A5034021650- Atmospheric chemistry and aerosols
- Atmospheric Ozone and Climate
- Spectroscopy and Laser Applications
- Air Quality Monitoring and Forecasting
- Indoor Air Quality and Microbial Exposure
- Air Quality and Health Impacts
- Atmospheric and Environmental Gas Dynamics
- Odor and Emission Control Technologies
- Advanced Combustion Engine Technologies
- Catalytic Processes in Materials Science
- Combustion and flame dynamics
- Advanced Chemical Sensor Technologies
- Water Quality Monitoring and Analysis
- Vehicle emissions and performance
- Building Energy and Comfort Optimization
- Recycling and Waste Management Techniques
- Wind and Air Flow Studies
- Environmental Impact and Sustainability
- Nuclear reactor physics and engineering
- Advanced Photocatalysis Techniques
- Plant responses to elevated CO2
- Free Radicals and Antioxidants
- Advanced Chemical Physics Studies
- Atmospheric aerosols and clouds
- Impact of Light on Environment and Health
Université de Lille
2013-2024
PhysicoChimie des Processus de Combustion et de l'Atmosphère
2015-2024
Centre National de la Recherche Scientifique
2013-2023
Université Lille Nord de France
2011-2014
Gheorghe Asachi Technical University of Iași
2011
Radboud University Nijmegen
2004-2007
Laboratoire de Physique des Lasers, Atomes et Molécules
2004
The hydroxyl (OH) radical is the most important oxidant in atmosphere since it controls its self-oxidizing capacity. main sources of OH radicals are photolysis ozone and nitrous acid (HONO). Due to attenuation solar radiation indoor environment, possibility formation through photolytic pathways indoors has been ignored up now. In air, ozonolysis alkenes suggested as an alternative route formation. Models indirect measurements performed now according this hypothesis suggest concentrations on...
Abstract. Hydroxyl (OH) radical reactivity (kOH) has been measured for 18 years with different measurement techniques. In order to compare the performances of instruments deployed in field, two campaigns were conducted performing experiments atmospheric simulation chamber SAPHIR at Forschungszentrum Jülich October 2015 and April 2016. Chemical conditions chosen either be representative atmosphere or test potential limitations instruments. All types that are currently used measurements one...
•OH and •HO2 radicals are known to be the key species in development of ignition. A direct measurement these under low-temperature oxidation conditions (T = 550-1,000 K) has been achieved by coupling a technique named fluorescence assay gas expansion, an experimental designed for quantification free atmosphere, jet-stirred reactor, device study combustion chemistry. Calibration allows conversion relative signals absolute mole fractions. Such radical fraction profiles will serve as benchmark...
The reaction between CH3O2 and OH radicals has been shown to be fast play an appreciable role for the removal of radials in remote environments such as marine boundary layer. Two different experimental techniques have used here determine products this reaction. HO2 yield obtained from simultaneous time-resolved measurements absolute concentration CH3O2, OH, by cw-CRDS. possible formation a Criegee intermediate measured broadband cavity enhanced UV absorption. A ϕHO2 = (0.8 ± 0.2) upper limit...
Indoor air quality was characterized in 10 recently built energy-efficient French schools during two periods of 4.5 days. Carbon dioxide time-resolved measurements occupancy clearly highlight the key role ventilation rate (scheduled or indexed), especially this type building, which tightly sealed and equipped with a dual-flow system to provide refreshment. Volatile organic compounds (VOCs) inorganic gases (ozone NO2) were measured indoors outdoors by passive techniques occupied unoccupied...
Hydrogen peroxide (H2O2) is an important reactive oxygen species (ROS) involved in photocatalysis. To study the photocatalytic behavior of H2O2, decomposition H2O2 on illuminated TiO2 films was investigated using cavity ring down spectroscopy (CRDS). A mixture and O2 gas flowed through a reactor which contained TiO2-coated plate. The removal accompanying production HO2 radicals were monitored phase just above film irradiated by UV light-emitting diode (LED) (375 nm). tested this mainly...
The reaction between CH3O2 and OH radicals has been studied in a laser photolysis cell using the of F atoms with CH4 H2O for simultaneous generation both radicals, generated through 248 nm XeF2. An experimental setup combining cw-Cavity Ring Down Spectroscopy (cw-CRDS) high repetition rate laser-induced fluorescence (LIF) to used. absolute concentration was measured by cw-CRDS, while relative OH(v = 0) determined LIF. To remove dubiety from quantification cw-CRDS near-infrared, its...
