Secondary organic aerosol formed by condensing anthropogenic vapours over China’s megacities

Nature Geoscience, Journal Year: 2022, Volume and Issue: 15(4), P. 255 - 261

Published: April 1, 2022

Language: Английский

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Molecular insights into the composition, sources, and aging of atmospheric brown carbon

Chemical Society Reviews, Journal Year: 2025, Volume and Issue: unknown

Published: Jan. 1, 2025

The light-absorbing chemical components of atmospheric organic aerosols are commonly referred to as Brown Carbon (BrC), reflecting the characteristic yellowish brown appearance aerosol.

Language: Английский

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Multigeneration Chemistry in Secondary Organic Aerosol Formation from Nitrate Radical Oxidation of Isoprene

ACS Earth and Space Chemistry, Journal Year: 2025, Volume and Issue: unknown

Published: Jan. 26, 2025

The nitrate radical (NO3) oxidation of isoprene is an important contributor to secondary organic aerosol (SOA). Isoprene has two double bonds which allow for multigeneration occur. effects chemistry on the gas- and particle-phase product distributions + NO3 system are not fully understood. In this study, we conduct chamber experiments by varying ratio N2O5 (precursor NO3) concentration from 1:1 14:1 investigate formation products in both phases under different levels. Multigeneration leads gas-phase then partition into particle phase depending volatility; first-generation (15–36% total SOA) such as C5H9NO5 C10H16N2O9 have volatility (log10C* = 1.0–3.0 using partitioning method log10C* 2.6–4.5 formula method) 1–5 orders magnitude higher than second-generation (37–57% SOA, −0.8–2.1 −3.7–1.8 C5H8,10N2O8, C5H9N3O10, C10H17N3O13. fast reaction rate constants (estimated be order 10–13 cm3 molecules–1 s–1 at 295 K) lower result increased SOA yields when availability increases enhanced. Specifically, increase up 300% yield observed N2O5/isoprene 3:1; 5.7% (organic mass concentration, ΔMo 4.2 μg/m3) 16.3% (ΔMo 11.9 reacted 25 ppb 3.1% 1.2 12.4% 5.4 15 ppb. maximum occurs greater or equal 3:1 a combined peroxy radicals (RO2) fate. We encourage future studies consider factors, can vary laboratory ambient conditions, comparing better understand any differences observed. Our results highlight that updated parameters including distribution should considered enable more comprehensive representation prediction atmospheric models.

Language: Английский

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Highly oxygenated organic molecule (HOM) formation in the isoprene oxidation by NO<sub>3</sub> radical

Atmospheric chemistry and physics, Journal Year: 2021, Volume and Issue: 21(12), P. 9681 - 9704

Published: June 29, 2021

Abstract. Highly oxygenated organic molecules (HOM) are found to play an important role in the formation and growth of secondary aerosol (SOA). SOA is type with significant impact on air quality climate. Compared oxidation volatile compounds by ozone (O3) hydroxyl radical (OH), HOM nitrate (NO3), oxidant at nighttime dawn, has received less attention. In this study, reaction isoprene NO3 was investigated SAPHIR chamber (Simulation Atmospheric PHotochemistry a large Reaction chamber). A number HOM, including monomers (C5), dimers (C10), trimers (C15), both closed-shell open-shell peroxy radicals (RO2), were identified classified into various series according their formula. Their pathways proposed based observed known mechanisms literature, which further constrained time profiles after sequential addition differentiate first- second-generation products. containing one three N atoms (1–3N-monomers) formed, starting carbon double bond, forming radicals, followed autoxidation. 1N-monomers formed direct first-generation 2N-monomers (e.g., C5H8N2On(n=7–13), C5H10N2On(n=8–14)) likely termination products C5H9N2On⚫, C5-hydroxynitrate (C5H9NO4), product bond. 2N-monomers, products, dominated accounted for ∼34 % all indicating + under our experimental conditions. H shift alkoxy form subsequent autoxidation (“alkoxy–peroxy” pathway) be pathway formation. mostly accretion monomer RO2 via reactions dimer possibly C5–RO2 isoprene. RO2. The concentrations different showed distinct during reaction, linked pathway. either typical profile or combination both, multiple and/or isomers. Total molar yield estimated 1.2 %-0.7%+1.3%, corresponded ∼3.6 assuming molecular weight C5H9NO6 as lower limit. This suggests that may contribute fraction NO3.

