PUBLICATION RELATIVES AU PROJET BREATHE
LA METROLOGIE PARTICIPATIVE DE LA QUALITE DE L’AIR AU SERVICE DE L’ACTION DE LA PARTICIPATION CITOYENNE
Ci-dessous le résumé de l’article étude participative quartier Arceaux Montpellier corédigé avec les participants.
This paper details the operating experience about a case study carried out as a citizen science approach to monitor magnetic particulate matter (PM) in a street canyon in Montpellier, France. A total of 60 passive filters and 12 Hedera Helix pot plants were deployed in 29 households for a period of 3 months, from December 2020 to March 2021. This street canyon was chosen by the academic team because dwellers were already mobilized against the street traffic and its adverse environmental effect on air quality, and because they were in conflict on this issue with policy makers. Despite the project aimed at including all the stakeholders through co-construction, dwellers, elected officials, and staff from technical department of the city were not fully embedded. The announcement of the closure of the street to through traffic during the metrological campaign and the absence of agreement curbed their involvement and motivation. However, the feedbacks from the citizen partners promote the fact that this study supported their claims and brought them a deeper understanding on the micro-scale air quality monitoring. Indeed, it is increasingly difficult for citizens, who seemed specifically interested in what is happening right outside their front door, to understand this measure with the emergence of ever more low-cost sensors. For that reason, we examined the citizen’s degree of confidence in magnetic monitoring of air quality and how can this technique be useful in their claims. The results show that magnetism can be a measurement technique favorable to citizen participation because it provides a large amount of data at the micro-scale of the street, while the data from the certified associations for monitoring air quality requires a spatial interpolation to map variations on a neighborhood scale. In this study, we proposed a magnetic air quality index to standardize and democratize the magnetic monitoring of air quality to facilitate the dialogue with all stakeholders.
A supervised machine learning approach to classify traffic-derived PM sources based on their magnetic properties.
Environmental magnetism techniques are increasingly used to map the deposition of particulate pollutants on
any type of accumulative surfaces. The present study is part of a collective effort that begun in recent years to
evaluate the efficiency of these techniques involving a large range of measurements to trace the source signals.
Here we explore the possibilities provided by the very simple but robust k-near-neighbors algorithm (kNN) for
classification in a source-to-sink approach. For this purpose, in a first phase, the magnetic properties of the
traffic-related sources of particulate matter (tire, brake pads, exhaust pipes, etc.) are used to parameterize and
train the model. Then, the magnetic parameters measured on accumulating surfaces exposed to a polluted air as
urban plant leaves and passive filters are confronted to the model. The results are very encouraging. The algorithm
predicts the dominant traffic-related sources for different kinds of accumulative surfaces. The model
predictions are generally consistent according to the sampling locations. Its resolution seems adequate since
different dominant sources could be identified within one street. We demonstrate the possibility to trace trafficderived
pollutants from sources to sinks based only on magnetic properties, and to eventually quantify their
contributions in the total magnetic signal measured. Because magnetic mapping has a high-resolution efficiency,
these results open the opportunity to complement conventional methods used to measure air quality and to
improve the numerical models of pollutant dispersion.
Magnetic properties of PM in indoor/outdoor domestic environments , EGU General Assembly 2021, online, 19–30 Apr 2021, EGU21-14416
Da Silva Leite, A., Macouin, M., Rousse, S., Leon, J.-F., Drigo, L., and Ivan Ferreira da Trindade, R.
The finer fraction of the particulate matter (PM) is the most harmful health wise, as it has more capacity to reach deeper parts of the respiratory system. Among other constituents, PM also contains iron oxides, allowing for the use of magnetic methods in its investigation as proxies for the whole of PM. Those methods present advantages in comparison to traditional ones, being quick, cost effective and sensible to investigate iron oxides among PM.
To better understand the risks related to PM exposition in the domestic context, the assessment of magnetic parameters may be used in outdoor and indoor environments, giving us information on the concentration of iron oxides (and consequently, PM) and its dispersion from one environment to the other.
