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Environmental Science and Pollution... Aug 2023With the global emphasis on environmental protection and the proposal of the climate goal of "carbon neutrality," countries around the world are calling for reductions... (Review)
Review
With the global emphasis on environmental protection and the proposal of the climate goal of "carbon neutrality," countries around the world are calling for reductions in carbon dioxide, nitrogen oxide, and particulate matter pollution. These pollutants have severe impacts on human lives and should be effectively controlled. Engine exhaust is the most serious pollution source, and diesel engine is an important contributor to particulate matter. Diesel particulate filter (DPF) technology has proven to be an effective technology for soot control at the present and in the future. Firstly, the exacerbating effect of particulate matter on human infectious disease viruses is discussed. Then, the latest developments in the influence of key factors on DPF performance are reviewed at different observation scales (wall, channel, and entire filter). In addition, current soot catalytic oxidant schemes are presented in the review, and the significance of catalyst activity and soot oxidation kinetic models are highlighted. Finally, the areas that need further research are determined, which has important guiding significance for future research. Current catalytic technologies are focused on stable materials with high mobility of oxidizing substances and low cost. The challenge of DPF optimization design is to accurately calculate the balance between soot and ash load, DPF regeneration control strategy, and exhaust heat management strategy.
Topics: Humans; Soot; Particulate Matter; Air Pollutants; Vehicle Emissions; Air Pollution; Dust
PubMed: 37421534
DOI: 10.1007/s11356-023-28405-z -
Nanotoxicology Jun 2023This study collects toxicity data from animal inhalation studies of some nanomaterials and their bulk and ionic counterparts. To allow potential grouping and... (Review)
Review
This study collects toxicity data from animal inhalation studies of some nanomaterials and their bulk and ionic counterparts. To allow potential grouping and interpretations, we retrieved the primary physicochemical and exposure data to the extent possible for each of the materials. Reviewed materials are compounds (mainly elements, oxides and salts) of carbon (carbon black, carbon nanotubes, and graphene), silver, cerium, cobalt, copper, iron, nickel, silicium (amorphous silica and quartz), titanium (titanium dioxide), and zinc (chemical symbols: Ag, C, Ce, Co, Cu, Fe, Ni, Si, Ti, TiO, and Zn). Collected endpoints are: a) pulmonary inflammation, measured as neutrophils in bronchoalveolar lavage (BAL) fluid at 0-24 hours after last exposure; and b) genotoxicity/carcinogenicity. We present the dose descriptors no-observed-adverse-effect concentrations (NOAECs) and lowest-observed-adverse-effect concentrations (LOAECs) for 88 nanomaterial investigations in data-library and graph formats. We also calculate 'the value where 25% of exposed animals develop tumors' (T25) for carcinogenicity studies. We describe how the data may be used for hazard assessment of the materials using carbon black as an example. The collected data also enable hazard comparison between different materials. An important observation for poorly soluble particles is that the NOAEC for neutrophil numbers in general lies around 1 to 2 mg/m. We further discuss why some materials' dose descriptors deviate from this level, likely reflecting the effects of the ionic form and effects of the fiber-shape. Finally, we discuss that long-term studies, in general, provide the lowest dose descriptors, and dose descriptors are positively correlated with particle size for near-spherical materials.
Topics: Animals; Lung; Nanotubes, Carbon; Soot; Pneumonia; Nanostructures; Bronchoalveolar Lavage Fluid; Particle Size; Inhalation Exposure
PubMed: 37300873
DOI: 10.1080/17435390.2023.2221728 -
Chemosphere Apr 2021The main purpose of this work was to quantify and characterize chemically and morphologically the emission of soot particles from the open burning of several common...
