Numerical simulation of thermal water delivery in the human nasal cavity.

This work describes an extensive numerical investigation of thermal water delivery for the treatment of inflammatory disorders in the human nasal cavity. The numerical simulation of the multiphase air-droplets flow is based upon the Large Eddy Simulation (LES) technique, with droplets of thermal water described via a Lagrangian approach. Droplet deposition is studied for different sizes of water droplets, corresponding to two different thermal treatments, i.e. aerosol and inhalation. Numerical simulations are conducted on a patient-specific anatomy, employing two different grid sizes, under steady inspiration at two breathing intensities. The results are compared with published in vivo and in vitro data. The effectiveness of the various thermal treatments is then assessed qualitatively and quantitatively, by a detailed analysis of the deposition patterns of the droplets. Discretization effects on the deposition dynamics are addressed. The level of detail of the present work, together with the accuracy afforded by the LES approach, leads to an improved understanding of how the mixture of air-water droplets is distributed within the nose and the paranasal sinuses.

Risk communication, the West Nile virus epidemic, and bioterrorism: responding to the communication challenges posed by the intentional or unintentional release of a pathogen in an urban setting.

The intentional or unintentional introduction of a pathogen in an urban setting presents severe communication challenges. Risk communication--a science-based approach for communicating effectively in high-concern situations--provides a set of principles and tools for meeting those challenges. A brief overview of the risk communication theoretical perspective and basic risk communication models is presented here, and the risk communication perspective is applied to the West Nile virus epidemic in New York City in 1999 and 2000 and to a possible bioterrorist event. The purpose is to provide practical information on how perceptions of the risks associated with a disease outbreak might be perceived and how communications would be best managed.

Olfaction and symptoms in the multiple chemical sensitivities syndrome.

Whereas most idiosyncratic environmental sensitivity complaints do not fit known diagnoses, the multiple chemical sensitivities syndrome (MCS) is an extreme presentation that has defined diagnostic criteria. MCS symptomatics claim that they acquired a sensitized state as the result of a chemical exposure, usually to a solvent or pesticide, but not to a fragrance. Before this exposure, they did not experience symptoms. Following sensitization, symptoms increasing in number and severity with time are attributed by the MCS symptomatic to various exposures that are innocuous to most individuals. Although phenomenological studies have provided no evidence that particular odors elicit MCS symptoms, low levels of fragrances and perfumes are frequently associated with the reporting of MCS symptoms. This evaluation examines proposed mechanisms by which odorants and fragrances might cause either sensitization or elicitation of MCS symptoms, including altered odor sensitivity, primary irritancy or irritancy-induced upper airway reactivity, neurogenic switching of trigeminal irritancy signals, time-dependent sensitization and limbic kindling, CNS toxicity, and various psychiatric conditions. In no case was there persuasive evidence that any olfactory mechanism involving fragrance underlies either induction of a sensitized state or the triggering of MCS symptoms. Fragrances and other odorants could, however, be associated with symptoms as claimed by MCS symptomatics, because they are recognizable stimuli, but fragrance has not been demonstrated to be causal in the usual sense.

The determinants of trust and credibility in environmental risk communication: an empirical study.

This study examines a key component of environmental risk communication; trust and credibility. The study was conducted in two parts. In the first part, six hypotheses regarding the perceptions and determinants of trust and credibility were tested against survey data. The hypotheses were supported by the data. The most important hypothesis was that perceptions of trust and credibility are dependent on three factors: perceptions of knowledge and expertise; perceptions of openness and honesty; and perceptions of concern and care. In the second part, models were constructed with perceptions of trust and credibility as the dependent variable. The goal was to examine the data for findings with direct policy implications. One such finding was that defying a negative stereotype is key to improving perceptions of trust and credibility.

Industry response to SARA Title III: pollution prevention, risk reduction, and risk communication.

This paper reports results from a survey designed to: (1) evaluate changes in industrial pollution prevention practices since the passage of the landmark environmental legislation, the Emergency Planning and Community Right-to-Know Act of 1986, also known as SARA Title III, and (2) identify those factors that may contribute to an industrial facility engaging in pollution prevention and risk communication activities. The survey was conducted under a Cooperative Agreement between the U.S. Environmental Protection Agency and the Columbia University Center for Risk Communication. Evidence from the survey indicates that a wide variety of waste and pollution reduction activities have been undertaken since passage of the Act. Virtually all facilities surveyed in the pulp and paper, chemical, and petroleum and refining industries reported that they had reduced pollutants or wastes on at least one of ten measures, including reducing toxic air emissions. Most facilities indicated paying more attention to pollution prevention activities as a result of SARA Title III and half reported that their communication activities have also increased.

Asbestos in the air of public buildings: a public health risk?

The Environmental Health and Safety Council of the American Health Foundation has examined current estimates of cancer risks associated with the presence of asbestos-containing materials (ACM) in public buildings. The Council finds that even complete removal of asbestos from all of these buildings will provide no measurable benefit to public health. The removal of nonfriable ACM only can be postulated to protect the public against a small hypothetical risk that cannot be measured epidemiologically. Moreover, examination of the assumptions used in the risk assessment calculations leads to the conclusion that these small calculated risks are likely to represent overestimates. In recent surveys, the measured asbestos levels in indoor air cast some doubt on whether occupant exposure to asbestos levels are contributed to significantly by ACM even when some of the material is friable or in bad condition. Furthermore, the models used for cancer risk estimates assume no threshold level for cancer and conclude that any exposure is carcinogenic. This may be unjustified in light of information on the mechanisms for some asbestos-caused disease. Based on the best available data, it is very unlikely that cancer will result from indoor asbestos exposure, especially where ACM is well maintained.

Decision analysis and risk management decision making: issues and methods.

This paper provides an overview of decision analysis and its use in risk management decision making. The paper discusses the distinctive characteristics of decision analysis and compares these characteristics with those of its principal alternative--cost-benefit analysis. The paper also discusses each of the steps in a decision analysis and the strengths and limitations of the method.