Persistent sulfate formation from London Fog to Chinese haze

Proceedings of the National Academy of Sciences, Journal Year: 2016, Volume and Issue: 113(48), P. 13630 - 13635

Published: Nov. 14, 2016

Significance Exceedingly high levels of fine particulate matter (PM) occur frequently in China, but the mechanism severe haze formation remains unclear. From atmospheric measurements two Chinese megacities and laboratory experiments, we show that oxidation SO 2 by NO occurs efficiently aqueous media under polluted conditions: first, during 1952 London Fog via in-cloud oxidation; second, on PM with NH 3 neutralization China. We suggest effective mitigation is achievable intervening sulfate process emission control measures. Hence, our results explain outstanding sulfur problem historic elucidate chemical

Language: Английский

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Formation of Urban Fine Particulate Matter

Chemical Reviews, Journal Year: 2015, Volume and Issue: 115(10), P. 3803 - 3855

Published: May 5, 2015

ADVERTISEMENT RETURN TO ISSUEPREVReviewNEXTFormation of Urban Fine Particulate MatterRenyi Zhang*†§, Gehui Wang†∥, Song Guo†§, Misti L. Zamora†, Qi Ying‡, Yun Lin†, Weigang Wang†⊥, Min Hu§, and Yuan Wang#View Author Information† †Departments Atmospheric Sciences Chemistry ‡Department Civil Engineering, Texas A&M University, College Station, 77843, United States§ State Key Joint Laboratory Environmental Simulation Pollution Control, Peking Beijing 100871, People's Republic China⊥ ∥Key Aerosol Physics Chemistry, Loess Quaternary Geology, Institute Earth Environment, ⊥State for Structural Unstable Stable Species, National Molecular (BNLMS), Chinese Academy Sciences, 100864, China# Jet Propulsion Laboratory, California Technology, Pasadena, 91125, States*E-mail: [email protected]Cite this: Chem. Rev. 2015, 115, 10, 3803–3855Publication Date (Web):May 5, 2015Publication History Received2 February 2015Published online5 May inissue 27 2015https://pubs.acs.org/doi/10.1021/acs.chemrev.5b00067https://doi.org/10.1021/acs.chemrev.5b00067review-articleACS PublicationsCopyright © 2015 American Chemical SocietyRequest reuse permissionsArticle Views17488Altmetric-Citations927LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum full text article downloads since November 2008 (both PDF HTML) across all institutions individuals. These metrics regularly updated to reflect usage leading up last few days.Citations number other articles citing this article, calculated by Crossref daily. Find more information about citation counts.The Altmetric Attention Score is a quantitative measure attention that research has received online. Clicking on donut icon will load page at altmetric.com with additional details score social media presence given article. how calculated. Share Add toView InAdd Full Text ReferenceAdd Description ExportRISCitationCitation abstractCitation referencesMore Options onFacebookTwitterWechatLinked InRedditEmail Other access optionsGet e-Alertsclose SUBJECTS:Aerosols,Anions,Nanoparticles,Particulate matter,Volatile organic compounds Get e-Alerts

Language: Английский

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Reactive nitrogen chemistry in aerosol water as a source of sulfate during haze events in China

Science Advances, Journal Year: 2016, Volume and Issue: 2(12)

Published: Dec. 2, 2016

Fine-particle pollution associated with winter haze threatens the health of more than 400 million people in North China Plain. Sulfate is a major component fine particles. Record sulfate concentrations up to ~300 μg m-3 were observed during January 2013 event Beijing. State-of-the-art air quality models that rely on production mechanisms requiring photochemical oxidants cannot predict these high levels because weak photochemistry activity events. We find missing source and particulate matter can be explained by reactive nitrogen chemistry aerosol water. The water serves as reactor, where alkaline components trap SO2, which oxidized NO2 form sulfate, whereby reaction rates are sustained neutralizing capacity atmosphere northern China. This mechanism self-amplifying higher mass concentration corresponds content, leading faster severe pollution.

Language: Английский

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Identifying airborne transmission as the dominant route for the spread of COVID-19

Proceedings of the National Academy of Sciences, Journal Year: 2020, Volume and Issue: 117(26), P. 14857 - 14863

Published: June 11, 2020

Various mitigation measures have been implemented to fight the coronavirus disease 2019 (COVID-19) pandemic, including widely adopted social distancing and mandated face covering. However, assessing effectiveness of those intervention practices hinges on understanding virus transmission, which remains uncertain. Here we show that airborne transmission is highly virulent represents dominant route spread disease. By analyzing trend in Wuhan, China, Italy, New York City, from January 23 May 9, 2020, illustrate impacts are discernable trends pandemic. Our analysis reveals difference with without covering determinant shaping pandemic three epicenters. This protective measure alone significantly reduced number infections, is, by over 78,000 Italy April 6 9 66,000 City 17 9. Other measures, such as United States, insufficient themselves protecting public. We conclude wearing masks public corresponds most effective means prevent interhuman this inexpensive practice, conjunction simultaneous distancing, quarantine, contact tracing, likely fighting opportunity stop COVID-19 work also highlights fact sound science essential decision-making for current future health pandemics.

Language: Английский

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Severe haze in northern China: A synergy of anthropogenic emissions and atmospheric processes

Proceedings of the National Academy of Sciences, Journal Year: 2019, Volume and Issue: 116(18), P. 8657 - 8666

Published: April 15, 2019

Significance Severe haze events with large temporal/spatial coverages have occurred frequently in wintertime northern China. These extremes result from a complex interplay between emissions and atmospheric processes provide unique scientific platform to gain insights into many aspects of the relevant chemistry physics. Here we synthesize recent progress understanding severe formation In particular, highlight that improved emission sources, physical/chemical during evolution, interactions meteorological/climatic changes are necessary unravel causes, mechanisms, trends for pollution. This viewpoint established on basis sound science is critical improving prediction/forecast, formulating effective regulatory policies by decision makers, raising public awareness environmental protection.

