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Environmental Science & Technology Feb 2022Fossil fuel (FF) combustion emissions account for a large, but uncertain, amount of the soot in the atmosphere, play an important role in climate change, and adversely...
Fossil fuel (FF) combustion emissions account for a large, but uncertain, amount of the soot in the atmosphere, play an important role in climate change, and adversely affect human health. However, historical estimates of FF contributions to air pollution are limited by uncertainties in fuel usage and emission factors. Here, we constrained FF soot emissions from southeastern China over the past 110 years, based on a novel radiocarbon method applied to sedimentary soot. The reconstructed soot accumulations reflect the integrated effects of increased FF use caused by economic development and reductions in emissions due to pollution controls. A sharp increase in FF soot started in 1950 as southeastern China industrialized and developed economically, but decreased FF soot fluxes in recent years suggest that pollution controls reduced soot emissions. We compare FF soot history to changes in CO emissions, industrial and economic activities, and pollution controls and show that FF soot fluxes are more readily controlled than atmospheric CO. Our independent FF soot record provides insights into the effects of economic development and controls on air pollution and the environmental impacts from the changes in soot emissions.
Topics: Carbon; Carbon Dioxide; China; Environmental Monitoring; Fossil Fuels; Humans; Soot
PubMed: 35007066
DOI: 10.1021/acs.est.1c05424 -
Environmental Science and Pollution... Feb 2023The second most potent forcer of climate change, soot, has severe harmful effects on both human health and the environment. Accurate numerical modeling of soot formation...
The second most potent forcer of climate change, soot, has severe harmful effects on both human health and the environment. Accurate numerical modeling of soot formation is extremely complex and has a high computational cost due to its dependence on many physical and chemical interactions, specifically in turbulent flames. The high computational cost of coupling chemistry, fluid dynamics, thermodynamics, and heat transfer raise the need for a novel, precise, and computationally cost-effective numerical technique for predicting soot concentrations. This study applies machine learning (ML) to predict soot formation in a turbulent flame. It has been discovered that the local soot volume fraction is correlated to the histories of gas properties strongly correlative to soot formation and oxidation. A library with the Lagrangian temporal histories of soot-containing fluid parcels is created from turbulent diffusion flame data computed using direct numerical simulation (DNS). This library is then used to train an ML algorithm to predict soot volume fraction along randomly selected trajectories (pathlines) in the domain. The prediction capability is tested over 10% of the entire dataset, and it is seen that soot volume fraction can be predicted well along the selected pathlines with low error and computational cost. To describe quantitative results, the calculated R in the current work is equal to 0.92, which shows good accuracy of the predictions.
Topics: Humans; Soot; Hot Temperature; Hydrodynamics; Fires
PubMed: 36378371
DOI: 10.1007/s11356-022-24161-8 -
ACS Applied Materials & Interfaces Aug 2023Intracellular delivery of bioactive macromolecules and functional materials plays a crucial role in fundamental biological research and clinical applications....
Intracellular delivery of bioactive macromolecules and functional materials plays a crucial role in fundamental biological research and clinical applications. Nondestructive and efficient harvesting of engineered cells is also required for some specific applications. In this work, we develop a multifunctional platform based on candle soot modified with copolymer brushes containing temperature-responsive poly(-isopropylacrylamide) (PNIPAAm) and sugar-responsive phenylboronic acid (PBA) components. This platform possesses a high cell adhesion capacity due to the inherent hierarchical structure of candle soot and the formation of boronate ester bonds between the PBA groups and glycoproteins on the cell membrane. Under the irradiation of a near-infrared laser, the excellent light-to-heat conversion ability of candle soot enables the highly efficient delivery of macromolecules into diverse cells (including hard-to-transfect cells) attached to the surface via a photothermal-poration mechanism. Owing to the temperature-responsive properties of PNIPAAm and the sugar-responsive properties of PBA, the engineered cells could be harvested nondestructively from the platform by a mild treatment using a cold fructose solution. A proof-of-concept experiment demonstrates that fibroblasts attached to the surface could be transfected by a functional plasmid encoding basic fibroblast growth factor and then harvested efficiently and recultured with improved proliferation and migration ability. The whole delivery-harvesting process required less than 1 h, allowing the cells to be engineered without compromising their viability. This platform thus provides a widely applicable method for both the intracellular delivery of diverse macromolecules efficiently as well as harvesting engineered cells simply and safely, holding great potential for biomedical applications.
