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

Nature Geoscience, Год журнала: 2023, Номер 16(3), С. 217 - 223

Опубликована: Янв. 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

Язык: Английский

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The unexpected high frequency of nocturnal surface ozone enhancement events over China: characteristics and mechanisms

Atmospheric chemistry and physics, Год журнала: 2022, Номер 22(23), С. 15243 - 15261

Опубликована: Ноя. 30, 2022

Abstract. Surface ozone concentrations typically peak during the daytime, driven by active photochemical production, and decrease gradually after sunset, due to chemical destruction dry deposition. Here, we report that nocturnal enhancement (NOE, defined as an increase of more than 5 ppbv h−1 in 1 any 2 adjacent hours between 20:00 06:00 LT, local time) events are observed at multiple monitoring sites China a high frequency, which has not been recognized previous studies. We present overview general characteristics NOE explore possible mechanisms based on 6 years observations from national network. find mean annual frequency is 41±10 % (i.e., about 140 d would experience event per year) averaged over all 814 Chinese 2014 2019, 46 larger Europe or United States. The higher industrialized city clusters (>50 %) regions with lighter pollution, it warm season (46 cold (36 %), consistent spatiotemporal evolution levels. reaches 37±6 season. enhancements within 5–15 85 events; however, 10 cases, increases can exceed 20 h−1. propose photochemistry-induced daytime provides rich source nighttime residual layer, determining overall China, enhanced atmospheric mixing then triggers allowing ozone-rich air layer mix into boundary layer. This supported our analyses show 70 (65 associated friction velocity (planetary height), indicative mixing, also sharp decreases surface NO2 CO events, typical signal Three case studies Beijing Guangzhou synoptic processes such convective storms low-level jets lead aggravating vertical mixing. Horizontal transport plumes may be supplementary driver events. Our results summarize, for first time, mechanism nationwide long-term observations, findings emphasize need direct measurements modeling

Язык: Английский

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Formation mechanism and control strategy for particulate nitrate in China

Journal of Environmental Sciences, Год журнала: 2022, Номер 123, С. 476 - 486

Опубликована: Сен. 26, 2022

Язык: Английский

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Significant Reductions in Secondary Aerosols after the Three-Year Action Plan in Beijing Summer

Environmental Science & Technology, Год журнала: 2023, Номер 57(42), С. 15945 - 15955

Опубликована: Окт. 12, 2023

Air quality in China has continuously improved during the Three-Year Action Plan (2018-2020); however, changes aerosol composition, properties, and sources Beijing summer remain poorly understood. Here, we conducted real-time measurements of composition five summers from 2018 to 2022 along with WRF-Community Multiscale Quality simulations characterize chemistry roles meteorology emission reductions. Largely different winter, secondary inorganic photochemical-related organic (SOA) showed significant decreases by 55-67% summer, most occurred 2021. Comparatively, primary species gaseous precursors were comparably small. While decreased atmospheric oxidation capacity as indicated ozone played an important role changing SOA large decrease liquid water small increase particle acidity critical for nitrate decreasing gas-particle partitioning substantially (∼28%). Analysis meteorological influences demonstrated clear similar transitions formation mechanisms at a relative humidity 50-60% summers. Model revealed that controls decisive reducing sulfate, OA, anthropogenic Plan, while affected more biogenic SOA.

Язык: Английский

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Nocturnal ozone enhancement in Shandong Province, China, in 2020–2022: Spatiotemporal distribution and formation mechanisms

The Science of The Total Environment, Год журнала: 2024, Номер 925, С. 171542 - 171542

Опубликована: Март 6, 2024

Язык: Английский

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Responses of sulfate and nitrate to anthropogenic emission changes in eastern China - in perspective of long-term variations

The Science of The Total Environment, Год журнала: 2022, Номер 855, С. 158875 - 158875

Опубликована: Сен. 18, 2022

Язык: Английский

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Polar Nitrated Aromatic Compounds in Urban Fine Particulate Matter: A Focus on Formation via an Aqueous-Phase Radical Mechanism

Environmental Science & Technology, Год журнала: 2023, Номер 57(13), С. 5160 - 5168

Опубликована: Март 20, 2023

Polar nitrated aromatic compounds (pNACs) are key ambient brown carbon chromophores; however, their formation mechanisms, especially in the aqueous phase, remain unclear. We developed an advanced technique for pNACs and measured 1764 atmospheric fine particulate matter sampled urban Beijing, China. Molecular formulas were derived 433 compounds, of which 17 confirmed using reference standards. Potential novel species with up to four rings a maximum five functional groups found. Higher concentrations detected heating season, median 82.6 ng m-3 Σ17pNACs. Non-negative matrix factorization analysis indicated that primary emissions particularly coal combustion dominant season. While non-heating aqueous-phase nitration could generate abundant carboxyl group, was by significant association aerosol liquid water content. Aqueous-phase 3- 5-nitrosalicylic acids instead isomer 4-hydroxy-3-nitrobenzoic acid suggests existence intermediate where intramolecular hydrogen bond favors kinetics-controlled NO2• nitration. This study provides not only promising pNAC measurement but also evidence formation, facilitating further evaluation pNACs' climatic effects.

