Serge Mathot
A5012955138- Atmospheric chemistry and aerosols
- Atmospheric Ozone and Climate
- Particle Accelerators and Free-Electron Lasers
- Atmospheric aerosols and clouds
- Particle accelerators and beam dynamics
- Superconducting Materials and Applications
- X-ray Spectroscopy and Fluorescence Analysis
- Electron and X-Ray Spectroscopy Techniques
- Air Quality and Health Impacts
- Radiation Therapy and Dosimetry
- Atmospheric and Environmental Gas Dynamics
- Radiation Detection and Scintillator Technologies
- Medical Imaging Techniques and Applications
- Nuclear Physics and Applications
- Ion-surface interactions and analysis
- Particle Detector Development and Performance
- Advanced Materials Characterization Techniques
- Dark Matter and Cosmic Phenomena
- Solar and Space Plasma Dynamics
- Plasma Diagnostics and Applications
- Gyrotron and Vacuum Electronics Research
- Magnetic confinement fusion research
- Marine and coastal ecosystems
- Atomic and Subatomic Physics Research
- Microstructure and mechanical properties
European Organization for Nuclear Research
2016-2025
University of Namur
1989-1994
Université Libre de Bruxelles
1987
Nucleation of aerosol particles from trace atmospheric vapours is thought to provide up half global cloud condensation nuclei. Aerosols can cause a net cooling climate by scattering sunlight and leading smaller but more numerous droplets, which makes clouds brighter extends their lifetimes. Atmospheric aerosols derived human activities are have compensated for large fraction the warming caused greenhouse gases. However, despite its importance climate, nucleation poorly understood. Recently,...
Abstract About half of present-day cloud condensation nuclei originate from atmospheric nucleation, frequently appearing as a burst new particles near midday 1 . Atmospheric observations show that the growth rate often accelerates when diameter is between one and ten nanometres 2,3 In this critical size range, are most likely to be lost by coagulation with pre-existing 4 , thereby failing form typically 50 100 across. Sulfuric acid vapour involved in nucleation but too scarce explain...
Abstract Atmospheric aerosols and their effect on clouds are thought to be important for anthropogenic radiative forcing of the climate, yet remain poorly understood 1 . Globally, around half cloud condensation nuclei originate from nucleation atmospheric vapours 2 It is that sulfuric acid essential initiate most particle formation in atmosphere 3,4 , ions have a relatively minor role 5 Some laboratory studies, however, reported organic without intentional addition acid, although...
Atmospheric new-particle formation affects climate and is one of the least understood atmospheric aerosol processes. The complexity variability atmosphere has hindered elucidation fundamental mechanism from gaseous precursors. We show, in experiments performed with CLOUD (Cosmics Leaving Outdoor Droplets) chamber at CERN, that sulfuric acid oxidized organic vapors concentrations reproduce particle nucleation rates observed lower atmosphere. reveal a involving clusters containing molecules...
Observations made in the CLOUD chamber at CERN illuminate atmospheric particle formation.
Significance The formation of nanoparticles by condensable vapors in the atmosphere influences radiative forcing and therefore climate. We explored detailed mechanism particle formation, particular role oxidized organic molecules that arise from oxidation monoterpenes, a class volatile compounds emitted plants. mimicked atmospheric conditions well-controlled laboratory setup found these organics form initial clusters directly with single sulfuric acid molecules. then grow further addition...
For atmospheric sulfuric acid (SA) concentrations the presence of dimethylamine (DMA) at mixing ratios several parts per trillion by volume can explain observed boundary layer new particle formation rates. However, concentration and molecular composition neutral (uncharged) clusters have not been reported so far due to lack suitable instrumentation. Here we report on experiments from Cosmics Leaving Outdoor Droplets chamber European Organization for Nuclear Research revealing particles...
Atmospheric aerosol formation from biogenic vapors is strongly affected by air pollutants, like NO x , SO 2 and NH 3 .
A list of authors and their affiliations appears at the end paper New-particle formation is a major contributor to urban smog1,2, but how it occurs in cities often puzzling3. If growth rates particles are similar those found cleaner environments (1-10 nanometres per hour), then existing understanding suggests that new should be rapidly scavenged by high concentration pre-existing particles. Here we show, through experiments performed under atmospheric conditions CLOUD chamber CERN, below...
Significance Aerosol particles can form and grow by gas-to-particle conversion eventually act as seeds for cloud droplets, influencing global climate. Volatile organic compounds emitted from plants are oxidized in the atmosphere, resulting products drive particle growth. We measure growth biogenic vapors with a well-controlled laboratory setup over wide range of tropospheric temperatures. While higher temperatures lead to increased reaction rates concentrations highly molecules, lower allow...
Faster than expected Iodine species are one of only a handful atmospheric vapors known to make new aerosol particles, which play central role in controlling the radiative forcing climate. He et al. report experimental evidence from CERN Cosmics Leaving Outdoor Droplets, or CLOUD, chamber demonstrating that iodic acid and iodous rapidly form particles can compete with sulfuric pristine regions. Science , this issue p. 589
Significance A mechanism for the formation of atmospheric aerosols via gas to particle conversion highly oxidized organic molecules is found be dominant aerosol process in preindustrial boundary layer over land. The inclusion this a global model raises baseline concentrations and could lead reduction 27% estimates anthropogenic radiative forcing.