The main purpose of this work was to quantify and characterize chemically and morphologically the emission of soot particles from the open burning of several common solid waste including paperboard, wood, peel, chemical fiber, polyethylene (PE) and polyvinyl chloride (PVC). The experiment was conducted in a laboratory-scale open-burning combustor with a dilution sampling system to obtain soot particles. The thermogravimetric profiles (TGA) showed an increasing order of oxidation reactivity: PE > PVC > fiber > paper ≈ peel > wood. High resolution transmission electron microscopy (HRTEM) images revealed more detailed information about the morphology and the particle size of soot aggregates. Subsequent quantification of nanostructure by fringe analysis showed that plastics generated soot particles with the looser carbon layers with higher tortuosity compared to the three kind of biomass. Raman spectroscopy further confirms the observed differences. In addition, wood soot exhibited the highest content of C-OH group (17.5%) among the six samples (X-Ray photoelectron spectroscopy, XPS), whereas PE and PVC soot exhibited the highest absorption peaks of aliphatic C-H groups (Fourier transform infrared spectroscopy, FTIR). Comparative analysis revealed that the interlayer distance was more important on the evaluation of reactivity than soot morphologies. The present work concluded that the physiochemical characteristics of soot particles releasing during open burning are strongly depending on waste composition and provided new data for the understanding of soot emissions from open burning.
Topics: Nanostructures; Particle Size; Solid Waste; Soot; Wood
PubMed: 33385669
DOI: 10.1016/j.chemosphere.2020.129395 -
Journal of Forensic Sciences Mar 2022Soot is deposited from 20-30 cm from the muzzle of most handguns and arranged concentrically around the entry wound. We examined a case of a self-inflicted gunshot...
Soot is deposited from 20-30 cm from the muzzle of most handguns and arranged concentrically around the entry wound. We examined a case of a self-inflicted gunshot wound from a 9-mm pistol that left an unusual pattern of soot deposition consisting of two circular 3-mm deposits of soot located 2 cm from the entry wound. Examination of the weapon and test-firing it against a cloth reproduced the soot deposits, which were caused by two ports on the top of the barrel. Examination of the weapon and comparing the barrel with the entry wound and surrounding skin may provide important information about the type of weapon, the muzzle-to-target distance, and atypical soot deposits.
Topics: Firearms; Forensic Ballistics; Humans; Soot; Suicidal Ideation; Wounds, Gunshot
PubMed: 34617276
DOI: 10.1111/1556-4029.14910 -
Environmental Pollution (Barking, Essex... Apr 2021This study investigates the morphology and nanostructure of soot particles during cold-start and hot-start engine operation of a diesel engine using oxygenated fuels....
This study investigates the morphology and nanostructure of soot particles during cold-start and hot-start engine operation of a diesel engine using oxygenated fuels. The soot samples were analysed using transmission electron microscopy. The oxygen content in the fuel was varied between 0 and 12%. The results showed that the primary particles during cold-start have significantly smaller size when compared to hot-start engine operation. The addition of oxygenated fuels also resulted in smaller sized primary particles. Smaller radius of gyration and higher fractal dimension of soot aggregates during cold-start would mean smaller aggregate size with a more compact structure. Shorter fringes with a higher inter-fringe spacing for cold-start would mean lower graphitisation of soot particles that could be related to higher oxidation reactivity of soot particles.
