Molecular Chemistry of Atmospheric Brown Carbon Inferred from a Nationwide Biomass Burning Event

Environmental Science & Technology, Год журнала: 2017, Номер 51(20), С. 11561 - 11570

Опубликована: Июль 31, 2017

Lag Ba'Omer, a nationwide bonfire festival in Israel, was chosen as case study to investigate the influence of major biomass burning event on light absorption properties atmospheric brown carbon (BrC). The chemical composition and optical BrC chromophores were investigated using high performance liquid chromatography (HPLC) platform coupled photo diode array (PDA) resolution mass spectrometry (HRMS) detectors. Substantial increase coefficient observed during night-long event. Most attributed nitroaromatic compounds (NAC), comprising 28 elemental formulas at least 63 structural isomers. NAC, combination, accounted for 50-80% total visible (>400 nm) by solvent extractable BrC. results highlight that particular nitrophenols, are important contributors organic aerosol (BBOA), suggesting night time chemistry •NO3 N2O5 with particles may play significant role transformations Nitrophenols related especially BBOA. spectra influenced extraction solution pH, implying acidity is an factor controlling

Язык: Английский

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Comprehensive Molecular Characterization of Atmospheric Brown Carbon by High Resolution Mass Spectrometry with Electrospray and Atmospheric Pressure Photoionization

Analytical Chemistry, Год журнала: 2018, Номер 90(21), С. 12493 - 12502

Опубликована: Окт. 8, 2018

Light-absorbing components of atmospheric organic aerosols, which are collectively termed "brown carbon" (BrC), ubiquitous in the atmosphere. They affect absorption solar radiation by aerosols atmosphere and human health as some them have been identified potential toxins. Understanding sources, formation, evolution, environmental effects BrC requires molecular identification characterization light-absorption properties chromophores. Identification is challenging due to complexity aerosols. In this study, we employ two complementary ionization techniques, pressure photo (APPI) electrospray (ESI), obtain broad coverage both polar nonpolar using high-resolution mass spectrometry (HRMS). These techniques combined with chromatographic separation compounds high performance liquid chromatography (HPLC), their light a photodiode array (PDA) detector, chemical composition HRMS. We demonstrate that approach enables more comprehensive biomass burning (BBOAs) emitted from test burns sage brush biofuel. particular, found chromophores such PAHs only detected positive mode APPI. Meanwhile, negative ESI results detection nitroaromatics, aromatic acids, phenols. For material examined over 40% solvent-extractable attributed water insoluble, semipolar derivatives, require APPI for identification. contrast, polar, water-soluble compounds, ESI, account less than 30% BrC.

Язык: Английский

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Aging of Atmospheric Brown Carbon Aerosol

ACS Earth and Space Chemistry, Год журнала: 2021, Номер 5(4), С. 722 - 748

Опубликована: Апрель 5, 2021

Emitted by numerous primary sources and formed secondary sources, atmospheric brown carbon (BrC) aerosol is chemically complex. As BrC ages in the atmosphere via a variety of chemical physical processes, its composition optical properties change significantly, altering impacts on climate. Research past decade has considerably expanded our understanding reactions both gas condensed phases. We review these recent advances aging chemistry with focus phase leading to formation, aqueous in-cloud particle reactions. Connections are made between single component proxies more complex mixtures as well laboratory field measurements chemistry. General conclusions that can darken particles over short time scales hours close source considerable photobleaching oxidative whitening will occur when day or removed from source.

Язык: Английский

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Review of brown carbon aerosols: Recent progress and perspectives

The Science of The Total Environment, Год журнала: 2018, Номер 634, С. 1475 - 1485

Опубликована: Апрель 18, 2018

Язык: Английский

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From Measurements to Models: Toward Accurate Representation of Brown Carbon in Climate Calculations

Current Pollution Reports, Год журнала: 2020, Номер 6(2), С. 90 - 104

Опубликована: Март 19, 2020

Язык: Английский

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The Aerosols, Radiation and Clouds in Southern Africa Field Campaign in Namibia: Overview, Illustrative Observations, and Way Forward

Bulletin of the American Meteorological Society, Год журнала: 2019, Номер 100(7), С. 1277 - 1298

Опубликована: Март 6, 2019

Abstract The Aerosol, Radiation and Clouds in southern Africa (AEROCLO-sA) project investigates the role of aerosols on regional climate Africa. This is a unique environment where natural anthropogenic semipermanent widespread stratocumulus (Sc) cloud deck are found. aims to understand dynamical, chemical, radiative processes involved aerosol–cloud–radiation interactions over land ocean under various meteorological conditions. AEROCLO-sA field campaign was conducted August September 2017 Namibia. An aircraft equipped with active passive remote sensors aerosol situ probes performed total 30 research flight hours. In parallel, ground-based mobile station state-of-the-art sensing instrumentation implemented coastal Namibia, complemented by balloonborne observations thermodynamical, physical properties lower troposphere. focus laid mineral dust emitted from salty pans ephemeral riverbeds northern advection biomass-burning plumes Angola subsequently transported Atlantic Ocean, marine boundary layer at ocean–atmosphere interface. article presents an overview results airborne surface measurements. These provide new knowledge radiation cloudy clear skies connection atmospheric dynamics They will foster advanced simulations enhance capability spaceborne sensors, ultimately allowing better prediction future weather

