PDC 408: Understanding the Challenges of Exposure Variability in the Workplace

Jerome Lavoue Lead Instructor
University of Montreal
Montreal, Quebec 
Sun, 5/23: 8:00 AM - 5:00 PM
Professional Development Course 
Room: Virtual 6 
CM Credit Hours:


*All PDCs have an additional fee and require preregistration*
To register, please visit: https://www.aihceexp.org/2021/register-2021
Is a group compliant with the OEL? Are individuals in the group likely to experience higher risk than the group average? What effect does an intervention have on the exposure distribution? The answers to these questions are paramount to the practice of industrial hygiene. Unfortunately, the variability observed in occupational exposure levels represents a considerable challenge to obtaining them reliably. There is a lack of practical applications to support day-to-day decision-making when analyzing exposure measurement data. Even fewer applications tackle frequent methodological issues such as the presence of nondetects or present the results in a format easy to communicate. The Expostats platform (www.expostats.ca) is a free web application developed at University of Montreal, Canada, to support the interpretation of occupational exposure measurements. This PDC session will present: a) the challenge of exposure variability; b) the current theory underpinning the interpretation of workplace exposure levels; c) a primer in Bayesian statistics; and d) how decision-making can be conducted using the Expostats tools.

Course Outline

• Statistical Background
• Exposure Variability Illustrations
• Parameters Used for Risk Assessment
• Primer on Bayesian Statistics
• Expostats Platform and Hands-on Session with Exercises
• Recent Proposed Guidelines for Exposure Data Interpretation
• Description of the Dutch-British Guideline
• Use of Expostats to Evaluate Potential Exposure Determinants 

Learning Outcomes

Upon completion, the participant will be able to:

• Discuss workplace exposure variability impact on IH risk assessments.
• Describe the most common metrics used to define overexposure.
• Explain the basic principles underlying Bayesian statistics.
• Leverage Bayesian statistics in industrial hygiene data analysis.
• Use Expostats to perform risk assessments for similar exposure groups.
• Implement sampling strategy guidelines proposed in the U.S. and Europe.
• Evaluate the whether an exposure group is homogenous and workers might be at risk.
• Calculate the association between exposure levels and a categorical variable.
• Assess the effect of an intervention. 

Value Added

Participants will leave with the ability to perform state of the art data interpretation using the www.expostats.ca platform. 

Business Case/IH Value Statement

Traditional exposure statistics rely on confidence intervals and hypothesis tests to demonstrate overexposure. The methods described in the PDC will allow practitioners to express their results in the form: "there is a 75% chance that this group is overexposed", which is better understood by management. 

Course Level


Learning Aids



Available as part of AIHce OnDemand
Computer/Mobile Apps and Tools
Hazard Recognition/Exposure Assessment
Risk Assessment and Management

Transfer of Knowledge

Hands-on demonstrations and practicum
Interactive games
Practice exercises
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