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Abstracts (PDF file, 1.8MB) - Society for Risk Analysis

Abstracts (PDF file, 1.8MB) - Society for Risk Analysis

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SRA 2013 Annual Meeting <strong>Abstracts</strong><br />

M3-E.2 Jiao, W; Frey, HC*; North Carolina State University;<br />

frey@ncsu.edu<br />

Measurement and Comparison of PM2.5 AND CO<br />

Microenvironmental Exposure Concentrations <strong>for</strong><br />

Selected Transportation Modes<br />

Daily commutes may contribute disproportionately to overall<br />

daily exposure to urban air pollutants such as fine particulate<br />

matter (PM2.5) and carbon monoxide (CO). The on-road and<br />

near-road microenvironments are of concern because of<br />

proximity to on-road traffic emissions. A field data collection<br />

study design was developed based on factors that may affect<br />

variability in in-transit concentration, including transportation<br />

mode, time of day, traffic volume, weather, vehicle ventilation<br />

conditions, road geometry and traffic control, traffic vehicle<br />

mix, and proximity to intersections. PM2.5 and CO<br />

concentrations were measured and compared across<br />

pedestrian, bus, and car modes during lunchtime and afternoon<br />

rush hour within a three-week time period on pre-selected<br />

round trip routes in Raleigh, NC. Variability in the<br />

transportation mode concentration ratios of PM2.5 and CO is<br />

quantified. Factors affecting variability in PM2.5 and CO<br />

concentrations are identified. The average pedestrian<br />

concentration is compared with fixed site monitor (FSM) data<br />

to determine if FSM is an appropriate surrogate <strong>for</strong> near-road<br />

concentration. Preliminary results indicate that on-road or<br />

near-road microenvironmental concentrations are sensitive to<br />

transportation mode, traffic volume, and proximity to onroad<br />

emission sources. In general, pedestrians experienced the<br />

highest PM2.5 concentrations among all measured<br />

transportation modes. Peaks in pedestrian PM2.5 concentration<br />

are typically associated with a passing truck. In comparison,<br />

the average PM2.5 concentration in-car is the lowest because<br />

the selected ventilation conditions helped to prevent ingress of<br />

particles. A positive association was found between traffic<br />

counts and average CO concentrations. Field studies such as<br />

this are needed to develop data <strong>for</strong> input to population-based<br />

stochastic exposure simulation models to more accurately<br />

predict transportation mode exposure concentrations.<br />

M3-E.1 Jiao, W*; Frey, HC; North Carolina State University;<br />

wjiao@ncsu.edu<br />

Comparison of predicted exposures versus ambient fine<br />

particulate matter concentrations<br />

Persons 65 and older are particularly susceptible to adverse<br />

effects from PM2.5 exposure. Using the Stochastic Human<br />

Exposure and Dose Simulation model <strong>for</strong> Particulate Matter<br />

(SHEDS-PM), distributions of inter-individual variability in daily<br />

PM2.5 exposures are estimated <strong>for</strong> Bronx, Queens and New<br />

York Counties in the New York City area <strong>for</strong> the years 2002 to<br />

2006 based on ambient concentration, air exchange rate,<br />

penetration factor, deposition rate, indoor emission sources,<br />

census data, and activity diary data. Three research questions<br />

are addressed: (1) how much is variability in estimated daily<br />

average exposure to ambient air pollution influenced by<br />

variability in ambient concentration compared to other<br />

exposure factors?; (2) what is the inter-annual variation in daily<br />

average exposure?; and (3) what key factors and values of these<br />

key factors lead to high exposure? In comparison with CMAQ<br />

input ambient concentrations, daily average exposure estimates<br />

have more variability. Variation in estimated exposure to<br />

pollutants ambient origin is mostly affected by variation in<br />

ambient concentration, air exchange rate, and human activity<br />

patterns. Estimated daily average exposure to ambient PM2.5 is<br />

about 30 to 40 percent less than the ambient concentration.<br />

Seasonal differences in estimated exposure are mainly caused<br />

by seasonal variation in ACH. There was relatively little<br />

estimated inter-annual variation in the daily average exposure<br />

to concentration ratio (Ea/C), since factors affecting exposure<br />

such as ACH, housing type and activity patterns were assumed<br />

to be relatively stable across years. The distribution of<br />

inter-individual variability in the Ea/C ratio can be used to<br />

identify highly exposed subpopulations to help in<strong>for</strong>m risk<br />

