Overview - ISO 16000-18:2011 (Indoor air - Sampling by impaction)
ISO 16000-18:2011 specifies a standardized method for short-term (1 to 10 minute) sampling of airborne moulds in indoor air by impaction onto solid agar media. Samples collected according to this part are intended for subsequent cultivation and enumeration of moulds in line with ISO 16000-17 (culture‑based method). The standard addresses equipment, media (e.g. DG18, malt‑extract or potato dextrose agar), sampling procedure, calibration, quality assurance and method limitations for reliable indoor air quality (IAQ) assessments.
Key topics and technical requirements
- Sampling duration and volume: Short-term active sampling defined as 1 minute to 10 minutes.
- Sampling principle: Air is drawn through an impactor so particles (mould spores) inertially impact on agar plates for direct cultivation.
- Impactor types: Slit samplers (rotating agar plates) and single‑stage sieve impactors (perforated plate) are described; validation data are provided mainly for single‑stage sieve impactors using 9 cm agar plates.
- Cut-off characteristics: The impactor should have a cut‑off aerodynamic diameter preferably ≤ 1 µm and shall not exceed 2 µm to capture relevant spore sizes (~2–30 µm).
- Culture media: Use of DG18 (dichloran 18% glycerol agar) and malt‑extract or potato dextrose agar is specified for recovery and growth.
- Apparatus & calibration: Requirements for sampling device, vacuum pump, gas volume meter, timer, and routine calibration of flow rate and function control are included.
- Quality assurance: Protocols, performance characteristics and documentation (sampling protocol, transport and storage) to ensure reproducibility and valid colony counts (CFU).
- Limitations: The standard outlines sampling efficiency, biological preservation efficiency and situations where additional methods (e.g. long‑term filtration per ISO 16000‑16) may be required.
- Safety warning: Users must follow appropriate biosafety and health precautions when handling environmental samples and cultures.
Applications and typical users
- Indoor air quality consultants and industrial hygienists conducting building assessments, mould investigations and post‑remediation verification.
- Environmental and public health laboratories performing culturable mould enumeration (CFU).
- Facilities managers, building inspectors, HVAC professionals and researchers studying airborne mould exposure in homes, offices, schools, hospitals and industrial settings.
- Use cases include identifying active mould sources, comparing indoor vs outdoor concentrations, validating remediation, and supporting epidemiological or exposure studies.
Related standards
- ISO 16000‑17 - Detection and enumeration of moulds (culture‑based method)
- ISO 16000‑16 - Detection and enumeration of moulds - Sampling by filtration (longer sampling periods)
- ISO 16000 series - broader indoor air quality standards and sampling strategies
Keywords: ISO 16000-18, mould sampling by impaction, indoor air quality, airborne mould, DG18 agar, impactor sampling, CFU, short-term air sampling.
