Published: Dec. 20, 2022
Language: Английский
Environmental Science & Technology, Journal Year: 2024, Volume and Issue: 58(16), P. 7099 - 7112
Published: March 27, 2024
Reduced nitrogen-containing organic compounds (NOCs) in aerosols play a crucial role altering their light-absorption properties, thereby impacting regional haze and climate. Due to the low concentration levels of individual NOCs air, utilization accurate detection quantification technologies becomes essential. For first time, this study investigated diurnal variation, chemical characteristics, potential formation pathways urban ambient Shanghai using versatile aerosol enrichment system (VACES) coupled with HPLC-Q-TOF-MS. The results showed that accounted over 60% identified components aerosols, O/N < 3 being major contributors (>70%). predominance positive ionization mode suggested prevalence reduced NOCs. Higher relative intensities number fractions were observed during nighttime, while CHO an opposite trend. Notably, correlation between intensity ammonium nighttime was observed, suggesting reaction form imines may be pathway for nighttime. Seven prevalent types autumn winter characterized by CH2 long-chain homologues. These included alkyl, cyclic, aromatic amides CHON compounds, as well heterocyclic or cyclic amines aniline homologue series CHN which associated anthropogenic activities capable forming light-absorbing chromophores posing harm human health. findings highlight significant contributions both primary emissions chemistry, particularly amination processes, pollution Shanghai's atmosphere.
Language: Английский
Citations
10
Environmental Science & Technology, Journal Year: 2023, Volume and Issue: 57(51), P. 21570 - 21580
Published: Nov. 21, 2023
The limited characterization and detection capacity of unknown compounds hinder our understanding the molecular composition toxic in PM2.5. present study applied Fourier transform ion cyclotron resonance mass spectrometry coupled with negative positive electrospray ionization sources (ESI–/ESI+ FT-ICR-MS) to probe characteristics dynamic formation processes effective proinflammatory components organic aerosols (OAs) PM2.5 Guangzhou for one year. We detected abundant molecules OAs, mainly classified as CHON (compounds composed C, H, O, N atoms) elemental nitroaromatic (NACs) structures. From perspective process, we discovered that these molecules, especially NACs, were largely driven by secondary nitrate biomass burning (in emission source), well SO2 atmospheric evolution). In addition, results indicated had replaced primary main contributing source OAs. This highlights importance community measures control production derived from urban areas.
Language: Английский
Citations
21
Environmental Science & Technology, Journal Year: 2023, Volume and Issue: 57(43), P. 16500 - 16511
Published: Oct. 16, 2023
Nitrogen-containing organic compounds (NOCs), a type of important reactive-nitrogen species, are abundant in aerosols haze events observed Northern China. However, due to the complex nature NOCs, sources, formation, and influencing factors still ambiguous. Here, molecular composition matters (OMs) hourly PM2.5 samples collected during event China was characterized using Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS). We found that CHON (formulas containing C, H, O, N atoms) dominated OM fractions showed high chemodiversity transformability. Relying on newly developed revised-workflow oxidation-hydrolyzation knowledge for compounds, 64% major aromatic (>80%) could be derived from oxidization or hydrolyzation processes. Results FT-ICR MS data analysis further aerosol liquid water (ALW)-involved aqueous-phase reactions distribution aromatic-CHON besides coal combustion, ALW-involved compound formation daytime nighttime different. Our results improve understanding composition, potential which can help advance evolution, control haze.
Language: Английский
Citations
20
Atmospheric measurement techniques, Journal Year: 2024, Volume and Issue: 17(2), P. 423 - 439
Published: Jan. 22, 2024
Abstract. This study aims to enhance the understanding and application of Aerodyne high-resolution aerosol mass spectrometer (HR-AMS) for comprehensive characterization organic nitrogen (ON) compounds in particles atmospheric droplets. To achieve this goal, we analyzed 75 N-containing compounds, representing a diverse range ambient non-organonitrate ON (NOON) types, including amines, amides, amino acids, N heterocycles, protein, humic acids. Our results show that NOON can produce significant levels NHx+ NOx+ ion fragments, which are typically recognized as ions representative inorganic species. We also identified presence CH2N+ at m/z = 28.0187, an fragment rarely quantified datasets due substantial interference from N2+. As result, utilization updated calibration factor 0.79 is necessary accurate quantification via HR-AMS. assessed relative ionization efficiencies (RIEs) various species found average RIE (1.52 ± 0.58) aligns with commonly used default value 1.40 aerosol. Moreover, through careful examination HR-AMS spectral features propose fingerprint series aid speciation analysis. For instance, CnH2n+2N+ closely linked CH4N+ indicating primary C2H6N+ suggesting secondary C3H8N+ tertiary amines. CnH2nNO+ (especially n values 1–4) very likely derived amides. The co-existence three ions, C2H4NO2+, C2H3NO+, CH4NO+, serves indicator Additionally, CxHyN2+ indicates occurrence 2N-heterocyclic compounds. Notably, elevated abundance NH4+ distinct signature amines ammonium salts only negligible amounts Finally, contents submicron (PM1) fog water Fresno, California, PM1 New York City (NYC). revealed both Fresno NYC aerosols, whereas concurrently collected contained broader species, aromatic heterocycle (e.g., imidazoles) These findings highlight potential employing widespread measurements aerosols droplets our sources, transformation processes, environmental impacts associated atmosphere.