management strategies and to provide advisory in<strong>for</strong>mation to<br />

the public.<br />

T4-H.3 John, RS*; Rosoff, HR; University of Southern<br />

Cali<strong>for</strong>nia; richardj@usc.edu<br />

Validation of Adversary Utility Assessment by Proxy<br />

Most adversaries are not available <strong>for</strong> or willing to allow <strong>for</strong><br />

direct elicitation. Such adversaries have a strong interest in<br />

countering or foiling others; these instances range from<br />

criminal organizations, terrorist organizations, corporations<br />

engage seeking to gain a market advantage, political<br />

organizations seeking to promote their views and hindering<br />

rivals from making progress, and sports rivalries. In such cases<br />

it is necessary to construct a representation of preferences<br />

using in<strong>for</strong>mation that is known about adversary motivations,<br />

objectives, and beliefs. Such in<strong>for</strong>mation includes a variety of<br />

sources, including past adversary behavior, public statements<br />

by the adversary, adversary web sites, and intelligence. An<br />

adversary objectives hierarchy and MAU model based on this<br />

in<strong>for</strong>mation can be constructed by proxy, using judgments from<br />

an adversary values expert (AVE). The construction of value<br />

models by proxy raises the question of whether such models<br />

can accurately capture adversary preferences using only<br />

secondary and tertiary sources. There is no published research<br />

to date on the validity of utility models constructed by proxy. In<br />

this paper, we report two validation studies comparing MAU<br />

models <strong>for</strong> two different politically active non-profit<br />

organizations that utilize civil disobedience to achieve political<br />

objectives. In both cases, we constructed an objectives<br />

hierarchy and MAU model using AVEs who have access to<br />

publicly available in<strong>for</strong>mation about the organizations’ motives,<br />

objectives, and beliefs, but no direct contact with organization<br />

leaders. We then independently compared these MAU model<br />

parameters and constructed preferences to those based on<br />

direct assessment from a representative of the organization. In<br />

both cases, we demonstrate good convergence between the<br />

proxy model and the model assessed by direct contact with a<br />

decision maker. The proxy MAU models provided a complete<br />

and accurate representation of the organizations’ values,<br />

including objectives, trade-offs, risk attitudes, and beliefs about<br />

consequence impacts.<br />

M4-H.3 John, RS*; Scurich, N; University of Southern<br />

Cali<strong>for</strong>nia and University of Cali<strong>for</strong>nia, Irivine;<br />

richardj@usc.edu<br />

Public perceptions and trade-offs related to randomized<br />

security schedules<br />

Although there are theoretical advantages to randomized<br />

security strategies, and they have been adopted in several<br />

major areas, there has been no research evaluating the public’s<br />

perception of such measures. Perhaps the most challenging<br />

hurdle <strong>for</strong> randomized security strategies is the potential <strong>for</strong><br />

perceived unfairness by the public. Randomization is clumpy,<br />

and random selections <strong>for</strong> search will often appear nonrandom<br />

to an individual who observes some relatively small number of<br />

searches while waiting in line. Individuals observing random<br />

searches may exhibit a confirmation bias that magnifies the<br />

perception of unfair search patterns in short sequences due to<br />

(1) biased observation seeking to confirm hypothesized<br />

inequities, and (2) biased interpretation and recollection of<br />

observed searches. In short, the perception of safety can be as<br />

important as the reality of safety. Likewise, the perception of<br />

fairness can weigh as heavily as the reality of fairness. If<br />

randomized security schedules are perceived as inefficacious<br />

and/or unfair, potential patrons might protest their use and<br />

pursue alternatives that actually increase the net societal risk.<br />

In the present experiment, over 200 respondents were asked to<br />

make choices between attending a venue that employed a<br />

traditional (i.e., search everyone) or a random (i.e., a<br />

probability of being searched) security schedule. The<br />

probability of detecting contraband was manipulated (i.e., 1/10;<br />

1/4; 1/2) but equivalent between the two schedule types. In<br />

general, participants were indifferent to either security<br />

schedule, regardless of the probability of detection. The<br />

randomized schedule was deemed more convenient, but the<br />

traditional schedule was considered fairer and safer,<br />

suggesting a perceived trade-off between safety, fairness, and<br />

convenience. There were no differences between traditional<br />

and random search in terms of effectiveness or deterrence.<br />

December 8-11, 2013 - Baltimore, MD

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