Measurement report: Characteristics of nitrogen-containing organics in PM_2.5 in Ürümqi, northwestern China – differential impacts of combustion of fresh and aged biomass materials

Atmospheric chemistry and physics, Journal Year: 2024, Volume and Issue: 24(7), P. 4331 - 4346

Published: April 15, 2024

Abstract. Nitrogen-containing organic compounds (NOCs) are abundant and important aerosol components deeply involved in the global nitrogen cycle. However, sources formation processes of NOCs remain largely unknown, particularly city (Ürümqi, China) farthest from ocean worldwide. Here, PM2.5 collected Ürümqi over a 1-year period were characterized by ultra-high-resolution mass spectrometry. The abundance CHON (mainly oxygen-poor unsaturated aliphatic-like species) positive ion mode was higher warm than cold period, which attributed to contribution fresh biomass material combustion (e.g., forest fires) associated with amidation fatty acids rather oxidation processes. nitro-aromatic negative increased significantly tightly related aged dry straws) wintertime Ürümqi. For CHN compounds, alkyl nitriles aromatic species showed periods, respectively. Alkyl can be derived dehydration amides (the main period). In contrast, burning. These findings further suggested different impacts materials on NOC compositions seasons. overall results shed light mechanisms release during combustion.

Language: Английский

---

Nitroaromatic compounds in six major Chinese cities: Influence of different formation mechanisms on light absorption properties

The Science of The Total Environment, Journal Year: 2024, Volume and Issue: 930, P. 172672 - 172672

Published: April 23, 2024

Language: Английский

---

Field Evidence for Constraints of Nearly Dry and Weakly Acidic Aerosol Conditions on the Formation of Organosulfates

Environmental Science & Technology Letters, Journal Year: 2024, Volume and Issue: 11(9), P. 981 - 987

Published: Aug. 6, 2024

A global perspective on the abundance and formation of organosulfates (OSs) during field studies (relative humidity 53% to 77%) suggested that investigated particles are generally nondry acidic (pH < 6). However, key factors affecting OS in nearly dry weakly aerosol conditions remain elusive. This topic was resolved by examining composition OSs PM2.5 collected Urumqi (dry dusty) over a one-year period. Anthropogenic accounted for 49 ± 8% total OSs, indicating large anthropogenic contribution (particularly winter). The low liquid water (ALW) concentration (2 2 μg m–3) weak particle acidity = 7 2) summer were important limiting formation. increased ALW (100 70 5 1) winter significantly promoted production. most isoprene- monoterpene-derived also constrained unfavorable acidity, resulting biogenic levels being lower than winter. study provides observational evidence constraints dusty atmospheric conditions.

Language: Английский

---

Sources of NH₄⁺ in PM_2.5 and Their Seasonal Variations in Urban Tianjin China: New Insights From the Seasonal δ¹⁵N Values of NH₃ Source

Journal of Geophysical Research Atmospheres, Journal Year: 2024, Volume and Issue: 129(9)

Published: April 29, 2024

Abstract The stable nitrogen isotopic composition (δ 15 N) has been widely used to quantify sources of ammonium (NH 4 + ) in PM 2.5 . However, the overlap and uncertainty δ N values from different NH 3 sources, coupled with their seasonal variability, hinder accurate identification source. Here, various source samples collected by active sampler were determined. Subsequently, we measured , which seasonally Tianjin. We found that combustion‐related (c‐NH exhibiting higher compared volatile (v‐NH ), but all was fell within range reported previous studies. Furthermore, inconsistent variations observed N‐NH originating emissions agricultural soil human excreta. application Bayesian isotope mixing model (MixSIAR model) revealed a significant increase contribution v‐NH when incorporating current data, as opposed for Notably, (53.1%) almost equivalent c‐NH (46.9%) considering signatures Additionally, estimated exhibited is more reasonable than non‐seasonal scenario. This study demonstrated contributed Tianjin equally, it highlighted should be considered estimating contributions MixSIAR model.

Language: Английский

---

Elaborating the Atmospheric Transformation of Combined and Free Amino Acids From the Perspective of Observational Studies

Journal of Geophysical Research Atmospheres, Journal Year: 2024, Volume and Issue: 129(16)

Published: Aug. 17, 2024

Abstract Proteinaceous matter (PrM) is a substantial component of bioaerosols. Although numerous studies have examined the characteristics and sources PrM in atmosphere, its interactions with atmospheric oxidants remain uncertain. A 1‐year observation PM 2.5 was performed both urban Nanchang (eastern China) suburban Guiyang (southwestern China), respectively. Glycine dominant free amino acid (FAA) species Nanchang. In contrast, proline dominated total acids (FAAs) combined (CAAs) Guiyang. We found that oxidative degradation can significantly promote release FAAs, especially glycine, from CAAs The controlled experiment on protein oxidation by hydroxyl radical suggested contribution glycine to FAA fraction tended increase during CAAs, supporting predominance FAAs most previous observations. composition mainly influenced primary weak PrM. These results suggest aerosol be responsible for difference between biosphere also imply may potential source secondary organic nitrogen compounds aerosols. Thus, this study improve current understanding as well liquid phase reactions proteinaceous oxidants.

