Tropical and Boreal Forest – Atmosphere Interactions: A Review

Tellus B, Год журнала: 2022, Номер 74(1), С. 24 - 24

Опубликована: Март 25, 2022

This review presents how the boreal and tropical forests affect atmosphere, its chemical composition, function, further that affects climate and, in return, ecosystems through feedback processes. Observations from key tower sites standing out due to their long-term comprehensive observations: The Amazon Tall Tower Observatory Central Amazonia, Zotino Siberia, Station Measure Ecosystem-Atmosphere Relations at Hyytiäla Finland. is complemented by short-term observations networks large experiments. discusses atmospheric chemistry observations, aerosol formation processing, physiochemical aerosol, cloud condensation nuclei properties finds surprising similarities important differences two ecosystems. concentrations are similar, particularly concerning main components, both dominated an organic fraction, while ecosystem has generally higher of inorganics, influence long-range transported air pollution. emissions biogenic volatile compounds isoprene monoterpene regions, respectively, being precursors fraction. modeling studies show change deforestation such carbon hydrological cycles Amazonia changing neutrality precipitation downwind. In Africa, so far maintaining sink. It urgent better understand interaction between these major ecosystems, climate, which calls for more observation sites, providing data on water, carbon, other biogeochemical cycles. essential finding a sustainable balance forest preservation reforestation versus potential increase food production biofuels, critical services global stability. Reducing warming vital forests.

Язык: Английский

---

Organic Peroxides in Aerosol: Key Reactive Intermediates for Multiphase Processes in the Atmosphere

Chemical Reviews, Год журнала: 2023, Номер 123(4), С. 1635 - 1679

Опубликована: Янв. 11, 2023

Organic peroxides (POs) are organic molecules with one or more peroxide (−O–O−) functional groups. POs commonly regarded as chemically labile termination products from gas-phase radical chemistry and therefore serve temporary reservoirs for oxidative radicals (HOx ROx) in the atmosphere. Owing to their ubiquity, active gas-particle partitioning behavior, reactivity, key reactive intermediates atmospheric multiphase processes determining life cycle (formation, growth, aging), climate, health impacts of aerosol. However, there remain substantial gaps origin, molecular diversity, fate due complex nature dynamic behavior. Here, we summarize current understanding on POs, a focus identification quantification, state-of-the-art analytical developments, molecular-level formation mechanisms, chemical transformation pathways, well environmental impacts. We find that interactions SO2 transition metal ions generally fast PO pathways liquid water, lifetimes estimated be minutes hours, while hydrolysis is particularly important α-substituted hydroperoxides. Meanwhile, photolysis thermolysis likely minor sinks POs. These distinctly different fates, such reaction OH radicals, which highlights need understand By summarizing advances remaining challenges investigation propose future research priorities regarding fate,

Язык: Английский

---

Oxygenated and Nitrated Polycyclic Aromatic Hydrocarbons in Ambient Air—Levels, Phase Partitioning, Mass Size Distributions, and Inhalation Bioaccessibility

Environmental Science & Technology, Год журнала: 2020, Номер 54(5), С. 2615 - 2625

Опубликована: Янв. 17, 2020

Among the nitrated and oxygenated polycyclic aromatic hydrocarbons (NPAHs OPAHs) are some of most hazardous substances to public health, mainly because their carcinogenicity oxidative potential. Despite these concerns, concentrations fate NPAHs OPAHs in atmospheric environment largely unknown. Ambient air 18 NPAHs, 5 quinones, other were determined at two urban one regional background sites central Europe. At sites, total (gas particulate) Σ10OPAHs 10.0 ± 9.2 ng/m3 winter 3.5 1.6 summer. The gradient site exceeded 1 order magnitude. Σ18NPAH typically magnitude lower than OPAHs. OPAHs, 9-fluorenone (9,10)-anthraquinone abundant species, accompanied by benzanthrone winter. (9,10)-Anthraquinone represented two-thirds quinones. We found that a large fraction target substance particulate mass was carried submicrometer particles. derived inhalation bioaccessibility PM10 size is be ≈5% ambient concentration up ≈2% for NPAHs. For (9,10)-anthraquinone, 86 18%, respectively, rural site. Our results indicate water solubility could function as limiting factor inhaled without considerable effect surfactant lipids proteins lung lining fluid.

