbonate (PC) and carbon tabs (CT), were employed for the UNC sampling. Sampling was carried out for 4–25 hours.

Results: The UNC samplers underestimated the concentrations compared to PM₁₀ and PM_2.5 impactor data. At the location with the highest aerosol concentration, the time-averaged mean of PC showed 24% and CT 35% of the impactor result for PM_2.5. For PM₁₀, it was 39% with PC and 58% with CT. Sample blank values differed between PC and CT. For PM_2.5, PC blank values were ~7 times higher than those of CT, but only 1.8 times higher for PM₁₀. The blank variations were larger for PC than for CT.

Conclusions: Particle mass concentrations appear to be underestimated by the UNC sampler compared to impactors, more so for PM_2.5 than for PM₁₀. CT may be preferred as a collection surface because the blank values were lower and less variable than for PC. Future validations in the working environment should include respirable dust sampling.

PURPOSE: To describe the self-reported ambient cold exposure in northern Sweden and to relate the level of cumulative cold exposure to the occurrence of sensory and vascular hand symptoms. We hypothesize that cold exposure is positively related to reporting such symptoms.

METHODS: A questionnaire about cold exposure and related symptoms was sent out to 35,144 subjects aged 18-70 years and living in northern Sweden.

RESULTS: A total of 12,627 out of 35,144 subjects returned the questionnaire (response rate 35.9%). Subjects living in the rural alpine areas reported more extensive cold exposure both during work and leisure time compared to the urbanized coastal regions. Frostbite in the hands was present in 11.4% of men and 7.1% of women, cold sensitivity was present in 9.7 and 14.4%, and Raynaud's phenomenon was present in 11.0% of men and 14.0% of women. There was a positive association between cumulative cold exposure and neurovascular hand symptoms.

CONCLUSION: The present study demonstrates that the cold environment in northern Sweden might be an underestimated health risk. Our hypothesis that cold exposure is positively related to reporting of neurovascular hand symptoms was supported by our findings. In addition, such symptoms were common not only in conjunction with an overt cold injury. Our results warrant further study on pathophysiological mechanisms and suggest the need for confirmatory prevalence studies to support national public health planning.

Objectives: To characterise cold sensitivity using a semi-structured interview, physical examination, thermal quantitative sensory testing (QST), and laser speckle contrast analysis (LASCA).

Methods: Eight women and four men, ages 22–74, with cold sensitivity were interviewed andexamined by an occupational physician. Thermal perception thresholds were established using QST, on the pulp of the index and little finger of the most affected hand. Skin perfusion in the dorsum of the hand was measured using LASCA, at baseline, after two-minute 12°C water immersion, and during rewarming.

Results: The physical examination yielded few findings indicative of vascular or neurosensory pathology. One subject (8%) had impaired thermal perception thresholds. LASCA at baseline showed absent proximal-distal perfusion gradients in six subjects (50%), and a dyshomogeneousperfusion pattern in five (42%). Perfusion on a group level was virtually unchanged by cold stress testing (median 52.5 PU; IQR 9.0 before versus 51.3 PU; IQR 27.2 afterwards).

Conclusions: Physical examination and thermal QST offered little aid in diagnosing cold sensitivity, which challenges the neurosensory pathophysiological hypothesis. LASCA indicated disturbances in microvascular regulation and could prove a useful tool in future studies on cold sensitivity.

Aim To identify possible risk factors for cold sensitivity, by comparing cases to controls with regard to demographic and anthropometric characteristics, previous illnesses and injuries as well as ambient exposures.

Methods Through a questionnaire responded to by the general population (n=12,627) cold sensitivity cases (n=502) and matched controls (n=1,004) were identified and asked to respond to a second questionnaire with focus on different aspects of cold sensitivity, hereditary factors, previous diseases, medication, tobacco use as well as exposure to ambient cold climate and hand-arm vibration (HAV).

Results In total, 997 out of 1506 study subjects answered the second questionnaire, 374 cases and 623 match controls. Identified risk factors among the cases were frostbite of the hands Odds Ratio (OR) 10.3 (95% confidence interval (CI) 5.5-19.3), rheumatic disease OR 3.1 (95% CI 1.7-5.7), upper extremity nerve injury OR 2.0 (95% CI 1.3-3.0), and vascular disease OR 1.9 (95% CI 1.2-2.9). Sex differences in risk factors were HAV exposure for men and cold exposure for women increased the risk of cold sensitivity. Rheumatic diseases and migraine increased the risk of cold sensitivity among women but not among men.

