Continuous and comprehensive atmospheric observations in Beijing: a station to understand the complex urban atmospheric environment

Big Earth Data, Год журнала: 2020, Номер 4(3), С. 295 - 321

Опубликована: Июль 2, 2020

Due to profound impact on climate and human health, air quality has attracted attention from all levels of the civil society. The key step in provision required tools for society tackle complex problem is characterize it a comprehensive manner with long-term perspective. Here, we describe continuous observation station its accompanying state-of-the-art instrumentation that was established investigate urban atmospheric environment rapidly developing Chinese Megacity. station, located downtown Beijing, aims study by identifying major pollutants processes determining their formation loss mechanisms. A few hundreds parameters are continuously measured instruments, including trace gas concentrations, aerosol particle size distributions, mass covering chemical composition molecules micrometer-sized particles. This produced long-term, big data around 1×1011 bytes per year. In this paper, provide an overview facilities used, workflow observations examples results 2018 2019 basis establishing modern other megacities.

Язык: Английский

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Molecular understanding of new-particle formation from α-pinene between −50 and +25 °C

Atmospheric chemistry and physics, Год журнала: 2020, Номер 20(15), С. 9183 - 9207

Опубликована: Авг. 3, 2020

Abstract. Highly oxygenated organic molecules (HOMs) contribute substantially to the formation and growth of atmospheric aerosol particles, which affect air quality, human health Earth's climate. HOMs are formed by rapid, gas-phase autoxidation volatile compounds (VOCs) such as α-pinene, most abundant monoterpene in atmosphere. Due their abundance low volatility, can play an important role new-particle (NPF) early aerosols, even without any further assistance other low-volatility sulfuric acid. Both reaction forming NPF rates expected be strongly dependent on temperature. However, experimental data both effects limited. Dedicated experiments were performed at CLOUD (Cosmics Leaving OUtdoor Droplets) chamber CERN address this question. In study, we show that a decrease temperature (from +25 −50 ∘C) results reduced HOM yield oxidation state products, whereas (J1.7 nm) increase substantially. Measurements with two different chemical ionization mass spectrometers (using nitrate protonated water reagent ion, respectively) provide molecular composition gaseous two-dimensional volatility basis set (2D VBS) model provides distribution. The decreases from 6.2 % 25 ∘C 0.7 ∘C. there is strong reduction saturation vapor pressure each reduced. Overall, leads nucleation up 3 orders magnitude compared addition, enhancement ions decreasing temperature, since neutral clusters have increased stability against evaporation. resulting quantify how interplay between temperature-dependent pathways associated pressures biogenic level. Our measurements, therefore, improve our understanding pure for wide range tropospheric temperatures precursor concentrations.

Язык: Английский

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New particle formation in the remote marine boundary layer

Nature Communications, Год журнала: 2021, Номер 12(1)

Опубликована: Янв. 22, 2021

Marine low clouds play an important role in the climate system, and their properties are sensitive to cloud condensation nuclei concentrations. While new particle formation represents a major source of globally, prevailing view is that rarely occurs remote marine boundary layer over open oceans. Here we present evidence regular frequent occurrence upper part following cold front passages. The facilitated by combination efficient removal existing particles precipitation, air temperatures, vertical transport reactive gases from ocean surface, high actinic fluxes broken field. newly formed subsequently grow contribute substantially thereby impact clouds.

Язык: Английский

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Molecular understanding of the suppression of new-particle formation by isoprene

Atmospheric chemistry and physics, Год журнала: 2020, Номер 20(20), С. 11809 - 11821

