Uncertainty in risk assessment

Morgan, M. Granger; Henrion, Max; Morris, S.C.; Amaral, Deborah A. L.

doi:10.1021/es00138a002

Cited by 27 publications

(9 citation statements)

References 2 publications

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“…The intent is to provide an example framework for integrating the computational results provided by the model with broader considerations that influence the costs and benefits expected from future research. The sources of input into this ranking process should be broadened by scientifically collecting opinions from experts in the future [35].…”

Section: Discussionmentioning

confidence: 99%

Prioritizing Risks and Uncertainties from Intentional Release of Selected Category A Pathogens

et al. 2012

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This paper synthesizes available information on five Category A pathogens (Bacillus anthracis, Yersinia pestis, Francisella tularensis, Variola major and Lassa) to develop quantitative guidelines for how environmental pathogen concentrations may be related to human health risk in an indoor environment. An integrated model of environmental transport and human health exposure to biological pathogens is constructed which 1) includes the effects of environmental attenuation, 2) considers fomite contact exposure as well as inhalational exposure, and 3) includes an uncertainty analysis to identify key input uncertainties, which may inform future research directions. The findings provide a framework for developing the many different environmental standards that are needed for making risk-informed response decisions, such as when prophylactic antibiotics should be distributed, and whether or not a contaminated area should be cleaned up. The approach is based on the assumption of uniform mixing in environmental compartments and is thus applicable to areas sufficiently removed in time and space from the initial release that mixing has produced relatively uniform concentrations. Results indicate that when pathogens are released into the air, risk from inhalation is the main component of the overall risk, while risk from ingestion (dermal contact for B. anthracis) is the main component of the overall risk when pathogens are present on surfaces. Concentrations sampled from untracked floor, walls and the filter of heating ventilation and air conditioning (HVAC) system are proposed as indicators of previous exposure risk, while samples taken from touched surfaces are proposed as indicators of future risk if the building is reoccupied. A Monte Carlo uncertainty analysis is conducted and input-output correlations used to identify important parameter uncertainties. An approach is proposed for integrating these quantitative assessments of parameter uncertainty with broader, qualitative considerations to identify future research priorities.

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Section: Discussionmentioning

confidence: 99%

Prioritizing Risks and Uncertainties from Intentional Release of Selected Category A Pathogens

et al. 2012

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“…The judgmental interpretation of probability is also known as Bayesian interpretation. The Bayesian viewpoint is that probabilities represent an individual's degree of belief about a given quantity rather than a measured property of the world (20).…”

Section: Decision Analytic Approachmentioning

confidence: 99%

Current assessment practices for noncancer end points.

Shoaf

1991

Environ Health Perspect

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The need for assessing noncancer risks for agents to which humans are routinely exposed indoors arises from the large amount of time spent indoors (i.e., employed persons spend about 60% of their time at home indoors, 30% at work indoors, and 5% in transit). Sources ofair poilutants include heating and coolig systems, combustion appliances, personal use products, furnishings, tobacco products, pesticides, biodefluents from humansand animals, and other microbial contamination such as toxins fromn molds. The purpose of this paper is to describe current dose-response a ent mhods appliable to as risk follwing exposure to indoor air uant The role ofstuture-activity riationships in hazard identification is also described.Risk ments from exposure to indoor air pollutants require exposure ssements and dose-response assessments.Dose-response assessment methodologies include the inhalation reference concentration (RfC), structure-activity relationships, dose-rponse models, and the decision analytic approach. The RfC is an estimate (with uncertainty spanning perhaps an order of magnitude) ofa daily exposure to the human population (including sensitve subgroups) that is likely to be without an appreciable risk ofdeleterious effects during a lifetime. The current RfC method provides guidelines for mking the necessary dometric adjustments for gases and aerosols. Human equivalent cocentus for no-observedadverse-effect levels in animals are determined by using mathematical relationships that adjust for regional deposition, solubility, ventilation rate, and blood:air partition coefficients. The RfC methodology exists as an interim methodology.Future scientific advancements are expected to further refine the approach.

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“…A common method of using experts to arrive at a consensus is the Delphi method. 47 In the first round of this method, the experts give independent opinions. In subsequent rounds, these opinions are shared and each has a chance to modify the first estimate.…”

Section: Uncertainty Analysismentioning

confidence: 99%