Language: Английский
Citations
6
Atmospheric chemistry and physics, Journal Year: 2024, Volume and Issue: 24(12), P. 6987 - 6999
Published: June 18, 2024
Abstract. While aqueous-phase processing is known to contribute the formation of nitrogen-containing organic compounds (NOCs), specific pathways involved remain poorly understood. In this study, we aimed characterize NOCs present in both pre-fog aerosols and fog water collected at a suburban site northern China. Fourier-transform ion cyclotron resonance mass spectrometry was utilized analyze molecular composition negative positive modes electrospray ionization (ESI− ESI+). samples, constituted significant portion, accounting for over 60 % all assigned formulas ESI− more than 80 ESI+. By comparing originating from biomass burning, coal combustion, vehicle emissions, identified that 72.3 were attributed primary anthropogenic sources (pNOCs), while remaining categorized as secondary formed within (saNOCs). Unique found classified (sfNOCs). Through comprehensive “precursor–product pair” screening involving 39 reaction pathways, observed nitration reaction, amine pathway, intramolecular N-heterocycle pathway NH3 addition reactions contributed 43.6 %, 22.1 11.6 saNOCs, respectively. contrast, these 26.8 28.4 29.7 sfNOCs, This disparity likely influenced by diverse precursors, aqueous acidity, gas-phase species partitioning. Correspondingly, saNOCs contain higher abundance carbohydrate-like highly oxygenated with two nitrogen atoms compared pNOCs. Conversely, sfNOCs exhibited content lipid-like fewer oxygen atoms. These results underscore distinct processes contributing diversity water, which may lead their different climate effects.
Language: Английский
Citations
3
npj Climate and Atmospheric Science, Journal Year: 2024, Volume and Issue: 7(1)
Published: Oct. 1, 2024
Language: Английский
Citations
3
Published: Feb. 5, 2024
Abstract. While aqueous-phase processing contributes to the formation of nitrogen-containing organic compounds (NOCs), detailed pathways are not well understood. In this study, molecular composition NOCs in both pre-fog aerosols and fog water collected at a suburban site northern China was characterized using Fourier-transform ion cyclotron resonance mass spectrometry negative positive modes electrospray ionization (ESI- ESI+). water, account for number fractions more than 60 % all assigned formulas ESI- mode 80 ESI+ mode. By comparing biomass burning, coal combustion, vehicle emissions, 72.3 were as originating from these primary anthropogenic sources (pNOCs), while remaining regarded secondary formed aerosol (saNOCs). On other hand, unique (sfNOCs). According “precursor-product pair” screening involving 39 reaction pathways, we found that nitration reaction, amine pathway intramolecular N-heterocycle NH3 addition reactions contribute 43.6 %, 22.1 11.6 saNOCs, but 26.8 28.4 29.7 sfNOCs, respectively. Such distinct most likely attributed diverse precursors aqueous acidity. Correspondingly, saNOCs contain abundant carbohydrates-like highly oxygenated with two nitrogen atoms compared pNOCs, whereas sfNOCs lipids-like fewer oxygen atoms. The results reveal disparity processes richness water. findings valuable understanding control pollution.
Language: Английский
Citations
1
Published: Aug. 10, 2023
Abstract. This study aims to enhance the understanding and application of Aerodyne high-resolution aerosol mass spectrometer (HR-AMS) for comprehensive characterization organic nitrogen (ON) compounds in particles atmospheric droplets. To achieve this, we analyzed seventy-five N-containing compounds, representing a diverse range ambient ON types, including amines, amides, amino acids, N-heterocycles, protein, humic acids. Our results show that can produce significant levels NHx+ NOx+ ion fragments, which are typically recognized as ions representative inorganic species. We also discovered presence CH2N+ at m/z = 28.0187, an fragment is rarely quantified datasets due substantial interference from air-related N2+. As result, determined updated calibration factor 0.79 necessary accurately quantify content using spectrometry. assessed relative ionization efficiencies (RIEs) different species found average RIE (1.52 ± 0.58) aligns with commonly used default value 1.40 (OA). Moreover, through careful examination HR-AMS spectral features various propose fingerprint series aid speciation analysis. The CnH2n+2N+ closely linked CH4N+ indicating primary C2H6N+ suggesting secondary C3H8N+ tertiary amines. CnH2nNO+ (especially n values 1–4) very likely derived amides. co-existence three ions, C2H4NO2+, C2H3NO+, CH4NO+, serves indicator Additionally, CxHyN2+ indicates occurrence 2N-heterocyclic compounds. Notably, elevated abundance NH4+ distinct signature amines ammonium salts only negligible amounts HR-AMS. Finally, contents submicron (PM1) fog waters Fresno, California PM1 New York City (NYC). revealed both Fresno NYC aerosols, whereas concurrently collected contained broader species, aromatic heterocycle (e.g., imidazoles) These findings highlight potential employing widespread measurements aerosols droplets our sources, transformation processes, environmental impacts associated atmosphere.
Language: Английский
Citations
3
Sustainability, Journal Year: 2023, Volume and Issue: 15(11), P. 8568 - 8568
Published: May 25, 2023
By quantifying the absorption of black carbon (BC), brown (BrC) and lensing effect, we found that BrC dominates total at 450 nm, largest contribution proportion could reach 78.3% during heavy pollution. The average enhancement (Eabs) 530 nm was only 1.38, indicating BC is not coated well here. value Ångstrom exponent (AAE) between 5.3, suggesting a high concentration in Wangdu. CHN+ greatest contributor to light molecules detected MSOC with 12.2–22.4%, which polycyclic aromatic nitrogen heterocycles (PANHs) were dominant compounds. C6H5NO3 its homologous series accounted for 3.0–11.3%, C15H9N series, including one C16H11N three C17H13N compounds, 5.1–12.3%. these PANHs comparable nitro–aromatics, should attract more attention impact climate radiative forcing.
Language: Английский
Citations
2
Environmental Science Nano, Journal Year: 2023, Volume and Issue: 11(1), P. 309 - 323
Published: Nov. 15, 2023
The intensity of light illumination played an important role in the formation organic ammonium salts on nano-hematite.
Language: Английский
Citations
1