Topics: Fractals; Gasoline; Microscopy, Electron, Transmission; Nanostructures; Particle Size; Soot; Vehicle Emissions
PubMed: 33582631
DOI: 10.1016/j.envpol.2021.116592 -
On determining soot maturity: A review of the role of microscopy- and spectroscopy-based techniques.Chemosphere Aug 2020Incomplete combustion is the main source of airborne soot, which has negative impacts on public health and the environment. Understanding the morphological and chemical... (Review)
Review
Incomplete combustion is the main source of airborne soot, which has negative impacts on public health and the environment. Understanding the morphological and chemical evolution of soot is important for assessing and mitigating the impact of soot emissions. Morphological and chemical structures of soot are commonly studied using microscopy or spectroscopy, and the best technique depends on the parameter of interest and the stage of soot formation considered (i.e., maturity). For the earliest stages of soot formation, particles exhibit simple morphology yet complex and reactive chemical composition, which is best studied by spectroscopic techniques sensitive to the large number of soot precursor species. The only microscope that can offer some morphological information at this stage is the scanning probe microscopy, which can image single polycyclic aromatic hydrocarbons, the precursors of soot. A broader range of types of spectrometers and microscopes can be used by increasing the soot maturity. Mature soot is primarily carbon, and exhibits complex fractal-like morphology best studied with electron microscopy and techniques sensitive to thin oxide or organic coatings. Each characterization technique can target different morphological and chemical properties of soot, from the early to the late stage of its formation. Thus, a guideline for the selection of the appropriate technique can facilitates studies on environmental samples involving the presence of soot.
Topics: Carbon; Microscopy; Organic Chemicals; Polycyclic Aromatic Hydrocarbons; Soot; Spectrum Analysis
PubMed: 32229356
DOI: 10.1016/j.chemosphere.2020.126532 -
Environmental Science & Technology Jun 2022It is known that there are semiconductor oxides involved in mineral dust, which have photocatalytic properties. However, soot particles contained in carbonaceous aerosol...
Photocatalytic Role of Atmospheric Soot Particles under Visible-Light Irradiation: Reactive Oxygen Species Generation, Self-Oxidation Process, and Induced Higher Oxidative Potential and Cytotoxicity.
It is known that there are semiconductor oxides involved in mineral dust, which have photocatalytic properties. However, soot particles contained in carbonaceous aerosol and their photoactivity under sunlight are rarely realized. In this study, reactive oxygen species (ROS) such as superoxide anions and hydroxyl radicals were generated upon visible-light irradiation of soot particles, and the production activity was consistent with the carbonaceous core content, indicating that the atmospheric soot particles can serve as a potential photocatalyst. The increase of oxygen-containing functional groups, environmentally persistent free radicals, oxygenated polycyclic aromatic hydrocarbons, and the oxidative potential (OP) of soot after irradiation confirmed the occurrence of visible-light-triggered photocatalytic oxidation of the soot itself. The mechanism analyses suggested that the carbonaceous core caused the production of ROS, which subsequently oxidize the extractable organic species on the soot surface. It is oxidized organic extracts that are responsible for the enhancements of the OP, cell mortality, and intracellular ROS generation. These new findings shed light on both the photocatalytic role of the soot and the importance of ROS during the photochemical self-oxidation of soot triggered by visible light and will promote a more comprehensive understanding of both the atmospheric chemical behavior and health effects of soot particles.
Topics: Light; Oxidation-Reduction; Oxidative Stress; Reactive Oxygen Species; Soot
PubMed: 35537182
DOI: 10.1021/acs.est.2c00420 -
Black soot exposure induced hypothalamic and testicular oxidative stress and apoptosis in male rats.Andrologia Dec 2020Air pollution constitutes the largest cause of environmental risks today. At present, no scientific publication linking environmental black soot and derangement in the...
Air pollution constitutes the largest cause of environmental risks today. At present, no scientific publication linking environmental black soot and derangement in the hypothalamus and testis of rats exists. This study investigated the effect of black soot exposure on hypothalamic and testicular functions of male rats exposed to black soot for 4, 8 and 12 weeks respectively. The hypothalamus and testis were processed for biochemical analysis. Results show that black soot exposure for 4, 8 and 12 weeks significantly (p < .05) increased oxidative stress markers both in the testis and in the hypothalamus of rats. Also, black soot exposure significantly (p < .05) decreased the alkaline phosphatase, acid phosphatase as well as lactate dehydrogenase activities in the testis. Furthermore, the result demonstrated an upregulation of the protein expression of caspase-3, an indication of increased apoptosis which led to the disruption of the histological architecture of the hypothalamus and testis. Taken together, black soot exposure induced hypothalamic and testicular oxidative stress and apoptosis in male rats.
