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1.
Skin Res Technol ; 29(1): e13220, 2023 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-36609868

RESUMO

OBJECTIVE: Based on in vivo data, in vitro models and new methods are created to mimic the impact of aerial pollution onto the hair surface and assess the efficacy of different formulae prototypes. MATERIAL AND METHODS: Two protocols are developed to mimic the pollution effect, in vitro, on purchased swatches, and in vivo, on scalps and forearms. First, with an artificial sebum mixed with Carbon Black particles, named "sebollution," we evaluated, through an instrumental color measurement, the cleansing efficacy of some shampoo on scalp and hair. The second protocol allowed to assess the interaction between hair care product deposit (shampoo, conditioner, mask, and leave-on) on hair and carbon black particles spread on fiber. The quantification of particle coverage allowed to evaluate the efficiency of a formula to limit the aerial pollution deposit on hair fiber. RESULTS: To simplify and accelerate the evaluation of 42 shampoo formulae, an extrapolation of the scalp cleaning process was validated on forearm. The respective cleanabilities were calculated and covered a large range of efficacy, from 5%, for a basic bland shampoo generally used to reset swatches, to a strong deep cleansing efficacy of 100%. On hair swatches, cleanability efficiencies of five shampoo were also evaluated to eliminate the deposited of sebollution, in a range of 40%-80%. To quantify the efficacy of preventing the deposition of carbon particle on hair surface, the percentage of coverage of 45 different products was measured, from 2% to 16%. The performance depended of the product category (shampoo, conditioner, mask, and leave-on), driven by the performance of the product deposit, and the capacity of this deposit to interact with aerial pollution. CONCLUSION: Three new protocols and evaluation methods are proposed to evaluate and quantify the performance of hair care product, to remove/clean, limit, and protect the hair fibers against the aerial pollution that could interact with hair, scalp and sebum. The validation of these approaches was done through the testing of a large panel of hair care product leading to a complete and sincere evaluation of cleansing and anti-deposit efficacy. Combining the knowledge acquired on pollution impact on hair and the development of specific way of evaluation, this work reinforced the rationale of using and developing new cosmetic products that reduced the impact of pollution upon some hair properties.


Assuntos
Preparações para Cabelo , Fuligem , Humanos , Preparações para Cabelo/farmacologia , Pele , Cabelo , Couro Cabeludo
2.
Environ Pollut ; 319: 120991, 2023 Feb 15.
Artigo em Inglês | MEDLINE | ID: mdl-36596374

RESUMO

Although real-time personal exposure monitoring devices have the ability to capture a wealth of data regarding fluctuations in pollutant levels, only a few studies have defined 'peaks' in black carbon (BC) exposure utilizing high-resolution data. Furthermore, studies to assess and characterize various features of peak exposure are very limited especially among children. A better understanding of characteristics of BC peak exposure would improve our understanding of health risks associated with BC. By capturing personal BC exposure at 5-min intervals using a real-time monitor during 24-hr monitoring periods among children in New York City (NYC), we defined 'peak characteristics' in 4 different ways across three major microenvironments (school vs. commute vs. home): 1) mean concentrations of BC across the 3 microenvironments, 2) 'peak duration' or time spent above the peak threshold (i.e., ≥1.5 µg/m3), 3) 'peak intensity' or the rate of exposure, defined as time spent above the threshold within each microenvironment divided by the total time spent in the microenvironment and 4) a novel metric of 'peak variability', defined as frequency of peaks (i.e., data points with +50% and -50% changes compared to the preceding and the subsequent data points), divided by the total time spent in the microenvironment. While peak duration was greatest at home, the intensity of peak exposure was greatest during commute hours, despite the short time spent in commute (p < 0.05). Peak variability was highest during commute, yet lowest in home environments (p < 0.05), particularly during non-sleeping hours. Children residing in a high-density urban setting spent on average, 5.4 hr per day above our peak threshold (≥1.5 µg/m3) in their everyday environments. Policies that limit children's exposure during high traffic periods and improved efforts to increase the number of vehicles using clean air technology could reduce the intensity of peaks and peak variability in children's BC exposure.


