The tactile signal detection task and why it could change how we measure workload.

In Human Factors research, measuring the construct of workload is common. This often takes the form of using subjective questionnaires such as the NASA-TLX. Another approach analyses operators' performance in a secondary task to quantify and measure workload.

Public health and chronic low chlordecone exposures in Guadeloupe; Part 2: Health impacts, and benefits of prevention.

Background: Inhabitants of Guadeloupe are chronically exposed to low doses of chlordecone via local food due to its past use in banana plantations. The corresponding health impacts have not been quantified. We develop a quantitative method and present the results in two articles: 1.

Public health and chronic low chlordecone exposure in Guadeloupe, Part 1: hazards, exposure-response functions, and exposures.

Background: Inhabitants of Guadeloupe are chronically exposed to low dose of chlordecone via local food. The corresponding health impacts have not been quantified. Nevertheless the public authority implemented an exposure reduction program in 2003.

Costs of Health Damage from Atmospheric Emissions of Toxic Metals: Part 2-Analysis for Mercury and Lead.

In this part of the series we explain the detailed literature review and the calculations of impacts and damage costs of mercury and lead. Methodology and general assumptions are explained in the companion article, Part 1 of this series, and the spreadsheet with the calculations is available as a supplementary file of Part 1. For mercury, the damage cost is 22,937 € /kg if there is a no-effect threshold, 52,129 € /kg if there is none; 91% is due to mortality from heart disease, the rest from loss of IQ points.

Costs of Health Damage from Atmospheric Emissions of Toxic Metals: Part 1-Methods and Results.

Significant quantities of toxic metals are emitted to the air by the incineration of waste, as well as by the combustion of coal and oil. To optimize the regulations for their emissions one needs to know the cost of their damage. That requires an impact pathway analysis, with realistic dispersion models, exposure-response functions, and monetary values.

Impact of the 1990 Hong Kong legislation for restriction on sulfur content in fuel.

Introduction: After the implementation of a regulation restricting sulfur to 0.5% by weight in fuel on July 1, 1990, in Hong Kong, sulfur dioxide (SO2*) levels fell by 45% on average and as much as 80% in the most polluted districts (Hedley et al. 2002).

How to determine life expectancy change of air pollution mortality: a time series study.

Background: Information on life expectancy (LE) change is of great concern for policy makers, as evidenced by discussions of the "harvesting" (or "mortality displacement") issue, i.e. how large an LE loss corresponds to the mortality results of time series (TS) studies.

Improving health through policies that promote active travel: a review of evidence to support integrated health impact assessment.

Background: Substantial policy changes to control obesity, limit chronic disease, and reduce air pollution emissions, including greenhouse gasses, have been recommended. Transportation and planning policies that promote active travel by walking and cycling can contribute to these goals, potentially yielding further co-benefits. Little is known, however, about the interconnections among effects of policies considered, including potential unintended consequences.

Estimation of incidence and social cost of colon cancer due to nitrate in drinking water in the EU: a tentative cost-benefit assessment.

Background: Presently, health costs associated with nitrate in drinking water are uncertain and not quantified. This limits proper evaluation of current policies and measures for solving or preventing nitrate pollution of drinking water resources. The cost for society associated with nitrate is also relevant for integrated assessment of EU nitrogen policies taking a perspective of welfare optimization.

Global health impacts and costs due to mercury emissions.

Since much of the emission is in the form of metallic Hg whose atmospheric residence time is long enough to cause nearly uniform mixing in the hemisphere, much of the impact is global. This article presents a first estimate of global average neurotoxic impacts and costs by defining a comprehensive transfer factor for ingestion of methyl-Hg as ratio of global average dose rate and global emission rate. For the dose-response function (DRF) we use recent estimates of IQ decrement as function of Hg concentration in blood, as well as correlations between blood concentration and Hg ingestion.

Environmental impacts and costs of solid waste: a comparison of landfill and incineration.

The methodology for evaluating the impacts and damage costs ('external costs') due to pollution from waste treatment is described and the results are presented, based on the ExternE project series of the European Commission. The damage costs of landfill and incineration of municipal solid waste are compared, with due account for energy and materials recovery, as well as possible differences in transport distance. We have not been able to quantify the total damage costs of leachates because of the complexity of the environmental pathways and of the long time horizon of some persistent pollutants, but we consider an extreme scenario to show that they are not worth worrying about in the sense that reducing the pollutants in leachates beyond current regulations would bring negligible benefit in comparison with the abatement of other sources of the same pollutants.

Reflectors for uniform far-field irradiance: fundamental limits and example of an axisymmetric solution.

We establish a fundamental bound on the field of view over which strictly uniform far-field irradiance can be achieved in symmetric two-dimensional (2D, troughlike) and three-dimensional (3D, conelike) illumination systems. Earlier results derived for particular 2D devices are shown to be special cases of the general formula. For a rotationally symmetric 3D luminaire with a Lambertian disk light source and a prescribed uniform core region half-angle theta(c), no more than tan2(theta(c)) can be projected within a uniform core region.

Improving policy responses to the risk of air pollution.

