The Science of The Total Environment, Journal Year: 2021, Volume and Issue: 800, P. 149419 - 149419
Published: Aug. 2, 2021
Language: Английский
Journal of Exposure Science & Environmental Epidemiology, Journal Year: 2023, Volume and Issue: 33(4), P. 524 - 536
Published: June 28, 2023
Non-targeted analysis (NTA) and suspect screening (SSA) are powerful techniques that rely on high-resolution mass spectrometry (HRMS) computational tools to detect identify unknown or suspected chemicals in the exposome. Fully understanding chemical exposome requires characterization of both environmental media human specimens. As such, we conducted a review examine use different NTA SSA methods various exposure samples, including results detected. The literature was by searching databases, such as PubMed Web Science, for keywords, "non-targeted analysis", "suspect analysis" media. Sources discussed this include water, air, soil/sediment, dust, food consumer products. discovery biospecimen is also reviewed. space has been captured using varies analyzed analytical platform. In each were frequently detected were: per- polyfluoroalkyl substances (PFAS) pharmaceuticals pesticides polyaromatic hydrocarbons (PAHs) soil sediment, volatile semi-volatile organic compounds flame retardants plasticizers products, plasticizers, pesticides, halogenated samples. Some studies reviewed herein used liquid chromatography (LC) gas (GC) HRMS increase (16%); however, majority (51%) only LC-HRMS fewer GC-HRMS (32%). Finally, knowledge technology gaps must be overcome fully assess potential exposures NTA. Understanding essential identifying prioritizing our sources prior exposures. IMPACT STATEMENT: This examines analyzing samples based non-targeted (SSA).
Language: Английский
Citations
89
Atmospheric chemistry and physics, Journal Year: 2022, Volume and Issue: 22(1), P. 273 - 293
Published: Jan. 10, 2022
Abstract. Vanillin (VL), a phenolic aromatic carbonyl abundant in biomass burning emissions, forms triplet excited states (3VL∗) under simulated sunlight leading to aqueous secondary organic aerosol (aqSOA) formation. Nitrate and ammonium are among the main components of aerosols cloud or fog water. Under atmospherically relevant conditions, solutions composed either VL only with nitrate were subjected irradiation compare aqSOA formation via direct photosensitized oxidation absence presence nitrate. The reactions characterized by examining decay kinetics, product compositions, light absorbance changes. Both conditions generated oligomers, functionalized monomers, oxygenated ring-opening products, promoted functionalization nitration, likely due its photolysis products (⚫OH, ⚫NO2, NO2- HONO). Moreover, potential imidazole derivative observed suggested that participated reactions. majority most from both brown carbon (BrC) chromophores. effects oxygen (O2), pH, reactants concentration molar ratios on also explored. Our findings show O2 plays an essential role reactions, oligomer was enhanced at pH <4. Also, dominant low concentrations, whereas oligomerization favored high concentrations. Furthermore, oligomers hydroxylated detected guaiacol (a non-carbonyl phenol) Last, pathways proposed. This study indicates may be important source areas influenced underscores importance aqueous-phase processing carbonyls.
Language: Английский
Citations
82
Atmospheric chemistry and physics, Journal Year: 2023, Volume and Issue: 23(4), P. 2859 - 2875
Published: March 2, 2023
Abstract. Aromatic carbonyls (e.g., methoxybenzaldehydes), an important class of photosensitizers, are abundant in the atmosphere. Photosensitization and nitrate-mediated photo-oxidation can occur simultaneously, yet studies about their interactions, particularly for aqueous secondary organic aerosol (aqSOA) formation, remain limited. This study compared non-phenolic (3,4-dimethoxybenzaldehyde, DMB) phenolic (vanillin, VL) methoxybenzaldehydes as photosensitizers aqSOA formation via guaiacol (GUA) oxidation absence presence ammonium nitrate (AN) under atmospherically relevant cloud fog conditions. GUA by triplet excited states DMB (3DMB∗) (GUA + was ∼ 4 times faster exhibited greater light absorption than 3VL∗ VL). Both VL formed composed oligomers, functionalized monomers, oxygenated ring-opening species, N-containing products AN. The observation N-heterocycles such imidazoles indicates participation reactions. majority generated comprises potential brown carbon (BrC) chromophores. Oligomerization functionalization dominated VL, but appeared to be more due contributions from itself. AN did not significantly affect kinetics, it had distinct effects on product distributions, likely differences photosensitizing abilities structural features VL. In particular, extensive fragmentation AN, increased oligomers may VL-derived phenoxy radicals induced ⚫OH or ⚫NO2 photolysis. Furthermore, nitrated observed both alone imply that photosensitized reactions promote nitration. work demonstrates how non-carbonyl phenol oxidation. Potential interactions between photosensitization photolysis were also elucidated. These findings facilitate a better understanding highlight importance these
Language: Английский
Citations
26
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: 2022, Volume and Issue: 56(11), P. 7017 - 7028
Published: March 18, 2022
The molecular composition of atmospheric particulate matter (PM) in the urban environment is complex, and it remains a challenge to identify its sources formation pathways. Here, we report seasonal variation organic aerosols (OA), based on 172 PM2.5 filter samples collected Beijing, China, from February 2018 March 2019. We applied hierarchical cluster analysis (HCA) large nontarget-screening data set found strong difference OA chemical composition. Molecular fingerprints major compound clusters exhibit unique pattern Van Krevelen-space. that summer Beijing features higher degree oxidation proportion organosulfates (OSs) comparison during wintertime, which exhibits high contribution (nitro-)aromatic compounds. OSs appeared with intensity summer-haze conditions, indicating importance anthropogenic enhancement secondary Beijing. Furthermore, quantified four main total using surrogate standards. With this approach, are able explain small fraction (∼11–14%) monitored by Time-of-Flight Aerosol Chemical Speciation Monitor (ToF-ACSM). However, observe correlation between sum measured ToF-ACSM, identified represent variability cycles. This study highlights potential nontarget screening combination HCA for gaining better understanding origin environment.
