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Biological particles, as a fraction of organic particles, potentially play a crucial role in ice nucleation processes. However, the contributions and relationships of biological components and organic matter (OM) to atmospheric ice nucleation remain largely unexplored. Here, total ice nucleating particles (INPs), heat‐resistant INPs, lysozyme‐resistant INPs, nanoscale INPs (<0.22 μm), and heat‐resistant nanoscale INPs in precipitation collected at the summit of Mt. Lu, China, were determined using droplet freezing assays coupled with corresponding pretreatments. Heat‐sensitive INPs and lysozyme‐sensitive INPs were considered as biological INPs and bacterial INPs, respectively. Microorganisms and OM molecules in precipitation were identified by high‐throughput sequencing technology and ultrahigh‐resolution mass spectrometry, respectively. Results revealed a predominant biological (heat‐sensitive) composition (78.8% and 93.2%) of total and nanoscale INPs at temperatures above −15°C. Specifically, bacterial (lysozyme‐sensitive) INPs accounted for 36.1% of the biological INPs at temperatures above −15°C. A notable correlation between sulfur‐containing organic compounds, mainly proteinaceous and lignin‐like substances, and INPs was uncovered, with a co‐occurrence network linking these compounds to Gram‐positive bacteria and Agaricomycetes. This study underscored the possible significance of sulfur‐containing organic compounds in the ice nucleation capacity of biological INPs, further shedding light on the ice nucleation mechanisms and potential sources of biological INPs. Plain Language Summary: Ice nucleating particles (INPs) are particles that facilitate the freezing of water at temperatures above the homogenous freezing point, impacting cloud formation and precipitation processes in the atmosphere. This study identified different types of INPs, microbes, and organic matter in precipitation sampled from Mt. Lu in southeastern China and investigated the connections among them. The findings suggested that a significant portion of INPs were of biological origin. Sulfur‐containing organic compounds likely played an important role in ice nucleation, which may originate from certain microbial taxa. This study helps us understand the role of microbes and organic molecules in ice formation, which has broader implications in areas such as preserving biological materials at low temperatures or facilitating artificial snow production. Key Points: Biological materials predominated among the ice nucleating particles (INPs) identified in precipitationSulfur‐containing organic compounds, associated with specific microbial taxa, likely acted as efficient INPs in precipitationThis study provides a preliminary understanding of the connections among INPs, organic matter, and microorganisms [ABSTRACT FROM AUTHOR]

Environmental context: Atmospheric particulate NH4+, primarily produced from the reaction of NH3 and acids, is an important component of PM2.5. In this study, nitrogen stable isotope analyses and an atmospheric chemistry model were used to estimate the contribution of major NH3 sources to particulate NH4+ in Tianjin, a megacity in North China Plain (NCP). Our research has implications for investigations of NH3 emission sources and relevant pollution control in Tianjin and NCP. Rationale: The North China Plain (NCP) has been identified as an NH3 emission hotspot. Source apportionment of NH3 is a prerequisite for controlling NH3 or NH4+ pollution. Nitrogen stable isotope (δ 15N) analysis is a promising method for NH3 source apportionment but its accuracy is still in question. Methodology: In this study, daytime and nighttime PM2.5 samples were collected from two sites in Tianjin, NCP, in autumn. Concentrations and δ 15N of particulate NH4+ were then measured. Nitrogen stable isotope analyses and isotope mixing model (MixSIAR), and an atmospheric chemistry model (WRF-CMAQ-ISAM) were used to estimate the sources of NH3 in Tianjin. Results: Results from the MixSIAR and WRF-CMAQ-ISAM models suggested that all the sources including livestock breeding, N-fertiliser application, fossil fuels, NH3 slip (especially from traffic), human waste and biomass burning (mostly from bioapplication) were non-negligible to NH3 and NH4+ in Tianjin. This high complexity is due to significant agricultural and industrial production and residential life in Tianjin and the surrounding regions. Our results indicate all NH3 sources need to be considered if we want to reduce NH4+ pollution in Tianjin in autumn. Environmental context. Atmospheric particulate NH4+, primarily produced from the reaction of NH3 and acids, is an important component of PM2.5. In this study, nitrogen stable isotope analyses and an atmospheric chemistry model were used to estimate the contribution of major NH3 sources to particulate NH4+ in Tianjin, a megacity in North China Plain (NCP). Our research has implications for investigations of NH3 emission sources and relevant pollution control in Tianjin and NCP. Photograph by Libin Wu. This article belongs to the collection Dedication to Roy Harrison. [ABSTRACT FROM AUTHOR]