Язык: Английский

---

Characterization and comparison of PM_2.5 oxidative potential assessed by two acellular assays

Atmospheric chemistry and physics, Год журнала: 2020, Номер 20(9), С. 5197 - 5210

Опубликована: Май 4, 2020

Abstract. The capability of ambient particles to generate in vivo reactive oxygen species (ROS), called oxidative potential (OP), is a metric for evaluating the health effects particulate matter (PM) and supported by several recent epidemiological investigations. Studies using various types OP assays differ their sensitivities varying PM chemical components. In this study, we systematically compared two health-relevant acellular that track depletion antioxidants or reductant surrogates: (i) synthetic respiratory-tract lining fluid (RTLF) assay tracks ascorbic acid (AA) glutathione (GSH) (ii) dithiothreitol (DTT) DTT. Yearlong daily samples were collected at an urban site Atlanta, GA (Jefferson Street), during 2017, both DTT RTLF performed measure water-soluble PM2.5 mass major components, including metals, ions, organic elemental carbon also analyzed. Correlation analysis found as measured AA (OPDTT OPAA, respectively) correlated with organics some metal species, whereas from GSH (OPGSH) was exclusively sensitive Cu. These moderately each other due common contribution ions. OPDTT OPAA Pearson's r=0.55 0.56, respectively, OPGSH exhibited lower correlation (r=0.24). There little seasonal variation levels all weak seasonality OP-associated species. Multivariate linear regression models developed predict measures particle composition data. Variability not only attributed concentrations ions (mainly Fe Cu) compounds but antagonistic metal–organic metal–metal interactions. change Cu brown (BrC), proxy humic-like substances.

Язык: Английский

---

Atmospheric conditions and composition that influence PM<sub>2.5</sub> oxidative potential in Beijing, China

Atmospheric chemistry and physics, Год журнала: 2021, Номер 21(7), С. 5549 - 5573

Опубликована: Апрель 12, 2021

Epidemiological studies have consistently linked exposure to PM2.5 with adverse health effects. The oxidative potential (OP) of aerosol particles has been widely suggested as a measure their toxicity. Several acellular chemical assays are now readily employed OP; however, uncertainty remains regarding the atmospheric conditions and specific components that drive OP. A limited number simultaneously utilised multiple OP wide range concurrent measurements investigated seasonality In this work, filter samples were collected in winter 2016 summer 2017 during pollution human Chinese megacity campaign (APHH-Beijing), was analysed using four methods: ascorbic acid (AA), dithiothreitol (DTT), 2,7-dichlorofluorescin/hydrogen peroxidase (DCFH) electron paramagnetic resonance spectroscopy (EPR). Each assay reflects different oxidising properties PM2.5, including particle-bound reactive oxygen species (DCFH), superoxide radical production (EPR) catalytic redox chemistry (DTT/AA), combination these provided detailed overall picture at central site Beijing. Positive correlations (normalised per volume air) all mass observed, stronger compared summer. contrast, when values normalised for particle mass, days higher concentrations (μgm-3) found lower mass-normalised measured by AA DTT. This finding supports total alone may not always be best indicator Univariate analysis an extensive additional measurements, 107 total, composition, gas-phase composition meteorological data, insight into processes determine variability. Multivariate statistical analyses highlighted associations responses varying both mass- volume-normalised data. DTT well predicted small set linear regression (MLR) models indicated fossil fuel combustion, vehicle emissions biogenic secondary organic (SOA) influential sources response. Mass MLR associated compositional source profiles almost models, illustrating influence on particle-level multivariate showed cover spaces, through comparison data we demonstrate provides more nuanced drivers analysis. study constitutes one most comprehensive datasets currently available unique opportunity explore variations how they affect species.

Язык: Английский

---

Connecting the Oxidative Potential of Secondary Organic Aerosols with Reactive Oxygen Species in Exposed Lung Cells

Environmental Science & Technology, Год журнала: 2019, Номер 53(23), С. 13949 - 13958

Опубликована: Окт. 25, 2019

It has been hypothesized that the cytotoxicity of secondary organic aerosols (SOA) is mediated through formation reactive oxygen species (ROS) in exposed cells. Here, lung epithelial cells (A549) residing at air-liquid interface were to proxies anthropogenic and biogenic SOA photochemically aged under varying nitrogen oxide (NOx) concentrations an oxidation flow reactor. The total peroxides ROS radical content quantified by iodometric spectrophotometric method continuous-wave electron paramagnetic resonance. effect exposure was evaluated measuring cell viability cellular production following exposure. results demonstrate absence NOx contained more than fresh toxic toward cells, while conditions had no significant influence on levels their toxicity. Analysis using cytometry showed a similar trend with SOA. This study provides first direct observation such association.

