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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Atmospheric new particle formation and growth: review of field observations

Environmental Research Letters, Journal Year: 2018, Volume and Issue: 13(10), P. 103003 - 103003

Published: Sept. 6, 2018

This review focuses on the observed characteristics of atmospheric new particle formation (NPF) in different environments global troposphere. After a short introduction, we will present theoretical background that discusses methods used to analyze measurement data NPF and associated terminology. We update our current understanding regional NPF, i.e. taking simultaneously place over large spatial scales, complement with full reported growth rates during events. shortly at sub-regional scales. Since newly-formed particles into larger sizes is great interest, briefly discuss observation-based which gaseous compounds contribute particles, what implications this have cloud condensation nuclei formation. finish summary main findings future outlook outlines remaining research questions needs for additional measurements.

Language: Английский

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The acidity of atmospheric particles and clouds

Atmospheric chemistry and physics, Journal Year: 2020, Volume and Issue: 20(8), P. 4809 - 4888

Published: April 24, 2020

Abstract. Acidity, defined as pH, is a central component of aqueous chemistry. In the atmosphere, acidity condensed phases (aerosol particles, cloud water, and fog droplets) governs phase partitioning semivolatile gases such HNO3, NH3, HCl, organic acids bases well chemical reaction rates. It has implications for atmospheric lifetime pollutants, deposition, human health. Despite its fundamental role in processes, only recently this field seen growth number studies on particle acidity. Even with growth, many fine-particle pH estimates must be based thermodynamic model calculations since no operational techniques exist direct measurements. Current information indicates acidic fine particles are ubiquitous, but observationally constrained limited spatial temporal coverage. Clouds fogs also generally acidic, to lesser degree than have range that quite sensitive anthropogenic emissions sulfur nitrogen oxides, ambient ammonia. Historical measurements indicate droplet changed recent decades response controls emissions, while trend data aerosol may relatively constant due nature key buffering particles. This paper reviews synthesizes current state knowledge phases, specifically droplets. includes recommendations estimating standard nomenclature, synthesis observations, new local global scale.

Language: Английский

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New Particle Formation in the Atmosphere: From Molecular Clusters to Global Climate

Journal of Geophysical Research Atmospheres, Journal Year: 2019, Volume and Issue: 124(13), P. 7098 - 7146

Published: June 25, 2019

Abstract New particle formation (NPF) represents the first step in complex processes leading to of cloud condensation nuclei. Newly formed nanoparticles affect human health, air quality, weather, and climate. This review provides a brief history, synthesizes recent significant progresses, outlines challenges future directions for research relevant NPF. developments include emergence state‐of‐the‐art instruments that measure prenucleation clusters newly nucleated down about 1 nm; systematic laboratory studies multicomponent nucleation systems, including collaborative experiments conducted Cosmics Leaving Outdoor Droplets chamber at CERN; observations NPF different types forests, extremely polluted urban locations, coastal sites, polar regions, high‐elevation sites; improved theories parameterizations account atmospheric models. The lack understanding fundamental chemical mechanisms responsible aerosol growth under diverse environments, effects SO 2 NO x on NPF, contribution anthropogenic organic compounds It is also critical develop can detect composition particles from 3 20 nm improve represent over wide range conditions precursor, temperature, humidity.

Language: Английский

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Rapid growth of new atmospheric particles by nitric acid and ammonia condensation

Nature, Journal Year: 2020, Volume and Issue: 581(7807), P. 184 - 189

Published: May 13, 2020

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 about +5 degrees Celsius, nitric acid ammonia vapours can condense onto freshly nucleated as small few diameter. Moreover, when cold enough (below -15 Celsius), nucleate directly an acid-base stabilization mechanism form ammonium nitrate Given these one thousand times more abundant than sulfuric acid, resulting particle extremely high, reaching well above 100 hour. However, require gas-particle system out equilibrium order sustain gas-phase supersaturations. In view strong temperature dependence measure for supersaturations, expect such transient occur inhomogeneous settings, especially wintertime, driven vertical mixing local sources traffic. Even though rapid from condensation may last only minutes, nonetheless fast shepherd smallest size range where they most vulnerable scavenging loss, thus greatly increasing survival probability. We also nucleation important relatively clean upper free troposphere, convected continental boundary layer electrical storms4,5.

Language: Английский

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Rapid growth of organic aerosol nanoparticles over a wide tropospheric temperature range

Proceedings of the National Academy of Sciences, Journal Year: 2018, Volume and Issue: 115(37), P. 9122 - 9127

Published: Aug. 28, 2018

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 additional, but less oxidized, species condense. rapid full temperature our study, indicating that organics play an important role aerosol throughout troposphere. Our finding will help sharpen predictions models.

Language: Английский

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A large source of cloud condensation nuclei from new particle formation in the tropics

Nature, Journal Year: 2019, Volume and Issue: 574(7778), P. 399 - 403

Published: Oct. 16, 2019

Language: Английский

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Differing Mechanisms of New Particle Formation at Two Arctic Sites

Geophysical Research Letters, Journal Year: 2020, Volume and Issue: 48(4)

Published: Dec. 29, 2020

Abstract New particle formation in the Arctic atmosphere is an important source of aerosol particles. Understanding processes secondary crucial due to their significant impact on cloud properties and therefore amplification. We observed molecular new particles from low‐volatility vapors at two sites with differing surroundings. In Svalbard, sulfuric acid (SA) methane sulfonic (MSA) contribute some extent condensation nuclei (CCN). This occurs via ion‐induced nucleation SA NH 3 subsequent growth by mainly MSA during springtime highly oxygenated organic molecules summertime. By contrast, ice‐covered region around Villum, we driven iodic but its concentration was insufficient grow nucleated CCN sizes. Our results provide insight about sources precursors

Language: Английский

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Frequent new particle formation over the high Arctic pack ice by enhanced iodine emissions

Nature Communications, Journal Year: 2020, Volume and Issue: 11(1)

Published: Oct. 1, 2020

Abstract In the central Arctic Ocean formation of clouds and their properties are sensitive to availability cloud condensation nuclei (CCN). The vapors responsible for new particle (NPF), potentially leading CCN, have remained unidentified since first aerosol measurements in 1991. Here, we report that all observed NPF events from 2018 expedition driven by iodic acid with little contribution sulfuric acid. Iodic largely explains growth ultrafine particles (UFP) most events. concentration increases significantly summer towards autumn, possibly linked ocean freeze-up a seasonal rise ozone. This leads one order magnitude higher UFP autumn. Measurements residuals suggest smaller than 30 nm diameter can activate as CCN. Therefore, iodine has potential influence over Ocean.

Language: Английский

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Role of iodine oxoacids in atmospheric aerosol nucleation

Science, Journal Year: 2021, Volume and Issue: 371(6529), P. 589 - 595

Published: Feb. 4, 2021

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

Language: Английский

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