Topics: Animals; Apoptosis; Hypothalamus; Male; Oxidative Stress; Rats; Soot; Testis
PubMed: 33118230
DOI: 10.1111/and.13866 -
Environmental Science and Pollution... Aug 2022With the awakening of environmental awareness, the importance of air quality to human health and the proper functioning of social mechanisms is becoming increasingly... (Review)
Review
With the awakening of environmental awareness, the importance of air quality to human health and the proper functioning of social mechanisms is becoming increasingly prominent. The low cost and high efficiency of catalytic technique makes it a natural choice for achieving deep air purification. Stainless steel alloys have demonstrated their full potential for application in a variety of catalytic fields. The diversity of 3D networks or fibrous structures increases the turbulence within the heterogeneous catalysis, balance the temperature distribution in the reaction bed and, in combination with a highly thermally conductive skeleton, avoid agglomeration and deactivation of the active components; corrosion resistance and thermal stability are adapted to highly endothermic/exothermic or corrosive reaction environments; oxide layers formed by bulk transition metals activated by thermal treatment or etching can significantly alter the physico-chemical properties between the substrate and active species, further improving the stability of stainless steel catalysts; suitable electronic conductivity can be applied to the electrothermal catalysis, which is expected to provide guidance for the reduction of intermittent emission exhausts and the storage of renewable energy. The current applications of stainless steel as catalyst or support in the air purification have covered soot particle capture and combustion, catalytic oxidation of VOCs, SCR, and air sterilization. This paper summarizes several preparation methods and presents the relationships between the preparation process and the activity, and reviews its application and the current status of research in atmospheric environmental management, proposing the advantages and challenges of the stainless steel-based catalysts.
Topics: Air Pollution; Catalysis; Corrosion; Humans; Soot; Stainless Steel
PubMed: 35672638
DOI: 10.1007/s11356-022-21079-z -
Journal of Environmental Sciences... Jan 2020Soot particles, mainly coming from fuel combustion, affect climate forcing through absorbing light and also result in adverse human health outcomes. Though biodiesel or...
Soot particles, mainly coming from fuel combustion, affect climate forcing through absorbing light and also result in adverse human health outcomes. Though biodiesel or additives blending with diesel was considered environmentally friendly, the understanding on absorbing and oxidative capacity of soot emitted from them are still unclear. The water-soluble organic carbon (WSOC) content, surface chemical structure, light absorption and oxidative potential (OP) of soot from biodiesel/diesel and chemicals/diesel blends were investigated utilizing total organic carbon analyzer, X-ray photoelectron spectrometer, ultraviolet-visible spectrophotometry and dithiothreitol (DTT) assay. The differences and correlations between soot properties were statistically analyzed. Chemicals/diesel blends soot owned significantly higher WSOC content, ratio of mass absorbing efficiency (MAE) in 250 and 365 nm (E/E), OP, and higher surface carbonyl content. Coconut biodiesel/diesel blends soot contained evidently higher aromatic carbon-oxygen single bond (Ar_C-O) content, and higher MAE. The individual comparison of biodiesel/diesel blends showed 20% coconut biodiesel blend owned the lowest WSOC, E/E and OP, while highest Ar_C-O and MAE, representing strongest absorbing properties. Association analysis showed OP was significantly positively correlated with WSOC. Further, the evident negative correlation between MAE and OP was observed. Our results showed coconut biodiesel/diesel blends soot induced lower levels of oxidative potential, whereas absorption of light was higher, which have far reaching consequences on climate forcing. Therefore, it is important to evaluate the balance point between light-absorbing properties and oxidative potential, under the wide use of biodiesel.
Topics: Air Pollutants; Biofuels; Particulate Matter; Soot; Vehicle Emissions
PubMed: 31791491
DOI: 10.1016/j.jes.2019.06.014