Atmel (France)

<p>The Bois Canal footbridge is an Ultra High Performances Fiber Reinforced Concrete monolithic structure, that tries to get the most of this materials’ proprieties, that’s to say its long-lasting durability, high compressive strength, lightness and environmental performance. The location of the project is typical of the Saone River 20th century short span footbridges. Nowadays it only remains disjointed masonry supports and an 11 meters long gap after the dismantle of the old wooden deck. The proposal for new footbridge draws on the current know-how in the Saone Valley, especially the presence of numerous fine sand quarries and prefabrication factories. It takes shape as a monolithic lateral-beam bridge made of UHPFRC. The footbridge is fully built in a prefabrication factory, then delivered and craned into place. It can be realised using only a formwork table for precast panels and punch dies made of wooden planks, leading to a low-cost structure adapted to this "ordinary" crossing. The beams shape is the result of both an architectural and a technical design. The variation of thickness optimizes the structure’s efficiency by creating a Vierendeel beam. The form of the punch dies echoes the Art Deco architecture of the early 20th century, which earned Pont-de-Veyle its reputation. The approach developed in this project aims at finding the right shape adapted to its context by drastically limiting the technical means involved and the resources. The comparative life cycle assessment of the footbridge shows a reduction by 80% of CO2eq between an UHPRFC structure and an equivalent aluminium structure.</p>

This research explores the development and implementation of SIRANet, an advanced deep learning-based emulator designed for fine-scale air quality modeling. Leveraging the computational efficiency of neural networks, SIRANet builds upon the establishe

This research explores the development and implementation of SIRANet, an advanced deep learning-based emulator designed for fine-scale air quality modeling. Leveraging the computational efficiency of neural networks, SIRANet builds upon the establishe

<strong class="journal-contentHeaderColor">Abstract.</strong> A comprehensive atmospheric dataset including hourly meteorological parameters, pollutants and methane mixing ratio and weekly beryllium-7 and sodium-22 activity concentration measured at the Observatoire P&eacute;renne de l&rsquo;Environnement (OPE) station from 2012 to 2023 was used to assess the interannual and intraseasonal variability of ozone. Weekly parameters were computed to characterize mean afternoon, mean nighttime, baseline and peak events for ozone as well as for NO_X, CO, CH₄. The mean afternoon O₃ concentrations did not show a significant trend, while baseline O₃ exhibited a significant increase of 0.7 &micro;g.m^-3per year. The intra-seasonal variability of surface weekly ozone anomalies revealed two different periods. During the November to February period, ozone anomalies were related to CO, CH₄ and NO_x anomalies but not with meteorological parameters or Stratosphere to Troposphere Transport (STT) proxies. From April to September, the relations between CH₄, CO and NO_Xdiminished while stronger association of O₃residuals were observed with STT proxies, but also with temperature, solar radiation and relative humidity. The surface O₃ enhancement associated with positive anomalies of ⁷Be and ²²Na suggests a direct stratospheric O₃ contribution but also a local photochemical contribution which is favored by warmer and drier air masses and increased solar radiations.

The Aix-Marseille metropolis is the second most populated urbanized area of France. It aims at reaching carbon neutrality in 2050. Located in the south-east of France under a Mediterranean climate, this area is known as a hot-spot regarding climate change. Its west part is strongly industrialized. The local air quality monitoring agency&amp;#160; ATMOSUD delivers a high resolved greenhouse gas emissions inventory that represents the reference for local stakeholders in matter of emissions trajectory. However, this inventory is still quite uncertain and requires independent assessments. In this aim, in the framework of the ANR COoL-AMmetropolis projet (2019-2025) we set-up a local greenhouse gas monitoring network based on Cavity Ring Down Spectrometry analyzers. This local network comprises the OHP ICOS-France station, located 80 km north of Marseille city. Local meteorological features such as sea and land breezes impact local greenhouse gas concentrations through advection and boundary layer dynamical processes. Isotopic analysis of 14C and 13C in CO2, as well as CO2 correlations with NOx, CO, black carbon and SO2, show a strong impact of fossil fuel emissions on the CO2 local urban greenhouse gas atmospheric plumes. The identified fossil sources are mostly traffic, building, industrial and maritime activities. Modern sources such as wood burning may account for a larger part than assessed by the local inventory.

