Total and respirable dust exposures among carpenters and demolition workers during indoor work in Denmark

BACKGROUND Within the construction industry the risk of lung disorders depends on the specific professions probably due to variations in the levels of dust exposure, and with dust levels depending on the work task and job function. We do not know the extent of exposure in the different professions or the variation between the different work tasks. The purpose of this study was therefore to assess if there were differences in dust exposure between carpenters and demolition workers who were expected to have low and high dust exposure, respectively. METHODS Through interviews of key persons in the construction industry the most common work tasks were selected, and the concentration of dust during these tasks (indoors) were measured by personal sampling varying between 4 and 6 h of a working day. In total 38 measurements of total dust, and 25 of respirable dust on seven different work tasks were carried out for carpenters and 20 measurements of total dust, 11 of respirable dust and 11 of respirable crystalline silica dust on four different works tasks for demolition workers. Dust measurements were tested for differences using linear regression, t-test and one-way ANOVA. RESULTS For carpenters the geometric mean for all the measurements of total dust was 1.26 mg/m(3) (geometric standard deviation 2.90) and the respirable dust was 0.27 mg/m(3) (geometric standard deviation 2.13). For demolition workers the geometric mean of total dust for all the measurements was 22.3 mg/m(3) (geometric standard deviation 11.6) and the respirable dust was 1.06 mg/m(3) (geometric standard deviation 5.64). The mean difference between total dust for demolition workers and carpenters was 11.4 (95 % confidence interval 3.46-37.1) mg/m(3). The mean difference between respirable dust for demolition workers and carpenters was 3.90 (95 % confidence interval 1.13-13.5) mg/m(3). Dust exposure varied depending on work task for both professions. The dustiest work occurred during demolition, especially when it was done manually. Only few workers used personal respiratory protection and only while performing the dustiest work. CONCLUSIONS This study confirmed that the exposure to dust and especially total dust was much higher for demolition workers compared to carpenters. TRIAL REGISTRATION (ISRCTN registry): The study is not a clinical trial and are thus not registered.