Production of N<sub>2</sub>O<sub>5</sub> and ClNO<sub>2</sub> in summer in urban Beijing, China

Atmospheric chemistry and physics, Journal Year: 2018, Volume and Issue: 18(16), P. 11581 - 11597

Published: Aug. 16, 2018

Abstract. The heterogeneous hydrolysis of dinitrogen pentoxide (N2O5) has a significant impact on both nocturnal particulate nitrate formation and photochemistry the following day through photolysis nitryl chloride (ClNO2), yet these processes in highly polluted urban areas remain poorly understood. Here we present measurements gas-phase N2O5 ClNO2 by high-resolution time-of-flight chemical ionization mass spectrometer (ToF-CIMS) during summer Beijing, China as part Air Pollution Human Health (APHH) campaign. show large day-to-day variations with average (±1σ) mixing ratios 79.2±157.1 174.3±262.0 pptv, respectively. High reactivity N2O5, τ (N2O5)−1 ranging from 0.20 × 10−2 to 1.46 s−1, suggests active chemistry potential via uptake. lifetime (N2O5), decreases rapidly increase aerosol surface area, it varies differently function relative humidity highest value peaking at ∼ 40 %. uptake coefficients estimated product rates are range 0.017–0.19, corresponding direct loss 0.00044–0.0034 s−1. Further analysis indicates that fast boundary layer Beijing is mainly attributed its indirect NO3, for example reactions volatile organic compounds NO, while contribution comparably small (7–33 %). yields 0.10 0.35 were also observed, which might have important implications air quality affecting ozone formation.

Language: Английский

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NO3 and N2O5 chemistry at a suburban site during the EXPLORE-YRD campaign in 2018

Atmospheric Environment, Journal Year: 2019, Volume and Issue: 224, P. 117180 - 117180

Published: Nov. 25, 2019

Language: Английский

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Effects of Anthropogenic Chlorine on PM_2.5 and Ozone Air Quality in China

Environmental Science & Technology, Journal Year: 2020, Volume and Issue: 54(16), P. 9908 - 9916

Published: June 29, 2020

China has large anthropogenic chlorine emissions from agricultural fires, residential biofuel, waste incineration, coal combustion, and industrial processes. Here we quantify the effects of on fine particulate matter (PM2.5) ozone air quality across by using GEOS-Chem chemical transport model with comprehensive detailed representation gas-phase heterogeneous chemistry. Comparison to observed ClNO2, HCl, Cl– concentrations shows that reactive in is mainly anthropogenic, unlike other continental regions where it mostly marine origin. The successful reproducing their distributions, lending confidence emission estimates resulting We find increase total inorganic PM2.5 as much 3.2 μg m–3 an annual mean basis through formation ammonium chloride, partly compensated a decrease nitrate because ClNO2 competes N2O5 hydrolysis. Annual MDA8 surface increases up 1.9 ppb, chemistry, while reactivities volatile organic compounds (by 48% for ethane). sufficient chemistry models can be obtained consideration HCl/Cl– thermodynamics more complicated aspects have relatively minor effect.

Language: Английский

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Wintertime N2O5 uptake coefficients over the North China Plain

Science Bulletin, Journal Year: 2020, Volume and Issue: 65(9), P. 765 - 774

Published: Feb. 10, 2020

Language: Английский

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Important Role of NO₃ Radical to Nitrate Formation Aloft in Urban Beijing: Insights from Triple Oxygen Isotopes Measured at the Tower

Environmental Science & Technology, Journal Year: 2021, Volume and Issue: 56(11), P. 6870 - 6879

Published: Aug. 25, 2021

Until now, there has been a lack of knowledge regarding the vertical profiles nitrate formation in urban boundary layer (BL) based on triple oxygen isotopes. Here, we conducted measurements anomaly (Δ17O-NO3–) 325 m meteorological tower Beijing during winter and summer. The simultaneous suggested different mechanisms aerosols at ground level 120 260 due to less efficient mixing under stable atmospheric conditions. Particularly, chemical processes three heights were found between clean days polluted winter. On days, nocturnal chemistry (NO3 + HC N2O5 uptake) contributed production equally with OH/H2O NO2 level, while it dominated aloft (contributing 80% m), higher aerosol liquid water content O3 concentration there. reactions heights. contribution pathway increased from might be attributed hydrolysis HONO then further photolysis OH radicals day. In contrast, proportion H2O decreased m, likely low relative humidity that inhibited residual layer. Our results highlighted differences meteorology gaseous precursors could largely affect particulate within BL.

