Particulate nitrate photolysis in the atmosphere

Environmental Science Atmospheres, Journal Year: 2022, Volume and Issue: 2(2), P. 111 - 127

Published: Jan. 1, 2022

Particulate nitrate photolysis can lead to the formation of secondary inorganic and organic aerosols that affect climate, air quality, human health.

Language: Английский

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Global Changes in Secondary Atmospheric Pollutants During the 2020 COVID‐19 Pandemic

Journal of Geophysical Research Atmospheres, Journal Year: 2021, Volume and Issue: 126(8)

Published: April 15, 2021

Abstract We use the global Community Earth System Model to investigate response of secondary pollutants (ozone O 3 , organic aerosols SOA) in different parts world modified emissions primary during COVID‐19 pandemic. quantify respective effects reductions NOx and volatile carbon (VOC) emissions, which, most cases, affect oxidants opposite ways. Using model simulations, we show that level has been reduced by typically 40% China February 2020 similar amounts many areas Europe North America mid‐March mid‐April 2020, good agreement with space surface observations. that, relative a situation which emission are ignored despite calculated increase hydroxyl peroxy radicals, ozone concentration increased only few NOx‐saturated regions (northern China, northern Europe, US) winter months pandemic when titration this molecule was reduced. In other regions, where is NOx‐controlled, decreased. SOA concentrations decrease concurrent reduction VOC emissions. The also shows atmospheric meteorological anomalies produced substantial variations chemical species for example, large fraction associated anomalies, while Plain, enhanced resulted primarily from pollutants.

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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The formation and mitigation of nitrate pollution: comparison between urban and suburban environments

Atmospheric chemistry and physics, Journal Year: 2022, Volume and Issue: 22(7), P. 4539 - 4556

Published: April 8, 2022

Abstract. Ambient nitrate has been of increasing concern in PM2.5, while there are still large uncertainties quantifying the formation aerosol. The pathways aerosol at an urban site and a suburban Pearl River Delta (PRD) investigated using observation-constrained box model. Throughout campaigns, pollution episodes were constantly accompanied with increase concentrations fractions both sites. simulations demonstrate that chemical reactions daytime night contributed significantly to boundary layer two However, nighttime predominantly occurred aloft residual site, downward transport from morning is important source (53 %) for surface whereas similar amounts produced nocturnal which results little ground site. We show was volatile-organic-compound-limited (VOC-limited) regime transition identical response ozone reduction VOC emissions can be efficient approach mitigate areas through influencing hydroxyl radical (OH) N2O5 production, will also beneficial synergistic control regional pollution. highlight relative importance site-specific, quantitative understanding various provide insights developing mitigation strategies.

Language: Английский

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Contributions of various driving factors to air pollution events: Interpretability analysis from Machine learning perspective

Environment International, Journal Year: 2023, Volume and Issue: 173, P. 107861 - 107861

Published: March 1, 2023

The air quality in China has been improved substantially, however fine particulate matter (PM2.5) still remain at a high level many areas. PM2.5 pollution is complex process that attributed to gaseous precursors, chemical, and meteorological factors. Quantifying the contribution of each variable can facilitate formulation effective policies precisely eliminate pollution. In this study, we first used decision plot map out Random Forest (RF) model for single hourly data set constructed framework analyzing causes using multiple interpretable methods. Permutation importance was qualitatively analyze effect on concentrations. sensitivity secondary inorganic aerosols (SIA): SO42-, NO3- NH4+ verified by Partial dependence (PDP). Shapley Additive Explanation (Shapley) quantify drivers behind ten events. RF accurately predict concentrations, with determination coefficient (R2) 0.94, root mean square error (RMSE) absolute (MAE) 9.4 μg/m3 5.7 μg/m3, respectively. This study revealed order SIA NH4+＞NO3-＞SO42-. Fossil fuel biomass combustion may be contributing factors events Zibo 2021 autumn-winter. contributed 19.9-65.4 among (APs). K, NO3-, EC OC were other main drivers, 8.7 ± 2.7 6.8 7.5 3.6 5.8 2.5 2.0 Lower temperature higher humidity vital promoted formation NO3-. Our provide methodological precise management.

Language: Английский

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Optimization of a NO_x and VOC Cooperative Control Strategy Based on Clean Air Benefits

Environmental Science & Technology, Journal Year: 2021, Volume and Issue: 56(2), P. 739 - 749

Published: Dec. 28, 2021

Serious ambient PM2.5 and O3 pollution is one of the most important environmental challenges China, necessitating an urgent cost-effective cocontrol strategy. Herein, we introduced a novel integrated assessment system to optimize NOx volatile organic compound (VOC) control strategy for synergistic reduction pollution. Focusing on Beijing–Tianjin–Hebei cities their surrounding regions, which are experiencing serious in found that emission (64–81%) essential attain air quality standard no matter how much VOC reduced. However, strongly recommended considering its substantially human health crop production benefits, estimated up 163 (PM2.5-related) 101 (O3-related) billion CHY during considerable emissions. Notably, such benefits will be greatly reduced if delayed. This study also highlights necessity simultaneous winter while enhancing summer, contrary current adopted China. These findings point out right pathways future policy making comitigating China other countries.

Language: Английский

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An unexpected large continental source of reactive bromine and chlorine with significant impact on wintertime air quality

National Science Review, Journal Year: 2020, Volume and Issue: 8(7)

Published: Dec. 25, 2020

Abstract Halogen atoms affect the budget of ozone and fate pollutants such as hydrocarbons mercury. Yet their sources significances in polluted continental regions are poorly understood. Here we report observation unprecedented levels (averaging at 60 parts per trillion) bromine chloride (BrCl) a mid-latitude site North China during winter. Widespread coal burning rural households photo-assisted process were primary source BrCl other gases. contributed about 55% both chlorine atoms. The halogen increased abundance ‘conventional’ tropospheric oxidants (OH, HO2 RO2) by 26%–73%, enhanced oxidation hydrocarbon nearly factor two net production 55%. Our study reveals significant role reactive winter atmospheric chemistry deterioration air quality where uncontrolled combustion is prevalent.

Language: Английский

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PM2.5 and O3 relationships affected by the atmospheric oxidizing capacity in the Yangtze River Delta, China

The Science of The Total Environment, Journal Year: 2021, Volume and Issue: 810, P. 152268 - 152268

Published: Dec. 10, 2021

Language: Английский

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Drivers for the poor air quality conditions in North China Plain during the COVID-19 outbreak

Atmospheric Environment, Journal Year: 2020, Volume and Issue: 246, P. 118103 - 118103

Published: Nov. 25, 2020

Language: Английский

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Diverse response of surface ozone to COVID-19 lockdown in China

The Science of The Total Environment, Journal Year: 2021, Volume and Issue: 789, P. 147739 - 147739

Published: May 15, 2021

Language: Английский

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