[Assessment of exposure to chemical substances in the air at the workplace for comparison with limit values and measurement strategy. Presentation of the work of the European Committee on Normalization in its current state].

After summarizing the various difficulties or uncertainties involved in sampling and measuring procedures at the workplace, two phases to assess workplace exposures are described: an initial appraisal and, when applicable, periodic measurements. The initial assessment includes the identification of potential exposures, the determination of workplace factors, and the assessment of exposures. For exposure measurements, the selection of workers, pattern of sampling and number of samples have to be determined. Conclusions are drawn from the results.