Язык: Английский

---

Urban organic aerosol composition in eastern China differs from north to south: molecular insight from a liquid chromatography–mass spectrometry (Orbitrap) study

Atmospheric chemistry and physics, Год журнала: 2021, Номер 21(11), С. 9089 - 9104

Опубликована: Июнь 15, 2021

Abstract. Air pollution by particulate matter in China affects human health, the ecosystem and climate. However, chemical composition of aerosol, especially organic fraction, is still not well understood. In this study, aerosol samples with a diameter ≤2.5 µm (PM2.5) were collected January 2014 three cities located northeast, east southeast China, namely Changchun, Shanghai Guangzhou. Organic (OA) PM2.5 was analyzed an ultrahigh-performance liquid chromatograph (UHPLC) coupled to high-resolution Orbitrap mass spectrometer both negative mode (ESI-) positive electrospray ionization (ESI+). After non-target screening including assignment molecular formulas, compounds classified into five groups based on their elemental composition, i.e., CHO, CHON, CHN, CHOS CHONS. The CHON CHN present dominant signal abundances 81 %–99.7 % spectra majority these assigned mono- polyaromatics, suggesting that anthropogenic emissions are major source urban OA all cities. characteristics varied between different degree aromaticity number polyaromatic substantially higher from which could be attributed large residential heating (i.e., coal combustion) during wintertime northeast China. Moreover, ESI- analysis showed H/C O/C ratios for Guangzhou compared indicating undergoes more intense photochemical oxidation processes lower-latitude regions and/or affected larger biogenic sources. sulfur-containing (CHOS CHONS) aliphatic low degrees unsaturation aromaticity. Here again, show greater similarity but differ largely those Changchun. It should noted conclusions drawn study mainly comparison formulas weighted peak abundance thus associated inherent uncertainties due efficiencies species.

Язык: Английский

---

Water-soluble brown carbon in atmospheric aerosols along the transport pathway of Asian dust: Optical properties, chemical compositions, and potential sources

The Science of The Total Environment, Год журнала: 2021, Номер 789, С. 147971 - 147971

Опубликована: Май 24, 2021

Язык: Английский

---

Ambient volatile organic compounds in tropical environments: Potential sources, composition and impacts – A review

Chemosphere, Год журнала: 2021, Номер 285, С. 131355 - 131355

Опубликована: Июнь 30, 2021

Язык: Английский

---

Mass accommodation and gas–particle partitioning in secondary organic aerosols: dependence on diffusivity, volatility, particle-phase reactions, and penetration depth

Atmospheric chemistry and physics, Год журнала: 2021, Номер 21(3), С. 1565 - 1580

Опубликована: Фев. 4, 2021

Abstract. Mass accommodation is an essential process for gas–particle partitioning of organic compounds in secondary aerosols (SOA). The mass coefficient commonly described as the probability a gas molecule colliding with surface to enter particle phase. It often applied, however, without specifying if and how deep has penetrate beneath be regarded being incorporated into condensed phase (adsorption vs. absorption). While this aspect usually not critical liquid particles rapid surface–bulk exchange, it can important viscous semi-solid or glassy solid distinguish resolve kinetics at surface, transfer across interface, further transport bulk. For purpose, we introduce novel parameter: effective αeff that depends on penetration depth function coefficient, volatility, bulk diffusivity, particle-phase reaction rate coefficient. Application traditional Fuchs–Sutugin approximation mass-transport interface yields SOA results are consistent detailed kinetic multilayer model (kinetic interactions clouds, KM-GAP; Shiraiwa et al., 2012) two-film solutions (Model Simulating Aerosol Interactions Chemistry, MOSAIC; Zaveri 2014) but deviate substantially from earlier modeling approaches considering influence related parameters. highly particles, show remains similar case low-volatility compounds, whereas decrease by several orders magnitude semi-volatile compounds. Such effects explain apparent inconsistencies between studies deriving coefficients experimental data molecular dynamics simulations. Our findings challenge approach models using fixed regardless state depth. introduced study provides efficient new way accounting reactions well regional global air quality models. limitations may planetary boundary layer (PBL), likely amorphous free upper troposphere (FT–UT) PBL low relative humidity temperature.

Язык: Английский

---