Increased night-time oxidation over China despite widespread decrease across the globe

Nature Geoscience, Journal Year: 2023, Volume and Issue: 16(3), P. 217 - 223

Published: Jan. 26, 2023

Nitrogen oxides (NOx = NO + NO2) emitted from combustion and natural sources are reactive gases that regulate the composition of Earth's atmosphere. Nocturnal oxidation driven by nitrate radicals is an important but poorly understood process in atmospheric chemistry, affecting lifetimes NOx ozone particulate pollution levels. Understanding trends to formulating effective mitigation strategies understanding influence on climate. Here we analyse publicly available monitoring data assess production rates surface 2014 2021 across globe. We show have undergone strong increases China during 2014–2019 exhibited modest decreases United States European Union. Accelerated night-time has shortened lifetime summer 30% 2014–2019. This change will strongly affect formation policy implications for joint control fine pollution. Measurements increased decreased Union 2019. suggests increasing contribution air

Language: Английский

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Insufficient Condensable Organic Vapors Lead to Slow Growth of New Particles in an Urban Environment

Environmental Science & Technology, Journal Year: 2022, Volume and Issue: 56(14), P. 9936 - 9946

Published: June 24, 2022

Atmospheric new particle formation significantly affects global climate and air quality after newly formed particles grow above ∼50 nm. In polluted urban atmospheres with 1-3 orders of magnitude higher rates than those in clean atmospheres, growth are comparable or even lower for reasons that were previously unclear. Here, we address the slow Beijing advanced measurements size-resolved molecular composition nanoparticles using thermal desorption chemical ionization mass spectrometer gas precursors nitrate CI-APi-ToF. A model combining condensational particle-phase acid-base chemistry was developed to explore mechanisms. The 8-40 nm during events is dominated by organics (∼80%) sulfate (∼13%), remainder from base compounds, nitrate, chloride. With increase sizes, fraction decreases, while slow-desorbed organics, organic acids, increases. simulated consistent measured results most cases, they both indicate vapors H2SO4 major pathway reactions play a minor role. comparison high concentrations gaseous sulfuric acid amines cause rates, concentration condensable comparably under NOx levels, relatively high-volatility nitrogen-containing oxidation products higher. insufficient lead growth, which further causes low survival environments. Thus, some extent, counteract impact on

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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Increasing contribution of nighttime nitrogen chemistry to wintertime haze formation in Beijing observed during COVID-19 lockdowns

Nature Geoscience, Journal Year: 2023, Volume and Issue: 16(11), P. 975 - 981

Published: Oct. 12, 2023

Language: Английский

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Photocatalytic O2 activation carried out by organic aerosol: A case study of 1, 8-naphthalic anhydride

Applied Catalysis B Environment and Energy, Journal Year: 2024, Volume and Issue: 349, P. 123889 - 123889

Published: April 24, 2024

Language: Английский

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Novel Triple-Oxygen Isotope Study Indicates Unprecedented Ozone–Particulate Interaction Pathways in Atmospheric Pollution Chemistry

ACS Omega, Journal Year: 2025, Volume and Issue: 10(5), P. 4388 - 4394

Published: Jan. 31, 2025

Ozone plays a fundamental role in the chemistry of atmosphere, mediating oxidation reactions phases and at phase boundaries. Here, we investigate least-explored solid-phase heterogeneous processes involving ozone to understand reaction pathways O3 with airborne aerosols. Using triple oxygen isotope ratios as tracers, found that oxidizes organic particles produces carbon dioxide, atoms largely from O3. Along formation CO2, an equal amount O2 water decomposition is inferred. Chemical kinetics, however, yet be identified. One hypothetical pathway through Criegee intermediates, formed by aldehyde/ketone-like compounds (unsaturated hydrocarbons) catalyzed metal oxides. Inclusion process chemistry-transport model could yield significant change budget. The study shows importance ozone-induced chemical on aerosol surfaces occurring polluted atmospheres.

Language: Английский

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Promotion Effect of Strong CeO2/Co3O4 Interfacial Interaction for Light Alkane Catalytic Removal

Applied Catalysis B Environment and Energy, Journal Year: 2025, Volume and Issue: unknown, P. 125150 - 125150

Published: Feb. 1, 2025

Language: Английский

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Fate of Oxygenated Volatile Organic Compounds in the Yangtze River Delta Region: Source Contributions and Impacts on the Atmospheric Oxidation Capacity

Environmental Science & Technology, Journal Year: 2022, Volume and Issue: 56(16), P. 11212 - 11224

Published: Aug. 4, 2022

The Community Multiscale Air Quality model (CMAQv5.2) was implemented to investigate the sources and sinks of oxygenated volatile organic compounds (OVOCs) during a high O3 PM2.5 season in Yangtze River Delta (YRD) region, based on constraints from observations. tends overpredict non-oxygenated VOCs underpredict OVOCs, which has been improved with adjusted emissions all VOCs. OVOCs YRD are dominated by ketones, aldehydes, alcohols. Ketones aldehydes mainly originate direct secondary formation northern YRD, primarily southern part influenced biogenic emissions. concentration aerosols (SOA) produced is 0.5-1.5 μg/m3, 40-80% originated nitrates, 20-70% dicarbonyls, 0-20% isoprene epoxydiols. influences atmospheric oxidation capacity OH• pathway day (∼350%) NO3• at night (∼150%). Consequently, enhanced 30-70% YRD. Aerosols also 50-140%, 20-80%, ∼20% for SOA, nitrate, sulfate, respectively.

Language: Английский

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Evidence for Reducing Volatile Organic Compounds to Improve Air Quality from Concurrent Observations and In Situ Simulations at 10 Stations in Eastern China

Environmental Science & Technology, Journal Year: 2022, Volume and Issue: 56(22), P. 15356 - 15364

Published: Oct. 31, 2022

Ground-level ozone (O3) has been an emerging air pollution in China and interacts with fine particulate matters (PM2.5). We synthesized observations of O3 its precursors two summer months 2020 at 10 sites the Zhejiang province, East simulated situ photochemistry. northeastern province was more serious than that southwest. The site-average daytime increment correlated well (R2 = 0.73) total reactivity volatile organic compounds (VOCs) carbon monoxide toward hydroxyl radical (OH) urban areas. Model simulation revealed main function nitrogen oxides (NOx) rural where isoprene accounted for >85% OH VOCs to facilitate cycling. With NOx reduction from 0 90%, self-reactions between peroxy radicals (Self-Rxns), a proven pathway secondary aerosol formation, were intensified by up 23-fold NOx-rich environment. In contrast, reducing could weaken Self-Rxns while production rate atmospheric oxidation capacity. This study observes simulates chemistry based on extensive measurements typical Chinese cities, highlighting necessity co-benefit PM2.5.

Language: Английский

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