C. R. Hoyle
A5060987493- Atmospheric chemistry and aerosols
- Atmospheric Ozone and Climate
- Atmospheric aerosols and clouds
- Air Quality and Health Impacts
- Atmospheric and Environmental Gas Dynamics
- Air Quality Monitoring and Forecasting
- Icing and De-icing Technologies
- Cryospheric studies and observations
- Meteorological Phenomena and Simulations
- Catalytic Processes in Materials Science
- Wind and Air Flow Studies
- Laser-induced spectroscopy and plasma
- Climate change and permafrost
- Astronomical and nuclear sciences
- Aerosol Filtration and Electrostatic Precipitation
- nanoparticles nucleation surface interactions
- Nuclear Issues and Defense
- Global Energy and Sustainability Research
- Astro and Planetary Science
- Geomagnetism and Paleomagnetism Studies
- Methane Hydrates and Related Phenomena
- Arctic and Antarctic ice dynamics
- Radioactive contamination and transfer
- Advanced Chemical Physics Studies
- Spaceflight effects on biology
ETH Zurich
2011-2025
Paul Scherrer Institute
2014-2023
École Polytechnique Fédérale de Lausanne
2011-2020
Swiss Federal Institute for Forest, Snow and Landscape Research
2014-2017
University of Oslo
2007-2012
Institute of Atmospheric Sciences and Climate
2009
Physikalisch-Meteorologisches Observatorium Davos
2004
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...
From neutral to new Many of the particles in troposphere are formed situ, but what fraction all tropospheric do they constitute and how exactly made? Bianchi et al. report results from a high-altitude research station. Roughly half were newly by condensation highly oxygenated multifunctional compounds. A combination laboratory results, field measurements, model calculations revealed that nucleation is more than 10 times faster ion-induced nucleation, particle growth rates size-dependent,...
<strong class="journal-contentHeaderColor">Abstract.</strong> This paper evaluates the current status of global modeling organic aerosol (OA) in troposphere and analyzes differences between models as well observations. Thirty-one chemistry transport (CTMs) general circulation (GCMs) have participated this intercomparison, framework AeroCom phase II. The simulation OA varies greatly terms magnitude primary emissions, secondary (SOA) formation, number species used (2 to 62), complexity...
Abstract New particle formation has been estimated to produce around half of cloud‐forming particles in the present‐day atmosphere, via gas‐to‐particle conversion. Here we assess importance new (NPF) for both and preindustrial atmospheres. We use a global aerosol model with parametrizations NPF from previously published CLOUD chamber experiments involving sulfuric acid, ammonia, organic molecules, ions. find that produces 67% cloud condensation nuclei at 0.2% supersaturation (CCN0.2%) level...
Atmospheric aerosol formation from biogenic vapors is strongly affected by air pollutants, like NO x , SO 2 and NH 3 .
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...
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.
To better understand the role of aromatic hydrocarbons in new-particle formation, we measured particle-phase abundance and volatility oxidation products following reaction with OH radicals. For this used thermal desorption an iodide-adduct Time-of-Flight Chemical-Ionization Mass Spectrometer equipped a Filter Inlet for Gases AEROsols (FIGAERO-ToF-CIMS). The measurements confirm that toluene naphthalene can contribute to initial growth newly formed particles. Toluene-derived (C7) have similar...
Abstract. A high-resolution global aerosol model (Oslo CTM2) driven by meteorological data and allowing a comparison with variety of observations is used to simulate radiative forcing (RF) the direct effect. The simulates all main components, including several secondary components such as nitrate organic carbon. reproduces chemical composition size features observed during large campaigns. Although compares best ground-based measurement over land for modelled sulphate, no systematic...
Abstract. In order to use knowledge of past climate change improve our understanding the sensitivity system, detailed about time development radiative forcing (RF) earth atmosphere system is crucial. this study, series anthropogenic from pre-industrial times until 2010, for all well established agents, are estimated. This includes presentation RF histories mixed greenhouse gases, tropospheric ozone, direct- and indirect aerosol effects, surface albedo changes, stratospheric ozone water...
