A Study of the Validity of Two Exposure Assessment Tools: Stoffenmanager and the Advanced REACH Tool

The use of exposure modelling tools for estimating chemical airborne exposure has increased since the European Union's REACH legislation for safe use of industrial chemicals came into force. Two tools that European Chemicals Agency recommends are Stoffenmanager® and the Advanced REACH Tool (ART). The aim of this study was to investigate the validity of these two exposure modelling tools by comparing the lack of agreement between estimated and measured exposure. We examined the airborne chemical exposure at companies in seven different types of industries: wood, printing, foundry, spray painting, flour milling, chemical industry, and plastic moulding industry. The inhalable exposure of liquids or powders at two to three situations at each company was modelled with both tools and measured. To study the validity of the tools, the mean differences and precisions (lack of agreement) of exposures from both situations handling liquids and powders were calculated by using the 50th percentile outcome of the tools and the geometric mean of the measured exposure (all data were ln transformed). For Stoffenmanager, the mean difference and precision of the situations concerning liquids were 0.22 ± 1.0 and for powders -0.024 ± 0.66. It was also shown that Stoffenmanager overestimated low exposures and underestimated high exposures. Stoffenmanager showed higher agreement with the measured exposure in the wood and flour mill industries than in foundry and the plastic moulding industry. For ART, the mean difference and precision of liquids were -0.55 ± 0.88 and for powders -1.4 ± 1.6. ART showed lower agreement with the measured exposure in the wood industry.