Language: Английский

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Rapid sulfate formation from synergetic oxidation of SO2 by O3 and NO2 under ammonia-rich conditions: Implications for the explosive growth of atmospheric PM2.5 during haze events in China

The Science of The Total Environment, Journal Year: 2021, Volume and Issue: 772, P. 144897 - 144897

Published: Jan. 29, 2021

Language: Английский

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Formation of Secondary Nitroaromatic Compounds in Polluted Urban Environments

Journal of Geophysical Research Atmospheres, Journal Year: 2022, Volume and Issue: 127(10)

Published: May 14, 2022

Abstract Nitroaromatic compounds (NACs) are important light absorption contributors to atmospheric brown carbon; however, their formation pathways and the key influential factors in polluted urban atmospheres largely unknown. Herein, we present molecular characterization of particulate NACs Shanghai by applying ultra‐high‐performance liquid chromatography coupled Orbitrap mass spectrometry, investigated seasonal diel variations pathways. The total number abundance increased significantly during air pollution episodes, these exhibited greatest relative among CHON compounds. 12 quantified higher levels winter (52.3 ± 29.1 ng m −3 ) than summer (7.83 3.30 ), owing masses mostly passing through northern heating regions. Among NACs, 4‐nitrophenol 4‐nitrocatechol were most abundant species. Most enhanced via photooxidation day summer, while day‐night not as obvious. Further analysis relevance suggested that nitrophenol its methylated derivatives mainly formed gas‐phase photochemical reactions, whereas aqueous‐phase oxidation processing could be an pathway form methyl‐nitrocatechols. Formation was relatively sensitive NO 2 under low‐NO x conditions, became independent high‐NO conditions. A larger fraction transformed into inorganic nitrate products when less abundant, implying would play more roles aerosol properties with decline concentrations.

Language: Английский

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Seasonal variation in oxygenated organic molecules in urban Beijing and their contribution to secondary organic aerosol

Atmospheric chemistry and physics, Journal Year: 2022, Volume and Issue: 22(15), P. 10077 - 10097

Published: Aug. 5, 2022

Abstract. Oxygenated organic molecules (OOMs) are crucial for atmospheric new particle formation and secondary aerosol (SOA) growth. Therefore, understanding their chemical composition, temporal behavior, sources is of great importance. Previous studies on OOMs mainly focus environments where biogenic predominant, yet sites with dominant anthropogenic emissions, such as megacities, have been lacking. Here, we conducted long-term measurements OOMs, covering four seasons the year 2019, in urban Beijing. The OOM concentration was found to be highest summer (1.6×108 cm−3), followed by autumn (7.9×107 spring (5.7×107 cm−3) winter (2.3×107 suggesting that enhanced photo-oxidation together rise temperature promote OOMs. Most contained 5 10 carbon atoms 3 7 effective oxygen (nOeff=nO-2×nN). average nOeff increased increasing capacity, which lowest autumn. By performing a newly developed workflow, were classified into following types: aromatic aliphatic isoprene monoterpene Among them, (29 %–41 %) (26 main contributors all seasons, indicating Beijing dominated sources. contribution significantly (33 %), much higher than those other three (8 %–10 %). Concentrations (0.2–5.3×107 (1.1–8.4×106 lower reported at sites, they possessed nitrogen contents due high NOx levels (9.5–38.3 ppbv – parts per billion volume) With regard content two composed CHO CHON species, while CHON2 ones. Such prominent differences suggest varying pathways between these combining an dynamic model, estimated SOA growth rate through condensation could reach 0.64, 0.61, 0.41, 0.30 µg m−3 h−1 autumn, summer, spring, winter, respectively. Despite similar concentrations former had volatilities and, therefore, showed contributions (46 %–62 latter (14 %–32 contrast, limited low abundances or volatilities, 8 %–12 % %–5 %, Overall, our results improve concentration, seasonal variation, potential impacts can help formulate refined restriction policy specific control areas.

Language: Английский

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Air humidity affects secondary aerosol formation in different pathways

The Science of The Total Environment, Journal Year: 2020, Volume and Issue: 759, P. 143540 - 143540

Published: Nov. 7, 2020

Language: Английский

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Molecular Characterization of Organosulfates in Highly Polluted Atmosphere Using Ultra‐High‐Resolution Mass Spectrometry

Journal of Geophysical Research Atmospheres, Journal Year: 2020, Volume and Issue: 125(8)

Published: April 8, 2020

Abstract Organosulfates (OSs) have recently been observed to be a potentially important constituent of secondary organic aerosol (SOA); however, their molecular characterization in highly polluted atmospheres has not probed detail. This study thoroughly presents the OSs air and demonstrates seasonal diurnal variations, formation mechanisms, contributions aerosol. Atmospheric PM 2.5 samples were collected from an urban Shanghai site across winter summer 2017. characterized by ultra‐high‐performance liquid chromatography (UHPLC) coupled with Orbitrap mass spectrometry (MS). Based on exact formulae conjunction previous chamber studies, hundreds sulfur‐containing compounds tentatively identified as OSs. The number abundance increased significantly during pollution episodes. clean dominant biogenic products, whereas had distinctive anthropogenic characteristics. Aromatics long‐chain alkanes emissions might precursors. By using synthesized standards, total concentrations 14 quantified ranged 21.6–161 ng m −3 5.85–84.3 winter, respectively. Among these OSs, glycolic acid sulfate was most abundant species (1.13–122 ). Further analysis variations suggests possible multiple including acid‐catalyzed NO 3 ‐initiated oxidation reactions. Our results highlight that pollutant (e.g., x SO 2 ) can enhance SOA burden biogenically influenced areas.

Language: Английский

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