Final Program - Society for Risk Analysis

inter-donation interval to mitigate iron deficiency in frequent blood donors whilepreserving an adequate blood supply. Increasing the inter-donation interval allowsmore time for recovery of iron stores, but the concern is that such a change maynegatively affect the blood supply by reducing the donation rate of frequent donors.A related issue is that data have been presented that suggest the current hemoglobinthresholds for donation may allow potentially iron deficient males to donate bloodand a significant number of female donors considered ‘normal’ may be deferred fromdonation. Low hemoglobin concentration is the most common cause of donor loss,and hemoglobin deferrals have a negative effect on donor return rates. In order toaddress this complex issue, CBER investigators explored what the potential blooddonor loss would be due to changes in the inter-donation interval. An Ordinary DifferentialEquation (ODE) compartment model, which defined rates at which eligibledonors donate, depending on the inter-donation deferral time, and rates at whichdeferred donors become eligible, was developed. The sum of the two compartmentsrepresented the total number of potential donors, while a counter described the totalnumber of donations accumulated. Results from the model applied to empirical dataand data gathered from the American Red Cross (ARC) showed that the compartmentmodel is a useful tool for investigating potential changes in the blood donor loss.P.47 Foster SA, Chrostowski PC, Porter TJ; sf@cpfassociates.comCPF Associates, Inc., Wheelabrator Environmental Technologies, Inc.ULTRAFINE PARTICLES IN COMBUSTION SOURCE EMISSIONS:THE ROLE OF WASTE-TO-ENERGY FACILITIESOver the past decade, information about potential adverse human health effectsof ultrafine particles has raised concerns about human health risks from ultrafineparticle emissions from many industrial and commercial sectors, and all typesof combustions sources including waste-to-energy (WTE) facilities. This paper presentsultrafine particle number concentrations reported from numerous recent studiesworldwide for a wide variety of different sources, including WTE facilities, powerplants, motor vehicles and household activities, and in ambient air. For example, measuredparticle number concentrations in WTE facility stack emissions have been reportedto range from roughly 60 - 200,000 particles/cm3. Concentrations in fossilfuel and biomass combustion emissions have been reported to range from 140,000- 600,000,000 particles/cm3 and in vehicle emissions at 5,000 - 10,000,000 particles/cm3. Concentrations along roadways have been reported at roughly 800 - 1,000,000particles/cm3 and in ambient air from roughly 2,000 - 130,000 particles/cm3. Thepaper also discusses challenges related to estimating exposures and potential risks, ina risk assessment framework, associated with combustion source emissions of ultrafineparticles. While more research is still needed, available data indicate that ultrafineparticle emissions from WTE facilities have a minor impact on ultrafine particle concentrationsin ambient air compared to many other stationary combustion sourcesand motor vehicles. Potential downwind ambient air concentrations associated withWTE ultrafine particle emissions are also substantially lower than concentrations resultingfrom some household cooking activities and concentrations already present inbackground ambient air.P.73 Foster CB; cfoster1225@aol.comUniversity of South CarolinaIMPACTS OF SCIENCE AND TECHNOLOGY CITIZENS’ SCHOOLSON EXPERT PRESENTERSScience and technology make possible much that wasn’t just 10 years ago ‘longer,healthier lives; bigger, faster-growing foods; cheaper, cleaner power,’ but theseadvances carry risks non-experts often don’t expect or understand. Deficits in the“public understanding of science” can lead to unrealistic expectations and preventcitizens from effectively engaging in science policy making. Helping citizens understandtheir work has challenged the scientific community, which rarely prepares itsmembers for such work or rewards them for it. Researchers studying the ways scientistsspeak about science to nonscientists have called for a shift from a “deficit model”of science communication, in which experts perceive their role as communicatorsof information to lay publics lacking science knowledge, toward a more interactivemodel. Ideally, such a dialogic or deliberative approach has impacts on the experts’ways of knowing and speaking about their work, as well as on the public’s understandingand expectations of that work. A number of studies have explored experts’perspectives in the risk communication process, but most have featured perceptionsof scientists who had little or no experience with public engagement. The proposedpresentation will draw on in-depth interviews with experts (n=21) from a varietyof disciplines who participated in a series of public engagement forums called Citizens’Schools (covering environment, energy, and nanotechnology issues). With thepurpose of evaluating an existing model of science and risk communication, thisresearch explores benefits/drawbacks of the Citizens’ Schools forums in promotingeffective communication between experts and lay citizens. Initial analysis of the datasuggest that this type of communication has the potential to make experts better (andmore willing) communicators by teaching them to listen as well as talk, and to makethem better researchers by allowing them to see their research from the perspectivesof non-scientists.W4-C.2 Fowler BA, Abadin H, Chou S, Demchuk E, Tie Y, Ruiz P, Mumtaz M,Wheeler J; drtox@earthlink.netAgency for Toxic Substances and Disease Registry (ATSDR)ATSDR APPORACHES FOR INCREASING TRANSPARENCY, SPEEDAND STAKE-HOLDER INVOLVEMENT IN CHEMICAL RISK ASSESS-MENTSThe science of risk assessment is a rapidly evolving field which is expandingto include a number of both technical and social considerations in order to reach99