Assuntos
Poluentes Atmosféricos , Poluição do Ar , Humanos , Criança , Poluentes Atmosféricos/análise , Exposição Ambiental/análise , Monitoramento Ambiental , Material Particulado/análise , Ambiente Domiciliar , Poluição do Ar/análise , Fuligem/análise , Carbono
3.
Nat Commun ; 14(1): 271, 2023 Jan 17.
Artigo em Inglês | MEDLINE | ID: mdl-36650124

RESUMO

Black carbon emitted by incomplete combustion of fossil fuels and biomass has a net warming effect in the atmosphere and reduces the albedo when deposited on ice and snow; accurate knowledge of past emissions is essential to quantify and model associated global climate forcing. Although bottom-up inventories provide historical Black Carbon emission estimates that are widely used in Earth System Models, they are poorly constrained by observations prior to the late 20th century. Here we use an objective inversion technique based on detailed atmospheric transport and deposition modeling to reconstruct 1850 to 2000 emissions from thirteen Northern Hemisphere ice-core records. We find substantial discrepancies between reconstructed Black Carbon emissions and existing bottom-up inventories which do not fully capture the complex spatial-temporal emission patterns. Our findings imply changes to existing historical Black Carbon radiative forcing estimates are necessary, with potential implications for observation-constrained climate sensitivity.


Assuntos
Clima , Combustíveis Fósseis , Atmosfera , Fuligem/análise , Carbono
4.
Environ Monit Assess ; 195(2): 256, 2023 Jan 03.
Artigo em Inglês | MEDLINE | ID: mdl-36595082

RESUMO

The present investigation outlines the crucial factors that influence the black carbon (BC) concentrations over a polluted metropolis, Kolkata (22.57° N, 88.37° E), India. Located in the eastern part of the Indo Gangetic Plain (IGP) outflow region and close to the land-ocean boundary, Kolkata is subject to contrasting seasonal maritime airflow from the Bay of Bengal and continental air mass from the IGP and Tibetan plateau region, which modulates the local concentration of BC. The origin of aerosol transport and associated atmospheric dynamics with high and low BC activities over Kolkata are examined during 2012-2015 using data from multi-technique sources which include measurements of ground-based instruments of aethalometer and multi-frequency microwave radiometer, reanalysis data from ERA-5 and MEERA-2, and model outputs from HYPSLIT back trajectory model simulations. The study highlights the control of IGP wind inflow on the occurrence of anomalous enhancements in BC concentration during weekends and holidays when local emissions are low. High BC events are associated with enhanced atmospheric heating below the boundary layer (2000 m) and significant negative surface radiative forcing. The response of the boundary layer to high and low BC episodes, shown in the diurnal variation in comparison with the seasonal mean, is investigated. Dominant suppression of morning and night-time boundary layer height is observed on high BC days. During the daytime in pre-monsoon, post-monsoon, and winter seasons, boundary layer height peaks are found to be strongly controlled by high BC episode occurrences as obtained from the hourly data of ERA-5.


Assuntos
Poluentes Atmosféricos , Poluentes Atmosféricos/análise , Monitoramento Ambiental/métodos , Estações do Ano , Vento , Fuligem/análise , Aerossóis/análise , Índia , Carbono/análise
5.
Toxicology ; 485: 153428, 2023 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-36641057

