Publications by authors named "Haijie Tong"

10 Publications

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The maximum carbonyl ratio (MCR) as a new index for the structural classification of secondary organic aerosol components.

Rapid Commun Mass Spectrom 2021 Jul;35(14):e9113

Department of Chemistry, Johannes Gutenberg University, Mainz, 55128, Germany.

Rationale: Organic aerosols (OA) account for a large fraction of atmospheric fine particulate matter and thus are affecting climate and public health. Elucidation of the chemical composition of OA is the key for addressing the role of ambient fine particles at the atmosphere-biosphere interface and mass spectrometry is the main method to achieve this goal.

Methods: High-resolution mass spectrometry (HRMS) is on its way to becoming one of the most prominent analytical techniques, also for the analysis of atmospheric aerosols. The combination of high mass resolution and accurate mass determination allows the elemental compositions of numerous compounds to be easily elucidated. Here a new parameter for the improved classification of OA is introduced - the maximum carbonyl ratio (MCR) - which is directly derived from the molecular composition and is particularly suitable for the identification and characterization of secondary organic aerosols (SOA).

Results: The concept is exemplified by the analysis of ambient OA samples from two measurement sites (Hyytiälä, Finland; Beijing, China) and of laboratory-generated SOA based on ultrahigh-performance liquid chromatography (UHPLC) coupled to Orbitrap MS. To interpret the results, MCR-Van Krevelen (VK) diagrams are generated for the different OA samples and the individual compounds are categorized into specific areas in the diagrams. The results show that the MCR index is a valuable parameter for representing atmospheric SOA components in composition and structure-dependent visualization tools such as VK diagrams.

Conclusions: The MCR index is suggested as a tool for a better characterization of the sources and the processing of atmospheric OA components based on HRMS data. Since the MCR contains information on the concentration of highly electrophilic organic compounds in particulate matter (PM) as well as on the concentration of organic (hydro)peroxides, the MCR could be a promising metric for identifying health-related particulate matter parameters by HRMS.
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http://dx.doi.org/10.1002/rcm.9113DOI Listing
July 2021

Oxygenated and Nitrated Polycyclic Aromatic Hydrocarbons in Ambient Air-Levels, Phase Partitioning, Mass Size Distributions, and Inhalation Bioaccessibility.

Environ Sci Technol 2020 03 11;54(5):2615-2625. Epub 2020 Feb 11.

Multiphase Chemistry Department, Max Planck Institute for Chemistry, Mainz 55128, Germany.

Among the nitrated and oxygenated polycyclic aromatic hydrocarbons (NPAHs and OPAHs) are some of the most hazardous substances to public health, mainly because of their carcinogenicity and oxidative potential. Despite these concerns, the concentrations and fate of NPAHs and OPAHs in the atmospheric environment are largely unknown. Ambient air concentrations of 18 NPAHs, 5 quinones, and 5 other OPAHs were determined at two urban and one regional background sites in central Europe. At one of the urban sites, the total (gas and particulate) concentrations of ΣOPAHs were 10.0 ± 9.2 ng/m in winter and 3.5 ± 1.6 ng/m in summer. The gradient to the regional background site exceeded 1 order of magnitude. ΣNPAH concentrations were typically 1 order of magnitude lower than OPAHs. Among OPAHs, 9-fluorenone and (9,10)-anthraquinone were the most abundant species, accompanied by benzanthrone in winter. (9,10)-Anthraquinone represented two-thirds of quinones. We found that a large fraction of the target substance particulate mass was carried by submicrometer particles. The derived inhalation bioaccessibility in the PM size fraction is found to be ≈5% of the total ambient concentration of OPAHs and up to ≈2% for NPAHs. For 9-fluorenone and (9,10)-anthraquinone, up to 86 and 18%, respectively, were found at the rural site. Our results indicate that water solubility could function as a limiting factor for bioaccessibility of inhaled particulate NPAHs and OPAHs, without considerable effect of surfactant lipids and proteins in the lung lining fluid.
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http://dx.doi.org/10.1021/acs.est.9b06820DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7307896PMC
March 2020

Radical Formation by Fine Particulate Matter Associated with Highly Oxygenated Molecules.

Environ Sci Technol 2019 Nov 7;53(21):12506-12518. Epub 2019 Oct 7.

Institute for Atmospheric and Earth System Research/Physics Faculty of Science , University of Helsinki , FI-00014 Helsinki , Finland.