We developed a citizen sciences experiment in the city of Toulouse, France. Tree barks were used as bio-collectors. Garlands composed of tree bark pieces were distributed to the population in May-2019, and placed in both indoors and outdoors of flats and homes to capture PM. They were retrieved after one year. Measurement of magnetic susceptibility, ARM, SIRM, S -ratio and estimation of superparamagnetic concentration were performed. A total of 86 bio-collectors kits were successfully analyzed. The preliminary results indicate a higher concentration of iron oxides outdoors, with a mean difference between outdoor and indoor measurements of 6.58×10-9m3/kg and 1.38×10-5Am2/kg in susceptibility and SIRM respectively. The concentration of the SP fraction also follows this trend of higher outdoor values. The magnetic mineralogy is mostly dominated by low coercivity magnetite-like carriers.
Biomagnetic Monitoring vs. CFD Modeling: A Real Case Study of Near-Source Depositions of Traffic-Related Particulate Matter along a Motorway
Sarah Letaeïf et al.
A test site located along a 12-lane motorway east of Montpellier, France, is used to evaluate the potential of biomagnetic monitoring on traffic-related particulate matter (PM) to parametrize a computational fluid dynamics (CFD) simulation of the local airflow. Two configurations were established on the site with three vegetated flat-top earth berms of a basic design, and a fourth one was located windward to the traffic roofed with a 4-m-high precast concrete wall. As a first step, PM deposition simultaneously on plant leaves, on low-cost passive artificial filters, and on soils was estimated from proxies supplied by magnetic and X-ray fluorescence measurements on both sides of the motorway. These latter revealed that traffic-related pollutants are present on soils samples highlighted with a clear fingerprint of combustion residues, and wears of breaks, vehicles, and highway equipment. Maximum PM accumulations were detected in the lee of the berm–wall combination, while no significant deposition was observed on both sides of the flat-top earth berms. These results are in line with measurements from PM µ-sensors operated by the regional state-approved air quality agency. Finally, we compared the experimental measurements with the outcomes of a computational fluid dynamics (CFD) modeling based on the Reynolds-Averaged Navier–Stokes (RANS) equations that consider the traffic-induced momentum and turbulence. The CFD modeling matches the experimental results by predicting a recirculated flow in the near wake of the berm–wall combination that enhances the PM concentration, whereas the flat-top berm geometry does not alter the pollutants’ transport and indeed contributes to their atmospheric dispersion.
Lionel Scotto d’Apollonia et al.
Résumé Après avoir dressé un état des lieux des évolutions de la Recherche Action Participative (RAP) et des Sciences Citoyennes (SC), cet article présente un dispositif innovant nommé Artivistes-atelier (AA) visant à accompagner les politiques publiques sur
la qualité de l’air en intégrant le citoyen dans la boucle décisionnelle prenant en compte le champ de contraintes sociales et environnementales y compris les épineux aspects métrologiques. Il détaille comment le dispositif (AA) s’intègre et se développe dans deux projets de recherche complémentaire (Air-Climat-Santé-Société & Art et BREATHE) sur la qualité de l’air pour apporter des réponses concrètes à des problèmes complexes dans un esprit résolument pragmatique, critique et réflexif
Dosias Perla Davia et al.
Cet article décrit d’une part la construction d’un dispositif participatif stable intégrant une ingénierie de la participation et d’autre part sa phase d’opérationnalisation dans le cadre d’un projet de Recherche Action Participative (RAP) « Air Climat Santé Société & Art » financé par l’ADEME visant à accompagner les huit communes du territoire pilote du Pays de l’Or dans l’élaboration de son Plan Climat Air Énergie Territorial (PCAET) de novembre 2017 à novembre 2019. L’objectif du projet de Recherche était d’analyser les freins et les leviers inhérents à la fabrique des politiques publiques sur les enjeux Air Climat Santé et plus particulièrement le déficit de Participation citoyenne et d’efficacité des Actions à tous les niveaux d’échelle.
L’article détaille comment la prise en compte de la conflictualité politique et des asymétries de pouvoir au cours des différentes étapes de co-construction du diagnostic partagé a conduit à l’élaboration de l’ingénierie de la participation. Les premiers éléments d’analyse de sa phase d’opérationnalisation mettent en avant la stabilité du dispositif par sa capacité à être reproductible dans les différentes communes. L’analyse de ces bases comparatives et du processus d’institutionnalisation au sein de l’agglomération permettent d’identifier les apports et les limites du dispositif participatif et en retour d’identifier les freins et les leviers d’action en fonction des niveaux d’échelle de développement du processus participatif.