Secondary Formation of Atmospheric Brown Carbon in China Haze: Implication for an Enhancing Role of Ammonia

Environmental Science & Technology, Journal Year: 2023, Volume and Issue: 57(30), P. 11163 - 11172

Published: July 5, 2023

Optical characteristics and molecular compositions of brown carbon (BrC) were investigated during winter 2019 at a rural site China with focus on nitro-aromatic compounds (NACs) imidazoles (IMs). The abundance gaseous nitrophenols relative to CO the campaign maximized noontime, being similar O3, while particulate NACs haze periods strongly correlated toluene NO2, suggesting that in region are largely formed from gas-phase photooxidation. Strong correlations IMs dry mass ratio EC/PM2.5 concentration levoglucosan observed, indicating events derived biomass burning emissions. However, an increase increasing aerosol liquid water content pH was observed humid events, along much lower abundances K+ PM2.5, mostly aqueous reactions periods. These exponentially increased NH3 owing reaction carbonyls free ammonia. Our findings for first time revealed enhancing effect ammonia BrC formation China, especially

Language: Английский

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Optimal reactive nitrogen control pathways identified for cost-effective PM2.5 mitigation in Europe

Nature Communications, Journal Year: 2023, Volume and Issue: 14(1)

Published: July 17, 2023

Excess reactive nitrogen (Nr), including oxides (NOx) and ammonia (NH3), contributes strongly to fine particulate matter (PM2.5) air pollution in Europe, posing challenges public health. Designing cost-effective Nr control roadmaps for PM2.5 mitigation requires considering both efficiencies implementation costs. Here we identify optimal pathways Europe by integrating emission estimations, quality modeling, exposure-mortality experiments cost data. We find that phasing out emissions would reduce 2.3 ± 1.2 μg·m-3 helping many locations achieve the World Health Organization (WHO) guidelines reducing PM2.5-related premature deaths almost 100 thousand 2015. Low-ambition NH3 controls have similar as NOx Eastern but are less effective Western until reductions exceed 40%. The efficiency increases at high-ambition while slightly decreases. When costs considered, strategies regions uniformly shift favor of controls, up 50% remain 5-11 times more than per unit reduction, emphasizing priority policies Europe.

Language: Английский

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Nitrate-Enhanced Gas-to-Particle-Phase Partitioning of Water-Soluble Organic Compounds in Chinese Urban Atmosphere: Implications for Secondary Organic Aerosol Formation

Environmental Science & Technology Letters, Journal Year: 2022, Volume and Issue: 10(1), P. 14 - 20

Published: Dec. 29, 2022

To understand the gas-to-particle-phase partitioning process of water-soluble organic compounds (WSOCs) in atmosphere, we conducted simultaneous measurements gaseous WSOCs and particulate Shanghai during summer 2020. We found that pollution events (PEs) PM2.5 campaign can be classified as sulfate-dominated (SD) or nitrate-dominated (ND) episodes. The coefficients (Fp) ND episodes (0.36 ± 0.04) were 40% higher than those SD (0.25 0.05). These results largely driven by aerosol liquid water content acidity episodes, respectively. Such bulk-level are consistent with behaviors oxalic acid molecules PEs, demonstrating kinetics differed for two types PEs. thermodynamic model simulation Fp trend analysis composition revealed efficiency atmospheric throughout China past 20 years has increased increasing abundance nitrate relative to sulfate, indicating formation secondary aerosols will more efficient near future because increasingly WSOCs.

Language: Английский

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Measurement report: Large contribution of biomass burning and aqueous-phase processes to the wintertime secondary organic aerosol formation in Xi'an, Northwest China

Atmospheric chemistry and physics, Journal Year: 2022, Volume and Issue: 22(15), P. 10139 - 10153

Published: Aug. 9, 2022

Abstract. Secondary organic aerosol (SOA) plays an important role in particulate air pollution, but its formation mechanism is still not fully understood. The chemical composition of non-refractory matter with a diameter ≤2.5 µm (NR-PM2.5), OA sources, and SOA mechanisms were investigated urban Xi'an during winter 2018. fractional contribution to total mass (58 %) was larger than primary (POA, 42 %). Biomass-burning-influenced oxygenated (OOA-BB) resolved formed from the photochemical oxidation aging biomass burning (BBOA). OOA-BB more favorable on days fraction higher BBOA concentration. In comparison, aqueous-phase processed (aq-OOA) dependent secondary inorganic (SIA) content liquid water (ALWC), it showed large increase (to 50 % OA) SIA-enhanced periods. Further van Krevelen (VK) diagram analysis suggests that addition carboxylic acid groups fragmentation dominated reference days, while increased aq-OOA contributions periods likely reflect evolution due alcohol or peroxide groups.