Topics: Soot; Boronic Acids; Sugars
PubMed: 37587876
DOI: 10.1021/acsami.3c02738 -
Environmental Science & Technology Jul 2024Polycyclic aromatic hydrocarbons (PAHs) are the primary organic carbons in soot. In addition to PAHs with even carbon numbers (PAH), substantial odd-carbon PAHs (PAH)...
Polycyclic aromatic hydrocarbons (PAHs) are the primary organic carbons in soot. In addition to PAHs with even carbon numbers (PAH), substantial odd-carbon PAHs (PAH) have been widely observed in soot and ambient particles. Analyzing and understanding the photoaging of these compounds are essential for assessing their environmental effects. Here, using laser desorption ionization mass spectrometry (LDI-MS), we reveal the substantially different photoreactivity of PAH from PAH in the aging process and their MS detection through their distinct behaviors in the presence and absence of elemental carbon (EC) in soot. During direct photooxidation of organic carbon (OC) alone, the PAH are oxidized more rapidly than the PAH. However, the degradation of PAH becomes preponderant over PAH in the presence of EC during photoaging of the whole soot. All of these observations are proposed to originate from the more rapid hydrogen abstraction reaction from PAH in the EC-photosensitized reaction, owing to its unique structure of a single -hybridized carbon site. Our findings reveal the photoreactivity and reaction mechanism of PAH for the first time, providing a comprehensive understanding of the oxidation of PAHs at a molecular level during soot aging and highlight the enhanced effect of EC on PAH ionization in LDI-MS analysis.
Topics: Polycyclic Aromatic Hydrocarbons; Carbon; Soot; Photochemical Processes; Oxidation-Reduction; Photochemistry
PubMed: 38899536
DOI: 10.1021/acs.est.4c00764 -
The Science of the Total Environment Aug 2023Thermal elemental carbon (EC), optical black carbon (BC), organic carbon (OC), mineral dust (MD), and 7-wavelength optical attenuation of 24-hour ambient PM samples were...
Thermal elemental carbon (EC), optical black carbon (BC), organic carbon (OC), mineral dust (MD), and 7-wavelength optical attenuation of 24-hour ambient PM samples were measured/estimated at a regionally representative site (Bhopal, central India) during a business-as-usual year (2019) and the COVID-19 lockdowns year (2020). This dataset was used to estimate the influence of emissions source reductions on the optical properties of light-absorbing aerosols. During the lockdown period, the concentration of EC, OC, BC, and PM increased by 70 % ± 25 %, 74 % ± 20 %, 91 % ± 6 %, and 34 % ± 24 %, respectively, while MD concentration decreased by 32 % ± 30 %, compared to the same time period in 2019. Also, during the lockdown period, the estimated absorption coefficient (b) and mass absorption cross-section (MAC) values of Brown Carbon (BrC) at 405 nm were higher (42 % ± 20 % and 16 % ± 7 %, respectively), while these quantities for MD, i.e., b and MAC values were lower (19 % ± 9 % and 16 % ± 10 %), compared to the corresponding period during 2019. Also, b (115 % ± 6 %) and MAC (69 % ± 45 %) values increased during the lockdown period compared with the corresponding period during 2019. It is hypothesized that although anthropogenic emissions (chiefly industrial and vehicular) reduced drastically during the lockdown period compared to the business-as-usual period, an increase in the values of optical properties (b and MAC) and concentrations of BC and BrC, were likely due to the increased local and regional biomass burning emissions during this period. This hypothesis is supported by the CBPF (Conditional Bivariate Probability Function) and PSCF (Potential Source Contribution Function) analyses for BC and BrC.
Topics: Humans; Air Pollutants; Carbon; Communicable Disease Control; COVID-19; Dust; Environmental Monitoring; India; Particulate Matter; Respiratory Aerosols and Droplets; Soot
PubMed: 37149165
DOI: 10.1016/j.scitotenv.2023.163872 -
Microscopy Research and Technique Dec 2021Soot particles emitted from the burning of solid fuel sources in the households carry important environmental and public health implications. In this study, the indoor...
