Personal and static sample measurements of asbestos fibres during two abatement projects

Exposure assessment was performed during the abatement of amosite containing material (ACM) and chrysotile containing material (CCM). Mean fibre concentrations (MFC) in breathing zone (BZ) were 20.6+/-7.9 f/cc and 6.3+/-2.2 f/cc during abatements of ACM and CCM, respectively. At the fixed station, MFC were 5.4+/-3.5 f/cc for ACM and 2.9 f/cc+/-1.6 for CCM. For observer's BZ, MFC were 3.1+/-1.3 f/cc (ACM) and 1.8 f/cc (CCM) during the abatement. Though elevated, area and observer-type samples clearly underestimate exposure. Exposure remained unacceptable in the worksite with the class of respiratory protection used.