Ground-level ozone pollution in China: a synthesis of recent findings on influencing factors and impacts

Environmental Research Letters, Journal Year: 2022, Volume and Issue: 17(6), P. 063003 - 063003

Published: April 25, 2022

Abstract Ozone (O 3 ) in the troposphere is an air pollutant and a greenhouse gas. In mainland China, after Air Pollution Prevention Action Plan was implemented 2013—and despite substantial decreases concentrations of other pollutants—ambient O paradoxically increased many urban areas. The worsening pollution has fuelled numerous studies recent years, which have enriched knowledge about -related processes their impacts. this article, we synthesise key findings over 500 articles on China that were published past six years English-language journals. We focus changes concentrations, meteorological chemical drivers, complex responses to drastic decrease human activities during coronavirus disease 2019 lockdowns, several emerging processes, impacts crops trees, latest government interventions.

Language: Английский

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Global tropospheric halogen (Cl, Br, I) chemistry and its impact on oxidants

Atmospheric chemistry and physics, Journal Year: 2021, Volume and Issue: 21(18), P. 13973 - 13996

Published: Sept. 21, 2021

Abstract. We present an updated mechanism for tropospheric halogen (Cl + Br I) chemistry in the GEOS-Chem global atmospheric chemical transport model and apply it to investigate radical cycling implications oxidants. Improved representation of HOBr heterogeneous its pH dependence our simulation leads less efficient recycling mobilization bromine radicals enables include mechanistic sea salt aerosol debromination without generating excessive BrO. The resulting mean BrO mixing ratio is 0.19 ppt (parts per trillion), lower than previous versions GEOS-Chem. Model shows variable consistency biases comparison surface aircraft observations marine air, which are often near or below detection limit. underestimates daytime measurements Cl2 BrCl from ATom campaign over Pacific Atlantic, if correct would imply a very large missing primary source chlorine radicals. IO highest boundary layer uniform free troposphere, with 0.08 ppt, observations. modeled concentration Cl atoms 630 cm−3, contributing 0.8 % oxidation methane, 14 ethane, 8 propane, 7 higher alkanes. Halogen decreases burden ozone by 11 %, NOx 6 OH 4 %. Most decrease driven iodine-catalyzed loss. unbiased Southern Hemisphere but too low Northern Hemisphere.

Language: Английский

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Separating Daily 1 km PM_2.5 Inorganic Chemical Composition in China since 2000 via Deep Learning Integrating Ground, Satellite, and Model Data

Environmental Science & Technology, Journal Year: 2023, Volume and Issue: 57(46), P. 18282 - 18295

Published: April 28, 2023

Fine particulate matter (PM2.5) chemical composition has strong and diverse impacts on the planetary environment, climate, health. These effects are still not well understood due to limited surface observations uncertainties in model simulations. We developed a four-dimensional spatiotemporal deep forest (4D-STDF) estimate daily PM2.5 at spatial resolution of 1 km China since 2000 by integrating measurements species from high-density observation network, satellite retrievals, atmospheric reanalyses, Cross-validation results illustrate reliability sulfate (SO42-), nitrate (NO3-), ammonium (NH4+), chloride (Cl-) estimates, with high coefficients determination (CV-R2) ground-based 0.74, 0.75, 0.71, 0.66, average root-mean-square errors (RMSE) 6.0, 6.6, 4.3, 2.3 μg/m3, respectively. The three components secondary inorganic aerosols (SIAs) account for 21% 20% 14% (NH4+) total mass eastern China; we observed significant reductions 40-43% between 2013 2020, slowing down 2018. Comparatively, ratio SIA increased 7% across except Beijing nearby areas, accelerating recent years. SO42- been dominant component China, although it was surpassed NO3- some e.g., Beijing-Tianjin-Hebei region 2016. SIA, accounting nearly half (∼46%) mass, drove explosive formation winter haze episodes North Plain. A sharp decline concentrations an increase SIA-to-PM2.5 ratios during COVID-19 lockdown were also revealed, reflecting enhanced oxidation capacity particles.

