At these stationary sampling sites, air concentrations of inhalable dust exceeded the OEL of inorganic dust in 100%, 100%,
100% and 78% of the air samples in the wood-fired power plants,the recycled fuel-fired power plant, the pellet-fired power plants,and the peat-fired power plants, respectively. In the maintenance tasks inside the boilers the highest median air concentrations of inhalable dust was 9.4 mg m3 in the peat-fired power plants(Table 1). The inhalable dust concentrations were smaller outside the boilers