Abstract. Emulsion and bulk freezing experiments were performed to investigate immersion ice nucleation on clay minerals in pure water, using various kaolinites, montmorillonites, illites as well natural dust from the Hoggar Mountains Saharan region. Differential scanning calorimeter measurements three different kaolinites (KGa-1b, KGa-2 K-SA), two (Illite NX Illite SE) four acid-treated montmorillonites (SWy-2, STx-1b, KSF K-10). The emulsion provide information average behaviour...
Abstract. Highly oxygenated organic molecules (HOMs) contribute substantially to the formation and growth of atmospheric aerosol particles, which affect air quality, human health Earth's climate. HOMs are formed by rapid, gas-phase autoxidation volatile compounds (VOCs) such as α-pinene, most abundant monoterpene in atmosphere. Due their abundance low volatility, can play an important role new-particle (NPF) early aerosols, even without any further assistance other low-volatility sulfuric...
Abstract. A total of 12 natural surface dust samples, which were surface-collected on four continents, most them in source regions, investigated with respect to their ice nucleation activity. Dust collection sites distributed across Africa, South America, the Middle East, and Antarctica. Mineralogical composition has been determined by means X-ray diffraction. All samples proved be mixtures minerals, major contributions from quartz, calcite, clay K-feldspars, (Na, Ca)-feldspars. Reference...
NO x is important for particle growth as it can participate in HOM formation and alter the volatility distribution.
Terpenes are emitted by vegetation, and their oxidation in the atmosphere is an important source of secondary organic aerosol (SOA). A part this can proceed through autoxidation process, yielding highly oxygenated molecules (HOMs) with low saturation vapor pressure. They therefore contribute, even absence sulfuric acid, to new particle formation (NPF). The understanding mechanism its kinetics still far from complete. Here, we present a mechanistic kinetic analysis mass spectrometry data...
Abstract. There are strong indications that particles containing secondary organic aerosol (SOA) exhibit amorphous solid or semi-solid phase states in the atmosphere. This may facilitate heterogeneous ice nucleation and thus influence cloud properties. However, experimental studies of biogenic SOA scarce. Here, we investigated ability viscous particles. The were produced from ozone initiated oxidation α-pinene an chamber at temperatures range −38 to −10 °C 5–15 % relative humidity with...
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...
Biogenic vapors form new particles in the atmosphere, affecting global climate. The contributions of monoterpenes and isoprene to particle formation (NPF) have been extensively studied. However, sesquiterpenes received little attention despite a potentially important role due their high molecular weight. Via chamber experiments performed under atmospheric conditions, we report biogenic NPF resulting from oxidation pure mixtures β-caryophyllene, α-pinene, isoprene, which produces oxygenated...
Abstract Recent measurements with four independent particle instruments in cirrus clouds, which formed without convective or orographic influence, report high number densities of ice particles (as as nice = 50 cm−3) embedded broad density distributions (nice 0.1–50 cm−3). It is shown here that small-scale temperature fluctuations related to gravity waves, mechanical turbulence, other air motions are required explain these observations. These waves have typical peak-to-peak amplitudes 1–2 K...
Abstract. We describe version 2.0 of the chemistry-climate model (CCM) SOCOL. The new includes fundamental changes transport scheme such as transporting all chemical species individually and applying a family-based correction for mass conservation nitrogen, chlorine bromine groups, revised ozone, furthermore more detailed halogen reaction deposition schemes, cirrus parameterisation in tropical tropopause region. By means these manages to overcome or considerably reduce deficiencies recently...
Abstract. The global chemical transport model Oslo CTM2 has been extended to include the formation, and deposition of secondary organic aerosol (SOA). Precursor hydrocarbons which are oxidised form condensible species both biogenic such as terpenes isoprene, well emitted predominantly by anthropogenic activities (toluene, m-xylene, methylbenzene other aromatics). A simulation for 2004 gives an annual SOA production approximately 55 Tg. Of this total, 2.5 Tg is found consist oxidation...