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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Why is ozone in South Korea and the Seoul metropolitan area so high and increasing?

Atmospheric chemistry and physics, Journal Year: 2023, Volume and Issue: 23(7), P. 4031 - 4044

Published: April 5, 2023

Abstract. Surface ozone pollution in South Korea has increased over the past 2 decades, despite efforts to decrease emissions, and is pervasively exceedance of maximum daily 8 h average (MDA8) standard 60 ppb. Here, we investigate 2015–2019 trends surface NO2 concentrations Seoul metropolitan area (SMA), focusing on 90th percentile MDA8 as an air quality metric. We use a random forest algorithm remove effect meteorological variability find increase up 1.5 ppb a−1 April–May, while decreases by 22 %. Global 3-D atmospheric chemistry model simulations including recent chemical updates can successfully simulate China well very high free-tropospheric observed above km altitude (mean 75 May–June) reproduce emission-driven trend SMA its seasonality. Further investigation for May, when meteorology-corrected are highest, reveals that NOx emissions main driver increase. Although this result implies decreasing volatile organic compound (VOC) necessary ozone, would still remain 80 even if all anthropogenic were shut off. contributes only elevated background, ship contribute few parts per billion. Zeroing out East Asia indicates remarkably external background 56 ppb, consistent with free troposphere, implying not practically achievable unless be decreased.

Language: Английский

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Soil Emissions of Reactive Nitrogen Accelerate Summertime Surface Ozone Increases in the North China Plain

Environmental Science & Technology, Journal Year: 2023, Volume and Issue: 57(34), P. 12782 - 12793

Published: Aug. 19, 2023

Summertime surface ozone in China has been increasing since 2013 despite the policy-driven reduction fuel combustion emissions of nitrogen oxides (NOx). Here we examine role soil reactive (Nr, including NOx and nitrous acid (HONO)) 2013-2019 increase over North Plain (NCP), using GEOS-Chem chemical transport model simulations. We update add HONO based on observation-constrained parametrization schemes. The estimates significant daily maximum 8 h average (MDA8) enhancement from Nr 8.0 ppbv NCP 5.5 June-July 2019. identify a strong competing effect between sources production region. find that accelerate by 3.0 ppbv. contribution, however, is not primarily driven weather-induced increases emissions, but concurrent decreases which enhance efficiency pushing toward more NOx-sensitive regime. Our results reveal an important indirect emission trends highlighting necessity to consider interaction anthropogenic biogenic mitigation Plain.

Language: Английский

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Particulate Nitrate Photolysis as a Possible Driver of Rising Tropospheric Ozone

Geophysical Research Letters, Journal Year: 2024, Volume and Issue: 51(5)

Published: March 8, 2024

Abstract Tropospheric ozone is an air pollutant and a greenhouse gas whose anthropogenic production limited principally by the supply of nitrogen oxides (NO x ) from combustion. in northern hemisphere has been rising despite flattening NO emissions recent decades. Here we propose that this sustained increase could result photolysis nitrate particles (pNO 3 − to regenerate . Including pNO GEOS‐Chem atmospheric chemistry model improves consistency with observations. Our simulations show concentrations have increased since 1960s because ammonia falling SO 2 emissions, augmenting extratropics about 50% better match observed trend. will likely continue through 2050, which would drive continued even as decrease. More work needed understand mechanism rates photolysis.

Language: Английский

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Stratospheric influence on surface ozone pollution in China

Nature Communications, Journal Year: 2024, Volume and Issue: 15(1)

Published: May 14, 2024

Abstract Events of stratospheric intrusions to the surface (SITS) can lead severe ozone (O 3 ) pollution. Still, what extent SITS events impact O on a national scale over years remains long-lasting question, mainly due difficulty resolving three key metrics: frequency, duration and intensity. Here, we identify 27,616 China during 2015-2022 based spatiotemporally dense measurements carbon monoxide, two effective indicators SITS. An overview metrics is presented, illustrating large influences in China. We find that occur preferentially high-elevation regions, while those plain regions are more intense. enhances by 20 ppbv average, contributing 30-45% periods. Nationally, SITS-induced peaks spring autumn, 70% warm months exacerbate Over 2015-2022, shows declining trend. Our observation-based results have implications for mitigation policies short long terms.

Language: Английский

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Investigation on ozone formation mechanism and control strategy of VOCs in petrochemical region: Insights from chemical reactivity and photochemical loss

The Science of The Total Environment, Journal Year: 2024, Volume and Issue: 914, P. 169891 - 169891

Published: Jan. 6, 2024

Language: Английский

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Multidecadal ozone trends in China and implications for human health and crop yields: a hybrid approach combining a chemical transport model and machine learning

Atmospheric chemistry and physics, Journal Year: 2024, Volume and Issue: 24(1), P. 345 - 366

