Structured expert judgment to characterize uncertainty between PM2.5 exposure and mortality in Chile

Area of Science:

• Environmental Health
• Epidemiology
• Risk Assessment

Background:

• Public policies for air pollution require robust scientific evaluation.
• Expert elicitation methods, like structured expert judgment (SEJ), can inform policy decisions.
• Estimating the relationship between PM2.5 exposure and mortality is crucial for public health.

Purpose of the Study:

• To explore the strengths and weaknesses of SEJ for deriving a concentration-response (C-R) function for chronic PM2.5 exposure and premature mortality in Chile.
• To assess the applicability of SEJ in regions lacking specific epidemiological studies.
• To compare expert judgment from physicians and engineers on mortality impacts.

Main Methods:

• Structured Expert Judgment (SEJ) methodology was employed.
• Local experts were divided into physicians (Group 1) and engineers (Group 2).
• Cooke's Classical Model was used to aggregate expert assessments of mortality change due to PM2.5 reduction.

Main Results:

• Expert mortality estimations varied significantly between physicians and engineers.
• Physicians' estimates exceeded those from major international studies, while engineers' estimates were more aligned with existing research.
• Combined expert distributions differed substantially, influenced by expert calibration performance.

Conclusions:

• SEJ shows potential for estimating PM2.5 C-R functions and uncertainty in data-scarce regions.
• Successful SEJ implementation depends on careful consideration of expert selection and performance.
• Further analysis is needed to refine SEJ application for air pollution policy evaluation.