The basis for recommending the selection of samplers in determining occupational exposures to aerosols

Measurements are considered to be the basis of exposure assessments used to determine risks to workers. Inhalation exposure poses the greatest risk for most airborne chemicals, and measurements are based on collecting (sampling) and analyzing air samples. Samplers have been developed for more than 120 years. Each new design has been intended to address flaws perceived in earlier designs. Users are faced with a varied array of samplers from which to choose. Comparisons are difficult to make because tests of sampler performance were not standardized until recently and have not been applied consistently. The existing large body of work does allow some conclusions to be drawn regarding performance. Many samplers have been shown to work effectively with test aerosols under controlled conditions in the laboratory. Further testing in the field has shown that not all samplers perform equally well in every situation; for example, under different wind speeds and directions or with aerosols that maintain unusual physical characteristics. There is not one aerosol sampler that can be used for all situations. Further, the design of a sampler and how the sampler needs to be handled can have an enormous influence on the result. Quality of manufacture, material of construction, cost, reusability, ease of use, setting of flow rates, transportation issues, and wearer acceptability all have an impact on selecting from among different samplers with similar performance. The range of available samplers constitutes a toolkit from which the most appropriate sampler could be selected for a given specific situation. Common inhalable and respirable aerosol samplers are considered in respect of their history of design and manufacture, validated performance studies, environmental factors, and practical use. However, the impact of these considerations on sampler selection is minimized through generalized industry-specific or task-specific recommendations. An online web-based Sampler Selection Tool is under development. It will use the information presented in this Commentary to provide a ranked list of appropriate samplers to be used in specific situations.