RESUMO

Molybdenum disulphide (MoS2) is a constituent of many products. To protect humans, it is important to know at what air concentrations it becomes toxic. For this, we tested MoS2 particles by nose-only inhalation in mice. Exposures were set to 13, 50 and 150 mg MoS2/m3 (=8, 30 and 90 mg Mo/m3), corresponding to Low, Mid and High exposure. The duration was 30 min/day, 5 days/week for 3 weeks. Molybdenum lung-deposition levels were estimated based on aerosol particle size distribution measurements, and empirically determined with inductively coupled plasma-mass spectrometry (ICP-MS). Toxicological endpoints were body weight gain, respiratory function, pulmonary inflammation, histopathology, and genotoxicity (comet assay). Acellular reactive oxygen species (ROS) production was also determined. The aerosolised MoS2 powder had a mean aerodynamic diameter of 800 nm, and a specific surface area of 8.96 m2/g. Alveolar deposition of MoS2 in lung was estimated at 7, 27 and 79 µg/mouse and measured as 35, 101 and 171 µg/mouse for Low, Mid and High exposure, respectively. Body weight gain was lower than in controls at Mid and High exposure. The tidal volume was decreased with Low and Mid exposure on day 15. Increased genotoxicity was seen in bronchoalveolar lavage (BAL) fluid cells at Mid and High exposures. ROS production was substantially lower than for carbon black nanoparticles used as bench-mark, when normalised by mass. Yet if ROS of MoS2 was normalised by surface area, it was similar to that of carbon black, suggesting that a ROS contribution to the observed genotoxicity cannot be ruled out. In conclusion, effects on body weight gain and genotoxicity indicated that Low exposure (13 mg MoS2/m3, corresponding to 0.8 mg/m3 for an 8-hour working day) was a No Observed Adverse Effect Concentration (NOAEC,) while effects on respiratory function suggested this level as a Lowest Observed Adverse Effect Concentration (LOAEC).


Assuntos
Molibdênio , Fuligem , Humanos , Camundongos , Animais , Molibdênio/toxicidade , Espécies Reativas de Oxigênio , Aerossóis e Gotículas Respiratórios , Pulmão/patologia , Líquido da Lavagem Broncoalveolar/química , Aumento de Peso , Exposição por Inalação/efeitos adversos , Tamanho da Partícula
6.
Sci Total Environ ; 858(Pt 3): 160009, 2023 Feb 01.
Artigo em Inglês | MEDLINE | ID: mdl-36368398

RESUMO

In this study, the oxidation behaviors of soot particles from diesel engine when using neat diesel fuel (DF) and lubricating base oil-blended fuel (BBF) were investigated. The changes in the average particle size and nanostructure parameters during soot oxidation process were analyzed. Exhaust particulate matter (PM) samples were collected from a four-stroke, four-cylinder and turbo0charged diesel engine operated under 1200 rpm and 200 Nm. DF and BBF Soot samples with different oxidation weight losses of 20 %, 40 %, and 60 % were obtained by thermogravimetric isothermal oxidation experiments at 600 °C, and the particle size and nanostructure parameters (fringe length, La; fringe tortuosity, Tf) were characterized using high-resolution transmission electron microscopy (HRTEM). Results show that the DF soot particles exhibited an oxidation mode that was initially dominated by surface oxidation and gradually deviated to internal oxidation. Combustion of the base oil increased the soot internal oxidation tendency. HRTEM results showed that as the soot oxidation progressed, the primary particles showed a shell-core, onion-like and hollow structure gradually. The La of the primary particles gradually increased, and the Tf gradually decreased, indicating that the soot layer crystallites were rearranged during the oxidation process, which resulted in a disordered nanostructure that transitioned to a more graphitized nanostructure.


Assuntos
Fuligem , Emissões de Veículos
7.
J Environ Sci (China) ; 126: 668-682, 2023 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-36503792

RESUMO

In the present study, two nanosized MnO2 with ß and δ phase structures and potassium loaded MnO2 catalysts with varied K loading amounts (denoted as K/MnO2) were prepared. Temperature programmed oxidation and isothermal reactions in loose contact modes were employed to examine the soot oxidation activity of the as-prepared catalysts. Characterization results show that as compared with ß-MnO2, δ-MnO2 has larger surface area and higher content of hydroxyl groups. Upon K loading, abundant hydroxyl groups in δ-MnO2 effectively sequestrate K cation to form bound K species and free K species are available only at K loading above 3.0 wt.%. In contrast, the majority of K species present as free state in ß-MnO2 even at a K loading of 1.0 wt.% due to its very low hydroxyl group content. The O2 temperature-programmed desorption (O2-TPD) demonstrates that the catalysts with free K species exhibit strong ability in activating gaseous O2, whereas the catalysts only having bound K display minor O2 activation capability. As a result, despite of slightly lower activity of ß-MnO2 than δ-MnO2, the K/ß-MnO2 catalysts exhibit substantially higher activities than K/δ-MnO2 catalysts with identical K loadings. The finding in this study clearly demonstrates that for MnO2 based catalysts, the enhancement of catalytic activity for soot oxidation is highly K loading amount dependent and the dependency is strongly associated with the phase structure of MnO2.


