Asbestos air monitoring or airborne asbestos fibre sampling is an assessment method used to determine asbestos concentration levels in the atmosphere. This assessment must be performed by an accredited occupational hygienist in the case of the following circumstances:
- Deteriorating asbestos that is at risk of becoming airborne
- Monitoring of adjacent areas when asbestos is being removed from a particular site
- Monitoring of asbestos air fibres prior to re-occupancy in areas in which ACMs were removed
- Monitoring of conditions in areas in which the use of asbestos has not been banned in order to determine exposure levels.
Types of Asbestos Air Monitoring
There are essentially four types of asbestos air monitoring procedures: control, exposure, clearance and background monitoring.
- Control Asbestos Monitoring: This method is conducted with the use of static or positional instruments that are placed in fixed locations with the aim of measuring airborne asbestos fibres. It is usually performed during work on ACMs. The results are then analysed to evaluate the effectiveness of the control measures that were used.
- Exposure Asbestos Monitoring: Airborne asbestos fibres are tested in occupational areas to determine the risks involved in a person’s breathing zone. The results are then compared with the national exposure standard to analyse the exposure limits and risks.
- Clearance Monitoring: The air is tested with the use of static or positional samples after work on asbestos containing materials have been removed and the area thoroughly decontaminated. An area is designated “cleared” if the measured asbestos level is below 0.01 fibres/mL.
- Background Monitoring: Tests are carried out on the air to detect airborne fibres prior to conducting any type of activity that may alter asbestos containing materials.
How are the Results Reported?
The results are reported as fibres per 100 fields. A calculation of the number of fibres per millilitre (f/mL) is also done to compare it with the limit of 0.01 f/mL. This means that if the asbestos level in a given area is less than 0.01 f/mL, then the result is considered satisfactory.
Who Conducts the Air Monitoring Testing?
Accredited laboratory professionals who comply with the Guidance Note on the Membrane Filter Method for Estimating Airborne Asbestos Fibres 2nd Edition [NOHSC: 3003 (2005)] can carry out air monitoring testing.