Highly oxygenated molecules (HOMs) play an important role in the formation and evolution of secondary organic aerosols (SOA). However, the abundance of HOMs in different environments and their relation to the oxidative potential of fine particulate matter (PM) are largely unknown. Here, we investigated the relative HOM abundance and radical yield of laboratory-generated SOA and fine PM in ambient air ranging from remote forest areas to highly polluted megacities. By electron paramagnetic resonance and mass spectrometric investigations, we found that the relative abundance of HOMs, especially the dimeric and low-volatility types, in ambient fine PM was positively correlated with the formation of radicals in aqueous PM extracts. SOA from photooxidation of isoprene, ozonolysis of α- and β-pinene, and fine PM from tropical (central Amazon) and boreal (Hyytiälä, Finland) forests exhibited a higher HOM abundance and radical yield than SOA from photooxidation of naphthalene and fine PM from urban sites (Beijing, Guangzhou, Mainz, Shanghai, and Xi'an), confirming that HOMs are important constituents of biogenic SOA to generate radicals. Our study provides new insights into the chemical relationship of HOM abundance, composition, and sources with the yield of radicals by laboratory and ambient aerosols, enabling better quantification of the component-specific contribution of source- or site-specific fine PM to its climate and health effects.
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http://dx.doi.org/10.1021/acs.est.9b05149DOI Listing
November 2019

Reactive Oxygen Species Formed by Secondary Organic Aerosols in Water and Surrogate Lung Fluid.

Environ Sci Technol 2018 10 4;52(20):11642-11651. Epub 2018 Oct 4.

Multiphase Chemistry Department , Max Planck Institute for Chemistry , 55128 Mainz , Germany.

Reactive oxygen species (ROS) play a central role in adverse health effects of air pollutants. Respiratory deposition of fine air particulate matter can lead to the formation of ROS in epithelial lining fluid, potentially causing oxidative stress and inflammation. Secondary organic aerosols (SOA) account for a large fraction of fine particulate matter, but their role in adverse health effects is unclear. Here, we quantify and compare the ROS yields and oxidative potential of isoprene, β-pinene, and naphthalene SOA in water and surrogate lung fluid (SLF). In pure water, isoprene and β-pinene SOA were found to produce mainly OH and organic radicals, whereas naphthalene SOA produced mainly HO and O. The total molar yields of ROS of isoprene and β-pinene SOA were 11.8% and 8.2% in water and decreased to 8.5% and 5.2% in SLF, which can be attributed to ROS removal by lung antioxidants. A positive correlation between the total peroxide concentration and ROS yield suggests that organic (hydro)peroxides may play an important role in ROS formation from biogenic SOA. The total molar ROS yields of naphthalene SOA was 1.7% in water and increased to 11.3% in SLF. This strong increase is likely due to redox reaction cycles involving environmentally persistent free radicals (EPFR) or semiquinones, antioxidants, and oxygen, which may promote the formation of HO and the adverse health effects of anthropogenic SOA from aromatic precursors.
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http://dx.doi.org/10.1021/acs.est.8b03695DOI Listing
October 2018

Aerosol Health Effects from Molecular to Global Scales.

Environ Sci Technol 2017 Dec 27;51(23):13545-13567. Epub 2017 Nov 27.

National Institute for Environmental Studies , Tsukuba 305-8506, Japan.

Poor air quality is globally the largest environmental health risk. Epidemiological studies have uncovered clear relationships of gaseous pollutants and particulate matter (PM) with adverse health outcomes, including mortality by cardiovascular and respiratory diseases. Studies of health impacts by aerosols are highly multidisciplinary with a broad range of scales in space and time. We assess recent advances and future challenges regarding aerosol effects on health from molecular to global scales through epidemiological studies, field measurements, health-related properties of PM, and multiphase interactions of oxidants and PM upon respiratory deposition. Global modeling combined with epidemiological exposure-response functions indicates that ambient air pollution causes more than four million premature deaths per year. Epidemiological studies usually refer to PM mass concentrations, but some health effects may relate to specific constituents such as bioaerosols, polycyclic aromatic compounds, and transition metals. Various analytical techniques and cellular and molecular assays are applied to assess the redox activity of PM and the formation of reactive oxygen species. Multiphase chemical interactions of lung antioxidants with atmospheric pollutants are crucial to the mechanistic and molecular understanding of oxidative stress upon respiratory deposition. The role of distinct PM components in health impacts and mortality needs to be clarified by integrated research on various spatiotemporal scales for better evaluation and mitigation of aerosol effects on public health in the Anthropocene.
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http://dx.doi.org/10.1021/acs.est.7b04417DOI Listing
December 2017

Atmospheric protein chemistry influenced by anthropogenic air pollutants: nitration and oligomerization upon exposure to ozone and nitrogen dioxide.