Language: Английский

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Fine particulate matter (PM2.5) in China at a city level

Scientific Reports, Journal Year: 2015, Volume and Issue: 5(1)

Published: Oct. 15, 2015

Abstract This study presents one of the first long term datasets including a statistical summary PM 2.5 concentrations obtained from one-year monitoring in 190 cities China. We found only 25 out could meet National Ambient Air Quality Standards China and population-weighted mean Chinese are 61 μg/m 3 , ~3 times as high global mean, highlighting health risk. generally higher north than south regions due to relative large emissions unfavorable meteorological conditions for pollution dispersion. A remarkable seasonal variability is observed with highest during winter lowest summer. Due enhanced contributions dust particles open biomass burning, abundances also spring (in Northwest West Central China) autumn East China), respectively. In addition, we often occurs afternoon evening hours, respectively, associated daily variation boundary layer depth anthropogenic emissions. The diurnal distribution -to-CO ratio consistently displays pronounced peak periods, reflecting significant contribution secondary formation.

Language: Английский

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Enhanced haze pollution by black carbon in megacities in China

Geophysical Research Letters, Journal Year: 2016, Volume and Issue: 43(6), P. 2873 - 2879

Published: March 1, 2016

Abstract Aerosol‐planetary boundary layer (PBL) interactions have been found to enhance air pollution in megacities China. We show that black carbon (BC) aerosols play the key role modifying PBL meteorology and hence enhancing haze pollution. With model simulations data analysis from various field observations December 2013, we demonstrate BC induces heating PBL, particularly upper resulting decreased surface heat flux substantially depresses development of consequently enhances occurrences extreme episodes. define this process as “dome effect” suggest an urgent need for reducing emissions efficient way mitigate

Language: Английский

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Enhanced secondary pollution offset reduction of primary emissions during COVID-19 lockdown in China

National Science Review, Journal Year: 2020, Volume and Issue: 8(2)

Published: June 16, 2020

To control the spread of 2019 novel coronavirus (COVID-19), China imposed nationwide restrictions on movement its population (lockdown) after Chinese New Year 2020, leading to large reductions in economic activities and associated emissions. Despite such decreases primary pollution, there were nonetheless several periods heavy haze pollution eastern China, raising questions about well-established relationship between human air quality. Here, using comprehensive measurements modeling, we show that during COVID lockdown was driven by enhancements secondary pollution. In particular, NOx emissions from transportation increased ozone nighttime NO3 radical formation, these increases atmospheric oxidizing capacity turn facilitated formation particulate matter. Our results, afforded tragic natural experiment COVID-19 pandemic, indicate mitigation depends upon a coordinated balanced strategy for controlling multiple pollutants.

Language: Английский

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Aerosol and boundary-layer interactions and impact on air quality

National Science Review, Journal Year: 2017, Volume and Issue: 4(6), P. 810 - 833

Published: Sept. 16, 2017

Abstract Air quality is concerned with pollutants in both the gas phase and solid or liquid phases. The latter are referred to as aerosols, which multifaceted agents affecting air quality, weather climate through many mechanisms. Unlike pollutants, aerosols interact strongly meteorological variables strongest interactions taking place planetary boundary layer (PBL). PBL hosting bulk of lower atmosphere affected by aerosol radiative effects. Both scattering absorption reduce amount solar radiation reaching ground thus sensible heat fluxes that drive diurnal evolution PBL. Moreover, can increase atmospheric stability inducing a temperature inversion result radiation, suppresses dispersion leads further increases concentration Such positive feedback especially strong during severe pollution events. Knowledge crucial for understanding between meteorology. A key question how interacts vertical directions, affects quality. We review major advances measurements, processes their each other complex mechanisms, highlight priorities future studies.

Language: Английский

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Aerosol and monsoon climate interactions over Asia

Reviews of Geophysics, Journal Year: 2016, Volume and Issue: 54(4), P. 866 - 929

Published: Sept. 10, 2016

Abstract The increasing severity of droughts/floods and worsening air quality from aerosols in Asia monsoon regions are the two gravest threats facing over 60% world population living Asian regions. These dual have fueled a large body research last decade on roles impacting weather climate. This paper provides comprehensive review studies aerosols, monsoons, their interactions. region is primary source emissions diverse species both anthropogenic natural origins. distributions aerosol loading strongly influenced by distinct climatic regimes, which are, turn, modulated effects. On continental scale, reduce surface insolation weaken land‐ocean thermal contrast, thus inhibiting development monsoons. Locally, radiative effects alter thermodynamic stability convective potential lower atmosphere leading to reduced temperatures, increased atmospheric stability, weakened wind circulations. state, determines formation clouds, convection, precipitation, may also be altered serving as cloud condensation nuclei or ice nuclei. Absorbing such black carbon desert dust induce dynamical feedback processes, strengthening early affecting subsequent evolution monsoon. Many mechanisms been put forth regarding how modulate amplitude, frequency, intensity, phase different climate variables. A wide range theoretical, observational, modeling findings monsoon, interactions synthesized. new paradigm proposed investigating aerosol‐monsoon interactions, dust, biomass burning, biogenic vegetation considered integral components an intrinsic system, subject external forcing global warming, land use change. Future calls for integrated approach international collaborations based long‐term sustained observations, process measurements, improved models, well using observations constrain model simulations projections.

Language: Английский

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