Dissolved organic sulfur (DOS) is an important component of dissolved organic matter (DOM) and widely exists at the land‐atmosphere interface. However, the characterization of DOS at the molecular level among different environmental samples in coastal regions has not been sufficiently focused. Here, we investigated DOS in aerosol, rainwater, and river water samples in Shanghai using an improved method–online liquid chromatography coupled to Fourier transform ion cyclotron resonance mass spectrometry (LC‐FT‐ICR MS). This system is utilized to separate DOS from complicated environmental matrices. The results showed that the average relative abundance of DOS in three different environmental media (aerosol, rainwater, and river water samples) accounted for 16.8%, 21.9% and 13.1%, respectively. The common molecules of the three mediums in coastal Shanghai contain an abundance of aromatic and aliphatic DOS of anthropogenic origin in addition to the natural sources of sea spray. Notably, results from a new structural classification scheme for DOS demonstrate that anthropogenic sulfonates and their derivatives are widely spread, although their molecular diversity in different medium was recorded due to complex environmental conditions and diverse sources. Plain Language Summary: Ion suppression of abundant non‐sulfur containing species hinders the detection of dissolved organic sulfur species by direct infusion electrospray ionization mass spectrometry. A newly developed method is proposed to evaluate organic sulfur‐containing compounds at the molecular level using an online liquid chromatography coupled to ultrahigh resolution mass spectrometry, which was applied to aerosol, rainwater, and river water samples in Shanghai. Our study suggests that the novel method allows a detailed investigation of organic sulfur‐containing compounds and provides molecular evidence of the ubiquitous presence of anthropogenic DOS in the ambient environment. Key Points: The ubiquity of natural and anthropogenic dissolved organic sulfur was observed at the water‐atmosphere interfaceNatural dissolved organic sulfur at the coastal water‐atmosphere interface is mainly from sea spray‐based biological sourcesOnline liquid chromatography coupled to FT‐ICR Mass Spectrometry is an ideal system to separate dissolved organic sulfur [ABSTRACT FROM AUTHOR]

Bioaerosols play significant roles in causing health and climate effects. Sugar compounds in air have been widely used to trace the source of bioaerosols. However, knowledge about the association of sugar molecules and the microbial community at taxonomic levels in atmospheric aerosols remains limited. Here, microbial community compositions and sugar molecules in total suspended particles collected from a typical rural site, Gucheng, in the North China Plain were investigated by gas chromatography–mass spectrometry and high-throughput gene sequencing, respectively. Results show that fungal community structure exhibited distinct diurnal variation with largely enhanced contribution of Basidiomycota at night, while bacterial community structure showed no obvious difference between daytime and night. SourceTracker analysis revealed that fungi and bacteria were mainly from plant leaves and unresolved sources (presumably human-related emissions and/or long-distance transport). All the detected anhydrosugars and sugar alcohols and trehalose showed diurnal variations with lower concentrations in the daytime and higher concentrations at night, which may be affected by enhanced fungal emissions at night, while primary sugars (except trehalose) showed an opposite trend. Mantel's test showed that more sugar compounds exhibited significant associations with fungal community structure than bacterial community structure. Co-occurrence analysis revealed the strong associations between sugar compounds and a few saprophytic fungal genera with low relative abundances, e.g., Hannaella, Lectera, Peniophora, Hydnophlebia, Sporobolomyces and Cyphellophora. This study suggests that the entire fungal community, rather than specific fungal taxa, likely greatly contributes to sugar compounds in rural aerosols, while the contribution of bacteria is limited. [ABSTRACT FROM AUTHOR]

