Asbestos fiber levels from remediation work

• Airborne asbestos exposure was studied at 14 asbestos work scenarios. • In 11 scenarios the asbestos exposure exceeded the recently lowered Danish OEL. • Most respiratory masks provide insufficient protection at highest asbestos levels. • Found fiber length distributions call for thoughts on reliable fiber counting. • Development of automated AI driven SEM/EDS asbestos analysis is warranted. Release of asbestos fibers during remediation and maintenance work remains a concern in many countries, as asbestos containing materials are often present in buildings predating their ban. Despite awareness of the adverse health effects from asbestos exposure, there is a lack of knowledge on concentrations resulting from typical asbestos remediation tasks, and on the minimum protection level needed. The aim of this study was to map asbestos exposure levels during removal of asbestos containing materials, in order to assess asbestos exposure levels and the adequacy of applied risk management measures, including choice of protective equipment. The investigated removal processes included asbestos containing facade panels, roof tiles, ceiling panels, tile adhesives, and insulation materials for pipes and boilers. All filter samples were analyzed by scanning electron microscopy coupled with energy dispersive X-ray spectroscopy. The highest asbestos concentration of 0.35 fibers/cm 3 was found during removal of tiles with asbestos adhesives, though levels exceeding the current Danish occupational exposure limit of 0.003 f/cm 3 were found in breathing zone samples at 11 of the 14 investigated sites. Even when considering 8 h time weighted average concentrations, levels were often found to exceed the occupational exposure limit, despite assuming a narrow exposure window, typically between 0.5 and 2 h due to high dust levels or short tasks. An additional objective was to provide guidance for decision-making in relation to two OEL options given in a recent EU Directive, where member states are also expected to transition from optical microscopy to electron microscopy for asbestos measurements.