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Author

Zhen Zhou

Other affiliations: Shanghai University
Bio: Zhen Zhou is an academic researcher from Jinan University. The author has contributed to research in topics: Mass spectrometry & Aerosol. The author has an hindex of 21, co-authored 119 publications receiving 1597 citations. Previous affiliations of Zhen Zhou include Shanghai University.


Papers
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Journal ArticleDOI
TL;DR: In this article, a single particle laser desorption/ionization time of flight mass spectrometer capable of determining the size and chemical compositions of individual aerosol particles in real-time was presented.

212 citations

Journal ArticleDOI
TL;DR: In this article, the authors summarize the advances in real-time PM chemical characterization, focusing on the most widely used mass spectrometric and ion chromatographic techniques, and highlight the new insights gained from those findings and suggest future directions for further advancing our understanding of PM pollution in China via real time chemical characterization.

191 citations

Journal ArticleDOI
TL;DR: In this paper, a single particle aerosol mass spectrometer (SPAMS) was used to characterize the single particle size and chemical composition of submicron aerosols in the urban area of the Pearl River Delta region, China, for the period April 30 through May 22, 2010.

140 citations

Journal ArticleDOI
TL;DR: In this paper, a potentially important heterogeneous hydroxymethanesulfonate (HMS)chemical mechanism was proposed to account for up to about one third of the sulfate concentrations unexplained by current air quality models.
Abstract: . The chemical mechanisms responsible for rapid sulfate production, an important driver of winter haze formation in northern China, remain unclear. Here, we propose a potentially important heterogeneous hydroxymethanesulfonate (HMS) chemical mechanism. Through analyzing field measurements with aerosol mass spectrometry, we show evidence for a possible significant existence in haze aerosols of organosulfur primarily as HMS, misidentified as sulfate in previous observations. We estimate that HMS can account for up to about one-third of the sulfate concentrations unexplained by current air quality models. Heterogeneous production of HMS by SO2 and formaldehyde is favored under northern China winter haze conditions due to high aerosol water content, moderately acidic pH values, high gaseous precursor levels, and low temperature. These analyses identify an unappreciated importance of formaldehyde in secondary aerosol formation and call for more research on sources and on the chemistry of formaldehyde in northern China winter.

87 citations

Journal ArticleDOI
TL;DR: In this article, a single particle aerosol mass spectrometer (SPAMS) was deployed from April 22 to May 4, 2011 to investigate the composition and possible sources of aerosol particles in Beijing urban area.

80 citations


Cited by
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Journal ArticleDOI
TL;DR: In this paper, the missing source of sulfate and particulate matter can be explained by reactive nitrogen chemistry in aerosol water, where the alkaline aerosol components trap SO 2, which is oxidized by NO 2 to form sulfate, whereby high reaction rates are sustained by the high neutralizing capacity of the atmosphere.
Abstract: Fine-particle pollution associated with winter haze threatens the health of more than 400 million people in the North China Plain. Sulfate is a major component of fine haze particles. Record sulfate concentrations of up to ~300 μg m −3 were observed during the January 2013 winter haze event in Beijing. State-of-the-art air quality models that rely on sulfate production mechanisms requiring photochemical oxidants cannot predict these high levels because of the weak photochemistry activity during haze events. We find that the missing source of sulfate and particulate matter can be explained by reactive nitrogen chemistry in aerosol water. The aerosol water serves as a reactor, where the alkaline aerosol components trap SO 2 , which is oxidized by NO 2 to form sulfate, whereby high reaction rates are sustained by the high neutralizing capacity of the atmosphere in northern China. This mechanism is self-amplifying because higher aerosol mass concentration corresponds to higher aerosol water content, leading to faster sulfate production and more severe haze pollution.

821 citations

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TL;DR: It is highlighted that improved understanding of the emission sources, physical/chemical processes during haze evolution, and interactions with meteorological/climatic changes are necessary to unravel the causes, mechanisms, and trends for haze pollution.
Abstract: Regional severe haze represents an enormous environmental problem in China, influencing air quality, human health, ecosystem, weather, and climate. These extremes are characterized by exceedingly high concentrations of fine particulate matter (smaller than 2.5 µm, or PM2.5) and occur with extensive temporal (on a daily, weekly, to monthly timescale) and spatial (over a million square kilometers) coverage. Although significant advances have been made in field measurements, model simulations, and laboratory experiments for fine PM over recent years, the causes for severe haze formation have not yet to be systematically/comprehensively evaluated. This review provides a synthetic synopsis of recent advances in understanding the fundamental mechanisms of severe haze formation in northern China, focusing on emission sources, chemical formation and transformation, and meteorological and climatic conditions. In particular, we highlight the synergetic effects from the interactions between anthropogenic emissions and atmospheric processes. Current challenges and future research directions to improve the understanding of severe haze pollution as well as plausible regulatory implications on a scientific basis are also discussed.

586 citations

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

529 citations

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

495 citations