Nocturnal Chemistry in a Today's European Metropolis

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Urban air pollution has a great impact on both climate and human health. As policies increasingly focus on the reduction of pollutant emissions (e.g. nitrogen oxides, NOx), the evolving role of nocturnal atmospheric oxidation processes in urban air quality remains poorly understood. Even though the nitrate radical (NO3), formed from oxidation of NOx by ozone, is a powerful oxidizing agent at night, its impact on contemporary and future urban atmospheres is not yet well characterized. Model calculations as well as field measurements in China and the US imply that NO3 production rates significantly increase during the evolution NOx abatement acts. Nevertheless, there have been no recent assessments of NO3 mixing ratios in European cities during the night, especially considering the EU's latest mitigation efforts. The NOcturnal Chemistry in a Today's European Metropolis (NOCTEM) project aims to illuminate this neglected dark side of air pollution by combining field measurements of NO3 with means of cutting-edge absorption spectrocopy techniques atop a central tower in Paris, France, with chamber studies under controlled present and future NOx emission scenarios. The results from these studies are going to be implemented in the CHIMERE model used to predict the air quality in Île-de-France. The applicant offers expertise in nocturnal atmospheric chemistry, spectroscopy, and field work. This research project will not only broaden the applicant's experience and research skills but also strengthen the professional network, thereby advancing the long-term goal of securing a permanent researcher position.go