Conclusions The present study shows that cold sensitivity is associated with both inherent factors, acquired conditions and external exposures. Among acquired conditions, frostbite, vascular disease, nerve injury, joint disorders and migraine are significantly related to the reporting of cold sensitivity. Among external exposures, both cold climate and HAV exposure are significantly associated to cold sensitivity, and thus suitable targets for primary preventive measures. There was a difference in risk factors related to sex. HAV exposure for men and cold exposure for women increased the risk of cold sensitivity.

OBJECTIVE: To determine if occupational exposure to cold environments is associated with incident airway symptoms in previously healthy workers.

METHODS: A prospective, survey-based, closed-cohort study was conducted on a sample of 5017 men and women between 18 and 70 years of age, living in northern Sweden. Data on occupation, occupational and leisure-time cold exposure, airway symptoms, general health, and tobacco habits were collected during the winters of 2015 (baseline) and 2021 (follow-up). Stepwise multiple logistic regression was used to determine associations between baseline variables and incident airway symptoms.

RESULTS: For individuals working at baseline, without physician-diagnosed asthma or chronic obstructive pulmonary disease, reporting any occupational cold exposure was associated with incident wheeze (OR 1.41; 95% CI 1.06-1.87) and incident productive cough (OR 1.37; 95% CI 1.06-1.77), but not incident long-standing cough (OR 0.98; 95% CI 0.74-1.29), after adjusting for age, body mass index, daily smoking, and occupational physical workload. Detailed analysis of the occupational cold exposure rating did not reveal clear exposure-response patterns for any of the outcomes.

CONCLUSIONS: Occupational cold exposure was robustly associated with incident wheeze and productive cough in previously healthy workers. This adds further support to the notion that cold air is harmful for the airways, and that a structured risk assessment regarding occupational cold exposure could be considered for inclusion in the Swedish workplace legislation. Further studies are needed to elaborate on exposure-response functions, as well as suggest thresholds for hazardous cold exposure.

This cross-sectional study aimed to describe exposure to cold climate and hand-arm vibration (HAV) as well as neurosensory and vascular symptoms and clinical findings among open-pit Arctic miners. It was based on data from questionnaires and physical examinations, including 177 men and 75 women from two open-pit mines in Sweden and Norway (response rate 54%). Working outdoors or in an unheated building or machine for at least two hours per day was reported by 44% and HAV exposure of the same duration by 10%. Neurosensory symptoms (e.g. reduced perception of touch) in the hands were reported by 47% and Raynaud’s phenomenon by 14%. In brief conclusion, the study showed that Arctic miners were commonly exposed to both cold temperatures and HAV. They also reported a broad range of neurosensory and vascular symptoms in their hands and had abnormal clinical findings related to the symptoms. The results emphasise the need for additional preventive measures in this occupational setting.

Cold sensitivity, a common and disabling sequela of hand injury, can be assessed using the Cold Intolerance Symptom Severity (CISS) questionnaire, rating symptoms on a scale from 4 to 100. The primary objective of this study was to define a clinical cut-off for abnormal cold sensitivity based on the CISS score in a healthy working-age population. The secondary objective was to investigate how age, gender and previous injuries and diseases influence CISS scoring. In this study, 1239 out of 1582 selected healthy subjects of working age living in northern Sweden completed the questionnaire, yielding a response rate of 78%. The 95th percentile for the CISS score was 49.5 for men and 53.0 for women. The effects of age, gender and previous injuries and diseases were minor and not considered clinically relevant. The results support that a CISS score above 50 should be considered as abnormal cold sensitivity. Level of evidence: III

The aim of this study was to determine the association between individual and external exposure factors, and the reporting of Raynaud’s phenomenon, with or without concomitant cold sensitivity. In a population-based nested case–control study, cases with Raynaud’s phenomenon (N = 578), and matched controls (N = 1156), were asked to respond to a questionnaire focusing on different risk factors. Univariate and multiple conditional logistic regression were performed. Analyses were stratified according to whether the cases reported cold sensitivity or not. In total, 1400 out of 1734 study subjects answered the questionnaire (response rate 80.7%). In the final multiple model, the factor with the strongest association to Raynaud’s phenomenon, with and without cold sensitivity, was previous frostbite affecting the hands (OR 12.44; 95% CI 5.84–26.52 and OR 4.01; 95% CI 1.78–9.01, respectively). Upper extremity nerve injury was associated to reporting Raynaud’s phenomenon and cold sensitivity (OR 2.23; 95% CI 1.29–3.85), but not Raynaud’s phenomenon alone. Reporting any exposure to hand-arm vibration or cumulative cold exposure was significant in univariate analyses for cases with both Raynaud’s phenomenon and cold sensitivity, but not in the multiple model. Raynaud’s phenomenon is strongly associated to previous cold injury, with a larger effect size among those who also report cold sensitivity. The fact that only upper extremity nerve injury differed significantly between case groups in our multiple model offers additional support to the neural basis for cold sensitivity.