Language: Английский

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Measurement report: Effects of anthropogenic emissions and environmental factors on the formation of biogenic secondary organic aerosol (BSOA) in a coastal city of southeastern China

Atmospheric chemistry and physics, Journal Year: 2022, Volume and Issue: 22(11), P. 7827 - 7841

Published: June 16, 2022

Abstract. To better understand the formation of biogenic secondary organic aerosol (BSOA), samples with a 4 h time resolution were collected during summer and winter in southeast China, along online measurements trace gases, chemical compositions, meteorological parameters. The analyzed by gas chromatography–mass spectrometry for PM2.5-bound (SOA) tracers, including isoprene (SOAI), α/β-pinene (SOAM), β-caryophyllene (SOAC), toluene (ASOA). average concentrations total SOA tracers 38.8 111.9 ng m−3, respectively, predominance SOAM (70.1 % 45.8 %), followed SOAI (14.0 45.6 ASOA (11.0 6.2 %) SOAC (4.9 2.3 %). Compared to those winter, majority BSOA showed significant positive correlations Ox (O3+NO2) (r = 0.443–0.808), HONO 0.299–0.601), ultraviolet (UV) 0.382–0.588) temperature (T) 0.529–0.852), indicating influence photochemical oxidation under relatively clean conditions. However, significantly correlated PM2.5 0.407–0.867), NO3- 0.416–0.884), SO42- 0.419–0.813), NH3 0.440–0.757), attributed contributions anthropogenic emissions. Major both seasons linearly acidity (pH) 0.421–0.752), liquid water content (LWC) 0.403–0.876) 0.419–0.813). results indicated that acid-catalyzed reactive uptake onto sulfate particles enhanced BSOA. In summer, air mass originated from ocean, chlorine depletion was observed. We also found HCl (R2=0.545) ions 0.280–0.639) PM2.5, reflecting contribution Cl-initiated volatile compound (VOC) oxidations SOA. northeast dominant wind direction brought continental polluted monitoring site, affecting transformation tracers. This implied emissions, atmospheric capacity halogen chemistry have effects on coastal area.

Language: Английский

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Vehicular ammonia emissions: an underappreciated emission source in densely populated areas

Atmospheric chemistry and physics, Journal Year: 2023, Volume and Issue: 23(6), P. 3819 - 3828

Published: March 31, 2023

Abstract. On-road ammonia (NH3) emissions play a significant role in fine particulate matter (PM2.5) formation urban areas, posing severe risks for human health. Limited studies have depicted the spatial and temporal variations of on-road NH3 emissions, particular lacking detailed quantification their contributions within densely populated areas. In this study, we established comprehensive vehicular emission model compiled gridded inventory with high (3 km × 3 km) (monthly) resolution mainland China. China's annual are estimated to increase from 32.8 ± 1.7 87.1 37.5 kt during period 2000–2019. Vehicular significantly concentrated where agricultural relatively lower intensity. It is found that could exceed grids containing 23.0 2.1 % Chinese population 2019 (approximately 326.6 25.4 million people), ratio up 29.4 3.0 winter. For extremely populous megacities such as Beijing Shanghai, 69.2 1.2 72.0 1.3 resides, respectively. Thus, areas may been underappreciated. This study gave better insight into absolute value relative importance different regions, seasons densities China; important terms implications air quality.

Language: Английский

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Mist cannon trucks can exacerbate the formation of water-soluble organic aerosol and PM_2.5 pollution in the road environment

Atmospheric chemistry and physics, Journal Year: 2023, Volume and Issue: 23(12), P. 6775 - 6788

Published: June 20, 2023

Abstract. Mist cannon trucks have been widely applied in megacities China to reduce the road dust, since they are considered be more water saving and efficient than traditional sprinkling trucks. However, their effect on formation of water-soluble organic compounds pollution control fine particles (PM2.5) remains unknown. We characterized variations chemical compositions PM2.5 collected sides during simulated operations mist truck via Fourier transform ion cyclotron resonance mass spectrometry chromatography. The concentrations carbon showed a significant increase (62 %–70 %) after air spraying. Furthermore, we found that compounds, particularly nitrates, increased significantly interactions reactive gas-phase organics, atmospheric oxidants aerosol liquid spraying, although spraying had better suppressing dust ground aspersion. Moreover, segment where passed by was promoted, with an up 13 % concentration 25–35 min, average. Thus, application potentially worsens environment through levels production large number PM2.5. overall results provide not only valuable insights processes associated but also management strategies regulate operation China.

Language: Английский

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Role of gas-particle conversion of ammonia in haze pollution under ammonia-rich environment in Northern China and prospects of effective emission reduction

The Science of The Total Environment, Journal Year: 2024, Volume and Issue: 934, P. 173277 - 173277

Published: May 15, 2024

Language: Английский

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NH₃ Weakens the Enhancing Effect of SO₂ on Biogenic Secondary Organic Aerosol Formation

Environmental Science & Technology Letters, Journal Year: 2023, Volume and Issue: 10(2), P. 145 - 151

Published: Feb. 1, 2023

Anthropogenic air pollutants can be involved in biogenic secondary organic aerosol (SOA) formation. However, such interactions are currently one of the least understood aspects atmospheric chemistry. Herein, SOA formation via chemical between anthropogenic SO2, NH3, and O3 β-caryophyllene was investigated. It is shown that although SO2 considerably enhanced formation, this enhancing effect weakened by NH3 when coexisted. NH3-induced neutralization particle acidity generated oxidation may primary driving factor weakening effect. Molecular-level characterization using high-resolution quadrupole time-of-flight mass spectrometry revealed additional connections changes composition acidity. Specifically, lower relative abundances several main products presence than those formed only were consistent with their suppressed seed The suppression oligomer provided more evidence for acid-catalyzed processes caused neutralization. Accordingly, current study demonstrates as a less effectively regulated alkaline gas resulting from an unbalanced reduction different must considered caution evaluating effects on anthropogenic–biogenic interactions.

Language: Английский

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Understanding the multifaceted influence of urbanization, spectral indices, and air pollutants on land surface temperature variability in Hyderabad, India

Journal of Cleaner Production, Journal Year: 2024, Volume and Issue: 470, P. 143284 - 143284

Published: Aug. 1, 2024

Language: Английский

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