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Lausanne, Switzerland

Vernez D.,Institute of Work and Health IST | Milon A.,Institute of Work and Health IST | Francioli L.,University of Geneva | Bulliard J.-L.,University of Lausanne | And 2 more authors.
Photochemistry and Photobiology

Exposure to solar ultraviolet (UV) light is the main causative factor for skin cancer. UV exposure depends on environmental and individual factors. Individual exposure data remain scarce and development of alternative assessment methods is greatly needed. We developed a model simulating human exposure to solar UV. The model predicts the dose and distribution of UV exposure received on the basis of ground irradiation and morphological data. Standard 3D computer graphics techniques were adapted to develop a rendering engine that estimates the solar exposure of a virtual manikin depicted as a triangle mesh surface. The amount of solar energy received by each triangle was calculated, taking into account reflected, direct and diffuse radiation, and shading from other body parts. Dosimetric measurements (n = 54) were conducted in field conditions using a foam manikin as surrogate for an exposed individual. Dosimetric results were compared to the model predictions. The model predicted exposure to solar UV adequately. The symmetric mean absolute percentage error was 13%. Half of the predictions were within 17% range of the measurements. This model provides a tool to assess outdoor occupational and recreational UV exposures, without necessitating time-consuming individual dosimetry, with numerous potential uses in skin cancer prevention and research. © 2011 The Authors. Photochemistry and Photobiology © 2011 The American Society of Photobiology. Source

Vernez D.,Institute of Work and Health IST | Paccaud C.,University of Lausanne | Berode M.,Institute of Work and Health IST | Hopf N.,Institute of Work and Health IST | And 2 more authors.
Gefahrstoffe Reinhaltung der Luft

Hygiene practices in neonatal units require the use of disinfecting solutions containing ethanol or isopropanol. Newly disinfected hands or soaked swabs introduced inside the incubators may emit vapours leading to alcohol exposures to the neonates. Alcohol emissions from hands and other occasional sources (e.g. soaked disinfecting swabs) lead to measurable levels of vapours inside incubators. Average isopropanol and ethanol concentrations ranging from 33.1 to 171.4 mg/m 3 (13.8 to 71.4 ppm) and from 23.5 to more than 146 mg/m 3 (9.8 to > 6 ppm) respectively were measured inside occupied incubators (n = 11, measurement time about 230 min) in a neonatal unit of the Centre Hospitalier Universitaire Vaudois in Lausanne during regular activity. Exposure concentrations in a wide range of possible situations were then investigated by modeling using the one-box dispersion model. Theoretical modeling suggested typical isopropanol peaks and average concentrations ranging between 10 2 and 10 3 mg/m 3 (4·10 1 to 4·10 2 ppm), and 10 1 to 10 2 mg/m 3 (4 to 4·10 1 ppm), respectively. Based on our results we suggest several preventive measures to reduce the neonates' exposures to solvent vapours. Source

Paccaud C.,University of Lausanne | Vernez D.,Institute of Work and Health IST | Berode M.,Institute of Work and Health IST | Charriere N.,Institute of Work and Health IST | And 2 more authors.
Journal of Neonatal-Perinatal Medicine

Objective: To analyze the atmosphere inside incubators regarding alcoholic solvent such as isopropanol or ethanol which are commonly used in hand disinfecting solutions. Design: Observational. Setting: The third level neonatal unit of the Centre Hospitalier Universitaire Vaudois, Lausanne, Switzerland. Patients: Nine neonates with median (range) gestational age of 29 4/7 (25 5/7-39 0/7) weeks and birth weight of 960 (550-3050) grams. All neonates were inside incubators. Interventions: Alcoholic vapors inside incubators were directly and cumulatively measured by photoionisation and gas chromatography respectively after absorption on a charcoal sampling tube. Results: Eleven studies (mean study time: 230 ± 19 minutes) were performed. Highly variable isopropanol/ethanol concentrations profiles were found inside incubators. Peak value for isopropanol was 1982 part per million and for ethanol was 906 part per million. Conclusions: Incubators' inner atmosphere can be highly polluted by alcohol vapors. To reduce them staff should respect long evaporation time between hands disinfection and manipulations inside incubators. The use of an ethanol-based disinfecting solution, because of its short evaporation time, could be favored. As alcohol vapor toxicity for neonate remains largely unknown, further studies could be welcome. Source

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