Язык: Английский

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Changes in NO₃ Radical and Its Nocturnal Chemistry in Shanghai From 2014 to 2021 Revealed by Long‐Term Observation and a Stacking Model: Impact of China's Clean Air Action Plan

Journal of Geophysical Research Atmospheres, Год журнала: 2022, Номер 127(24)

Опубликована: Дек. 10, 2022

Abstract Nitrate radical (NO 3 ), an important nocturnal tropospheric oxidant, was observed continuously in the eastern Chinese megalopolis of Shanghai from July 2018 to August 2021using differential optical absorption spectroscopy equipped with LED lamp. To assess changes NO during implementation China's Clean Air Action Plan, a stacking model developed predict historical 2014 good performance. Combining and predicted data sets, highest concentration exceeded 300 pptv 2021, while monthly mean 36.2 ± 30.9 occurred summer 2017. The impact meteorology, precursors, emissions on evolution quantified using Kolmogorov‐Zurbenko filter. rapid increase annual 2017 caused by combination persistently high precursor O concentrations, insufficient SO 2 ‐represented primary pollutant reductions, meteorological conditions favorable . As clean air actions advanced further, significant CO‐represented emission reductions overcame significantly lowered levels between 2021. These efforts drastically affected chemistry, reducing loss rates approximately 30% both spring 2021 compared 2014, although were comparable years. In addition, substantial pollutants, as well effective management PM 2.5 , resulted varying decreases direct (removal reactions VOCs, etc.) indirect heterogeneous consumption N 5 ) losses, thereby moderating secondary aerosol formation.

Язык: Английский

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A review of gas-phase chemical mechanisms commonly used in atmospheric chemistry modelling

Journal of Environmental Sciences, Год журнала: 2022, Номер 123, С. 522 - 534

Опубликована: Окт. 31, 2022

Язык: Английский

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Evaluation of the first year of Pandora NO₂ measurements over Beijing and application to satellite validation

Atmospheric measurement techniques, Год журнала: 2024, Номер 17(2), С. 377 - 395

Опубликована: Янв. 19, 2024

Abstract. Nitrogen dioxide (NO2) is a highly photochemically reactive gas, has lifetime of only few hours, and at high concentrations harmful to human beings. Therefore, it important monitor NO2 with high-precision, time-resolved instruments. To this end, Pandora spectrometer been installed on the roof laboratory building Aerospace Information Research Institute Chinese Academy Sciences in Olympic Park, Beijing, China. The trace gases (including NO2, HCHO, O3) measured are made available through open-access database (https://data.pandonia-global-network.org/Beijing-RADI/Pandora171s1/, last access: 11 July 2023). In paper, an overview presented total tropospheric vertical column densities (VCDs) surface collected during first year operation, i.e., from August 2021 2022. data show that were winter low summer, diurnal cycle where reached minimum daytime. significantly lower 2022 Winter Olympics showing effectiveness emission control measures period. observations northerly winds, clean air transported Beijing concentrations, whereas southerly pollution surrounding areas high. contribution VCD varies daily seasonal timescales; monthly averages vary between 50 % 60 70 spring autumn. A comparison Pandora-measured collocated situ measurements using Thermo Scientific 42i-TL analyzer shows relationship Pandora-derived different for concentrations. Explanations these differences offered terms measurement techniques physical (transport) phenomena. use VCDs validation TROPOspheric Monitoring Instrument (TROPOMI) data, resampled 100 m × m, although average TROPOMI slightly lower, they well within expected error 0.5 Pmolec.cm-2 + (0.2 0.5) ⋅ VCDtrop (1 = 1 1015 molec cm−2). location instrument sub-orbital pixel 3.5 km 5.5 may result TROPOMI-derived 0.223 0.282 Pmolec.cm-2, 1.7 2 %. addition, also Beijing-RADI site representative area radius 10 km.

Язык: Английский

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