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No Measurable Impact of Acute 26 GHz 5G Exposure on Salivary Stress Markers in Healthy Adults
No full textInternational audienceThe rapid deployment of fifth generation (5G) wireless networks has raisedconcerns about potential health effects associated with exposure to novelradiofrequency electromagnetic field (RF) frequencies, particularly the 26 GHz bandwhich represents a new exposure scenario for the general population with limited prioruse in telecommunications. However, evidence regarding the acute biological impactof these exposures remains limited and inconclusive.This study aimed to assess whether short-term exposure (26.5 minutes) ofhealthy adults to 5G RF at 26 GHz, at levels representative of real-world environmentalconditions, affects salivary cortisol and alpha-amylase, two established biomarkers ofstress and autonomic nervous system activity. Thirty-one participants completed atriple-blind, randomized protocol with electroencephalography recordings. A subset ofsixteen participants from this group also participated in an exploratory protocol withcognitive testing and higher temporal sampling resolution (5minute intervals). Salivasamples were collected before, during, and after exposure in both protocols. RFexposure was delivered via a horn antenna at 2 V/m (head) and 1 V/m (torso), in linewith upper-range environmental measurements.Statistical analyses revealed no significant differences in salivary cortisol oralpha-amylase concentrations between real and sham exposures. Descriptiveexamination of the exploratory cognitive protocol, with higher temporal samplingresolution, showed consistent temporal stability of both biomarkers in both conditions.These findings suggest that acute 5G RF exposure at 26 GHz, under controlled andrealistic conditions, does not elicit measurable changes in stress biomarkers.Further research is warranted to evaluate the effects of repeated or long-termexposures and to investigate potential impacts in vulnerable populations
Characterization of gaseous and particulate atmospheric emissions, including the condensable particulate fraction, from small biomass boilers (150 kW-1.65 MW) in France
No full textInternational audienceBiomass combustion is the primary source of renewable energy in France. However, it also significantly contributes to outdoor air pollution. This energy sector is undergoing major changes, including evolving regulations, improved fuel types, and enhanced emission control technologies. While the performance of larger installations (>1 MW) is well documented, less is known about biomass boilers with lower capacities. It has become crucial to better understand the operation of smaller biomass boilers, assess their contribution to atmospheric pollution, and identify methods to reduce their emissions.The ACIBIOQA project investigated emissions from six biomass boilers with nominal power outputs ranging from 150 kW to 1.65 MW across France. Measurements included combustion gas-phase characterization (O2, CO2, CO, NOx, and organic gaseous compounds: OGCs) and particulate-phase characterization, covering total particulate matter (TPM), including both solid (SP) and condensable fractions, PM10, PM2.5, and PM1 by mass, 15 heavy metals, 8 polycyclic aromatic hydrocarbons (PAHs).Measured concentrations (corrected to 6 vol% O2) varied widely: CO ranged from 153 to 8841 mg Nm−3, NOx from 172 to 395 mg eq. NO2 Nm−3, and organic gaseous compounds from <1 to 634 mg eq. C Nm−3. TPM ranged from <1.5 to 475 mg Nm−3, with SP between <0.3 and 475 mg Nm−3. The condensable fraction contributed 4–26 % to TPM. PM1 dominated the mass size distribution, accounting for 60–100 %. PAHs ranged from 0.1 to 340 μg Nm−3, and heavy metals from 0.03 to 6.7 mg Nm−3.Emission levels were influenced by boiler nominal power output, combustion load, operating regime, and filtration technology. Particularly, CO, OGCs, and PAHs were highest under unstable and low-load conditions. SP emissions increased with the number of combustion cycles and decreased operating load, while bag filters appeared to reduce SP levels. Higher condensable fractions were observed in boilers with complete on/off cycles and lower nominal outputs.This study provides new insights into emissions from small biomass boilers and represents a pioneering effort to characterize the condensable particulate fraction at the national level. Emission factors were calculated and compared with literature and national inventory values
Unraveling Effects of a Pesticide Mixture on Earthworm Life-Cycle: Toxic Cocktails in our Soils: When Pesticides join Forces against Earthworms
