Should styrene be sampled on the left or right shoulder?--An important question in employee self-assessment

A self-operated personal sampling technique called 'self assessment of exposure' (SAE) has been suggested as an easy method for collecting inhalation exposure data, as the workers themselves are performing the sampling. Employers and employees have raised the question of whether a different estimate of the air concentration is likely to be obtained depending on whether the sampler is fastened at the left or the right shoulder. In order to answer this question, the exposure to styrene vapour in two different small enterprises within the reinforced plastics industry was measured. Seven workers participated and the air sampling was performed by diffusive sampling. We observed no statistically significant difference in the determined air concentration of styrene between the left and right shoulder (P = 0.878). The results strongly indicate that the fastening of a sampler on the left or right shoulder does not produce a difference in the estimation of the inhalation exposure. SAE can thus be used to collect reliable exposure data of styrene vapour. The reliability of SAE will most certainly inspire occupational hygienists, physicians and other experts to involve the workers in repeated exposure measurements. Taking the exposure variability into account, repeated measurements are crucial when evaluating acute and chronic health effects following inhalation exposure to gases and vapours from chemical hazards.