Опубликована: Окт. 20, 2020

Abstract. Nucleation of atmospheric vapours produces more than half global cloud condensation nuclei and so has an important influence on climate. Recent studies show that monoterpene (C10H16) oxidation yields highly oxygenated products can nucleate with or without sulfuric acid. Monoterpenes are emitted mainly by trees, frequently together isoprene (C5H8), which the highest emission all organic vapours. Previous have shown suppresses new-particle formation from monoterpenes, but cause this suppression is under debate. Here, in experiments performed conditions CERN CLOUD chamber, we reduces yield dimers 19 20 carbon atoms – drive particle nucleation early growth while increasing production 14 15 atoms. The (termed C20 C15, respectively) produced termination reactions between pairs peroxy radicals (RO2⚫) arising monoterpenes isoprene. Compared pure conditions, rates at 1.7 nm (depending ∕ ratio) approximately halves 1.3 3.2 nm. However, above nm, C15 contribute to secondary aerosol, unaffected We further increased hydroxyl radical (OH⚫) our chemical system rather enhances it as previously proposed, since increases isoprene-derived RO2⚫ reduce formation. emerges critical step determines molecule (HOM) distribution corresponding capability. Species yield, such NO, HO2 isoprene, thus effectively biogenic growth. Therefore rate aerosol a particular region atmosphere study will vary according precise ambient conditions.

Язык: Английский

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Influx of African biomass burning aerosol during the Amazonian dry season through layered transatlantic transport of black carbon-rich smoke

Atmospheric chemistry and physics, Год журнала: 2020, Номер 20(8), С. 4757 - 4785

Опубликована: Апрель 24, 2020

Abstract. Black carbon (BC) aerosols influence the Earth's atmosphere and climate, but their microphysical properties, spatiotemporal distribution, long-range transport are not well constrained. This study presents airborne observations of transatlantic BC-rich African biomass burning (BB) smoke into Amazon Basin using a Single Particle Soot Photometer (SP2) as several complementary techniques. We base our results on trace gases off Brazilian coast onboard HALO (High Altitude LOng range) research aircraft during ACRIDICON-CHUVA campaign in September 2014. During flight AC19 over land ocean at northeastern coastline Basin, we observed layer ∼3.5 km altitude with vertical extension ∼0.3 km. Backward trajectories suggest that fires grasslands, savannas, shrublands were main source this pollution BB had undergone more than 10 d atmospheric aging South Atlantic before reaching Basin. The aged is characterized by dominant accumulation mode, centered about 130 nm, particle concentration Nacc=850±330 cm−3. rBC particles account for ∼15 % submicrometer aerosol mass ∼40 total number concentration. corresponds to range from 0.5 2 µg m−3 (1st 99th percentiles) 90 530 Along rBC, high cCO (150±30 ppb) cO3 (56±9 mixing ratios support origin pronounced photochemical layer. Upon it started broaden subside, due convective entrainment boundary Satellite show layers frequently occurring process, seasonally peaking August/September. By analyzing together long-term data Tall Tower Observatory (ATTO), found has strong impact northern central Amazonian population BB-influenced season (July December). In fact, early September) part appears be dominated smoke, whereas later (October December) American fires. dichotomy reflected changes optical properties such single scattering albedo (increasing 0.85 August 0.90 November) BC-to-CO enhancement ratio (decreasing 11 6 ng ppb−1). Our that, despite fraction BC particles, acts efficient cloud condensation nuclei (CCN), potentially important implications aerosol–cloud interactions hydrological cycle Amazon.

Язык: Английский

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Formation and growth of sub-3-nm aerosol particles in experimental chambers

Nature Protocols, Год журнала: 2020, Номер 15(3), С. 1013 - 1040

Опубликована: Фев. 12, 2020

Язык: Английский

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Variation of size-segregated particle number concentrations in wintertime Beijing

Atmospheric chemistry and physics, Год журнала: 2020, Номер 20(2), С. 1201 - 1216

Опубликована: Янв. 31, 2020

Abstract. The spatial and temporal variability of the number size distribution aerosol particles is an indicator dynamic behavior Beijing's atmospheric pollution cocktail. This variation reflects strength different primary secondary sources, such as traffic new particle formation, well main processes affecting population. In this paper, we report size-segregated concentrations observed at a newly developed Beijing station during winter 2018. Our measurements covered distributions over diameter range 1.5 nm–1 µm (cluster mode, nucleation Aitken mode accumulation mode), thus being descriptive major fraction taking place in atmosphere Beijing. Here focus on explaining concentration variations modes, by relating them to potential sources sinks, understanding connections between these modes. We considered haze days formation event separately. results show that (NPF) increases cluster were observed, whereas high present. There was tight connection both NPF days. addition, correlated modes with trace gases other parameters measured our station. all NOx, which contribution whole submicron range. also estimated ion-induced Beijing, found be negligible.