Background: Raynaud’s phenomenon is common condition, but little is known about the natural course. The primary aim of this study was to determine the incidence, remission, and persistence proportions of Raynaud’s phenomenon in the general population of northern Sweden. Secondary aims were to determine how individual and exposure factors affect the course of Raynaud’s phenomenon, and to assess gender differences.

Methods: A prospective, survey-based, closed-cohort study was conducted on a sample of men and women between 18–70 years of age, living in northern Sweden. Data on Raynaud’s phenomenon characteristics and general health status were collected during the winters of 2015 (baseline) and 2021 (follow-up). Rates of incidence, remission, and persistence were calculated. Binary logistic regression was used to determine the association between baseline variables and the course of Raynaud’s phenomenon. Results: The study population consisted of 2703 women (53.9%) and 2314 men. There were 390 women (14.5%) and 290 men (12.7%) reporting Raynaud’s phenomenon in the follow-up survey. The annual incidence proportion was 0.7% among women and 0.9% among men (gender difference p = 0.04). The annual remission proportion was 4.4% and 5.5%, respectively (p = 0.05). Having sustained a cold injury affecting the hands since baseline was significantly associated with incident Raynaud’s phenomenon (OR 3.92; 95% CI 2.60–5.90), after adjusting for age and gender.

Conclusions: In the general population of northern Sweden, Raynaud’s phenomenon is a common but variable condition, where symptoms may remit over time. Men had a higher incidence proportion than women. The results support a possible causal pathway where cold injury can precede the onset of Raynaud’s phenomenon.

Objective: To determine if exposure to cold environments, during work or leisure time, was associated with increased reporting of airway symptoms in the general population of northern Sweden.

Methods: Through a population-based postal survey responded to by 12627 subjects, ages 18–70, living in northern Sweden, the occurrence of airway symptoms was investigated. Cold exposure during work or leisure time was self-reported on numerical rating scales. Binary logistic regression was used to determine the statistical association between cold exposure and airway symptoms.

Results: For currently working subjects (N=8740), reporting any occupational cold exposure was associated to wheeze (OR 1.3; 95% CI 1.1–1.4); chronic cough (OR 1.2; 95% CI 1.1–1.4); and productive cough (OR 1.3; 95% CI 1.1–1.4), after adjusting for gender, age, body mass index, daily smoking, asthma, and chronic obstructive pulmonary disease. Leisure-time cold exposure was not signifcantly associated to reporting airway symptoms.

Conclusions: Occupational cold exposure was an independent predictor of airway symptoms in northern Sweden. Therefore, a structured risk assessment regarding cold exposure could be considered for inclusion in the Swedish workplace legislation.

Studies on the effect from biobased materials and products on humans have indicated positive effects. This has earlier been shown in studies for e.g. hospitals, where indications of lower stress and pain in patients with wood as part ofinterior solutions. This paper describes the first step of a larger study that investigates the interior environment and the response of patients. The study presented here measured RH, temperature, emissions of volatile organic compounds (VOC) and microbial activities in two rooms at a hospital in Skellefteá, Orthopaedic ward. One room had a cross-laminated wood panel covering 42% ofwalls, window reveal and doors, and the other a control room with standard coverings. Results indicated only a small difference between the rooms in terms of temperature and RH. VOC emissions varied in both rooms but all concentrations were lower or much lower than threshold values for interior air quality standard limits. Biological contamination ofthe surfaces and from air sampling was also performed. Conclusions of this experimental study shows that from a regulatory perspective it is possible and safe to use wood as interior product.

Diffusive samplers for monitoring of air quality are user-friendly devices that can normally be operated by the user himself. Hence these samplers are suitable for self-assessment. Practical and work organisational aspects of self-assessment of chemical exposure were studied in different occupational settings. It was found that the diffusive sampler used in these studies, the Perkin-Elmer tube in combination with thermal desorption, worked well for the purpose and could be correctly handled by the individuals using it. The results from self-assessments agreed well with expert measurements carried out by an occupational hygienist. However, in order to obtain a sustainable system of self-assessment strong organizational support is needed.