Soot particles emitted from the burning of solid fuel sources in the households carry important environmental and public health implications. In this study, the indoor soot particles released from firewood, cow dung, and bagasse burning at households of selected rural areas of Khyber Pakhtunkhwa province of Pakistan were investigated by characterization analyses to study its morphological and elemental compositions. Results demonstrated diverse compositions of soot particles from each fuel source. The surface areas of soot particles emitted by the firewood, cow dung, and bagasse were about 0.3, 0.4, and 8.64 m g , respectively. For the soot particles emitted by the firewood burning, the major functional groups for aromatic compounds were C═C at the 1,431-1,599 at 1,000-2,000 cm . The absorbance rate of alkanes was about 1,599-1,431 at 1,000-2,000 cm . However, silicon band vibration was more prominent in bagasse soot particles as compared to other samples. The emission of soot particles with high surface area in the atmosphere could provide an elevated adsorption sites for atmospheric pollution and trap more energy resulting in increased atmospheric temperature. Findings from the present study suggest that current households' fuel combustion practices significantly contribute to increase the particulate matter in the atmosphere and possible enhance climate change phenomenon and related disasters in northern Pakistan.
Topics: Pakistan; Particulate Matter; Soot
PubMed: 34288234
DOI: 10.1002/jemt.23873 -
Environmental Science & Technology Jan 2020The rapid decrease in Arctic sea ice is motivating development and increasing oil and gas extraction activities. However, few observations of these local Arctic...
The rapid decrease in Arctic sea ice is motivating development and increasing oil and gas extraction activities. However, few observations of these local Arctic emissions exist, limiting the understanding of impacts on atmospheric composition and climate. To address this knowledge gap, the chemical composition of atmospheric aerosols was measured within the North Slope of Alaska oil fields during August and September 2016 using an aerosol time-of-flight mass spectrometer (ATOFMS) and a time-of-flight aerosol chemical speciation monitor (ToF-ACSM). Plumes from oil and gas extraction activities were characterized by soot internally mixed with sulfate (matching diesel soot) and organic carbon particles containing aminium sulfate salts. Sea spray aerosol at the coastal site was frequently internally mixed with sulfate and nitrate, from multiphase chemical processing from elevated NO and SO within the oil field. Background (nonplume) air masses were characterized by aged combustion aerosol. No periods of "clean" (nonpolluted) Arctic air were observed. The composition of the nonrefractory aerosol measured with the ACSM was similar during plume and background periods and was consistent with the mass concentrations of nonrefractory particles measured by ATOFMS. Two ultrafine aerosol growth events were observed during oil field background periods and were correlated with fine mode amine-containing particles.
Topics: Aerosols; Air Pollutants; Alaska; Amines; Environmental Monitoring; Oil and Gas Fields; Particle Size; Soot; Sulfates; Sulfuric Acid Esters
PubMed: 31840985
DOI: 10.1021/acs.est.9b04825 -
The Science of the Total Environment Jan 2022The signals of fire activity induced from climate and ancient human activities could be recorded in sedimentary strata. We examined a 6000-year black‑carbon (BC)...
The signals of fire activity induced from climate and ancient human activities could be recorded in sedimentary strata. We examined a 6000-year black‑carbon (BC) record-including char and soot-of a sediment core from the South Yellow Sea. The climate change had a threshold effect on the fire regime, and dominated the char emissions. The soot/BC signals depicted that the anthropogenic emissions related to the evolution of the Chinese civilization since the Early Bronze Age (~4 ka) have overwhelmed natural soot emissions. The soot variation in the record closely matched periods when there was large-scale use of coal or charcoal after the Han Dynasty and when indigenous coking technology was promoted after the Tang Dynasty; low soot-abundance in the record coincided with periods of social unrest. This work illustrates how soot signals can be a robust tracer of civilization evolution.