Language: Английский

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Pollution-Derived Br₂ Boosts Oxidation Power of the Coastal Atmosphere

Environmental Science & Technology, Journal Year: 2022, Volume and Issue: 56(17), P. 12055 - 12065

Published: Aug. 10, 2022

The bromine atom (Br•) has been known to destroy ozone (O3) and accelerate the deposition of toxic mercury (Hg). However, its abundance sources outside polar regions are not well-known. Here, we report significant levels molecular (Br2)─a producer Br•─observed at a coastal site in Hong Kong, with an average noontime mixing ratio 5 ppt. Given short lifetime Br2 (∼1 min noon), this finding reveals large daytime source. On basis laboratory field evidence, show that observed is generated by photodissociation particulate nitrate (NO3-) reactive uptake dinitrogen pentoxide (N2O5) on aerosols important nighttime Model-calculated Br• concentrations comparable OH radical─the primary oxidant troposphere, accounting for 24% oxidation isoprene, 13% increase net O3 production, nearly 10-fold production rate HgII. Our findings reveal bromines play larger role atmospheric chemistry air quality polluted maritime areas than previously thought. results also suggest tightening control emissions two conventional pollutants (NOx SO2)─thereby decreasing aerosol acidity─would alleviate halogen radical adverse impact quality.

Language: Английский

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Atmospheric NOx oxidation as major sources for nitrous acid (HONO)

npj Climate and Atmospheric Science, Journal Year: 2023, Volume and Issue: 6(1)

Published: April 11, 2023

Abstract Nitrous acid (HONO) is the major precursor of hydroxyl (OH) radicals to initiate tropospheric chemistry leading formation secondary pollutants. The sources atmospheric HONO, however, are not fully understood. Here we show two additional HONO that stem from oxidation nitrogen oxide (NO x = NO + 2 ). Nitric (HNO 3 ) formed photooxidation can be converted into with a yield ~53%, and dark by in presence H O produces 2%. diurnal variations levels field observations urban (Beijing) rural (Wangdu) areas North China Plain well reproduced WRF-Chem model when new taken account. findings imply pathways for which significantly accelerate ozone polluted regions as well.

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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Characteristics, Origins, and Atmospheric Processes of Amines in Fine Aerosol Particles in Winter in China

Journal of Geophysical Research Atmospheres, Journal Year: 2023, Volume and Issue: 128(14)

Published: July 9, 2023

Abstract Amines affect particle formation, aerosol acidity, nitrogen cycle, and climate change. However, little is known about the temporal spatial differences in composition, source, formation process of amines fine particulate matter (PM 2.5 ) different regions China. Seven (amine salts) were investigated PM collected Yangtze River Delta (YRD, Shanghai Nanjing), Pearl (PRD, Guangzhou), northern China (Xi'an Haerbin), background (Puding) areas winter 2017–2018. Methylamine was dominant amine species at YRD, China, sites, while diethylamine dominated PRD site; moreover, mass concentration fraction lowest site. These results could be attributed to changes sources atmospheric processes. Further, coal combustion biomass burning found important contributors cities winter. The contribution weakened other urban sites. In contrast, abundance site largely controlled by biogenic sources. Acid‐base chemistry displacement mechanism tightly associated with salts all particular, degradation hydroxyl radical (•OH) significant Nanjing, Guangzhou, Xi'an, Haerbin insignificant photochemical sites can explained differentiated sources, meteorological conditions, •OH levels. Overall, our findings deepen understanding origins processes amines.

Language: Английский

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Reactive Chlorine Species Advancing the Atmospheric Oxidation Capacities of Inland Urban Environments

Environmental Science & Technology, Journal Year: 2023, Volume and Issue: 57(39), P. 14638 - 14647

Published: Sept. 22, 2023

Chlorine (Cl) radicals from photolabile chlorine species are highly reactive and can affect the fate of air pollutants in atmosphere. Although several campaigns have been conducted, typically coastal environments, long-term observations their impacts on atmospheric oxidation capacities (AOCs) lacking. Here, we report nearly full-year Cl2 ClNO2 levels Beijing evaluate AOC with a box model coupled Cl chemistry. promote circulation OH–HO2–RO2 by accelerating OH chain lengths up to 12.6% average, hence boosting AOC, especially winter or spring. This promotion effect is nonlinearly dependent VOC NOx concentrations, thus leading slight shift ozone formation VOC-sensitive regime transition seasonal differences. Given ubiquitous chlorines polluted inland urban regions, AOCs secondary will be underestimated if neglected.

Language: Английский

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Morphogenetic Abnormalities of Bryobionts in Geochemically Contrasting Conditions of Donbass

Geochemistry International, Journal Year: 2023, Volume and Issue: 61(10), P. 1036 - 1047

Published: Oct. 1, 2023

Language: Английский

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The impacts of regional transport on anthropogenic source contributions of PM2.5 in a basin city, China

The Science of The Total Environment, Journal Year: 2024, Volume and Issue: 917, P. 170038 - 170038

Published: Jan. 19, 2024

Language: Английский

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