Objective: To investigate 38 Y-chromosome short tandem repeat (Y-STR) genetic polymorphisms in Beijing Han and analyze the genetic distance with neighboring or linguistically similar populations. Materials and Methods: In the study, we selected 531 unrelated male individuals of Beijing Han, and the results were statistically analyzed by testing with GSTAR™ 41Y reagents. Results: The allele peak heights were balanced among the Y loci, the amplified fragment ranged from 100 to 500 bps. A total of 531 haplotypes were detected in 531 samples. Eight null genotypes were observed on locus DYS448. One and three double alleles were observed on single-copy locus DYS576 and DYS19, respectively. DYS385 a/b, DYF387S1 a/b, and DYS527 a/b were more common in double copies, but 3, 13, and 11 triple alleles were detected, respectively. The gene diversity values of Y-STRs except DYS391, DYS438, and DYS645 were >0.5. Twenty-seven Y-STRs of Beijing Han population were selected for genetic distance comparison with 17 populations including Changchun Han, with Rst values ranging from 0.0002 to 0.1703. Conclusion: The 38 Y-STRs in this study have strong male lineage identification ability and have great potential for individual identification, kinship identification, Y-STR database construction, and genetic relationship research. [ABSTRACT FROM AUTHOR]

The surface of atmospheric aqueous aerosol is covered with an organic film. However, there have been limited studies about the photochemical process between the organic coating and aqueous samples such as fogwater, which contains light absorbing brown carbon (BrC). Here, the interactional aging process between unsaturated fatty acids and aqueous samples was performed by laboratory studies and field observations. On the one hand, glycine and alanine were selected as organic nitrogen‐containing compounds to form BrC with carbonyl compounds like glyoxal or methylglyoxal. Oleic acid was induced to form organic peroxy radicals through H‐abstraction by the excited triplet BrC or hydroxyl radical (OH). On the other hand, one type of aqueous formation pathway of Criegee intermediates (CIs) was proposed through the oxidation of oleic acid. CIs may be formed by OH addition to C=C bonds and scavenged by interfacial reactions. Results from ultra‐high resolution Fourier transform ion cyclotron resonance mass spectrometry show that the synergistic effect of oleic acid and OH may have a higher oxidative capacity than OH. Furthermore, our study demonstrates that oleic acid can improve the aqueous oxidation ability by producing oxygen‐containing radicals. These findings highlight that the formation of free radicals is greatly influenced by photochemical reactions, which further reveal the complexities of fog organic chemistry. Plain Language Summary: Little is known about how organic coating drives the molecular variance of atmospheric water droplets such as fogwater. Here we report the interactional photochemical process between unsaturated fatty acids and aqueous samples by laboratory studies and field observations. We found that unsaturated fatty acids can enhance the oxidation ability by forming oxygen‐containing radicals to participate in the aging process of aqueous organics. Our results provide unique insight toward a molecular level understanding of the origin, formation, and transformation of reactive intermediates at the air‐water interface, which further reveal the complexities of aqueous atmospheric chemistry. Key Points: Oleic acid is induced to form organic peroxy radicals by the excited triplet brown carbon or OHCriegee intermediates may be formed by OH addition to C=C bonds and scavenged by interfacial reactionsSynergistic effect of oleic acid and OH may have a higher oxidative capacity [ABSTRACT FROM AUTHOR]

Secondary organic aerosols (SOAs) play a key role in climate change and public health. However, the oxidation state and volatility of SOAs are still not well understood. Here, we investigated the highly oxygenated organic molecules (HOMs) in SOAs formed from ozonolysis of β -pinene and limonene. Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS) was used to characterize HOMs in aerosol filter samples, and a scanning mobility particle sizer (SMPS) was used to measure the concentration and size distribution of SOA particles. The relative abundance of HOMs (i.e., ratio of summed mass spectrometry peak intensity of HOMs to totally identified organic compounds) in limonene SOA was 14 %–20 %, higher than in β -pinene SOA (3 %–13 %), exhibiting different trends with increasing ozone concentrations. β -pinene oxidation-derived HOMs exhibit higher yield at high ozone concentration, accompanied by substantial formation of ultra-low-volatile organic compounds (ULVOCs). Limonene oxidation-derived HOMs exhibit higher yield at moderate ozone concentrations, with semi-, low-, and extremely low-volatile organic compounds (SVOCs, LOVCs, and ELVOCs) play a major role. Combined experimental evidence and theoretical analysis indicate that oxygen-increasing-based peroxy radical chemistry is a plausible mechanism for the formation of oxygenated organic compounds with 10 carbon atoms. Our findings show that HOMs and low-volatile species in β -pinene and limonene SOA are largely different. The ozone concentration-driven SOA formation and evolution mechanism for monoterpenes is suggested to be considered in future climate or exposure risk models, which may enable more accurate air quality prediction and management. [ABSTRACT FROM AUTHOR]

