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

---

Ozone pollution in the North China Plain spreading into the late-winter haze season

Proceedings of the National Academy of Sciences, Journal Year: 2021, Volume and Issue: 118(10)

Published: March 1, 2021

Surface ozone is a severe air pollution problem in the North China Plain, which home to 300 million people. Ozone concentrations are highest summer, driven by fast photochemical production of hydrogen oxide radicals (HO

Language: Английский

---

Global review of recent source apportionments for airborne particulate matter

The Science of The Total Environment, Journal Year: 2020, Volume and Issue: 740, P. 140091 - 140091

Published: June 9, 2020

Source apportionments have become increasingly performed to determine the origins of ambient particulate pollution. The results can be helpful in designing mitigation strategies improve air quality. specific matter (PM) concentrations are also being used health effects studies able focus attention on those sources most likely responsible for observed adverse effects. In 2015, World Health Organization (WHO) released its initial compilation source apportionment published through August 2014. This database was described by Karagulian et al. (Atmospheric Environment120 (2015) 475–483). present report, a new has been prepared since 2014 December 2019. addition, expanded include heavy metals, water-soluble components, and carbonaceous components PM. As result this work, we developed presented some perspectives going forward. We made series recommendations reporting them. It is essential papers provide minimum set information so that study adequately assessed, utilized others making policy decisions or as part other scientific studies.

Language: Английский

---

Control of particulate nitrate air pollution in China

Nature Geoscience, Journal Year: 2021, Volume and Issue: 14(6), P. 389 - 395

Published: April 26, 2021

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

---

A chemical cocktail during the COVID-19 outbreak in Beijing, China: Insights from six-year aerosol particle composition measurements during the Chinese New Year holiday

The Science of The Total Environment, Journal Year: 2020, Volume and Issue: 742, P. 140739 - 140739

Published: July 4, 2020

Language: Английский

---

Is reducing new particle formation a plausible solution to mitigate particulate air pollution in Beijing and other Chinese megacities?

Faraday Discussions, Journal Year: 2020, Volume and Issue: 226, P. 334 - 347

Published: Aug. 26, 2020

Atmospheric gas-to-particle conversion is a crucial or even dominant contributor to haze formation in Chinese megacities terms of aerosol number, surface area and mass. Based on our comprehensive observations Beijing during 15 January 2018-31 March 2019, we are able show that 80-90% the mass (PM2.5) was formed via atmospheric reactions days over 65% number concentration particles resulted from new particle (NPF). Furthermore, faster when subsequent growth newly enhanced. Our findings suggest practice almost all present-day episodes originate NPF, mainly since direct emission primary has considerably decreased recent years. We also reducing rate freshly by factor 3-5 would delay buildup 1-3 days. Actually, this decrease length each episode, so annual could be approximately halved. Such improvement air quality can achieved with targeted reduction gas-phase precursors for dimethyl amine ammonia, further reductions SO2 emissions. anthropogenic organic inorganic precursor emissions slow down newly-formed consequently reduce formation.

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

---

Field Determination of Nitrate Formation Pathway in Winter Beijing

Environmental Science & Technology, Journal Year: 2020, Volume and Issue: 54(15), P. 9243 - 9253

Published: June 26, 2020

Particulate nitrate (pNO3–) has often been found to be the major component of fine particles in urban air-sheds China, United States, and Europe during winter haze episodes recent years. However, there is a lack knowledge regarding experimentally determined contribution different chemical pathways formation pNO3–. Here, for first time, we combine ground tall-tower observations quantify pNO3– using observationally constrained model approach based on direct OH N2O5 air-shed. We find that gas-phase oxidation pathway (OH+NO2) daytime dominant channel over nocturnal uptake pollution episodes, with percentages 74% areas 76% suburban areas. This quite from previous studies some regions US, which was concluded account larger winter. These results indicate driving factor Beijing US different, as are mitigation strategies particulate nitrate.

Language: Английский

---

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

---