Assuntos
Compostos de Manganês , Fuligem , Óxidos , Gases , Potássio
8.
Environ Res ; 216(Pt 1): 114492, 2023 01 01.
Artigo em Inglês | MEDLINE | ID: mdl-36209792

RESUMO

BACKGROUND: Radon (222Rn) decay products can attach to particles in the air, be inhaled, and potentially cause airway damage. RESEARCH QUESTION: Is short-term exposure to particle radioactivity (PR) attributable to radon decay products emitted from particulate matter ≤2.5 µm in diameter (PM2.5) associated with pulmonary function in chronic obstructive pulmonary disease (COPD) patients? STUDY DESIGN AND METHODS: In this cohort study, 142 elderly, predominantly male patients with COPD from Eastern Massachusetts each had up to 4 one-week long seasonal assessments of indoor (home) and ambient (central site) PR and PM2.5 over the course of a year (467 assessments). Ambient and indoor PR were measured as α-activity on archived PM2.5 filter samples. Ratios of indoor/ambient PR were calculated, with higher ratios representing PR from an indoor source of radon decay. We also considered a measure of outside air infiltration that could dilute the concentrations of indoor radon decay products, the indoor/ambient ratio of sulfur concentrations in PM2.5 filter samples. Spirometry pre- and post-bronchodilator (BD) forced expiratory volume in 1 s (FEV1) and forced vital capacity (FVC) were conducted following sampling. Generalized additive mixed models were adjusted for meteorologic variables, seasonality, and individual-level determinants of pulmonary function. We additionally adjusted for indoor PM2.5 and black carbon (BC). RESULTS: PR exposure metrics indicating radon decay product exposure from an indoor source were associated with a reduction in FEV1 and FVC. Patients in homes with high indoor PR (≥median) and low air infiltration (

Assuntos
Poluentes Atmosféricos , Doença Pulmonar Obstrutiva Crônica , Radioatividade , Radônio , Humanos , Masculino , Idoso , Feminino , Produtos de Decaimento de Radônio , Poluentes Atmosféricos/análise , Estudos de Coortes , Material Particulado/análise , Fuligem , Exposição Ambiental/análise
9.
Environ Int ; 171: 107667, 2023 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-36516478

RESUMO

BACKGROUND: The link between exposure to ambient air pollution and mortality from cardiorespiratory diseases is well established, while evidence on neurodegenerative disorders including Parkinson's Disease (PD) remains limited. OBJECTIVE: We examined the association between long-term exposure to ambient air pollution and PD mortality in seven European cohorts. METHODS: Within the project 'Effects of Low-Level Air Pollution: A Study in Europe' (ELAPSE), we pooled data from seven cohorts among six European countries. Annual mean residential concentrations of fine particulate matter (PM2.5), nitrogen dioxide (NO2), black carbon (BC), and ozone (O3), as well as 8 PM2.5 components (copper, iron, potassium, nickel, sulphur, silicon, vanadium, zinc), for 2010 were estimated using Europe-wide hybrid land use regression models. PD mortality was defined as underlying cause of death being either PD, secondary Parkinsonism, or dementia in PD. We applied Cox proportional hazard models to investigate the associations between air pollution and PD mortality, adjusting for potential confounders. RESULTS: Of 271,720 cohort participants, 381 died from PD during 19.7 years of follow-up. In single-pollutant analyses, we observed positive associations between PD mortality and PM2.5 (hazard ratio per 5 µg/m3: 1.25; 95% confidence interval: 1.01-1.55), NO2 (1.13; 0.95-1.34 per 10 µg/m3), and BC (1.12; 0.94-1.34 per 0.5 × 10-5m-1), and a negative association with O3 (0.74; 0.58-0.94 per 10 µg/m3). Associations of PM2.5, NO2, and BC with PD mortality were linear without apparent lower thresholds. In two-pollutant models, associations with PM2.5 remained robust when adjusted for NO2 (1.24; 0.95-1.62) or BC (1.28; 0.96-1.71), whereas associations with NO2 or BC attenuated to null. O3 associations remained negative, but no longer statistically significant in models with PM2.5. We detected suggestive positive associations with the potassium component of PM2.5. CONCLUSION: Long-term exposure to PM2.5, at levels well below current EU air pollution limit values, may contribute to PD mortality.