Non-destructive plant stress phenotyping begins with traditional one-dimensional (1D) spectroscopy, followed by two-dimensional (2D) imaging, three-dimensional (3D) or even temporal-three-dimensional (T-3D), spectral-three-dimensional (S-3D), and temporal-spectral-three-dimensional (TS-3D) phenotyping, all of which are aimed at observing subtle changes in plants under stress. However, a comprehensive review that covers all these dimensional types of phenotyping, ordered in a spatial arrangement from 1D to 3D, as well as temporal and spectral dimensions, is lacking. In this review, we look back to the development of data-acquiring techniques for various dimensions of plant stress phenotyping (1D spectroscopy, 2D imaging, 3D phenotyping), as well as their corresponding data-analyzing pipelines (mathematical analysis, machine learning, or deep learning), and look forward to the trends and challenges of high-performance multi-dimension (integrated spatial, temporal, and spectral) phenotyping demands. We hope this article can serve as a reference for implementing various dimensions of non-destructive plant stress phenotyping. [ABSTRACT FROM AUTHOR]

Biomass burning is one of the key sources of urban aerosols in the North China Plain, especially during winter, when the impact of secondary organic aerosols (SOAs) formed from biogenic volatile organic compounds (BVOCs) is generally considered to be minor. However, little is known about the influence of biogenic SOA loading on the molecular composition of wintertime organic aerosols. Here, we investigated the water-soluble organic compounds in fine particulate matter (PM 2.5) from urban Tianjin by ultrahigh-resolution Fourier transform ion cyclotron resonanc mass spectrometry (FT-ICR MS). Our results show that most of the CHO and CHON compounds are derived from biomass burning which are poor in oxygen and contain aromatic rings that probably contribute to light-absorbing brown carbon (BrC) chromophores. Under moderate to high SOA-loading conditions, the nocturnal chemistry is more efficient than photooxidation to generate secondary CHO and CHON compounds with high oxygen content. Under low SOA loading, secondary CHO and CHON compounds with low oxygen content are mainly formed by photochemistry. Secondary CHO compounds are mainly derived from oxidation of monoterpenes. However, nocturnal chemistry may be more productive to sesquiterpene-derived CHON compounds. In contrast, the number- and intensity-weight of S-containing groups (CHOS and CHONS) increased significantly with the increase of biogenic SOA loading, which agrees with the fact that a majority of the S-containing groups are identified as organosulfates (OSs) and nitrooxy–organosulfates (nitrooxy–OSs) that are derived from the oxidation of BVOCs. Terpenes may be potential major contributors to organosulfates and nitrooxy–organosulfates. While the nocturnal chemistry is more beneficial to the formation of organosulfates and nitrooxy–organosulfates under low SOA loading. The SOA loading is an important factor that is associated with the oxidation degree, nitrate group content and chemodiversity of nitrooxy-organosulfates. Furthermore, our study suggests that the hydrolysis of nitrooxy-organosulfates is a possible pathway for the formation of organosulfates. [ABSTRACT FROM AUTHOR]

Atmospheric particulate matter (PM) has a significant impact on both the natural environment and human health. Iron is one of the most abundant elements in the earth's crust, playing an important role in geochemical processes, and is also an important trace component in atmospheric PM. In recent years, with the rapid development of non-traditional (metal) stable isotope technologies, new solutions and methods for the source apportionments of heavy metal elements have been put forward. Stable iron isotope analysis has become an effective tool to trace iron in atmospheric particles. This review paper briefly summarizes the recent progress of atmospheric iron isotope geochemistry. We show that some of the major natural and anthropogenic PM sources have different iron isotopic compositions. A Bayesian isotopic mixing model MixSIAR was used to quantitatively re-evaluate the contributions of different sources to iron in both urban and marine aerosols based on iron isotopic data in the literature. The results highlight the value of stable iron isotope analyses as an effective tool in the source apportionment of atmospheric aerosols. [ABSTRACT FROM AUTHOR]

