Workplace exposure monitoring is the monitoring of substances in a workplace that are chemical or biological hazards. It is performed in the context of workplace exposure assessment and risk assessment. Exposure monitoring analyzes hazardous substances in the air or on surfaces of a workplace, and is complementary to biomonitoring, which instead analyzes toxicants or their effects within workers.
A wide array of methods and instrumentation are used in workplace exposure monitoring. Direct-read instruments give immediate data, and include colorimetric indicators such as gas detector tubes, and electronic devices such as gas monitors and aerosol particle counters. In addition, samples may be collected and sent to a laboratory for slower but often more thorough analysis.