ISO/TC 146/SC 2/WG 1 - Particle size-selective sampling and analysis

ISO 13138:2012 specifies sampling conventions to define idealized samplers for estimating the deposition of non-volatile, non-hygroscopic, non-fibrous aerosols in five specific loci of the respiratory tract. The five loci consist of the anterior and posterior areas of the nasal passages, the ciliated and non-ciliated parts of the tracheobronchial area, and the alveolar (gas exchange) region. The conventions are separated into three independent sampling efficiencies defined in terms of thermodynamic diameter characterizing the diffusive (Brownian) motion of sub-micrometre particles and four efficiencies in terms of aerodynamic diameter 0,1 μm characterizing deposition by impaction, interception or gravitational settling. Each conventional curve has been developed as an average of 12 deposition curves corresponding to 12 breathing conditions ranging from sitting to heavy exercise, male vs female, and breathing mode (mouth vs nasal breathing).

ISO 28439:2011 provides guidelines for the determination of the number concentration and size distribution of ultrafine aerosols and nanoaerosols by use of mobility particle sizers (also called differential mobility analysers). Only the particle fraction of the aerosol is considered. For ultrafine aerosols and nanoaerosols, exposure metrics such as the number and surface area concentration are important. ISO 28439:2011 also gives guidelines for the determination of workplace exposure to ultrafine aerosols and nanoaerosols. Specifically, the differential mobility analysing system (DMAS), now available from several vendors, is discussed. Principles of operation, problems of sampling in the workplace environment, calibration, equipment maintenance, measurement uncertainty, and reporting of measurement results are covered. Potential problems and limitations are described, which need to be addressed when limit values are fixed and compliance measurements carried out.

ISO 15767:2009 provides recommendations for controlling the analytical uncertainty associated with aerosol collection medium instability, where collection medium or collection substrate includes any article used to collect particles (e.g. filter or foam material) as well as those supporting elements which must be analysed by weighing. ISO 15767:2009 is applicable to results compiled both from the literature and, if necessary and feasible, through laboratory experiment. Expected uncertainty associated with given aerosol capture methods is quantified where possible. Recommendations as to materials to be used are given. Means of minimizing uncertainty arising from instability are provided. Recommendations for the weighing procedure are given. A procedure for estimating weighing uncertainty is described. Finally, recommendations are given for the reporting of measured mass, including an uncertainty component and limits of detection and quantification.

Defines sampling conventions for particle size fractions for use in assessing possible health effects of airborne particles in the workplace and ambient environment. Defines conventions for the inhalable, thoracic and respirable fractions; extrathoracic and tracheobronchial conventions may be calculated from the defined conventions. The conventions should not be used in association with limit values defined in other terms, for example for limit values of fibres defined in terms of their length and diameter.

ISO 15767:2003 provides recommendations for controlling the analytical uncertainty associated with aerosol collection medium instability, where collection medium or substrate includes any article used to collect particles (e.g. filter or foam material) as well as those supporting elements which must be analysed by weighing. ISO 15767:2003 is applicable to results compiled both from the literature and, if necessary and feasible, through laboratory experiment. Expected errors associated with given aerosol capture methods are quantified where possible. Recommendations as to materials to be used are given. Means of controlling or correcting errors arising from instability are provided. Recommendations for the weighing procedure are given. A procedure for estimating weighing errors is described. Finally, recommendations are given for the reporting of measured masses.