Faraday Discuss 2017 08;200:413-427

Multiphase Chemistry Department, Max Planck Institute for Chemistry, Hahn-Meitner-Weg 1, 55128 Mainz, Germany.

The allergenic potential of airborne proteins may be enhanced via post-translational modification induced by air pollutants like ozone (O) and nitrogen dioxide (NO). The molecular mechanisms and kinetics of the chemical modifications that enhance the allergenicity of proteins, however, are still not fully understood. Here, protein tyrosine nitration and oligomerization upon simultaneous exposure of O and NO were studied in coated-wall flow-tube and bulk solution experiments under varying atmospherically relevant conditions (5-200 ppb O, 5-200 ppb NO, 45-96% RH), using bovine serum albumin as a model protein. Generally, more tyrosine residues were found to react via the nitration pathway than via the oligomerization pathway. Depending on reaction conditions, oligomer mass fractions and nitration degrees were in the ranges of 2.5-25% and 0.5-7%, respectively. The experimental results were well reproduced by the kinetic multilayer model of aerosol surface and bulk chemistry (KM-SUB). The extent of nitration and oligomerization strongly depends on relative humidity (RH) due to moisture-induced phase transition of proteins, highlighting the importance of cloud processing conditions for accelerated protein chemistry. Dimeric and nitrated species were major products in the liquid phase, while protein oligomerization was observed to a greater extent for the solid and semi-solid phase states of proteins. Our results show that the rate of both processes was sensitive towards ambient ozone concentration, but rather insensitive towards different NO levels. An increase of tropospheric ozone concentrations in the Anthropocene may thus promote pro-allergic protein modifications and contribute to the observed increase of allergies over the past decades.
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http://dx.doi.org/10.1039/c7fd00005gDOI Listing
August 2017

Reactive oxygen species formed in aqueous mixtures of secondary organic aerosols and mineral dust influencing cloud chemistry and public health in the Anthropocene.

Faraday Discuss 2017 08;200:251-270

Multiphase Chemistry Department, Max Planck Institute for Chemistry, Mainz, Germany.

Mineral dust and secondary organic aerosols (SOA) account for a major fraction of atmospheric particulate matter, affecting climate, air quality and public health. How mineral dust interacts with SOA to influence cloud chemistry and public health, however, is not well understood. Here, we investigated the formation of reactive oxygen species (ROS), which are key species of atmospheric and physiological chemistry, in aqueous mixtures of SOA and mineral dust by applying electron paramagnetic resonance (EPR) spectrometry in combination with a spin-trapping technique, liquid chromatography-tandem mass spectrometry (LC-MS/MS), and a kinetic model. We found that substantial amounts of ROS including OH, superoxide as well as carbon- and oxygen-centred organic radicals can be formed in aqueous mixtures of isoprene, α-pinene, naphthalene SOA and various kinds of mineral dust (ripidolite, montmorillonite, kaolinite, palygorskite, and Saharan dust). The molar yields of total radicals were ∼0.02-0.5% at 295 K, which showed higher values at 310 K, upon 254 nm UV exposure, and under low pH (<3) conditions. ROS formation can be explained by the decomposition of organic hydroperoxides, which are a prominent fraction of SOA, through interactions with water and Fenton-like reactions with dissolved transition metal ions. Our findings imply that the chemical reactivity and aging of SOA particles can be enhanced upon interaction with mineral dust in deliquesced particles or cloud/fog droplets. SOA decomposition could be comparably important to the classical Fenton reaction of HO with Fe and that SOA can be the main source of OH radicals in aqueous droplets at low concentrations of HO and Fe. In the human respiratory tract, the inhalation and deposition of SOA and mineral dust can also lead to the release of ROS, which may contribute to oxidative stress and play an important role in the adverse health effects of atmospheric aerosols in the Anthropocene.
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http://dx.doi.org/10.1039/c7fd00023eDOI Listing
August 2017

Release of free amino acids upon oxidation of peptides and proteins by hydroxyl radicals.

Anal Bioanal Chem 2017 Mar 20;409(9):2411-2420. Epub 2017 Jan 20.

