Analysis of In-Vehicle Black Carbon Exposure and Trip Characteristics Using GPS Logs and Diaries

Poster SP-26 presented at ISEE 2012 Seattle, USA. Title: Analysis of In-vehicle Black Carbon Exposure and Trip Characteristics Using GPS Logs and Diaries Abstract: Background: Global Positioning Systems (GPS) are being used more frequently in health research. To limit respondent burden, and because of technical problems with the development of miniaturized air quality sensors; exposure is determined afterwards by linking GPS traces with air pollution models or nearby monitoring stations. In-vehicle exposure may however be not only related to yearly averaged outdoor concentrations. Objectives: To investigate whether the levels of in-vehicle Black Carbon (BC) concentrations are influenced by trip duration, hour of the day, traffic intensities, and spatial parameters like degree of urbanization or road type. Methods: Personal exposure measurements were done using µ-aethalometers, trip diaries and GPS devices. More than 1000 car-trips were evaluated in Flanders, Belgium. GPS coordinates were assigned to road segments to allow BC concentrations to be linked with trip and road characteristics. Results: Due to loss of signal, technical issues or participant’s error, 30% of all car trips had no GPS coordinates. If the distance between a GPS point and the closest road with known traffic intensities was larger than 30m, the observation was omitted (23% of all recorded coordinates). Average BC concentrations on highways are comparable to concentrations on urban roads (8.3 µg/m3), but almost double the concentrations on rural roads (4.7 µg/m3). BC concentrations are elevated at lower speeds (<30 km/h) and at speeds above 80 km/h. Driving on roads with low instantaneous traffic intensities resulted in lower exposures than driving on roads with higher traffic intensities. Concentrations on traffic peak hours are higher compared to off-peak hours. We found no evidence of a buildup of BC particles inside a vehicle; but there is a link between trip length and use of certain road types. Conclusions: We found evidence that BC concentrations in vehicles depend on speed, timing of the trip, degree of urbanization, and traffic intensities

Utilisation de données acoustiques pour l'estimation des polluants liés au trafic routier

National audienceLa mesure en temps réel de la pollution liée au trafic routier en milieu urbain (bruit, NOx, Particules Ultra Fines (UFP), etc.) est indispensable pour une évaluation pertinente de la qualité de vie des citadins, et pour le développement de stratégies de réduction de l'exposition à cette pollution (proposition d'itinéraires appropriés, etc.). L'Université de Gand et VITO, dans le cadre du projet IDEA financé par l'IWTVlaanderen, réfléchissent à l'optimisation de réseaux de mesures pour évaluer cette exposition. En particulier, le coût de certaines mesures (en particulier la mesure des UFP, polluant très nocif mais dont la mesure est onéreuse), souligne le besoin de mesures de substitution, utilisables dans le cadre d'un réseau de mesures. Les mesures acoustiques semblent pouvoir être utilisées dans cet objectif. Il est nécessaire pour cela de s'intéresser dans un premier temps aux liens qui existent entre les différents polluants, le bruit, et les débits observés en un point du réseau. Ces données ont été mesurées de manière simultanée à Anvers (quartier de Borgerhout). Une réflexion a été menée sur les indicateurs acoustiques pouvant être utilisés pour une estimation des polluants observés, qui permet d'affiner l'information donnée par l'utilisation seule du LAeq. Il s'avère néanmoins que l'utilisation des données seules de trafic ou acoustique ne permet pas d'approximer de manière convenable les quantités de polluants observées. La possibilité d'associer des éléments météorologiques simples tels que la vitesse et direction du vent, à une mesure du flux de véhicules ou des niveaux de bruit, pour accéder à une estimation des UFP et de NOx observés, est étudiée

Cost-utility analysis of a one-time supervisor telephone contact at 6-weeks post-partum to prevent extended sick leave following maternity leave in The Netherlands: results of an economic evaluation alongside a randomized controlled trial

<p>Abstract</p> <p>Background</p> <p>Working women of childbearing age are a vital part of the population. Following childbirth, this group of women can experience a myriad of physical and mental health problems that can interfere with their ability to work. Currently, there is little known about cost-effective post-partum interventions to prevent work disability. The purpose of the study was to evaluate whether supervisor telephone contact (STC) during maternity leave is cost-effective from a societal perspective in reducing sick leave and improving quality-adjusted life years (QALYs) compared to common practice (CP).</p> <p>Methods</p> <p>We conducted an economic evaluation alongside a randomized controlled trial. QALYs were measured by the EuroQol 5-D, and sick leave and presenteeism by the Health and work Performance Questionnaire. Resource use was collected by questionnaires. Data were analysed according to intention-to-treat. Missing data were imputed via multiple imputation. Uncertainty was estimated by 95% confidence intervals, cost-utility planes and curves, and sensitivity analyses.</p> <p>Results</p> <p>541 working women from 15 companies participated. Response rates were above 85% at each measurement moment. At the end of the follow-up, no statistically significant between-group differences in QALYs, mean hours of sick leave or presenteeism or costs were observed. STC was found to be less effective and more costly. For willingness-to-pay levels from €0 through €50,000, the probability that STC was cost-effective compared to CP was 0.2. Overall resource use was low. Mean total costs were €3678 (95% CI: 3386; 3951). Productivity loss costs represented 37% of the total costs and of these costs, 48% was attributable to sick leave and 52% to work presenteeism. The cost analysis from a company's perspective indicated that there was a net cost associated with the STC intervention.</p> <p>Conclusions</p> <p>STC was not cost-effective compared to common practice for a healthy population of working mothers; therefore, implementation is not indicated. The cost-utility of STC for working mothers with more severe post-partum health problems, however, needs to be investigated. Work presenteeism accounted for half of the total productivity loss and warrants attention in future studies.</p> <p>Trial registration number</p> <p>ISRCTN: <a href="http://www.controlled-trials.com/ISRCTN73119486">ISRCTN73119486</a></p

Kinetische studie van de reacties van enkele haloalkylperoxyradicalen met NO

SIGLEKULeuven Campusbibliotheek Exacte Wetenschappen / UCL - Université Catholique de LouvainBEBelgiu

The Aeroflex: A Bicycle for Mobile Air Quality Measurements

sensor

A comparison of strategies for estimation of ultrafine particle number concentrations in urban air pollution monitoring networks

Abstract We propose three estimation strategies (local, remote and mixed) for ultrafine particles (UFP) at three sites in an urban air pollution monitoring network. Estimates are obtained through Gaussian process regression based on concentrations of gaseous pollutants (NOx, O3, CO) and UFP. As local strategy, we use local measurements of gaseous pollutants (local covariates) to estimate UFP at the same site. As remote strategy, we use measurements of gaseous pollutants and UFP from two independent sites (remote covariates) to estimate UFP at a third site. As mixed strategy, we use local and remote covariates to estimate UFP. The results suggest: UFP can be estimated with good accuracy based on NOx measurements at the same location; it is possible to estimate UFP at one location based on measurements of NOx or UFP at two remote locations; the addition of remote UFP to local NOx, O3 or CO measurements improves models' performance