No full textInternational audienceSoils play a critical role in ecosystem functioning, yet they are increasingly threatened by agricultural intensification leading to contamination with persistent mixtures of plant protection products (PPPs). While standard environmental risk assessment typically focuses on single compounds, soil organisms are exposed to complex mixtures of PPP residues, making it crucial to understand their combined effects. Our study aims to develop a DEB-TKTD model to understand the physiological mode of action of a mixture of two prevalent PPPs in agricultural soils: epoxiconazole (fungicide) and imidacloprid (insecticide). Using the earthworm Aporrectodea caliginosa as a model organism, we first characterized the toxicokinetics of both compounds before examining their effects on reproduction through an adapted OECD guideline 222 experiment using a ray design (n = 7 mono-substance doses, n = 21 mixture doses, n = 3 replicates). By monitoring cocoon production, hatching success, and juvenile growth over 28 days, we will gather essential data to parameterize our DEB-TKTD model. The integration of mixture toxicity data into the DEB framework will provide mechanistic insights into how these PPPs interact to affect earthworm life-history traits. This DEB-TKTD model will then be incorporated into an Individual-Based Model to predict long-term effects on population dynamics under realistic exposure scenarios. This multi-level modeling approach will help bridge the gap between individual and population responses to pesticide mixtures, contributing to more environmentally relevant risk assessment procedures
Pressure-Liquefied Ammonia Jet Dispersion: Multi-Model Intercomparison Using Desert Tortoise and FLADIS Field Data
No full textInternational audienceThis paper presents the findings of an international model inter-comparison exercise that was undertaken in the period 2021-2024 to assess the performance of atmospheric dispersion models for simulating releases of pressure-liquefied ammonia. The exercise used data from ammonia field trialsdating from the 1980s and 1990s: the Desert Tortoise and the FLADIS trials. Concentration data from two arcs of sensors in the Desert Tortoise trials and three arcs of sensors in the FLADIS trials were used. Twenty-one independent modelling teams from North America and Europe participated in the exercise and provided in total twenty-seven sets of results from a range of different models, including empirically-based nomograms, integral, Gaussian puff, Lagrangian particle, and Computational Fluid Dynamics (CFD) models. The work is novel in presenting the results from such a large cohort of models,examining specifically the dispersion behaviour of ammonia. This is particularly relevant at the current time, given the growing international interest in using ammonia as a clean energy vector and shipping fuel.The study found that the agreement between model predictions and measurements (as determined by performance measures such as geometric mean bias and geometric variance) varied between different models. At any downwind distance, the range in predicted plume arc-max concentrations spanned arange of up to one or two orders of magnitude about the measurements. Several modelling teams used the same models and, in most cases, their predictions differed. Given appropriate inputs, most models generally predicted concentrations that agreed with the data within commonly-used model acceptance criteria. There was no single class of model that provided superior predictions to others; predictions from several empirically-based nomograms, integral, Gaussian puff, Lagrangian particle, and CFD models were all in close agreement with the data (as defined by the model acceptance criteria).The findings of the exercise are being used to help plan a programme of future ammonia experiments in the USA, called the Jack Rabbit III trials. The results are also useful for assessing the performance of models that may be applied to assess risks at ammonia facilities, and for emergency planning and response
Combining sensitivity analysis and scaling analysis for nuclear thermal-hydraulic studies
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Population exposure to outdoor NO2, black carbon, and ultrafine and fine particles over Paris with multi-scale modelling down to the street scale