Language: Английский
Citations
32
Atmospheric chemistry and physics, Journal Year: 2022, Volume and Issue: 22(10), P. 6919 - 6935
Published: May 30, 2022
Abstract. Organosulfur compounds (OrgSs), especially organosulfates, have been widely reported to be present in large quantities particulate organic matter found various atmospheric environments. Despite hundreds of organosulfates and their formation mechanisms being previously identified, a fraction OrgSs remain unexplained at the molecular level, better understanding pathways critical environmental parameters is required explain variations concentrations. In this study, abundance composition fine samples collected Guangzhou were reported. The results revealed that ratio annual average mass sulfur total was 33 ± 12 %, had positive correlations with SO2 (r=0.37, p<0.05) oxidant (NOx + O3, r=0.40, p<0.01). A Fourier transform ion cyclotron resonance spectrometry (FT-ICR MS) analysis more than 80 % sulfur-containing formulas detected elemental o/(4s+3n)≥1, indicating they largely form oxidized or nitrooxy organosulfates. Many tentatively identified as having biogenic anthropogenic origins also freshly emitted aerosols derived from combustion sources. indicated through an epoxide intermediate pathway could account for up 46 upper bound estimation, levels 20 variation sulfur. our dataset FT-ICR MS suggested relative humidity, oxidation volatile via ozonolysis, NOx-related organosulfate major reasons OrgSs, possibly highlighting importance acid-catalyzed ring-opening epoxides, processes, heterogeneous reactions involving either uptake into additional unrecognized OrgSs.
Language: Английский
Citations
31
Environmental Science & Technology, Journal Year: 2023, Volume and Issue: 57(23), P. 8708 - 8718
Published: June 2, 2023
The molecular composition of organic aerosols in ambient PM2.5 was investigated an urban area the Guanzhong basin northwest China during a severe regional haze episode winter 2018/2019. Organic matter, accounting for 20–35% mass concentration, characterized using direct infusion and electrospray ionization coupled with high-resolution Orbitrap spectrometry. number formula assignments primarily dominated by organosulfur species (OrgS, including CHOS CHONS) negative ion mode. peak signal intensity OrgS distinctly increased episode. Organosulfates nitrooxy-organosulfates constituted majority (72–94%) over entire period. Although were mostly present aliphatic structures, increase polycyclic aromatic on days revealed enhanced contribution from anthropogenic sources. strongly correlated relative humidity oxidation ratios sulfur nitrogen, suggesting important roles aqueous phase chemistry atmospheric formation OrgS. A thorough understanding significance will be essential to assess mitigate adverse impacts pollution.
Language: Английский
Citations
19
Environmental Science & Technology, Journal Year: 2024, Volume and Issue: unknown
Published: Feb. 23, 2024
Particulate brown carbon (BrC) plays a crucial role in the global radiative balance due to its ability absorb light. However, effect of molecular formation on light absorption properties BrC remains poorly understood. In this study, atmospheric samples collected from six Chinese megacities winter and summer were characterized through ultrahigh-performance liquid chromatography coupled with Orbitrap mass spectrometry (UHPLC-Orbitrap MS) measurements. The average values coefficient at wavelength 365 nm (babs365) approximately 4.0 times higher than those summer. Nitrogen-containing organic molecules (CHNO) identified as critical components light-absorbing substances both seasons, underscoring importance N-addition BrC. These nitrogen-containing chromophores more closely related nitro-containing compounds originating biomass burning nitrogen oxides (NOx)/nitrate (NO3–) reactions winter. summer, they reduced N-containing formed ammonia (NH3)/ammonium (NH4+) reactions. NH3/NH4+-mediated contributed secondary winter, particularly southern cities. Compared O/Cw, lower molecule conjugation indicator (double bond equivalent, DBE), babs365 suggest possible bleaching mechanism during oxidation process. findings strengthen connection between composition BrC, providing insights into mechanisms across northern cities different seasons.
Language: Английский
Citations
8
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
Citations
7
Environmental Science & Technology, Journal Year: 2024, Volume and Issue: 58(18), P. 7924 - 7936
Published: April 23, 2024
Aromatic carbonyls have been mainly probed as photosensitizers for aqueous secondary organic aerosol (aqSOA) and light-absorbing (i.e., brown carbon or BrC) formation, but due to their nature, they can also undergo oxidation form aqSOA BrC. However, photochemical transformations of aromatic carbonyl photosensitizers, particularly in multicomponent systems, are understudied. This study explored formation from the irradiation mixed single systems under cloud/fog conditions. Mixed consisting phenolic only (VL + ActSyr SyrAld: vanillin [VL] acetosyringone [ActSyr] syringaldehyde [SyrAld]) another composed both nonphenolic (DMB 3,4-dimethoxybenzaldehyde [DMB], a carbonyl, SyrAld) were compared VL (VL*) DMB (DMB*), respectively. In shorter lifetimes indicate diminished capacity trigger other compounds (e.g., guaiacol [GUA], noncarbonyl phenol). contrast slow decay minimal photoenhancement DMB*, rapid photodegradation significant VL* efficient direct photosensitized self-photosensitization). Relative increased oxidant availability promoted functionalization SyrAld accelerated conversion early generation SyrAld. Moreover, oxidizable substrates countered by stronger oxidative limited contribution light absorption. suggests weaker radiative effect BrC photosensitizer than systems. Furthermore, more oxygenated oxidized was observed with increasing complexity reaction < GUA). work offers new insights into emphasizing dual role sources substrates.
Language: Английский
Citations
7