<strong class="journal-contentHeaderColor">Abstract.</strong> BTEX (benzene, toluene, ethylbenzene, m,p,o-xylene) are significant urban air pollutants. This study examines BTEX variability across seven European countries using data from 22 monitoring sites in different urban settings (urban background, traffic, industry, and suburban background). Results indicate that the relative abundance of BTEX in urban areas follows the order: toluene &gt; benzene &gt; m,p-xylene &gt; o-xylene &gt; ethylbenzene, with mean mixing ratios of 391 &plusmn; 451, 252 &plusmn; 324, 222 &plusmn; 297, 92 &plusmn; 119, and 78 &plusmn; 107 ppt from 2017 to 2022, respectively. Seasonal trends show benzene had similar median concentrations across urban background, traffic, and industrial sites, indicating mixed sources. Toluene levels were highest in traffic and industrial areas, highlighting road traffic and industrial emissions. Ethylbenzene and xylenes showed equivalent levels in traffic and industrial areas but were lower in urban backgrounds. Peak BTEX levels occurred during morning and evening rush hours, linked to traffic, heating, and atmospheric stagnation. B/T ratios ranged from 0.29 &plusmn; 0.11 to 1.35 &plusmn; 0.95, and X/E ratios ranged from 1.75 &plusmn; 0.91 to 3.68 &plusmn; 0.30, indicating primary pollution from local traffic, followed by solvents, coatings, and biomass burning. Lifetime Cancer Risk (LCR) values for BTEX exposure were below the definite risk threshold (10^&minus;4) but above the permissible risk level (10^&minus;6), suggesting moderate risk from benzene and ethylbenzene, particularly in traffic and industrial areas. This study offers essential insights into BTEX pollution in European urban environments.

Abstract. When anticyclonic conditions persist over mountainous regions in winter, cold-air pools (i.e. thermal inversion layers) develop in valleys and persist from a few days to a few weeks. During these persistent cold-air pool episodes (PCAPs) the atmosphere inside the valley is stable and vertical mixing is prevented, promoting the accumulation of pollutants close to the valley bottom and worsening air quality. It has been shown from reanalysis that the Greater Alpine Region has warmed by three degrees over the last four decades. The purpose of this paper is to address the impact of climate change on PCAPs until the end of this century for the alpine Grenoble valleys. The long-term projections produced with the general circulation model MPI downscaled over the Alps with the regional climate model MAR (Modèle Atmosphérique Régional) are used to perform a statistical study of PCAPs over the 21st century. The trends of the main characteristics of PCAPs, namely their duration, frequency, and intensity, are investigated for two future scenarios, SSP2-4.5 and SSP5-8.5. We find that the intensity of PCAPs over the 21st century displays a statistically significant decreasing trend for the SSP5-8.5 scenario only, with a very weak decay rate of 0.058 K km−1 decade−1. The impact of climate change on the detailed structure of PCAPs is next investigated by comparing two such episodes, in the past and around 2050 considering the worst-case scenario (SSP5-8.5). For this purpose, the WRF (Weather Research and Forecasting) model, forced by MAR, is used at a high resolution (111 m). The episodes are carefully selected so that a meaningful comparison can be performed. We find that these episodes present similar atmospheric circulation and heat deficit across the valley depth but different atmospheric stability and (therefore) a different inversion height. The future episode is characterised by stronger atmospheric stability and a lower inversion height and about 4 degrees warmer air both close to the surface and in altitude. Overall, this study shows that the atmosphere in the Grenoble valleys tends to be slightly less stable in the future, under the SSP5-8.5 scenario, but that intense PCAPs can still form.

Abstract African dust is transported to South America (SA) every winter and spring. Hypotheses suggest that either Western or Central North Africa (e.g., Bodélé Depression) is the main source of transported dust, yet these notions remain largely untested with geochemical data. Using 2 years of isotopic measurements (strontium and neodymium) of African dust collected in SA integrated into a statistical model, we identified strong interannual variability in dust source region. Central North Africa supplied 44% of long‐range transported dust in winter 2016 while the Western region accounted for 53% of dust in winter 2014. We propose the variability is due to differences in the strength of the Libyan High and precipitation over the Gulf of Guinea and Atlantic Ocean between the 2 years. Our findings can improve constraints of dust nutrient deposition and predictions of how changes in climate impact the source and magnitude of dust transported to the Amazon.

Long-term monitoring at sites with relatively low particulate pollution could provide an opportunity to identify changes in pollutant concentration and potential effects of current air quality policies. In this study, a 9-year sampling of PM10 (particles with an aerodynamic diameter below 10 µm) was performed in a rural background site in France from February 28, 2012 to December 22, 2020. The Positive Matrix Factorization (PMF) method was used to apportion sources of PM10 based on quantified chemical constituents and specific chemical tracers from collected filters. Oxidative potential (OP), an emerging health-metric that measures PM capability to potentially cause anti-oxidant imbalance in the lung, was also measured using two acellular assays: dithiothreitol (DTT) and ascorbic acid (AA). The contribution of PMF-resolved sources to OP were also estimated using multiple linear regression (MLR) analysis. In terms of mass contribution, the dominant sources are secondary aerosols (nitrate- and sulphate-rich), associated with long-range transport (LRT). However, in terms of OP contributions, the main drivers are traffic, mineral dust, and biomass burning factors. There is also some OP contribution apportioned to the sulphate- and nitrate-rich sources influenced by processes and aging during LRT that could have encouraged mixing with other anthropogenic sources. The study indicates much lower OP values than in urban areas. A substantial decrease (58 % reduction from year 2012 to 2020) in the mass contributions from the traffic factor was found, however, this is not clearly reflected in its OP contribution. Nevertheless, the findings in this long-term study in the OPE site could signal effectiveness of implemented emission control policies, as also seen in other long-term studies conducted in Europe, mainly for urban areas.