Published: Jan. 11, 2024

Abstract. Surface ozone (O3) is well known for posing significant threats to both human health and crop production worldwide. However, a multidecadal assessment of the impacts O3 on public yields in China lacking due insufficient long-term continuous observations. In this study, we used machine learning (ML) algorithm correct biases concentrations simulated by chemical transport model from 1981–2019 integrating multi-source datasets. The ML-enabled bias correction offers improved performance reproducing observed thus further improves our estimates yields. warm-season trends increasing Beijing–Tianjin–Hebei its surroundings (BTHs) as Yangtze River Delta (YRD), Sichuan Basin (SCB), Pearl (PRD) regions are 0.32, 0.63, 0.84, 0.81 µg m−3 yr−1 1981 2019, respectively. more recent years, experienced fluctuations four major regions. Our results show that only BTHs have perceptible trend during 2013–2019. Using accumulated over threshold 40 ppb (AOT40-China) exposure–yield response relationships, estimated relative yield losses (RYLs) wheat, rice, soybean, maize 17.6 %, 13.8 11.3 7.3 % 1981, 24.2 17.5 16.3 9.8 with an rate +0.03 yr−1, +0.04 +0.27 +0.13 annual all-cause premature deaths induced increased ∼55 900 ∼162 000 2019 ∼2980 per year. related respiratory cardiovascular disease ∼34 200 ∼40 300 1998 ∼26 500 ∼79 having change −546 +1770 year 1998–2019, first time, ML provide robust dataset past 4 decades China, enabling evaluation O3-induced impacts. These findings expected fill gap impact China.

Language: Английский

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Continuing benefits of the Montreal Protocol and protection of the stratospheric ozone layer for human health and the environment

Photochemical & Photobiological Sciences, Journal Year: 2024, Volume and Issue: 23(6), P. 1087 - 1115

Published: May 19, 2024

Abstract The protection of Earth’s stratospheric ozone (O 3 ) is an ongoing process under the auspices universally ratified Montreal Protocol and its Amendments adjustments. A critical part this assessment environmental issues related to changes in O . United Nations Environment Programme’s Environmental Effects Assessment Panel provides annual scientific evaluations some key arising recent collective knowledge base. This current update includes a comprehensive incidence rates skin cancer, cataract other eye diseases observed worldwide; effects UV radiation on tropospheric oxidants, air water quality; trends breakdown products fluorinated chemicals information their toxicity; technological innovations building materials for greater resistance radiation. These span wide range topics, including both harmful beneficial exposure radiation, complex interactions with climate change. While has succeeded preventing large reductions , future may occur due number natural anthropogenic factors. Thus, frequent assessments potential impacts are essential ensure that policies remain based best available knowledge. Graphical abstract

Language: Английский

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Understanding recent tropospheric ozone trends in the context of large internal variability: a new perspective from chemistry-climate model ensembles

Environmental Research Climate, Journal Year: 2022, Volume and Issue: 1(2), P. 025008 - 025008

Published: Oct. 22, 2022

Abstract Observational records of meteorological and chemical variables are imprinted by an unknown combination anthropogenic activity, natural forcings, internal variability. With a 15-member initial-condition ensemble generated from the CESM2-WACCM6 chemistry-climate model for 1950–2014, we extract signals (‘forced’) change noise internally arising climate variability on observed tropospheric ozone trends. Positive trends in free measured at long-term surface observatories, commercial aircraft, retrieved satellite instruments generally fall within range. also bracketed those larger constructed five additional models. Comparison multi-model with column northern tropics implies underestimate regional precursor emission growth over recent decades. clearly emerge 1950 to 2014, exceeding 0.2 DU yr −1 20–40 N all members. Tropospheric observations often only available decades, show that even two-decade record length is insufficient eliminate role variability, which can produce oppositely signed mean (forced) changes. By identifying regions seasons strong relative ensembles guide future observing systems seeking detect change. For example, analysis reveals year-round upper increases 1995 largest 30 S–40 during boreal summer. Lower most strongly winter hemisphere, leads opposite sign (ensemble overlaps zero) north 40 This decoupling lower troposphere suggests growing prominence as greenhouse gas despite efforts abate warm season ground-level ozone.

Language: Английский

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Diverging Ozone Trends Above Western North America: Boundary Layer Decreases Versus Free Tropospheric Increases

Journal of Geophysical Research Atmospheres, Journal Year: 2023, Volume and Issue: 128(8)

Published: April 4, 2023

Abstract This study has produced an improved percentile and seasonal (median) trend estimate of free tropospheric ozone above western North America (WNA), through a data fusion ozonesonde, lidar, commercial aircraft, field campaign measurements. Our method combines heterogeneous sets according to the consensus characteristics inherent uncertainty in order produce our best fused product. In response different collection environments (in situ or ground‐based), we investigate variability based on wide range percentiles, which is preferable for detection due ozone's high degree heteroscedasticity (i.e., inconsistent trends between percentiles). We then compare California sub‐domain full WNA region better understanding correlations regional scales. California, 1995–2021 (from 5th 95th) are clearly positive terms signal‐to‐noise ratios. The magnitude generally weaker over compared but reliable can still be found 10th 70th as well winter summer, whereas autumn shows negative same period. addition, dozens rural surface sites across selected represent boundary layer variability. contrast increasing ozone, find overall strong since 1995, with greatest divergence summer. Throughout analysis implications COVID‐19 economic downturn discussed.

Language: Английский

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