Sampling Strategies for Assessment of Occupational Exposure

M. Náray

National Institute of Occupational Health, Budapest, Hungary

CEJOEM 1997, Vol.3. No.4.:337

Results of occupational exposure measurements on chemical agents are affected by a whole host of factors, including measurement duration, location of measurement, and measurement strategies.
    The Hungarian standard (MSZ 21 461/1–1988) being valid until now did not include prescription for a definitive sampling strategy, only for a general calculation of time weighd average.
    The European Committee for Standardization (Technical Committee 137 “Assessment of Workplace Exposure”) adopted some standards, the two most important ones of which are: EN 482 (“General requirements for the performance of procedures for the measurement of chemical agents”) and EN 689 (“Guidance for the assessment of exposure by inhalation to chemical agents for comparison with limit values and measurement strategy”).
    EN 689 standard fixed the basic concept of assessment of occupational exposure (in two steps: “occupational exposure assessment and periodic measurement”) that is accepted all over the world, but in details the approach differs with the countries. Several approaches are annexed to this EN standard.
    In Hungary new regulations (ministerial decrees) related to occupational limit values are in preparation which will include some elements of sampling strategy referring primarily to peak concentrations (this regulation under preparation is very similar to the German: TRGS 402). The aforementioned two EN standards will be published in Hungary this year. There are other approaches related to the sampling strategy.
    The primary goals of exposure assessment for epidemiologic studies, field management, regulatory compliance are to provide representative, reliable, and precise exposure estimates. The occupational exposure databases (including long-term exposure assessment) demand validated exposure assessments.
    The governmental regulation and the risk assessment usually focus on the exposure of individual workers. The epidemiologic studies, on the other hand, require the estimation also of the representative exposures by occupational groups or work environments.
    The presentation makes discussion on the benefit of different sampling strategies considering the performance of measuring methods (overall uncertainty, LOD, sampling time, etc.).

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