Language: Английский

---

Measurement report: Occurrence of aminiums in PM_2.5 during winter in China – aminium outbreak during polluted episodes and potential constraints

Atmospheric chemistry and physics, Journal Year: 2024, Volume and Issue: 24(18), P. 10531 - 10542

Published: Sept. 23, 2024

Abstract. Amines and aminiums play an important role in particle formation, liquid-phase reactions, climate change have attracted considerable attention over the years. Here, we investigated concentrations compositions of PM2.5 11 Chinese cities during winter, focusing on characteristics polluted days key factors influencing aminium outbreak. Monomethylaminium was dominant species most cities, except Taiyuan Guangzhou, followed by dimethylaminium. Diethylaminium dominated total Guangzhou. Thus, main amine sources Guangzhou were significantly different from those other cities. The (TAs) increased days, while relatively weak outbreaks occurred Xi'an Beijing. Additionally, TAs Beijing insignificantly correlated with major acidic aerosol components, opposite pattern observed nine acid–base chemistry associated formation all Based sensitivity analysis : ammonium ratio to changes, as well excluding effects relative humidity atmospheric oxidation, proposed possibility competitive uptake ammonia versus amines aerosols or displacement (constraining outbreaks). Overall, this study deepens understanding spatiotemporal differences characteristic China. However, particles form relevant require further mechanistic research.

Language: Английский

---

Aqueous‐Phase Processing Affects the Formation and Size Distribution of Aerosol Organic Functional Groups During Heavy Pollution

Journal of Geophysical Research Atmospheres, Journal Year: 2025, Volume and Issue: 130(3)

Published: Feb. 4, 2025

Abstract Size‐resolved organic functional group (OFG) concentrations in aerosol particles were measured during January−February 2019 Hefei, a major urban city eastern China. Alkane, carboxylic acid, and hydroxyl groups the main components of (OA), contributing 35.0%, 22.5%, 21.8%, respectively. The mass size distributions OFGs strongly depended on ambient relative humidity (RH). Specifically, OFG 50% higher high‐RH periods than low‐RH periods. peak distribution was 0.56–1 μm periods, while 0.32–0.56 observed In addition, total OA, positively correlated with photochemical age (PCA), samples increasing faster (greater slope) PCA being associated oxygen‐to‐carbon ratio. These results suggest that aqueous‐phase processing likely enhanced production OFGs, especially oxygenated groups. Further analysis viscosity aerosols indicates secondary formed via surface‐limited mechanisms under conditions volume‐limited conditions. findings reinforce important role multiphase chemistry formation evolution OAs.

Language: Английский

---

The critical role of aqueous-phase processes in aromatic-derived nitrogen-containing organic aerosol formation in cities with different energy consumption patterns

Atmospheric chemistry and physics, Journal Year: 2025, Volume and Issue: 25(5), P. 2763 - 2780

Published: March 4, 2025

Abstract. Nitrogen-containing organic compounds (NOCs) impact air quality and human health. Here, the abundance, potential precursors, main formation mechanisms of NOCs in PM2.5 during winter were compared for first time among Haerbin (dependent on coal heating), Beijing (natural gas as heating energy), Hangzhou (no centralized policy). The total signal intensity CHON+, CHN+, CHON− was highest lowest Hangzhou. Anthropogenic aromatics accounted 73 %–93 % all identified precursors Haerbin. Although abundance aromatic-derived lower than Haerbin, also contributors to NOC Beijing. exhibited levels aromatic precursors. Furthermore, non-metric multidimensional scaling analysis indicated an overall reduction fossil fuel combustion pollution along route from We found that aqueous-phase processes (mainly condensation, hydrolysis, or dehydration reduced mainly oxidization hydrolysis oxidized NOCs) can promote transformation produce NOCs, leading most significant increase (particularly haze days). Reduced precursor emissions (the lowest) constrained NOCs. results suggest aerosol coal-dependent cities is controlled by anthropogenic processes. Thus, without effective emission controls, through may still pose a large threat quality.

Language: Английский

---

Amino Acid and Amine Compounds in Fine Aerosol Particles: A Review of Determination Methods, Abundances, Origins, and Atmospheric Processes

Aerosol Science and Engineering, Journal Year: 2025, Volume and Issue: unknown

Published: March 6, 2025

Language: Английский

---

Non-biogenic sources are an important but overlooked contributor to aerosol isoprene-derived organosulfates during winter in northern China

Atmospheric chemistry and physics, Journal Year: 2025, Volume and Issue: 25(5), P. 2967 - 2978

Published: March 12, 2025

Abstract. Previous measurement–model comparisons of atmospheric isoprene levels showed a significant unidentified source in some northern Chinese cities during winter. Here, spatial variability winter aerosol organosulfate (OS) formation typical southern (Guangzhou and Kunming) (Xi'an Taiyuan) cities, China, was investigated to reveal the influence potential non-biogenic contributor on OS pollution levels. Monoterpene-derived OSs were significantly higher than which attributed temperature-dependent emission monoterpenes (i.e., temperatures drove more monoterpene emissions). However, isoprene-derived (OSi) opposite trend, with cities. Principal component analysis combined field simulation combustion experiments suggested that biomass burning rather gasoline, diesel, coal contributed abundance OSi The comparison anthropogenic molecular characteristics between particles released from various sources ambient stronger fossil fuel activities promoted considerable OSs. Overall, this study provides direct evidence for first time can contribute China

Language: Английский

---