MSCA-COFUND-CLEAR-Doc - PhD Position #CD22-58: Multiscale approach from experimental characterization of ZnO depolluting panels to computer-aided urban planning to reduce air at the District Scale

According to the World Health Organization, 7 million of premature deaths per year are due to air pollution. The outdoor air pollution is mostly generated by traffic, industries, agriculture and housing. In fact, the traffic in urban areas leads to the formation of primary and secondary pollutants such as NO, NO2, SO2 and O3 which affect cardiovascular and respiratory human functions. To tackle this main environmental and health issue, as a complement to pollutant emission reduction actions, we propose to test and to efficiently design urban planning strategies integrating innovative technologies through the city digital twin.

PhD SUBJECT DESCRIPTION

In the proposed PhD subject, we focus on ZnO nanostructure based depolluting panels to reduce human exposure at the district scale. First studies on ZnO nanostructure-based photocatalyst panels have been carried out in the PhD work of Dr M. Le Pivert supervised by Pr Y. Leprince-Wang. It showed promising results to decrease CO, O3 and NOx concentrations. Herein, we aim to improve air quality in critical polluted area by a multi-scale approach involving experimental tests at the material scale and fluid dynamics simulations at the district scale. To get a fine characterization of ZnO depolluting material, experiments will be conducted firstly on small samples (about 10cm*10cm) in a dedicated test chamber developed at Université Gustave Eiffel. This experimental device will allow to quantify/evaluate the efficiency of ZnO depolluting sample for different pollutant like NO and NO2 under different controlled environmental conditions (sunlight irradiance, temperature, relative humidity, pollutant concentration …). Hence, the ZnO depolluting behavior described by means of a “constitutive law” will be obtained from these experimental tests at the material scale. Then, the knowledge of the constitutive law of the ZnO depolluting panels will be integrated in computational fluid dynamics simulations coupled with sunlight irradiance cartographies to predict the air quality improvement at the district scale. Virtual testing will be performed using the city digital twin to get a limited deployment and smart placement of depolluting ZnO panels in order to improve the air quality in highly polluted urban area. To validate the proposed multi-scale approach dealing with the deployment and the efficiency of ZnO depolluting panels in urban areas, we propose to make original tests in the “Sense-City” equipment. Sense-City is composed of a 3200m3 climatic chamber and two instrumented full-scale urban areas including a building, houses and a street layout. The climatic chamber provides a controlled environment to replicate weather conditions with temperature ranging from −10°C to 40°C, humidity ranging from 20% to 95%, rain events, sun exposure and air pollution. The urban areas are instrumented with more than 150 permanent sensors spread between the underground, the building’s facade, the indoors and the outdoor. This notably includes 60 temperature sensors and 30 sensors for air pollution monitoring, starting from Particulate Matter (PM) to gases such as NO2, O3, CO, CO2 and Volatile Organic Compounds (VOCs). With its various devices, the Sense-City platform provides an excellent and unique experimental environment for a wide variety of societal urban problems from sustainable water networks, soil pollution and indoor or outdoor air quality, to building energy efficiency. Using Sense-City, we will be able to compare the numerical prediction of air quality improvement with real sensor measurement data in a full-scale urban area for different placements of ZnO depolluting panels and for different scenarios.

HOST LABORATORY & RESEARCH TEAM

Six educational and research institutions with recognized specializations in the fields of sustainable cities are combining their skills to create a university of international standing: Université Gustave Eiffel. This new institution brought together in 2020 a university (UPEM), a research institute (IFSTTAR), a school of architecture (EAVT) and three engineering schools (EIVP, ENSG and ESIEE Paris). It represents a quarter of French research on the cities of tomorrow and brings together multidisciplinary skills to conduct quality research for the benefit of society, offer training adapted to the socio-economic world and support public policies.

The PhD student will joint the IMSE laboratory (COSYS department) and the ESYCOM laboratory of Université Gustave Eiffel in Champs sur Marne Campus (near Paris). The research of IMSE (COSYS department) covers the development and design of experimental tools, the measurement and equation of physical phenomena to the realization of computer tools for the digital city. It has extended its skills to the fields of inverse modeling, numerical fluid mechanics and fast methods for solving partial differential equations. The Nanomaterials research team in ESYCOM Laboratory is involved in synthesis and characterization of ZnO based nanomaterials for their applications in energy and environment, more precisely, for air and water purification.

The PhD student will be supervised by a research team whose activities are complementary: Yamin Leprince and Julien Waeytens. Yamin Leprince has a strong experience in the field of nanomaterials and pollution control systems using photocatalytic materials. Her work ranges from the fundamental study of photocatalysis by ZnO nanostructures to the fabrication of depolluting panels on civil engineering materials such as tiles, paving stones and asphalt road aggregates (International Patent). The research of Julien Waeytens focuses on measurements and model-based numerical simulations to address urban issues such as air quality and energy efficiency of buildings. He participated in research projects for the localization of pollutant sources in an indoor environment (indoor air quality) and for the cartography of air pollution at the district scale (outdoor air quality). He conducts experiments in Sense-City equipment to monitor the pollutant dispersion using gas sensors and to validate models and numerical simulations.