Highly Oxygenated Organic Molecules (HOM) from Gas-Phase Autoxidation Involving Peroxy Radicals: A Key Contributor to Atmospheric Aerosol

Chemical Reviews, Journal Year: 2019, Volume and Issue: 119(6), P. 3472 - 3509

Published: Feb. 25, 2019

Highly oxygenated organic molecules (HOM) are formed in the atmosphere via autoxidation involving peroxy radicals arising from volatile compounds (VOC). HOM condense on pre-existing particles and can be involved new particle formation. thus contribute to formation of secondary aerosol (SOA), a significant ubiquitous component atmospheric known affect Earth's radiation balance. were discovered only very recently, but interest these has grown rapidly. In this Review, we define describe currently available techniques for their identification/quantification, followed by summary current knowledge mechanisms physicochemical properties. A main aim is provide common frame quite fragmented literature studies. Finally, highlight existing gaps our understanding suggest directions future research.

Language: Английский

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Elemental ratio measurements of organic compounds using aerosol mass spectrometry: characterization, improved calibration, and implications

Atmospheric chemistry and physics, Journal Year: 2015, Volume and Issue: 15(1), P. 253 - 272

Published: Jan. 12, 2015

Abstract. Elemental compositions of organic aerosol (OA) particles provide useful constraints on OA sources, chemical evolution, and effects. The Aerodyne high-resolution time-of-flight mass spectrometer (HR-ToF-AMS) is widely used to measure elemental composition. This study evaluates AMS measurements atomic oxygen-to-carbon (O : C), hydrogen-to-carbon (H mass-to-organic carbon (OM OC) ratios, oxidation state (OS C) for a vastly expanded laboratory data set multifunctional oxidized standards. For the standard set, method introduced by Aiken et al. (2008), which uses experimentally measured ion intensities at all ions determine ratios (referred here as "Aiken-Explicit"), reproduces known O C H ratio values within 20% (average absolute value relative errors) 12%, respectively. more commonly method, empirically estimated H2O+ CO+ avoid gas phase air interferences these "Aiken-Ambient"), species 28 14% values. from latter are systematically biased low, however, with larger biases observed alcohols simple diacids. A detailed examination H2O+, CO+, CO2+ fragments in spectra compounds indicates that Aiken-Ambient underestimates especially produced many species. Combined AMS–vacuum ultraviolet (VUV) ionization indicate dehydration decarboxylation vaporizer (usually operated 600 °C). Thermal decomposition be efficient temperatures down 200 °C. These results together develop an "Improved-Ambient" analysis air. Improved-Ambient specific markers correct molecular functionality-dependent systematic individual standards 28% (13%) error smaller theoretical mixtures standards, representative complex mix present ambient OA. OA, produces 27% (11%) than previously published values; corresponding increase 9% OM OC imply has higher oxygen content estimated. OS calculated two methods agree well, however difference 0.06 units). robust metric C, likely since not affected hydration or dehydration, either atmosphere during analysis.

Language: Английский

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Recent advances in understanding secondary organic aerosol: Implications for global climate forcing

Reviews of Geophysics, Journal Year: 2017, Volume and Issue: 55(2), P. 509 - 559

Published: May 18, 2017

Abstract Anthropogenic emissions and land use changes have modified atmospheric aerosol concentrations size distributions over time. Understanding preindustrial conditions in organic due to anthropogenic activities is important because these features (1) influence estimates of radiative forcing (2) can confound the historical response climate increases greenhouse gases. Secondary (SOA), formed atmosphere by oxidation gases, represents a major fraction global submicron‐sized aerosol. Over past decade, significant advances understanding SOA properties formation mechanisms occurred through measurements, yet current models typically do not comprehensively include all processes. This review summarizes some developments during decade formation. We highlight importance processes that growth particles sizes relevant for clouds forcing, including extremely low volatility organics gas phase, acid‐catalyzed multiphase chemistry isoprene epoxydiols, particle‐phase oligomerization, physical such as viscosity. Several highlighted this are complex interdependent nonlinear effects on properties, formation, evolution SOA. Current neglect complexity nonlinearity thus less likely accurately predict project future sensitivity Efforts also needed rank most influential process‐related interactions, so be represented chemistry‐climate models.

Language: Английский

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Severe haze in northern China: A synergy of anthropogenic emissions and atmospheric processes

Proceedings of the National Academy of Sciences, Journal Year: 2019, Volume and Issue: 116(18), P. 8657 - 8666

Published: April 15, 2019

Significance Severe haze events with large temporal/spatial coverages have occurred frequently in wintertime northern China. These extremes result from a complex interplay between emissions and atmospheric processes provide unique scientific platform to gain insights into many aspects of the relevant chemistry physics. Here we synthesize recent progress understanding severe formation In particular, highlight that improved emission sources, physical/chemical during evolution, interactions meteorological/climatic changes are necessary unravel causes, mechanisms, trends for pollution. This viewpoint established on basis sound science is critical improving prediction/forecast, formulating effective regulatory policies by decision makers, raising public awareness environmental protection.

