Air Sampling & Exposure Monitoring

You cannot judge a dust or fume level by looking at it. Air monitoring measures what is actually in the air and in your breathing zone, so the employer can decide whether controls and respirators are needed.

• Workers
• Supervisors
• Health & Safety

Why monitor

• Some OSHA standards (lead, asbestos, silica, benzene and others) require monitoring when exposure may reach set levels.
• Monitoring shows whether controls work and whether workers need respirators or medical exams.
• It gives a record that can be used if a health problem appears later.

Types of samples

• Personal sample: a small pump and filter or tube is worn on the worker, with the intake in the breathing zone near the face. It shows that worker's exposure over a shift (a time-weighted average).
• Area sample: the device sits in a spot to show the level in that location.
• Direct-reading instruments: meters that show a result at once, for gases, vapors or dust. Useful for screening and alarms. See Gas Detectors.
• Filters and tubes are sent to an accredited laboratory for analysis.

What the results are compared with

• OSHA permissible exposure limits (PELs), action levels, and short-term limits where they exist. See Exposure Limits.
• Other guidance such as NIOSH limits or ACGIH values, which are often lower.

Your rights

• OSHA's standards for monitored substances require the employer to notify affected workers of results, in writing or by posting, usually within a set number of days.
• You can see exposure and medical records and get copies (29 CFR 1910.1020). Ask your employer.
• You or your representative may observe the monitoring.
• You can ask OSHA to inspect if you think the air is unsafe. See Worker Rights.

Doing it well

• A trained person (often an industrial hygienist) plans the sampling
• Samples represent the worst typical task and the full shift
• Pumps are calibrated before and after the shift
• Workers wear the sampler where it will not be blocked, and do not tamper with it
• Results are used to improve controls, not just filed away

Last updated: October 8, 2026