Язык: Английский

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A proxy for atmospheric daytime gaseous sulfuric acid concentration in urban Beijing

Atmospheric chemistry and physics, Год журнала: 2019, Номер 19(3), С. 1971 - 1983

Опубликована: Фев. 13, 2019

Abstract. Gaseous sulfuric acid (H2SO4) is known as one of the key precursors for atmospheric new particle formation (NPF) processes, but its measurement remains challenging. Therefore, a proxy method that able to derive gaseous concentrations from parameters can be measured relatively easily and accurately highly desirable chemistry community. Although such methods are available clean environments, works well in polluted atmosphere, found Chinese megacities, yet developed. In this study, concentration was February–March 2018, urban Beijing using nitrate based – long time-of-flight chemical ionization mass spectrometer (LToF-CIMS). A number were recorded concurrently including ultraviolet radiation B (UVB) intensity, O3, NOx (sum NO NO2), SO2, HONO, aerosol size distributions. daytime derived via statistical analysis UVB [SO2], condensation sink (CS), [O3], [HONO] (or [NOx]) predictor variables, where square brackets denote corresponding species. method, we considered reactions SO2 OH radicals during daytime, loss due onto preexisting particles. addition, explored conventional gas-phase photochemistry O3 photolysis HONO (and subsequently NOx) proxy. Our results showed intensity [SO2] dominant factors production acid, simplest could constructed with alone. When radical both homogenously heterogeneously formed considered, relative errors reduced by up 20 %.

Язык: Английский

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Airborne particulate matter

Philosophical Transactions of the Royal Society A Mathematical Physical and Engineering Sciences, Год журнала: 2020, Номер 378(2183), С. 20190319 - 20190319

Опубликована: Сен. 27, 2020

Airborne particulate matter (PM) is a pollutant of concern not only because its adverse effects on human health but ability to reduce visibility and soil buildings materials. It can be regarded as suite pollutants since PM covers very wide range particle sizes also has diverse chemical composition. Historically, much the arose from coal burning was measured black smoke. However, in second half twentieth century developed countries, there reduction smoke emissions steadily became dominated by carbonaceous particles road traffic exhaust secondary pollutants, ammonium salts organic carbon. This exemplified composition fine (referred 2.5 ) London, Delhi Beijing. Steadily, control strategies have addressed more tractable sources emissions, so previously unconventional emerged been seen make significant contribution airborne concentrations. Among these are non-exhaust traffic, cooking aerosol wood The size distribution hugely diverse, ranging newly formed few nanometres diameter through tens micrometres diameter. There great deal interest ultrafine (nano) suspicions enhanced toxicity, decrease source, regional nucleation processes become bigger relative contributors number, mass. article part discussion meeting issue ‘Air quality, past present future’.

Язык: Английский

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New Particle Formation: A Review of Ground-Based Observations at Mountain Research Stations

Atmosphere, Год журнала: 2019, Номер 10(9), С. 493 - 493

Опубликована: Авг. 26, 2019

New particle formation (NPF) was predicted to contribute a major fraction of free tropospheric number and cloud condensation nuclei (CCN) concentrations by global models. At high altitudes, pre-existing are low, leading limited condensational sinks for nucleation precursor gases, temperatures cooler compared lower whereas radiation is higher. These factors would all be in favor occur with an enhanced frequency at altitudes. In the present work, long term data from six altitude stations (and four continents) various altitudes (from 1465 5240 m a.s.l) were used derive statistically relevant NPF features (frequency, rates, growth rates) seasonal variability. The combined information together literature showed that frequencies events two Southern hemisphere (SH) some highest reported thus far (64% 67%, respectively). There indications favored preferential close interface troposphere (FT) planetary boundary layer (PBL) and/or vicinity clouds, which otherwise inhibit occurrence NPF. Particle rates found than low sites, but higher particles formed via charged pathway (mainly related positive ions) (BL) sites. Low (CS) not necessarily needed promote For 1000 a.s.l., CSs thought associated gases initiate early growth.

Язык: Английский

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