Abstract We report comprehensive, demonstrably contaminant‐free measurements of binary particle formation rates by sulfuric acid and water for neutral ion‐induced pathways conducted in the European Organization Nuclear Research Cosmics Leaving Outdoor Droplets chamber. The recently developed Atmospheric Pressure interface‐time flight‐mass spectrometer was used to detect contaminants charged clusters identify runs free any contaminants. Four parameters were varied cover ambient conditions:...
Abstract The growth of freshly formed aerosol particles can be the bottleneck in their survival to cloud condensation nuclei. It is therefore crucial understand how grow atmosphere. Insufficient experimental data has impeded a profound understanding nano-particle under atmospheric conditions. Here we study CLOUD (Cosmics Leaving OUtdoors Droplets) chamber, starting from formation molecular clusters. We present measured rates at sub-3 nm sizes with different atmospherically relevant...
Abstract. The formation of particles from precursor vapors is an important source atmospheric aerosol. Research at the Cosmics Leaving OUtdoor Droplets (CLOUD) facility CERN tries to elucidate which are responsible for this new-particle formation, and how in detail it proceeds. Initial measurement campaigns CLOUD stainless-steel aerosol chamber focused on investigating particle ammonia (NH3) sulfuric acid (H2SO4). Experiments were conducted presence water, ozone sulfur dioxide. Contaminant...
NO x is important for particle growth as it can participate in HOM formation and alter the volatility distribution.
Abstract. Nucleation of atmospheric vapours produces more than half global cloud condensation nuclei and so has an important influence on climate. Recent studies show that monoterpene (C10H16) oxidation yields highly oxygenated products can nucleate with or without sulfuric acid. Monoterpenes are emitted mainly by trees, frequently together isoprene (C5H8), which the highest emission all organic vapours. Previous have shown suppresses new-particle formation from monoterpenes, but cause this...
Abstract. New particle formation (NPF) is a significant source of atmospheric particles, affecting climate and air quality. Understanding the mechanisms involved in urban aerosols important to develop effective mitigation strategies. However, NPF rates reported polluted boundary layer span more than 4 orders magnitude, reasons behind this variability are subject intense scientific debate. Multiple vapours have been postulated participate NPF, including sulfuric acid, ammonia, amines...
Abstract New particle formation in the upper free troposphere is a major global source of cloud condensation nuclei (CCN) 1–4 . However, precursor vapours that drive process are not well understood. With experiments performed under tropospheric conditions CERN CLOUD chamber, we show nitric acid, sulfuric acid and ammonia form particles synergistically, at rates orders magnitude faster than those from any two three components. The importance this mechanism depends on availability ammonia,...
Phytoplanktonic activities were measured weekly during spring 1984 in Belgian coastal waters almost entirely dominated by Phaeocystis pouchetii colonies.Accurate methods developed to measure photosynthesis and growth rates colonial P. cells, mucus secretion excretion from colonies.Photosynthetic properties, although quite different for cellular secretion, found be independent of changes environmental conditions.Maximal photosynthetic respectively 0.09 0.16 h-' cells mucus.Cellular specific...
Abstract. We present the results of laboratory measurements ion–ion recombination coefficient at different temperatures, relative humidities and concentrations ozone sulfur dioxide. The experiments were carried out using Cosmics Leaving OUtdoor Droplets (CLOUD) chamber CERN, walls which are made conductive material, making it possible to measure small ions. produced ions in a 3.5 GeV c−1 beam positively charged pions (π+) generated by CERN Proton Synchrotron (PS). When PS was switched off,...
We investigated the nucleation of sulfuric acid together with two bases (ammonia and dimethylamine), at CLOUD chamber CERN. The chemical composition positive, negative, neutral clusters was studied using three Atmospheric Pressure interface-Time Of Flight (APi-TOF) mass spectrometers: were operated in positive negative mode to detect ions, while third equipped a nitrate ion ionization source allowing detection clusters. Taking into account possible fragmentation that can happen during...
Abstract Exposure to anthropogenic atmospheric aerosol is a major health issue, causing several million deaths per year worldwide. The oxidation of aromatic hydrocarbons from traffic and wood combustion an important source low-volatility species in secondary organic aerosol, especially heavily polluted environments. It not yet established whether the formation involves mainly rapid autoxidation, slower sequential steps or combination two. Here we reproduced typical urban haze ‘Cosmics...
h g t and dark rates of net protein synthesis by Phaeocystis pouchetii colonies were measured in Belgian coastal waters during the spring bloom 1984 following I4C-bicarbonate lSN03/15NH: assimilation into cellular proteins natural 1ight:dark cycles.A close agreement was found between 2 tracer methods.Ambient inorganic nitrogen shown to be most important factor controhng hght, which considered proceed at a constant rate whole euphotic layer.Protein dark, on other hand, controlled both N...