ISO 21832:2018

Overview

ISO 21832:2018 - "Workplace air - Metals and metalloids in airborne particles - Requirements for evaluation of measuring procedures" specifies performance requirements and test methods to validate procedures that measure metals and metalloids collected as airborne particles on a suitable substrate. The standard defines how to determine limits of detection and quantification, assess analytical recovery, and estimate measurement uncertainty for complete measuring procedures (sampling and analysis performed in separate stages). It excludes measurements of inorganic gases or vapours and particle/vapour mixtures.

Key topics and requirements

• Scope of method: Documented application range including which metals/metalloids are covered, analytical techniques, and the concentration ranges and recommended sampled air volumes for which the method meets acceptance criteria.
• Detection and quantification: Procedures for determining Instrumental Detection Limit (IDL), Limit of Detection (LOD) and Limit of Quantification (LOQ) - typically using repeated blank analyses (LOD ≈ 3× blank SD, LOQ ≈ 10× blank SD as commonly applied).
• Analytical recovery: Validation approaches depend on the procedure:
  • Spiked laboratory blanks for soluble forms,
  • Pure compounds, certified reference materials or reference air samples for total-metal methods involving dissolution,
  • Reference air samples, paired workplace samples with reference procedures, or theoretical estimates where analysis is performed on the collection substrate.
• Measurement uncertainty: A structured approach to identify random and systematic uncertainty components (cause-and-effect diagram), estimate individual components, combine them, and calculate expanded uncertainty consistent with ISO 20581 guidance.
• Method documentation: Requirements for method description, safety information, sampler and pump specifications, reagents, test materials, apparatus, test methods and reporting of validation results.
• Supporting guidance: Annexes provide practical guidance on analytical recovery, validation experiments, uncertainty estimation, interpolation of standard deviation, and worked examples.

Practical applications and users

ISO 21832 is intended for:

• Industrial hygienists and occupational health professionals assessing worker exposure to metal particulates
• Analytical laboratories validating and demonstrating performance of workplace air methods
• Health and safety agencies and regulators setting or verifying compliance
• Method developers and equipment manufacturers performing method validation and uncertainty estimation

Typical uses include method validation, choosing suitable sampling strategies, reporting method performance (LOQ, recovery, expanded uncertainty) and ensuring consistent, defensible exposure assessments.

Related standards

• ISO 20581 - general requirements for measurement procedure performance and uncertainty
• EN 13205-1, ISO 15767 - sample collection, transport and storage guidance
• ISO 13137, ISO 7708, ISO 18158, ISO 3696 - complementary workplace air and analytical references

ISO 21832:2018 provides a practical, standardized framework for validating and reporting measuring procedures for metals and metalloids in workplace air, helping ensure reliable occupational exposure assessment.