No full textInternational audienceThis study focuses on mapping the concentrations of pollutants of interest to health (NO2, black carbon (BC), PM2.5, and particle number concentration (PNC)) down to the street scale to represent the population exposure to outdoor concentrations at residences. Simulations are performed over the area of Greater Paris with the WRF-CHIMERE/MUNICH/SSH-aerosol chain, using either the top-down inventory EMEP or the bottom-up inventory Airparif, with correction of the traffic flow. The concentrations of the pollutants are higher in streets than in the regional-scale urban background, due to the strong influence of road traffic emissions locally. Model-to-observation comparisons were performed at urban background and traffic stations and evaluated using two performance criteria from the literature. For BC, harmonized equivalent BC (eBC) concentrations were estimated from concomitant measurements of eBC and elemental carbon. Using the bottom-up inventory with corrected road traffic flow, the strictest criteria are met for NO2, eBC, PM2.5, and PNC. Using the EMEP top-down inventory, the strictest criteria are also met for NO2, eBC, and PM2.5, but errors tend to be larger than with the bottom-up inventory for NO2, eBC, and PNC. Using the top-down inventory, the concentrations tend to be lower along the streets than those simulated using the bottom-up inventory, especially for NO2 concentrations, resulting in fewer urban heterogeneities. The impact of the size distribution of non-exhaust emissions was analysed at both regional and local scales, and it is higher in heavy-traffic streets. To assess exposure, a French database detailing the number of inhabitants in each building was used. The population-weighted concentration (PWC) was calculated by weighting populations by the outdoor concentrations to which they are exposed at the precise location of their home. An exposure scaling factor (ESF) was determined for each pollutant to estimate the ratio needed to correct urban background concentrations in order to assess exposure. The average ESF in Paris and the Paris ring road is higher than 1 for NO2, eBC, PM2.5, and PNC because the concentrations simulated at the local scale in streets are higher than those modelled at the regional scale. It indicates that the Parisian population exposure is underestimated using regional-scale concentrations. Although this underestimation is low for PM2.5, with an ESF of 1.04, it is very high for NO2 (1.26), eBC (between 1.22 and 1.24), and PNC (1.12). This shows that urban heterogeneities are important to be considered in order to represent the population exposure to NO2, eBC, and PNC but less so for PM2.5
Country- and species-dependent parameters for the heating degree day method to distribute NO x and PM emissions from residential heating in the EU 27: application to air quality modelling and multi-year emission projections
No full textInternational audienceThe combustion of fossil and biofuels in the residential sector can cause high background levels of air pollutants in winter but also pollution peaks during cold periods. Its emissions are dominated by space heating and show strong daily variations linked to changes in outside temperatures. The heating degree day (HDD) approach allows daily variations in space heating emissions to be represented. The method depends on a temperature threshold (“Tb”) below which building heating is activated and a fraction (“f”) considering the relative contribution of space heating to total residential combustion emissions. These parameters are fixed in the literature. However, they are likely to vary according to the country and pollutant. Using statistics on household energy consumption, we provide country- and species-dependent Tb and f parameters to derive daily temporal factors distributing PM and NOx emissions from the residential sector in the EU 27. Tested in the CHIMERE model, the simulations show better performance scores (temporal correlation and threshold exceedance detection) in winter, especially for PM, when compared to the simulation with a monthly temporal factor, or based on HDDs but using fixed parameters from the literature. Finally, the HDDs with fitted parameters are used as a method to project official annual residential combustion emissions in subsequent years, as these are typically reported with a 2-year time lag. Results show that this method performs better regarding the persistence method and remains within emission uncertainties for both PM and NOx emissions, indicating the importance of considering HDDs for air quality forecasting
Influence of the flammable cloud geometry on the gas explosion effects
No full textInternational audienceIn the context of industrial large cloud explosions such as the Buncefield accident, it is commonly accepted that the flammable cloud spreads over a large area on the ground but has a limited height. This can, therefore, be considered as the limiting dimension of the cloud. In this work at a small scale, Leyer highlighted the influence of the limited height of the flammable cloud in the case of cylindrical cloud explosions. Without prejudging the combustion mechanisms, this paper aims to present the influence of this limited dimension of the flammable cloud on the flame dynamics to assess more precisely the overpressure distances of a UVCE by better determining the energy involved in the explosion. The analysis is based on comparing the flame position over time from the fast video films and the overpressure signals recorded in the flammable clouds. The explosions examined are methane and hydrogen-free jets, methane jets interacting with the ground and rows of obstacles, and large propane clouds obstructed by rows of tree trunks