Although ether‐based electrolytes have gradually been identified as a vital factor to achieving the excellent electrochemical performance observed in transition metal sulfide (TMS) anodes in sodium‐ion batteries (SIBs), there is still a lack of a fundamental understanding about the origin of the positive effect of ether‐based electrolytes on TMS anodes. Herein, a microspherical CoS2 anode has been taken as a representative of TMS. It has been demonstrated that the sodiation process involves not only a traditional conversion reaction taking place between solid‐state CoS2 and Na2S, but also a solid–liquid phase conversion process between active materials and soluble sodium polysulfide (Na2Sn, 2 < n < 8). More importantly, it is first revealed that the long‐term stability and the reversibility of CoS2 anode are mainly due to the solid–liquid conversion behavior, which makes bulk CoS2 gradually develop into a stable porous structure with fast Na+ transport kinetics and small stress/strain during cycling. Consequently, the CoS2 electrode delivers remarkable long‐cycle life with an ultrahigh capacity retention rate of 94.8% even after 1500 cycles at 2 A g−1 (only 2.13 mAh g−1 fading per 100 cycles) and high volumetric capacity of 949 mAh cm−3 at a high active material loading of 3.3 mg cm−2. [ABSTRACT FROM AUTHOR]

Brown carbon (BrC) aerosols exert vital impacts on climate change and atmospheric photochemistry due to their light absorption in the wavelength range from near-ultraviolet (UV) to visible light. However, the optical properties and formation mechanisms of ambient BrC remain poorly understood, limiting the estimation of their radiative forcing. In the present study, fine particles (PM 2.5) were collected during 2016–2017 on a day/night basis over urban Tianjin, a megacity in northern China. Light absorption and fluorescence properties of water extracts of PM 2.5 were investigated to obtain seasonal and diurnal patterns of atmospheric water-soluble BrC. There were obvious seasonal, but no evident diurnal, variations in the light absorption properties of BrC. In winter, BrC showed much stronger light-absorbing ability, with a mass absorption efficiency at 365 nm (MAE 365) in winter (1.54±0.33 m 2 gC -1) that was 1.8 times larger than MAE 365 in summer (0.84±0.22 m 2 gC -1). Direct radiative effects by BrC absorption relative to black carbon in the UV range were 54.3±16.9 % and 44.6±13.9 % in winter and summer, respectively. In addition, five fluorescent components in BrC, including three humic-like fluorophores and two protein-like fluorophores were identified with excitation–emission matrix fluorescence spectrometry and parallel factor (PARAFAC) analysis. The less oxygenated components contributed more to winter and nighttime samples, while more oxygenated components increased in summer and daytime samples. The higher humification index (HIX), together with lower biological index (BIX) and fluorescence index (FI), suggests that the chemical compositions of BrC were associated with a high aromaticity degree in summer and daytime due to photobleaching. Fluorescent properties indicate that wintertime BrC were predominantly affected by primary emissions and fresh secondary organic aerosol (SOA), while summer ones were more influenced by aging processes. Results of source apportionments using organic molecular compositions of the same set of aerosols reveal that fossil fuel combustion and aging processes, primary bioaerosol emission, biomass burning, and biogenic and anthropogenic SOA formation were the main sources of BrC. Biomass burning contributed much more to BrC in winter and at nighttime, while biogenic SOA contributed more in summer and during the daytime. In particular, our study highlights that primary bioaerosol emission is an important source of BrC in urban Tianjin in summer. [ABSTRACT FROM AUTHOR]

Organic matter in the gas‐phase and particles are important components of the atmosphere. Photochemical degradation is a major transformation pathway of atmospheric organic matter, which changes the atmospherically related life time and the environmental, climatic, and health‐related effects of organic matter, as well as biogeochemical cycles of elements. In addition to field observations and model simulations, laboratory experiments based on smog chambers and flow tubes are important approaches to study the photodegradation mechanisms and influencing factors of atmospheric organics. Isotopic composition is also a useful tracer for photodegradation processes of different organics, for example, carboxylic acids. In this article, research progress on photodegradation of several significant categories of organic pollutants which have aroused widespread concern currently, for example, polycyclic aromatic hydrocarbons, carboxylic acids, brown carbon, organosulfates/organonitrates, microplastics, and bioaerosols, are reviewed. The effects of different degradation mechanisms including photochemical reactions, heterogeneous aqueous reactions, and microbial degradation are also compared. Although the photodegradation of atmospheric organics has been studied to a certain extent, much more effort should be made to fill the large knowledge gap between the actual and simulated photodegradation processes. [ABSTRACT FROM AUTHOR]