Assuntos
Poluentes Atmosféricos , Poluição do Ar , Poluentes Ambientais , Doença de Parkinson , Humanos , Poluentes Atmosféricos/efeitos adversos , Poluentes Atmosféricos/análise , Dióxido de Nitrogênio/análise , Exposição Ambiental/efeitos adversos , Exposição Ambiental/análise , Poluição do Ar/efeitos adversos , Poluição do Ar/análise , Material Particulado/efeitos adversos , Material Particulado/análise , Poluentes Ambientais/análise , Fuligem/análise
10.
J Environ Manage ; 329: 117087, 2023 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-36566733

RESUMO

Black carbon is a product of the incomplete combustion of carbonaceous fuels and has significant adverse effects on climate change, air quality, and human health. China has been a major contributor to global anthropogenic black carbon emissions. This study develops a black carbon inventory in China, using 2015 as the base year, and projects annual black carbon emissions in China for the period 2016-2050, under two scenarios: a Reference scenario and an Accelerated Reduction scenario. The study estimates that the total black carbon emissions in China in 2015 were 1100 thousand tons (kt), with residential use being the biggest contributor, accounting for more than half of the total black carbon emissions, followed by coke production, industry, agricultural waste burning, and transportation. This study then projects the total black carbon emissions in China in 2050 to be 278 kt in the Reference scenario and 86 kt in the Accelerated Reduction Scenario. Compared to the Reference scenario, the Accelerated Reduction scenario will achieve much faster and deeper black carbon reductions in all the sectors. The dramatic reductions can be attributed to the fuel switching in the residential sector, faster implementation of high-efficiency emission control measures in the industry, transportation, and coke production sectors, and faster phase-out of agricultural waste open burning. This analysis reveals the high potential of black carbon emission reductions across multiple sectors in China through the next thirty years.


Assuntos
Poluentes Atmosféricos , Poluição do Ar , Coque , Humanos , Poluentes Atmosféricos/análise , Poluição do Ar/prevenção & controle , Poluição do Ar/análise , China , Fuligem , Carbono/análise
11.
Environ Sci Technol ; 57(1): 440-450, 2023 01 10.
Artigo em Inglês | MEDLINE | ID: mdl-36508743

RESUMO

Short-term mobile monitoring campaigns are increasingly used to assess long-term air pollution exposure in epidemiology. Little is known about how monitoring network design features, including the number of stops and sampling temporality, impacts exposure assessment models. We address this gap by leveraging an extensive mobile monitoring campaign conducted in the greater Seattle area over the course of a year during all days of the week and most hours. The campaign measured total particle number concentration (PNC; sheds light on ultrafine particulate (UFP) number concentration), black carbon (BC), nitrogen dioxide (NO2), fine particulate matter (PM2.5), and carbon dioxide (CO2). In Monte Carlo sampling of 7327 total stops (278 sites × 26 visits each), we restricted the number of sites and visits used to estimate annual averages. Predictions from the all-data campaign performed well, with cross-validated R2s of 0.51-0.77. We found similar model performances (85% of the all-data campaign R2) with ∼1000 to 3000 randomly selected stops for NO2, PNC, and BC, and ∼4000 to 5000 stops for PM2.5 and CO2. Campaigns with additional temporal restrictions (e.g., business hours, rush hours, weekdays, or fewer seasons) had reduced model performances and different spatial surfaces. Mobile monitoring campaigns wanting to assess long-term exposure should carefully consider their monitoring designs.


