UFR de Physique

Propositions de stages en laboratoire -- M2

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Photoacoustic sensor for black carbon - NO2

  • Option International « Atmospheric Environnement » du parcours Lumière-Matière
  • Laboratoire: Laboratoire de Physico-Chimie de l'Atmosphère (LPCA)
  • Responsable du stage: Weidong CHEN (chen@univ-littoral.fr, 0328658264)
  • Mots clés: trace species monitoring, black carbon, NO2, laser photoacoustic spectroscopy
  • Fiche complète en PDF : Fiche complète en PDF

Despite significant improvements of air quality in European countries during the past two decades, air quality thresholds are still frequently exceeded and further efforts are particularly needed regarding reduction of particulate matter, nitrogen oxides and ozone. Nitrogen dioxide (NO2), a member of the nitrogen oxides (NOx = NO NO2), is an important reactive trace gas in the troposphere and plays a crucial role in many atmospheric processes with strong implications for ecosystem stability, climate change, and public health Sci. 333 (2011) 1737; Sci. Rep. 2 (.... Precise monitoring of atmospheric NO2 is essential to allow accurate modeling of the global nitrogen budget and the impact of nitrogen emissions for improved air quality forecasting. The most widely used "reference method" (so called "NOx analyzer"), recommended by the US EPA and by European legislation for routine measurement of NO2 in monitoring networks, involves chemiluminescence technique. However this method usually results in positive or negative interferences Atmos. Meas. Tech. 5 (2012) 149 impacting the measurement accuracy. Black carbon (BC), one of the most important short-lived climate pollutants with an atmospheric lifetime of about one week, is considered as the third most powerful climate-forcing agent in the atmosphere after CO2 and CH4 IPCC2013. The uncertainties associated to BC radiative forcing are, for now, larger than 70% and are mainly related to actual measurement techniques that provide limited information to distinguish BC from other aerosols and to its optical properties. In this context, we propose to develop un laser instrument based on photoacoustic spectroscopy capable of simultaneously direct measuring black carbon and NO2 concentration in the environment without any chemical conversion and sample preparation.