Research of fir-wood dust concentration in the working environment of cutters

This paper shows the results of measurement of daily exposure of cutters to respirable particles and total fir-wood dust during cutting and processing of dead standing fir-trees. The separators of non-respirable fraction (cyclones) are designed so as to imitate the separation of respirable particles in the respiratory system of a healthy adult person, with a medium efficiency (50 %) with aerodynamic diameter of 5
m. The mean value of mass concentration of total fir-wood dust was (1.29  0.419) mg/m3 and of respirable fraction (0.564  0.154) mg/m3. The results of this research show that no measured value (N = 26) in cutting and processing fir-trees exceeds the Croatian limit values (maximum permissible concentrations) for wood dust of softwood broadleaved species and conifers.