This paper offers a brief review of the need for cost-benefit analysis (CBA) and the available policy instruments for air pollution. To prioritize different possible actions, one needs to know which source of pollution causes how much damage. This requires an impact pathway analysis, that is, an analysis of the chain emission --> dispersion --> dose-response function --> monetary valuation.

Environmental impacts and costs of energy.

Environmental damage is one of the main justifications for continued efforts to reduce energy consumption and to shift to cleaner sources such as solar energy. In recent years there has been much progress in the analysis of environmental damages, in particular thanks to the ExternE (External Costs of Energy) Project of the European Commission. This article presents a summary of the methodology and key results for the external costs of the major energy technologies.

Analysis of air pollution mortality in terms of life expectancy changes: relation between time series, intervention, and cohort studies.

Background: Information on life expectancy change is of great concern for policy makers, as evidenced by the discussions of the so-called "harvesting" issue (i.e. the question being, how large a loss each death corresponds to in the mortality results of time series studies).

Air pollution mortality: harvesting and loss of life expectancy.

This article concerns the interpretation of epidemiological studies of air pollution mortality and the choice of indicators for quantifying the impact, for communication with policymakers. It is shown that the total mortality impact (measured by cohort studies) can only be quantified in terms of loss of life expectancy (LLE), not number of premature deaths. Time-series (TS) studies of mortality observe only acute impacts, that is, deaths due to short-term exposure ("acute mortality"); they allow the estimation of a number of deaths without providing any information on the LLE per death.

Uncertainty of air pollution cost estimates: to what extent does it matter?

How large is the social cost penalty if one makes the wrong choice because of uncertainties in the estimates of the costs and benefits of environmental policy measures? For discrete choices there is no general rule other than the recommendation to always carefully compare costs and benefits when introducing policies for environmental protection. For continuous choices (e.g.

Pathway analysis for population-total health impacts of toxic metal emissions.

This article describes a simple model for quantifying the health impacts of toxic metal emissions. In contrast to most traditional models it calculates the expectation value of the total damage (summed over the total population and over all time) for typical emission sites, rather than "worst-case" estimates for specific sites or episodes. Such a model is needed for the evaluation of many environmental policy measures, e.

Interpretation of air pollution mortality: number of deaths or years of life lost?

This paper examines the relation between the results of epidemiologic studies of air pollution mortality and impact indicators that can be informative for environmental policy decisions. Using models that are simple and transparent, yet contain the essential features, it is shown that (1) number of deaths is not meaningful for air pollution, whereas loss of life expectancy (LLE) is an appropriate impact indicator; (2) the usual short-term (time series) studies yield a change in daily number of deaths attributable to acute effects of pollution, without any information on the associated LLE (although some information on this has recently become available by extending the observation window of time series); and (3) long-term studies yield a change in age-specific mortality, which makes it possible to calculate the total population averaged LLE (acute and chronic effects) but not the total number of premature deaths attributable to air pollution. The latter is unobservable because one cannot distinguish whether few individuals suffer a large or many suffer a small LLE.

Air pollution and mortality: quantification and valuation of years of life lost.

To analyze the loss of life expectancy (LLE) due to air pollution and the associated social cost, a dynamic model was developed that took into account the decrease of risk after the termination of an exposure to pollution. A key parameter was the time constant for the decrease of risk, for which estimates from studies of smoking were used. A sensitivity analysis showed that the precise value of the time constant(s) was not critical for the resulting LLE.

Tailored edge-ray designs for illumination with tubular sources.

The rubric tailored edge-ray designs (TED's) refers to the procedure for tailoring lighting reflectors to produce a prescribed flux distribution for an extended Lambertian source while ensuring maximum radiative efficiency (no radiation being returned to the source). Most TED studies to date have been restricted to the case in which the two edges of the image of the source in the reflectors are bound by a source edge ray and a reflector edge. The extension to the more general, and challenging, solution in which both edges of the image can be bound by rays from opposite edges of the source was recently begun by Ries and Winston [J.

Tailoring lighting reflectors to prescribed illuminance distributions: compact partial-involute designs.

Reflectors for lighting can be tailored to produce the desired flux maps (illuminance distributions) precisely, from extended light sources, with a calculational procedure called tailored edge-ray designs (TED's). We generalize the TED procedure, which has so far been developed only for flat sources, to tubular sources within partial-involute reflectors. The governing differential equations for the reflectors are solved analytically.

Reflector design for illumination with extended sources: the basic solutions.

The goal of the optical design of luminaires and other radiation distributors is to attain the desired illumination on the target with a given source while minimizing losses. Whereas the required design procedure is well known for situations in which the source can be approximated as a point or as a line, the development of a general analytical design method for extended sources began only recently. One can obtain a solution for extended sources by establishing a one-to-one correspondence between target points and edge rays.

Edge-ray method for analysis of radiation transfer among specular reflectors.

The analysis of radiation transfer in specular reflector configurations, with multiple or distorted images of an extended radiation source, appears to be so complicated that the need for detailed ray tracing is usually considered inescapable. I show that the number of calculations can be greatly reduced when the source is isotropic. Starting from the fact that the radiation received from an isotropic source depends only on the emissive power of the source and on the angular contour subtended by the source, I show that only edge rays need to be traced, no matter what the curvature of the reflector.