Fast sulfate formation from oxidation of SO2 by NO2 and HONO observed in Beijing haze

Nature Communications, Journal Year: 2020, Volume and Issue: 11(1)

Published: June 5, 2020

Abstract Severe events of wintertime particulate air pollution in Beijing (winter haze) are associated with high relative humidity (RH) and fast production sulfate from the oxidation sulfur dioxide (SO 2 ) emitted by coal combustion. There has been considerable debate regarding mechanism for SO oxidation. Here we show evidence field observations a haze event that rapid nitrogen (NO nitrous acid (HONO) takes place, latter producing oxide (N O). Sulfate shifts to larger particle sizes during event, indicative fog/cloud processing. Fog cloud readily form under winter conditions, leading liquid water contents pH (>5.5) elevated ammonia. Such conditions enable aqueous-phase NO , HONO which can turn oxidize yield N O.This could provide an explanation formation some conditions.

Language: Английский

---

Sulfate formation is dominated by manganese-catalyzed oxidation of SO2 on aerosol surfaces during haze events

Nature Communications, Journal Year: 2021, Volume and Issue: 12(1)

Published: March 31, 2021

Abstract The formation mechanism of aerosol sulfate during wintertime haze events in China is still largely unknown. As companions, SO 2 and transition metals are mainly emitted from coal combustion. Here, we argue that the metal-catalyzed oxidation on surfaces could be dominant pathway investigate this hypothesis by integrating chamber experiments, numerical simulations in-field observations. Our analysis shows contribution manganese-catalyzed approximately one to two orders magnitude larger than previously known routes, contributes 69.2% ± 5.0% particulate sulfur production events. This explain missing source improve understanding atmospheric chemistry climate change.

Language: Английский

---

Aging of Atmospheric Brown Carbon Aerosol

ACS Earth and Space Chemistry, Journal Year: 2021, Volume and Issue: 5(4), P. 722 - 748

Published: April 5, 2021

Emitted by numerous primary sources and formed secondary sources, atmospheric brown carbon (BrC) aerosol is chemically complex. As BrC ages in the atmosphere via a variety of chemical physical processes, its composition optical properties change significantly, altering impacts on climate. Research past decade has considerably expanded our understanding reactions both gas condensed phases. We review these recent advances aging chemistry with focus phase leading to formation, aqueous in-cloud particle reactions. Connections are made between single component proxies more complex mixtures as well laboratory field measurements chemistry. General conclusions that can darken particles over short time scales hours close source considerable photobleaching oxidative whitening will occur when day or removed from source.

Language: Английский

---

Multiphase Oxidation of Sulfur Dioxide in Aerosol Particles: Implications for Sulfate Formation in Polluted Environments

Environmental Science & Technology, Journal Year: 2021, Volume and Issue: 55(8), P. 4227 - 4242

Published: March 24, 2021

Atmospheric oxidation of sulfur dioxide (SO2) forms sulfate-containing aerosol particles that impact air quality, climate, and human ecosystem health. It is well-known in-cloud SO2 frequently dominates over gas-phase on regional global scales. Multiphase involving particles, fog, cloud droplets has been generally thought to scale with liquid water content (LWC) so multiphase would be negligible for due their low LWC. However, recent field evidence, particularly from East Asia, shows fast sulfate formation prevails in cloud-free environments are characterized by high loadings. By assuming the kinetics chemistry most atmospheric models do not capture this phenomenon. Therefore, blossomed past decade, many processes proposed bridge difference between modeled observed mass This review summarizes advances fundamental understanding SO2, a focus environmental conditions affect rate, experimental challenges, mechanisms results individual reaction pathways, future research directions. Compared dilute conditions, paper highlights differences arise at molecular level extremely solute strengths present particles.

Language: Английский

---

Multiphase buffer theory explains contrasts in atmospheric aerosol acidity

Science, Journal Year: 2020, Volume and Issue: 369(6509), P. 1374 - 1377

Published: Sept. 10, 2020

Water content and mass matter more than composition for the acidity of atmospheric aerosols in ammonia-buffered regions.