Assuntos
Poluentes Atmosféricos , Poluição do Ar , Poluentes Atmosféricos/análise , Dióxido de Nitrogênio/análise , Dióxido de Carbono , Monitoramento Ambiental , Poluição do Ar/análise , Material Particulado/análise , Fuligem/análise
12.
Sci Total Environ ; 862: 160770, 2023 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-36502967

RESUMO

As a critical component of atmospheric ultrafine particulates, ultrafine carbon black (UFCB) brings great exposure risk to organisms. At present, the action pathway and activity regulation mechanism of UFCB on functional proteins in vivo are not clear, and the size-dependent effects of UFCB during this process need to be elucidated. Superoxide dismutase (SOD), one of the most applied biomarkers to assess the environmental impact of pollutants, plays crucial roles in resistance to oxidative stress. Here, based on the inactivation of SOD (84.79 %, 86.81 % and 91.70 %) in primary mouse hepatocytes exposed to UFCB (13 nm, 50 nm and 95 nm), oxidative stress, genotoxicity and protein molecular studies were employed to elucidate the inactivation mechanisms. Results showed that inhibition of UFCB-mediated superoxide anion (O2-) contributed to a decrease in SOD activity. Furthermore, the significant increase in 8-hydroxy-2-deoxyguanosine content and the comet tail formation indicated the occurrence of DNA damage, supporting that concomitant aberrant transcriptional and protein translational under gene regulation should be responsible for SOD inactivation. At the molecular level, the constricted backbone, reduced content of α-helix and fluorescence sensitization all demonstrated that the attachment-type binding of SOD on UFCB to form the 'protein corona' disrupted protein structure. Enzyme activity assays indicated that SOD backbone tightening and helix decay resulted in decreased activity, which should be another reason for intracellular SOD inactivation. More importantly, the particle sizes of UFCB exert powerful influences on SOD inactivation mechanisms. Smaller UFCB (13 nm) induced more severe O2- inhibition and DNA damage, while UFCB50nm with the best dispersity bound more SOD and induced stronger molecular toxicity, which are their different strengths in stressing SOD inactivation in hepatocytes. Our findings provide novel insights for exploring functional proteins activity and underscore a potentially size-dependent risk of nanoparticles.


Assuntos
Coroa de Proteína , Superóxidos , Camundongos , Animais , Fuligem/toxicidade , Superóxido Dismutase , Proteínas , Dano ao DNA
13.
Environ Pollut ; 318: 120885, 2023 Feb 01.
Artigo em Inglês | MEDLINE | ID: mdl-36529339

RESUMO

Black carbon (BC) can be transported over long distances and is an important trigger of climate warming and glacier melting at remote high mountains and polar regions. It is normally assumed that the variation of BC flux in remote regions is dominated by its emissions. However, after a comprehensive investigation of potential influencing factors on temporal variations of BC from ice cores of the Himalayas, this short communication shows that in addition to BC emissions, contributions from dust storms and precipitation are also important (up to 56% together) in regulating the variation of BC deposition flux and concentrations derived from remote Himalayan ice core measurements. Therefore, besides BC emissions, the influence of precipitation and BC transported by dust storms should also be considered to better quantify the lifetime and behavior of BC during its long-range transport from source to sink regions as well as to quantify the climatic effects of BC over remote Himalayan glaciers.


Assuntos
Monitoramento Ambiental , Camada de Gelo , Carbono/análise , Fuligem/análise , Poeira/análise
14.
J Colloid Interface Sci ; 634: 379-387, 2023 Mar 15.
Artigo em Inglês | MEDLINE | ID: mdl-36542968

RESUMO

HYPOTHESIS: The macroscopic properties of carbon black suspensions are primarily determined by the agglomerate microstructure built of primary aggregates. Conferring colloidal stability in aqueous carbon black suspensions should thus have a drastic impact on their viscosity and conductivity. EXPERIMENTS: Carbon black was treated with strong acids following a wet oxidation procedure. An analysis of the resulting particle surface chemistry and electrophoretic mobility was performed in evaluating colloidal stability. Changes in suspension microstructure due to oxidation were observed using small-angle X-ray scattering. Utilizing rheo-electric measurements, the evolution of the viscosity and conductivity of the carbon black suspensions as a function of shear rate and carbon content was thoroughly studied. FINDINGS: The carboxyl groups installed on the carbon black surface through oxidation increased the surface charge density and enhanced repulsive interactions. Electrostatic stability inhibited the formation of the large-scale agglomerates in favor of the stable primary aggregates in suspension. While shear thinning, suspension conductivities were found to be weakly dependent on the shear intensity regardless of the carbon content. Most importantly, aqueous carbon black suspensions formulated from electrostatically repulsive primary aggregates displayed a smaller rise in conductivity with carbon content compared to those formulated from attractive agglomerates.