Язык: Английский

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Formation of Secondary Brown Carbon in Biomass Burning Aerosol Proxies through NO₃ Radical Reactions

Environmental Science & Technology, Год журнала: 2019, Номер 54(3), С. 1395 - 1405

Опубликована: Ноя. 15, 2019

Atmospheric brown carbon (BrC) is an important contributor to the radiative forcing of climate by organic aerosols. Because molecular diversity BrC compounds and their dynamic transformations, it challenging predictively understand optical properties. OH radical O3 reactions, together with photolysis, lead diminished light absorption lower warming effects biomass burning BrC. The night-time aging on properties aerosols are less known. To address this knowledge gap, NO3 chemistry tar from wood pyrolysis was investigated in a flow reactor. This study shows that change because transformations driven reactions form new absorbing species significant enhancement over ultraviolet–visible (UV-vis) range. overnight increases mass coefficients factor 1.3–3.2 between 380 nm 650 nm. Nitrated compounds, particularly nitroaromatics, were identified as main products contribute enhanced secondary Night-time represents source can have pronounced effect atmospheric air pollution.

Язык: Английский

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Spherical tarball particles form through rapid chemical and physical changes of organic matter in biomass-burning smoke

Proceedings of the National Academy of Sciences, Год журнала: 2019, Номер 116(39), С. 19336 - 19341

Опубликована: Сен. 5, 2019

Biomass burning (BB) emits enormous amounts of aerosol particles and gases into the atmosphere thereby significantly influences regional air quality global climate. A dominant particle type from BB is spherical organic commonly referred to as tarballs. Currently, tarballs can only be identified, using microscopy, their uniquely shapes following impaction onto a grid. Despite abundance potential significance for climate, many unanswered questions related formation, emission inventory, removal processes, optical properties still remain. Here, we report analysis that supports tarball formation in which primary undergo chemical physical processing within ∼3 h emission. Transmission electron microscopy reveals number fractions ratios N O relative K, latter conserved tracer, increase with age more-spherical on substrates had higher K. Scanning transmission X-ray spectrometry energy loss analyses show these changes are accompanied by compounds contain nitrogen carboxylic acid. The results imply sphericity substrates, correlates surface tension viscosity, contribute during aging smoke. These findings will enable models better partition contributions radiative forcing and, so doing, help constrain events.

Язык: Английский

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Chemical Composition and Molecular-Specific Optical Properties of Atmospheric Brown Carbon Associated with Biomass Burning

Environmental Science & Technology, Год журнала: 2021, Номер 55(4), С. 2511 - 2521

Опубликована: Янв. 27, 2021

This study provides molecular insights into the light absorption properties of biomass burning (BB) brown carbon (BrC) through chemical characterization tar condensates generated from heated wood pellets at oxidative and pyrolysis conditions. Both liquid separated "darker oily" "lighter aqueous" immiscible phases. The composition these samples was investigated using reversed-phase chromatography coupled with a photodiode array detector high-resolution mass spectrometer. results revealed two sets BrC chromophores: (1) common to all four (2) specific "oily" fractions. chromophores consist polar, monoaromatic species. oil-specific include less-polar nonpolar polyaromatic compounds. most-light-absorbing oily phase (PO) aerosolized size-separated cascade impactor compare optical bulk versus BrC. coefficient (MAC300-500 nm) PO increased compared that bulk, due gas-phase partitioning more volatile less absorbing chromophores. were consistent previously reported ambient BB measurements. These suggest darkening atmospheric following non-reactive evaporation transforms aged aerosols.

Язык: Английский

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Molecular Analysis of Secondary Brown Carbon Produced from the Photooxidation of Naphthalene

Environmental Science & Technology, Год журнала: 2022, Номер 56(6), С. 3340 - 3353

Опубликована: Март 1, 2022

We investigate the chemical composition of organic light-absorbing components, also known as brown carbon (BrC) chromophores, formed in a proxy anthropogenic secondary aerosol generated from photooxidation naphthalene (naph-SOA) absence and presence NOx. High-performance liquid chromatography equipped with photodiode array detector electrospray ionization high-resolution mass spectrometer is employed to characterize naph-SOA its BrC components. provide molecular-level insights into optical properties individual components their relevance. This work reveals formation strongly absorbing nitro-aromatic chromophores under high-NOx conditions describes degradation during atmospheric aging. NOx addition enhanced light absorption while reducing wavelength-dependence, seen by coefficient (MAC) Ångström exponent (AAE). Optical parameters low- showed range values MACOM 405nm ∼ 0.12 m2 g–1 AAE300–450nm 8.87 (low-NOx) 0.19 7.59 (high-NOx), consistent "very weak" "weak" classes, respectively. The weak-BrC class commonly attributed biomass smoldering emissions, which appear have comparable naph-SOA. Molecular contributing were identified substantial nitro-aromatics, indicating that these species may be used source-specific markers related emissions.

Язык: Английский

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