Language: Английский

---

Revealing Drivers of Haze Pollution by Explainable Machine Learning

Environmental Science & Technology Letters, Journal Year: 2022, Volume and Issue: 9(2), P. 112 - 119

Published: Jan. 4, 2022

Many places on earth still suffer from a high level of atmospheric fine particulate matter (PM2.5) pollution. Formation pollution event or haze episode (HE) involves many factors, including meteorology, emissions, and chemistry. Understanding the direct causes key drivers behind HE is thus essential. Traditionally, this done via chemical transport models. However, substantial uncertainties are introduced into model estimation when there significant changes in emissions inventory due to interventions (e.g., COVID-19 lockdown). Here we applied Random Forest coupled with Shapley additive explanation algorithm, post hoc technique, investigate roles major meteorological primary chemistry five severe HEs that occurred before during lockdown China. We discovered that, addition PM2.5 these episodes was largely driven by effects (with average contributions 30–65 μg m–3 for HEs), followed (∼15–30 m–3). Photochemistry likely pathway formation nitrate, while air humidity predominant factor forming sulfate. Our results highlight machine learning data has potential be complementary tool predicting interpreting

Language: Английский

---

Acidity across the interface from the ocean surface to sea spray aerosol

Proceedings of the National Academy of Sciences, Journal Year: 2020, Volume and Issue: 118(2)

Published: Dec. 29, 2020

Significance Sea spray aerosol, produced through breaking waves, is one of the largest sources environmental particles. Once in atmosphere, sea aerosol influences cloud formation, serves as microenvironments for multiphase atmospheric chemical reactions, and impacts human health. All these are affected by acidity. Here we show that freshly emitted particles become highly acidic within minutes they transferred across ocean−air interface. These results have important implications chemistry climate, including aerosol/gas partitioning, heterogeneous speciation at surface aerosol.

Language: Английский

---

Acidity and the multiphase chemistry of atmospheric aqueous particles and clouds

Atmospheric chemistry and physics, Journal Year: 2021, Volume and Issue: 21(17), P. 13483 - 13536

Published: Sept. 10, 2021

Abstract. The acidity of aqueous atmospheric solutions is a key parameter driving both the partitioning semi-volatile acidic and basic trace gases their aqueous-phase chemistry. In addition, phases, e.g., deliquesced aerosol particles, cloud, fog droplets, also dictated by These feedbacks between chemistry have crucial implications for tropospheric lifetime air pollutants, composition, deposition to terrestrial oceanic ecosystems, visibility, climate, human health. Atmospheric research has made substantial progress in understanding multiphase during recent decades. This paper reviews current state knowledge on these with focus cloud systems, which involve inorganic organic Here, we describe impacts phase buffering phenomena. Next, review different regimes chemical reaction mechanisms kinetics, as well uncertainties subsystems incomplete information. Finally, discuss highlight need future investigations, particularly respect reducing emissions acid precursors changing world, advancements field laboratory measurements model tools.

Language: Английский

---

Aerosol pH and liquid water content determine when particulate matter is sensitive to ammonia and nitrate availability

Atmospheric chemistry and physics, Journal Year: 2020, Volume and Issue: 20(5), P. 3249 - 3258

Published: March 18, 2020

Abstract. Nitrogen oxides (NOx) and ammonia (NH3) from anthropogenic biogenic emissions are central contributors to particulate matter (PM) concentrations worldwide. The response of PM changes in the both compounds is typically studied on a case-by-case basis, owing part complex thermodynamic interactions these aerosol precursors with other constituents. Here we present simple but thermodynamically consistent approach that expresses chemical domains sensitivity NH3 HNO3 availability terms pH liquid water content. From our analysis, four policy-relevant regimes emerge sensitivity: (i) sensitive, (ii) (iii) (iv) insensitive or HNO3. For all regimes, remains sensitive nonvolatile precursors, such as cations sulfate. When this framework applied ambient measurements predictions gaseous “chemical regime” directly determined. use allows for novel insights, an important tool evaluate transport models. With extended understanding, associated content naturally previously ignored state parameters drive formation.

Language: Английский

---

A critical analysis of electrospray techniques for the determination of accelerated rates and mechanisms of chemical reactions in droplets

Chemical Science, Journal Year: 2020, Volume and Issue: 11(48), P. 13026 - 13043

Published: Jan. 1, 2020

The application of Electrospray and Electrosonic Spray Ionization Mass Spectrometry (ESI-MS ESSI-MS) to study accelerated reaction kinetics in droplets is examined using numerical models, new experimental data, prior literature.

Language: Английский

---