Abstract. Field campaigns have been carried out with the FAGE (fluorescence assay by gas expansion) technique in remote biogenic environments last decade to quantify situ concentrations of OH, main oxidant atmosphere. These data revealed OH radicals up a factor 10 higher than predicted models, whereby disagreement increases decreasing NO concentration. This was interpreted as major lack our understanding chemistry VOCs (volatile organic compounds), particularly isoprene, which are dominant...
Accurate measurements of organic peroxy radicals (RO₂) are critical to understanding the formation secondary pollutants, as loss rate RO2 determines and fraction ozone (O3) particulate matter formed. Due their large structural variability low concentrations in troposphere, measurement ambient air is challenging, with most techniques relying on conversion other species before detection.In summer 2022, a series experiments covering wide range chemical conditions were carried out...
The first reliable quantification of hydrogen peroxide (H(2)O(2)) formed during the low-temperature oxidation an organic compound has been achieved thanks to a new system that couples jet stirred reactor detection by continuous wave cavity ring-down spectroscopy (cw-CRDS) in near-infrared. this key for hydrocarbon regime obtained under conditions close those actually observed before autoignition. studied was n-butane, smallest alkane which behavior species present gasoline and diesel fuels.
Abstract. The investigation of hydroxyl radical (OH) chemistry during intensive field campaigns has led to the development several techniques dedicated ambient measurements total OH reactivity, which is inverse lifetime. Three are currently used campaigns, including loss rate method, pump–probe and comparative reactivity method. However, no formal intercomparison these been published so far, there a need ensure that consistent among different techniques. An two instruments, one based on...
Abstract Methanol is a benchmark for understanding tropospheric oxidation, but underpredicted by up to 100% in atmospheric models. Recent work has suggested this discrepancy can be reconciled the rapid reaction of hydroxyl and methylperoxy radicals with methanol branching fraction 30%. However, fractions below 15%, underprediction exacerbated. Theoretical investigations are challenging because intersystem crossing between singlet triplet surfaces – ∼45% products obtained via pre-product...
This paper reports on the findings from INDAIRPOLLNET (INDoor AIR POLLution NETwork), a recently completed European COST Action network. ran September 2018 to March 2023 with more than 200 indoor and outdoor air quality scientists universities, large small companies, research institutes around Europe beyond. The expertise of our interdisciplinary network members covered chemistry, biology, standardisation, household energy, particulate matter characterisation, toxicology, exposure...
The gas-phase oxidation of n-butane has been studied in an atmospheric jet-stirred reactor (JSR) at temperatures up to 950 K. For the first time, continuous wave cavity ring-down spectroscopy (cw-CRDS) near-infrared used, together with gas chromatography (GC), analyze products formed during its oxidation. In addition quantification formaldehyde and water, which is always difficult by GC, cw-CRDS allowed as well hydrogen peroxide (H2O2). A comparison obtained mole fraction temperature...
Radical quantum yields have been measured following the 248 nm photolysis of acetaldehyde, CH3CHO. HCO radical and H atom quantified by time resolved continuous wave Cavity Ring Down Spectroscopy in near infrared their conversion to HO2 radicals reaction with O2. The CH3 yield has determined using same technique into CH3O2. Absolute deduced for atoms through fitting profiles, obtained under various O2 concentrations, a complex model, while relative from CH3I. Time profiles very low...
Measurement and theory of CH<sub>3</sub>O + HO<sub>2</sub>and reactions, product yields for F CH<sub>3</sub>OH.
Abstract The HO 2 yield in the reaction of peroxy radicals with OH has been determined experimentally at 50 Torr helium by measuring simultaneously and concentration time profiles, following photolysis XeF presence different hydrocarbons O . yields have obtained: = (0.90 ± 0.1), (0.75 0.15), (0.41 0.08), (0.15 0.03). clear decrease increasing size alkyl moiety can be explained an increased stabilization trioxide adduct, ROOOH. This confirmed ab initio Rice–Ramsperger–Kassel–Marcus master...
The characteristics of indoor light (intensity, spectral, spatial distribution) originating from outdoors have been studied using experimental and modeling tools. They are influenced by many parameters such as building location, meteorological conditions, the type window. a direct impact on air quality through change in chemical processes varying photolysis rates pollutants. Transmittances different windows measured exhibit wavelength cutoffs, thus influencing potential species to be...