Language: Английский

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Seasonal variation in oxygenated organic molecules in urban Beijing and their contribution to secondary organic aerosol

Atmospheric chemistry and physics, Journal Year: 2022, Volume and Issue: 22(15), P. 10077 - 10097

Published: Aug. 5, 2022

Abstract. Oxygenated organic molecules (OOMs) are crucial for atmospheric new particle formation and secondary aerosol (SOA) growth. Therefore, understanding their chemical composition, temporal behavior, sources is of great importance. Previous studies on OOMs mainly focus environments where biogenic predominant, yet sites with dominant anthropogenic emissions, such as megacities, have been lacking. Here, we conducted long-term measurements OOMs, covering four seasons the year 2019, in urban Beijing. The OOM concentration was found to be highest summer (1.6×108 cm−3), followed by autumn (7.9×107 spring (5.7×107 cm−3) winter (2.3×107 suggesting that enhanced photo-oxidation together rise temperature promote OOMs. Most contained 5 10 carbon atoms 3 7 effective oxygen (nOeff=nO-2×nN). average nOeff increased increasing capacity, which lowest autumn. By performing a newly developed workflow, were classified into following types: aromatic aliphatic isoprene monoterpene Among them, (29 %–41 %) (26 main contributors all seasons, indicating Beijing dominated sources. contribution significantly (33 %), much higher than those other three (8 %–10 %). Concentrations (0.2–5.3×107 (1.1–8.4×106 lower reported at sites, they possessed nitrogen contents due high NOx levels (9.5–38.3 ppbv – parts per billion volume) With regard content two composed CHO CHON species, while CHON2 ones. Such prominent differences suggest varying pathways between these combining an dynamic model, estimated SOA growth rate through condensation could reach 0.64, 0.61, 0.41, 0.30 µg m−3 h−1 autumn, summer, spring, winter, respectively. Despite similar concentrations former had volatilities and, therefore, showed contributions (46 %–62 latter (14 %–32 contrast, limited low abundances or volatilities, 8 %–12 % %–5 %, Overall, our results improve concentration, seasonal variation, potential impacts can help formulate refined restriction policy specific control areas.

Language: Английский

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Recent Progress in Atmospheric Chemistry Research in China: Establishing a Theoretical Framework for the “Air Pollution Complex”

Advances in Atmospheric Sciences, Journal Year: 2023, Volume and Issue: 40(8), P. 1339 - 1361

Published: April 28, 2023

Atmospheric chemistry research has been growing rapidly in China the last 25 years since concept of "air pollution complex" was first proposed by Professor Xiaoyan TANG 1997. For papers published 2021 on air (only included Web Science Core Collection database were considered), more than 24 000 authored or co-authored scientists working China. In this paper, we review a limited number representative and significant studies atmospheric few years, including (1) sources emission inventories, (2) chemical processes, (3) interactions with meteorology, weather climate, (4) between biosphere atmosphere, (5) data assimilation. The intention not to provide complete all progress made but rather serve as starting point for learning about advances reviewed paper have enabled theoretical framework complex be established, provided robust scientific support highly successful control policies China, created great opportunities education, training, career development many graduate students young scientists. This further highlights that developing low-income countries are heavily affected can benefit from these advances, whilst at same time acknowledging challenges still remain hopefully addressed over next decades.

