Addressing the Challenges of Chemical Vapor Sample Assessment
The quantity of chemical vapors and dust measured in workplace air varies depending on where and when a sample was collected. This means we can’t get an accurate picture of the exposure to workers — and potential health hazards — with just one or two samples. So, just as polling firms extrapolate results from a small group to the entire population, exposure assessors extrapolate from a few samples to the days and times that weren’t sampled.
PDC 408: Exposure Statistics in IH – Challenges of Exposure Variability, taught by Jérôme Lavoué, PhD, MSc, covers this phenomenon: exposure variability and the challenges it poses for accurate decision-making. The course will also review the statistical methods that international organizations recommend to interpret measured exposure levels. Attendees will also learn to use the www.expostats.ca web app to implement these recommendations and create easily understood graphs, which they can send to workers and managers.
The statistical methods needed to interpret exposure data according to current best practice are not taught in generic statistics courses and cannot be performed by hand or with common tools such as spreadsheet software. As a result, although theoretical approaches were described some time ago in the scientific literature, they have not really trickled down to practice.
The course aims to correct this, by presenting the underlying theory in an accessible way, and describing how to use www.expostats.ca. In addition, while traditional statistical routines yield results that can be difficult to convey to non-specialists, the website platform yields simpler answers, such as “there is a 69% probability that these workers are overexposed.”
Those who attend this special course will also learn methods currently recommended by several prominent occupational health organizations such as AIHA, The European Community, and the British and Dutch industrial hygiene societies.
Trained as a chemist in France in 1996, Dr. Lavoué completed an MSc in Toxicology and a PhD in exposure sciences at the University of Montréal in Canada. After doing postdoctoral studies in industrial hygiene at the Institute for Work and Health in Lausanne, Switzerland, in 2008 he was hired as a Professor of Industrial Hygiene at the Department of Environmental and Occupational Health at University of Montréal.
Dr. Lavoué researches occupational exposure assessments, and is especially interested in retrospective assessments for epidemiological studies, development of statistical methods for industrial hygiene data analysis, and, more recently, development of software to facilitate data analysis for industrial hygienists, including the Expostats website.
He has been teaching industrial hygiene data interpretation for 15 years and is the lead author for a chapter about sampling and data interpretation strategies in an upcoming francophone industrial hygiene monograph edited by the Quebec Association for Occupational Safety and Health.