Passive sampler used for simultaneous measurement of breathing zone size distribution, inhalable dust concentration and other size fractions involving large particles

The particle size-dependent sampling velocity of the passive dust sampler developed by Vinzents (1996) is investigated under field conditions. Microscopical determination of the projected area equivalent diameter is used to quantify particles deposited on the sampler foils. Parameters for a semi-empirical model for particle deposition velocities on upward and forward facing foils are fitted to the data and it is shown that deposition mechanisms other than gravitational settling on the upward facing foil can be neglected. For calculation of airborne mass concentration no information on particle density is needed and only the ratio between the dynamic and volume shape factors needs to be known. Given the sampling velocity, the airborne mass per diameter interval is calculated from samples obtained in the wood industry, from which inhalable dust concentrations are calculated. The results are in line with parallel samples obtained with an inhalable dust sampler. A 'total' dust sampling characteristic can be fitted which reproduces measured 'total' dust with a closed face monitor. The results of this study demonstrate the validity of the passive dust sampling principle in environments involving even large (>100 microm) particles and the potential to predict the concentration of several size fractions.

Respiratory symptoms and lung function among Danish woodworkers

A cross-sectional study including 54 furniture factories and three control factories was conducted to survey lung function and prevalence of respiratory symptoms among woodworkers. Spirometry was performed on 2423 persons. Questionnaires regarding respiratory symptoms and wood dust exposure were completed by 2033 woodworkers and 474 controls. Personal passive dust measurements were performed on 1579 persons. The arithmetic mean +/- SD for equivalent inhalable dust was relatively low (1.19 +/- 0.86 mg/m3). Woodworkers had increased frequency of coughing with negative interaction between dust exposure and smoking. A dose-response relationship was seen between dust exposure and asthma symptoms, and a positive interaction for asthma was seen between female gender and dust exposure. Increased frequency of wheezing and a cross-shift decrease in forced expiratory volume in 1 second among workers using pinewood was seen. In conclusion, wood dust exposure might cause respiratory symptoms, despite a relatively low exposure level.

Nasal patency is related to dust exposure in woodworkers

OBJECTIVES

A cross sectional study of 54 furniture factories and three control factories was conducted to investigate the relation between subjective and objective nasal obstruction and exposure to wood dust.

METHODS

Acoustic rhinometry was performed on 161 woodworkers and 19 controls. For each person, four measuring rounds were performed: before work, after 4 hours of work, and after 7 hours of work before and after decongestion. Before the first and third measuring round, each person rated the current feeling of nasal obstruction in the left and right nostril separately, using a visual analogue scale. Personal passive dust measurements were performed on 140 woodworkers.

RESULTS

The mean (SD) of equivalent inhalable dust was relatively low, 1.17 (0.62) mg/m(3), range 0.17-3.44 mg/m(3). The exposure was divided into four levels: controls, low exposure, medium exposure, and high exposure. For the two highest concentrations of exposure, a significant increase in congestion--decreased nasal cavity volume and cross sectional areas--was found after 4 and 7 hours of work, compared with before work. Multivariate linear regression analysis showed positive correlations between concentration of dust and change in mucosal swelling. A significant increase in self rated nasal obstruction was found after work compared with before work for the two highest exposure groups. No correlation between objective nasal variables and self rated nasal obstruction was found.

CONCLUSION

Exposure to wood dust was related in a dose dependent manner to acute nasal obstruction measured by acoustic rhinometry and self reported obstruction, but no correlation was found between measured and self reported obstruction.

Variations in exposure to inhalable wood dust in the Danish furniture industry. Within- and between-worker and factory components estimated from passive dust sampling

Variability of exposure to wood dust at large factories in the Danish furniture industry was studied. Three repeated exposure measurements of 292 workers at 38 factories were included in the study. The measurements were carried out by use of personal passive dust monitors. The components of variance were estimated by means of a random effects ANOVA model. The ratio of within- to between-worker variance was 1.07. Based on this result, and three repeated exposure measurements, the observed relation between health outcome and exposure will be attenuated to 74% of the true value. Grouping by factory showed very poor exposure contrast, as the contrast in exposure level among factories was as low as 0.15.

Wood dust exposure in the Danish furniture industry using conventional and passive monitors

A study of wood dust exposure at furniture factories in one county in Denmark was performed as a cross sectional study. Dust exposure was measured with personal passive dust monitors and calibrated against active sampling on filters. Measurements of 1685 workers were included in the exposure assessment. The passive dust monitor conversion models for equivalent concentrations of inhalable dust and total dust based on data from the present study were not significantly different from the original models. Therefore models based on all available data were used. The parameters of the distribution of equivalent concentration of inhalable dust were 0.94 mg/m3 (geometric mean) and 2.10 (geometric standard deviation). Compared with a national cross sectional study from 1988 the exposure level (geometric mean) was reduced by a factor 2.0. Inhalable dust exposure was about 50% higher than exposure measured by the Danish 'total' dust method.

[Contact eczema caused by pine wood]

A 34 year-old woman, working with pine wood treated with sodium hydroxide and pyrogallol, developed dermatitis on arms, face and neck. Patch testing showed allergic reaction to colophony and pine wood, but not to sodium hydroxide or pyrogallol. Pine wood contains colophony. Since avoiding pine wood, she has had no further attack of dermatitis.

[Asthma, bronchitis and chronic obstructive pulmonary disease in occupational exposure to wood]

Two million workers worldwide are regularly exposed to wood dust in the work place. In Denmark alone approximately 40,000 workers are employed in the furniture industry where they are exposed to wood dust on a daily basis. This article reviews epidemiological at studies concerning the relationship between wood dust and the development of asthma, chronic obstructive pulmonary disease (COPD) and bronchitis. Fourteen cross-sectional studies and one register-based cohort study form the basis of this review. The conclusion is that despite possible methodological problems there seems to be a relationship between occupational exposure to the types of wood dust used in Denmark and the development of these pulmonary diseases. The results would indicate that further studies are clearly needed in order to study the incidence of these diseases and the relation to the specific types and amount of wood dust.