Multiphase Chemistry Department, Max Planck Institute for Chemistry, Hahn-Meitner-Weg 1, 55128, Mainz, Germany.

Hydroxyl radical-induced oxidation of proteins and peptides can lead to the cleavage of the peptide, leading to a release of fragments. Here, we used high-performance liquid chromatography tandem mass spectrometry (HPLC-MS/MS) and pre-column online ortho-phthalaldehyde (OPA) derivatization-based amino acid analysis by HPLC with diode array detection and fluorescence detection to identify and quantify free amino acids released upon oxidation of proteins and peptides by hydroxyl radicals. Bovine serum albumin (BSA), ovalbumin (OVA) as model proteins, and synthetic tripeptides (comprised of varying compositions of the amino acids Gly, Ala, Ser, and Met) were used for reactions with hydroxyl radicals, which were generated by the Fenton reaction of iron ions and hydrogen peroxide. The molar yields of free glycine, aspartic acid, asparagine, and alanine per peptide or protein varied between 4 and 55%. For protein oxidation reactions, the molar yields of Gly (∼32-55% for BSA, ∼10-21% for OVA) were substantially higher than those for the other identified amino acids (∼5-12% for BSA, ∼4-6% for OVA). Upon oxidation of tripeptides with Gly in C-terminal, mid-chain, or N-terminal positions, Gly was preferentially released when it was located at the C-terminal site. Overall, we observe evidence for a site-selective formation of free amino acids in the OH radical-induced oxidation of peptides and proteins, which may be due to a reaction pathway involving nitrogen-centered radicals.
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http://dx.doi.org/10.1007/s00216-017-0188-yDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5352754PMC
March 2017

Chemical exposure-response relationship between air pollutants and reactive oxygen species in the human respiratory tract.

Sci Rep 2016 09 8;6:32916. Epub 2016 Sep 8.

Max Planck Institute for Chemistry, Multiphase Chemistry Department, Hahn-Meitner-Weg 1, 55128 Mainz, Germany.

Air pollution can cause oxidative stress and adverse health effects such as asthma and other respiratory diseases, but the underlying chemical processes are not well characterized. Here we present chemical exposure-response relations between ambient concentrations of air pollutants and the production rates and concentrations of reactive oxygen species (ROS) in the epithelial lining fluid (ELF) of the human respiratory tract. In highly polluted environments, fine particulate matter (PM2.5) containing redox-active transition metals, quinones, and secondary organic aerosols can increase ROS concentrations in the ELF to levels characteristic for respiratory diseases. Ambient ozone readily saturates the ELF and can enhance oxidative stress by depleting antioxidants and surfactants. Chemical exposure-response relations provide a quantitative basis for assessing the relative importance of specific air pollutants in different regions of the world, showing that aerosol-induced epithelial ROS levels in polluted megacity air can be several orders of magnitude higher than in pristine rainforest air.
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http://dx.doi.org/10.1038/srep32916DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5015057PMC
September 2016

Molecular composition of organic aerosols at urban background and road tunnel sites using ultra-high resolution mass spectrometry.

Faraday Discuss 2016 07;189:51-68

Centre for Atmospheric Science, University of Cambridge, Lensfield Road, Cambridge, CB2 1EW, UK.

Organic aerosol composition in the urban atmosphere is highly complex and strongly influenced by vehicular emissions which vary according to the make-up of the vehicle fleet. Normalized test measurements do not necessarily reflect real-world emission profiles and road tunnels are therefore ideal locations to characterise realistic traffic particle emissions with minimal interference from other particle sources and from atmospheric aging processes affecting their composition. In the current study, the composition of fine particles (diameter ≤2.5 μm) at an urban background site (Elms Road Observatory Site) and a road tunnel (Queensway) in Birmingham, UK, were analysed with direct infusion, nano-electrospray ionisation ultrahigh resolution mass spectrometry (UHRMS). The overall particle composition at these two sites is compared with an industrial harbour site in Cork, Ireland, with special emphasis on oxidised mono-aromatics, polycyclic aromatic hydrocarbons (PAHs) and nitro-aromatics. Different classification criteria, such as double bond equivalents, aromaticity index and aromaticity equivalent are used and compared to assess the fraction of aromatic components in the approximately one thousand oxidized organic compounds at the different sampling locations.
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http://dx.doi.org/10.1039/c5fd00206kDOI Listing
July 2016