Language: Английский

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Particulate matter, air quality and climate: lessons learned and future needs

Atmospheric chemistry and physics, Journal Year: 2015, Volume and Issue: 15(14), P. 8217 - 8299

Published: July 24, 2015

Abstract. The literature on atmospheric particulate matter (PM), or aerosol, has increased enormously over the last 2 decades and amounts now to some 1500–2000 papers per year in refereed literature. This is part due enormous advances measurement technologies, which have allowed for an increasingly accurate understanding of chemical composition physical properties particles their processes atmosphere. growing scientific interest aerosol high importance environmental policy. In fact, constitutes one most challenging problems both air quality climate change policies. this context, paper reviews recent results within sciences policy needs, driven much increase monitoring mechanistic research decades. synthesis reveals many new developments science underpinning climate–aerosol interactions effects PM human health environment. However, while airborne responsible globally important influences premature mortality, we still do not know relative different components these effects. Likewise, magnitude overall remains highly uncertain. Despite uncertainty there are things that could be done mitigate local global PM. Recent analyses shown reducing black carbon (BC) emissions, using known control measures, would reduce warming delay time when anthropogenic temperature exceed °C. cost-effective measures ammonia, agricultural precursor gas secondary inorganic aerosols (SIA), regional eutrophication concentrations large areas Europe, China USA. Thus, environment population. A prioritized list actions full range currently undeliverable shortcomings knowledge science; among shortcomings, roles sources response land use remaining century prominent. any case, evidence from strongly advocates integrated approach

Language: Английский

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The role of low-volatility organic compounds in initial particle growth in the atmosphere

Nature, Journal Year: 2016, Volume and Issue: 533(7604), P. 527 - 531

Published: May 25, 2016

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 subsequent 5,6 leaving organic vapours plausible alternative, at least planetary boundary layer 7,8,9,10 Although recent studies 11,12,13 predict low-volatility contribute during initial growth, direct evidence has been lacking. The accelerating may result increased photolytic production condensable species afternoon 2 presence possible Kelvin (curvature) effect, which inhibits on smallest (the nano-Köhler theory) 2,14 so far remained ambiguous. Here we present experiments performed large chamber under conditions investigate role nucleated absence inorganic acids bases such sulfuric or ammonia amines, respectively. Using data same set experiments, it shown 15 alone can drive nucleation. We focus find have extremely low volatilities (saturation concentration less than 10 −4.5 micrograms per cubic metre). As increase barrier falls, primarily due more abundant slightly higher volatility concentrations −0.5 particle model quantitatively reproduces our measurements. Furthermore, implement parameterization first steps global aerosol change substantially response, is, up cent comparison previously assumed parameterizations.

Language: Английский

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Adsorption materials for volatile organic compounds (VOCs) and the key factors for VOCs adsorption process: A review

Separation and Purification Technology, Journal Year: 2019, Volume and Issue: 235, P. 116213 - 116213

Published: Oct. 15, 2019

Language: Английский

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Ion-induced nucleation of pure biogenic particles

Nature, Journal Year: 2016, Volume and Issue: 533(7604), P. 521 - 526

Published: May 25, 2016

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 contamination could not excluded 6,7 Here we present evidence aerosol particles highly oxidized biogenic absence large chamber under conditions. The oxygenated molecules (HOMs) produced by ozonolysis α-pinene. We find Galactic cosmic rays increase rate one two orders magnitude compared with neutral nucleation. Our experimental findings supported quantum chemical calculations cluster binding energies representative HOMs. Ion-induced pure constitutes potentially widespread source terrestrial environments low pollution.

Language: Английский

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Oxidation Products of Biogenic Emissions Contribute to Nucleation of Atmospheric Particles

Science, Journal Year: 2014, Volume and Issue: 344(6185), P. 717 - 721

Published: May 15, 2014

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 very first step. Inclusion this global model yields photochemically biologically driven seasonal cycle continental boundary layer, good agreement observations.

Language: Английский

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Atmospheric new particle formation from sulfuric acid and amines in a Chinese megacity

Science, Journal Year: 2018, Volume and Issue: 361(6399), P. 278 - 281

Published: July 19, 2018

Atmospheric new particle formation (NPF) is an important global phenomenon that nevertheless sensitive to ambient conditions. According both observation and theoretical arguments, NPF usually requires a relatively high sulfuric acid (H2SO4) concentration promote the of particles low preexisting aerosol loading minimize sink particles. We investigated in Shanghai were able observe precursor vapors initial clusters at molecular level megacity. High rates observed coincide with several familiar markers suggestive H2SO4-dimethylamine (DMA)-water (H2O) nucleation, including dimers H2SO4-DMA clusters. In cluster kinetics simulation, was enough explain growth ~3 nanometers under very condensation sink, whereas subsequent higher rate beyond this size believed result from added contribution condensing organic species. These findings will help understanding urban its air quality climate effects, as well formulating policies mitigate secondary China.

Language: Английский

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