Gestion de la pollution chimique des eaux de surface françaises :Quels enseignements tirer de la première décennie de surveillance au titre de la directive cadre sur l’eau (2009-2020) ?: Synthèse en français de l’étude« Multiyear and seasonal wide‑scale indicators for French surface waters contamination by WFD substances »parue dans Environmental Science and Pollution Researchhttps://doi.org/10.1007/s11356-024-35511-z
No full textThis document presents the summary in French of a detailed scientific study, published in Environmental Science and Pollution Research, on the management of chemical pollution in French surface waters between 2009 and 2020. The study analyses Water Framework Directive (WFD) monitoring data for 101 substances to assess contamination trends and the effectiveness of emission reduction policies. It introduces new, unbiased indicators for quantifying contamination and risk, taking into account the heterogeneity of laboratory quantification limits. The results show an overall reduction in pollution, but highlight growing concerns about metals and the importance of socio-environmental factors, such as agricultural and urban use, in the seasonality and transfer of pollutants. The study concludes with recommendations for improving the monitoring and management of chemical substances.Ce document présente la synthèse en français d'une étude scientifique détaillée, publiée dans Environmental Science and Pollution Research, concernant la gestion de la pollution chimique des eaux de surface françaises entre 2009 et 2020. L'étude analyse les données de surveillance de la Directive Cadre sur l’Eau (DCE) pour 101 substances afin d'évaluer les tendances de contamination et l'efficacité des politiques de réduction des émissions. Elle introduit de nouveaux indicateurs non biaisés pour quantifier la contamination et le risque, notamment en tenant compte de l'hétérogénéité des limites de quantification des laboratoires. Les résultats montrent une réduction globale de la pollution, mais soulignent des préoccupations croissantes concernant les métaux et l'importance des facteurs socio-environnementaux, comme les usages agricoles et urbains, dans la saisonnalité et le transfert des polluants. En conclusion, l'étude formule des recommandations pour améliorer la surveillance et la gestion des substances chimiques
A Review of the Evidence of the Toxicity of Chemical Substances Included in the European Union Ambient Air Quality and Drinking Water Directives: Perspectives for Health Impact Assessments
No full textInternational audienceThe European Union (EU) Ambient Air QualityDirective (AAQD) and Drinking Water Directive (DWD) are aimedat maintaining and improving air quality and ensuring high standardsfor potable water across the EU. Besides several other indicators, theAAQD and DWD consist of chemical parameters (substances orsubstance groups) that are regulated within this framework. All thesubstances are associated with various health outcomes, and many ofthem are classified as carcinogenic or probably/possibly carcinogenicwith causal links. To quantify the health burden of the chemicalsubstances included in the AAQD and DWD, we need informationregarding population exposure, current baseline mortality/morbidityrates in the populations, and exposure−response functions (ERFs) orunit risks (URs) from previous epidemiological studies. During thisstudy, we analyzed the availability of ERFs or URs and discussed their applicability in health impact assessments (HIAs). From theHIA perspective, ERFsin terms of relative risk (RR), standardized mortality ratio (SMR), odds ratio (OR), or UR datawereavailable for many of the analyzed substances. However, for some substances such as acrylamide, antimony, boron, chlorate andchlorite, copper, microcystin-LR, and selenium, no risk measures could be identified. The aim of this study is to derive ERFs, whichwill allow HIAs for a larger number of chemicals when exposure data and baseline mortality/morbidity data are available. Currently,HIAs have largely focused only on main ambient pollutants such as particulate matter (PM10), fine particulate matter (PM2.5),nitrogen oxides (NOX), and ozone (O3). In contrast, health risks related to exposure to chemicals are much more diverse, and thehealth burdens should be quantified to a much greater extent