Topics: Carbon; China; Civilization; Environmental Monitoring; Humans; Soot
PubMed: 34517331
DOI: 10.1016/j.scitotenv.2021.150209 -
International Journal of Hygiene and... Aug 2023Diesel exhaust has long been of health concern due to established toxicity including carcinogenicity in humans. However, the precise components of diesel engine...
Diesel exhaust has long been of health concern due to established toxicity including carcinogenicity in humans. However, the precise components of diesel engine emissions that drive carcinogenesis are still unclear. Limited work has suggested that nitrated polycyclic aromatic hydrocarbons (NPAHs) such as 1-nitropyrene and 2-nitrofluorene may be more abundant in diesel exhaust. The present study aimed to examine whether urinary amino metabolites of these NPAHs were associated with high levels of diesel engine emissions and urinary mutagenicity in a group of highly exposed workers including both smokers and nonsmokers. Spot urine samples were collected immediately following a standard work shift from each of the 54 diesel engine testers and 55 non-tester controls for the analysis of five amino metabolites of NPAHs, and cotinine (a biomarker of tobacco smoke exposure) using liquid chromatography-mass spectrometry. An overnight urine sample was collected in a subgroup of non-smoking participants for mutagenicity analysis using strain YG1041 in the Salmonella (Ames) mutagenicity assay. Personal exposure to fine particles (PM) and more-diesel-specific constituents (elemental carbon and soot) was assessed for the engine testers by measuring breathing-zone concentrations repeatedly over several full work shifts. Results showed that it was 12.8 times more likely to detect 1-aminopyrene and 2.9 times more likely to detect 2-aminofluorene in the engine testers than in unexposed controls. Urinary concentrations of 1-aminopyrene were significantly higher in engine testers (p < 0.001), and strongly correlated with soot and elemental carbon exposure as well as mutagenicity tested in strain YG1041 with metabolic activation (p < 0.001). Smoking did not affect 1-aminopyrene concentrations and 1-aminopyrene relationships with diesel exposure. In contrast, both engine emissions and smoking affected 2-aminofluorene concentrations. The results confirm that urinary 1-aminopyrene may serve as an exposure biomarker for diesel engine emissions and associated mutagenicity.
Topics: Humans; Mutagens; Vehicle Emissions; Soot; Polycyclic Aromatic Hydrocarbons; Nitrates; Biomarkers
PubMed: 37557062
DOI: 10.1016/j.ijheh.2023.114223 -
The Science of the Total Environment Jan 2022Black carbon (BC), characterized by high aromaticity and stability, has been recognized as a substantial fraction of the carbon pool in soil and sediment. The effect of...
Black carbon (BC), characterized by high aromaticity and stability, has been recognized as a substantial fraction of the carbon pool in soil and sediment. The effect of BC on the particulate organic carbon (POC) pool in lake water, which is an important medium of carbon transmission and transformation, has not been thoroughly studied. The investigations of BC composition and distribution, POC, polycyclic aromatic hydrocarbons (PAHs), and stable carbon and nitrogen isotopes were conducted in a eutrophic urban lake, Taihu Lake, which is the third largest freshwater lake in China. The results indicate that the BC is composed of 55 ± 12% char and 45 ± 12% soot and accounted for 12 ± 6% of POC (the maximum value is 31%). The comparatively high levels of BC and char are distributed in the northern Taihu Lake, especially in Meiliang Bay (0.72 ± 0.38 mg L and 0.45 ± 0.24 mg L). The distribution of soot presents a declining trend from the lakeshore to the central lake, particularly in the northern, western, and southern lakes. Source apportionment results from positive matrix factorization of PAHs suggest that consumption of fossil fuel (79 ± 20%) is the dominant source of BC, which agrees with the low ratio of char/soot (1.41 ± 0.71) and relatively depleted δC. The covariation of BC and PAHs and terrestrial dissolved organic carbon indicate that the effect of terrestrial input significantly regulates the distribution of BC in Taihu Lake, which is reflected in the high BC value along the lakeshore.
Topics: Carbon; China; Environmental Monitoring; Geologic Sediments; Lakes; Polycyclic Aromatic Hydrocarbons; Soot
PubMed: 34500269
DOI: 10.1016/j.scitotenv.2021.150057