Language: Английский

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Formation of condensable organic vapors from anthropogenic and biogenic volatile organic compounds (VOCs) is strongly perturbed by NO<sub><i>x</i></sub> in eastern China

Atmospheric chemistry and physics, Journal Year: 2021, Volume and Issue: 21(19), P. 14789 - 14814

Published: Oct. 6, 2021

Abstract. Oxygenated organic molecules (OOMs) are the crucial intermediates linking volatile compounds (VOCs) to secondary aerosols (SOAs) in atmosphere, but comprehensive understanding of characteristics OOMs and their formation from VOCs is still missing. Ambient observations using recently developed mass spectrometry techniques limited, especially polluted urban atmospheres where oxidants extremely variable complex. Here, we investigate OOMs, measured by a nitrate-ion-based chemical ionization spectrometer at Nanjing eastern China, through performing positive matrix factorization on binned spectra (binPMF). The binPMF analysis reveals three factors about anthropogenic VOC (AVOC) daytime chemistry, isoprene-related factors, biogenic (BVOC) nighttime nitrated phenols. All influenced NOx different ways extents. Over 1000 non-nitro have been identified then reconstructed selected solution binPMF, 72 % total signals contributed nitrogen-containing mostly regarded as nitrates formed peroxy radicals terminated nitric oxide or nitrate-radical-initiated oxidations. Moreover, multi-nitrates account for 24 signals, indicating significant presence multiple generations, isoprene (e.g., C5H10O8N2 C5H9O10N3). Additionally, distribution OOM concentration carbon number confirms precursors driven AVOCs mixed with enhanced BVOCs during summer. Our results highlight decisive role densely populated areas, encourage more studies dramatic interactions between emissions.

Language: Английский

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A Four Carbon Organonitrate as a Significant Product of Secondary Isoprene Chemistry

Geophysical Research Letters, Journal Year: 2022, Volume and Issue: 49(11)

Published: May 24, 2022

Oxidation of isoprene by nitrate radicals (NO3) or hydroxyl (OH) under high NOx conditions forms a substantial amount organonitrates (ONs). ONs impact concentrations and consequently ozone formation while also contributing to secondary organic aerosol. Here we show that the with chemical formula C4H7NO5 are significant fraction isoprene-derived ONs, based on chamber experiments ambient measurements from different sites around globe. From found isomers contribute 5%-17% all measured formed during nighttime constitute more than 40% after further daytime oxidation. In usually dominate both daytime, implying long residence time compared C5 which removed rapidly. We propose potential sources pathways, test them using box model an updated oxidation scheme.

Language: Английский

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Elevated Formation of Particulate Nitrate From N₂O₅ Hydrolysis in the Yangtze River Delta Region From 2011 to 2019

Geophysical Research Letters, Journal Year: 2022, Volume and Issue: 49(9)

Published: April 21, 2022

Abstract Aerosol nitrate has become the most abundant compound during aerosol pollution in eastern China. The Chinese government implemented a stringent policy 2013–2017 to tackle pollution. However, response of nitrogen oxides (NO x ) reduction is unclear owing limitation long‐term measurement. Here, we performed 9‐year continuous measurement compositions Shanghai and confirmed decrease species except nitrate. contribution fine particulate matter (PM 2.5 increased significantly, reaching up 35% episodes after 2017. This contrast evident NO emissions. We found that elevated dinitrogen pentoxide (N 2 O 5 hydrolysis responsible for observed trend. Increased ozone decreased dioxide (NO) facilitated formation N , proportion promoted uptake eventually enhanced conversion efficiency Our results highlight importance synergic control

Language: Английский

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Characteristics and sources of ambient Volatile Organic Compounds (VOCs) at a regional background site, YRD region, China: Significant influence of solvent evaporation during hot months

The Science of The Total Environment, Journal Year: 2022, Volume and Issue: 857, P. 159674 - 159674

Published: Oct. 22, 2022

Language: Английский

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