Montréal, January 27, 2020 – A large part of industrial hygienists’ work consists of measuring workers’ occupational exposure levels. The high variability in measured levels poses a considerable challenge when it comes to interpreting them relative to occupational exposure limits (OELs). Despite the existence of a consensus-based framework for this purpose, the associated approaches have not been widely adopted by industrial hygiene practitioners. They require calculations that are not feasible with current tools, and the statistical results obtained can be difficult to communicate to workers and managers.

The aim of the WebExpo project, funded by the Institut de recherche Robert-Sauvé en santé et en sécurité du travail (IRSST), was to improve current practices in the interpretation of occupational exposure measurements by creating a library of algorithmic solutions for the most frequent calculations performed in industrial hygiene risk assessment.

Greater flexibility
WebExpo used Bayesian statistics to perform the data interpretation calculations. “Bayesian methods were chosen because they provide direct answers to questions such as “What are the chances of this group of workers being overexposed?” or “What are the chances of my intervention reducing exposure by half?” This type of information makes it much easier to communicate risks to non-specialists,” explains Jérôme Lavoué, principal investigator and associate professor at the École de santé publique de l’Université de Montréal (ESPUM). “Bayesian statistics also address methodological questions that are rarely given sufficient consideration, particularly when it comes to non-detect values and the management of measurement error.”

The researchers involved in the WebExpo project set themselves three main objectives:

1. assess current needs regarding calculations, documentation and risk communication;
2. create a library of programming codes to address a series of frequently asked questions about exposure levels;
3. create tool prototypes for interpreting exposure levels and comparing them to OELs.

“The three objectives were attained and generated concrete results. For example, the list of pertinent calculations obtained from the first objective was used to develop mathematical formulae, which were then translated into algorithms. These, in turn, were used to create functional prototypes, which are all available free of charge on the Internet under open licence,” added Mr. Lavoué.

The WebExpo project should provide the industrial hygiene community with a comprehensive toolkit for interpreting occupational exposure levels. “What distinguishes the outcome of this study is that it offers users the flexibility of creating or adapting their own software instead of having to use a new one. A knowledge transfer project currently under way is also seeking to use WebExpo algorithms to create an IRSST Web application for interpreting exposure data.”

To read the full report, click here: https://www.irsst.qc.ca/en/publications-tools/publication/i/101066/n/webexpo

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Source
Noémie Boucher
Communications Advisor, IRSST
514-288-1551, ext. 206
[email protected]