WorkSafeBC has strict regulations and guidelines concerning air monitoring on job sites. Our process for asbestos air monitoring follows the NIOSH 7400 Method, which involves filtering the air being tested through a mixed cellolose ester membrane, which is further prepared in the lab and viewed under a positive phase-contrast microscope, where the samples are counted to determine a reading of fibres per mL of air. There are three types of air monitoring typically performed during asbestos abatement, and requirements vary depending on the risk level and material type. Air monitoring often includes:
Occupational air monitoring measures the worker exposure during the removal of material within the work area, and requires sampling a minimum of 40 litres of air. Occupational air monitoring ensures that controls and personal protective equipment are properly set up and the job site within the work zone is functioning properly.
The clean room is an area where workers remove their street clothes and put on their personal protective equipment, including impermeable suits, boots, gloves and respirators. When work is complete, it is also the space where they remove their respirators after decontamination and put their clothing back on. Clean Room sampling monitors the air in this area every day to ensure levels are safe.
Ambient air sampling is concerned with the area just outside of containment, ensuring that levels are within safe limits during work. Both Clean room and ambient sampling measure a minimum of 400 litres of air over at least four hours to ensure levels are consistent across abatement activities.