ASBESTOS AND OTHER FIBER LEVELS IN BUILDINGS

A Nuclepore filter/SEM method was used to determine the airborne concentration of asbestos and other fibres in office and plant buildings. The monitoring/SEM/XRMA conditions were chosen to match the collection efficiency, fibre detectability and convenience of the membrane filter/optical microscope method. Additionally, the SEM/XRMA technique provides identification of counted fibres and a detection limit of 1 fiber l.-1 under the routine conditions of occupational hygiene sampling. Application of the method to the collection of 193 air samples in the occupied areas of 22 asbestos-containing office and plant bulidings gave the following asbestos counts: 22 fibre l.-1 (1 sample); 3 fibre l.-1 (3 samples); 2 fibre l.-1 (5 samples); 1 fibre l.-1(22 samples); 0 fibre l.-1 (162 samples). Organic fibre levels ranged from 63-0 fibre l.-1 (median = 4 fibre l.-1). Mineral (non-asbestos) fibre levels ranged from 13 to 0 fibre l.-1 (median = 1 fibre l.-1).