Assuntos
Fuligem , Água , Suspensões , Eletricidade Estática , Água/química , Condutividade Elétrica
15.
Environ Res ; 216(Pt 2): 114613, 2023 01 01.
Artigo em Inglês | MEDLINE | ID: mdl-36272597

RESUMO

Notable warming trends have been observed in the Arctic, with tropospheric aerosols being one of the key drivers. Here the seasonal cycles of three-dimensional (3D) distributions of aerosol extinction coefficients (AECs) and frequency of occurrences (FoOs) for different aerosol subtypes in the troposphere over the Arctic from 2007 to 2019 are characterized capitalizing on Cloud-Aerosol Lidar with Orthogonal Polarization (CALIOP) Level-3 gridded aerosol profile product. Seasonal contributions of total and type-dependent aerosols through their partitioning within the planetary boundary layer (PBL) and free troposphere (FT) are also quantified utilizing the Modern-Era Retrospective Analysis for Research and Applications, version 2 (MERRA-2) PBL height data. The results show substantial seasonal and geographical dependence in the distribution of aerosols over the Arctic. Sulfate, black carbon (BC), and organic carbon (OC) contribute most of the total AEC, with Eurasia being the largest contributor. The vertical structure of AECs and FoOs over the Arctic demonstrates that the vertical influence of aerosols is higher in eastern Siberia and North America than in northern Eurasia and its coasts. When the total aerosol optical depth (TAOD) is partitioned into the PBL and FT, results indicate that the contributions of TAOD within the FT tend to be more significant, especially in summer, with the FT contributes 64.2% and 69.2% of TAOD over the lower (i.e., 60° N-70° N) and high (i.e., north of 70° N) Arctic, respectively. Additionally, seasonal trend analyses suggest Arctic TAOD exhibits a multi-year negative trend in winter, spring, and autumn and a positive trend in summer during 2007-2019, due to an overall decrease in sulfate from weakened anthropogenic emissions and a significant increase in BC and OC from enhanced biomass burning activities. Overall, this study has potential implications for understanding the seasonal cycles and trends in Arctic aerosols.


Assuntos
Poluentes Atmosféricos , Poluentes Atmosféricos/análise , Estações do Ano , Estudos Retrospectivos , Monitoramento Ambiental/métodos , Aerossóis/análise , Fuligem/análise , Carbono , Sulfatos
16.
Artigo em Inglês | MEDLINE | ID: mdl-36462796

RESUMO

Telomeres are repetitive DNA-protein sequences located at the end of chromosomes and play an essential role in preserving information in our genome by protecting against end-to-end fusion, nucleolytic degradation, breakage, and inappropriate recombination. The telomeres shorten with aging and this process can be affected by oxidative stress and inflammation. Environmental and occupational factors may contribute to telomere length (TL) shortening, as demonstrated by an increasing number of studies. In particular, air pollution was associated with aging-related health outcomes and molecular alterations, such as telomeric shortening. Leukocytes are widely used for TL measurement. However, buccal and salivary cells have more intimate contact with airborne pollutants and are easier to sample. The objective of this review was to identify whether salivary or buccal TL represents a valid marker for evaluating the effects of pollution on health. The reviewed studies investigated the association between TL and occupational exposure (genotoxic substances in mechanical workers, and pesticides in pesticides applicators), residential traffic exposure (NOx, NO2, PM2.5, PM10, and black carbon), and household air pollution (PM2.5 and black carbon from biomass stoves). The studies involved adults and children. Although few studies have yet been carried out, almost all reported a negative association between salivary or buccal TL and exposure to air pollutants stating that it could be a good indicator of occupational or airborne pollution exposure. However, further research is needed to evaluate the effect of acute versus long-term exposure on salivary or buccal TL as well as the role of confounding factors. Moreover, most of the reviewed studies were conducted on healthy adults, so it is important to deeply investigate how TL is associated with all-cause mortality such as cancer, diabetes, cardiovascular disease, and respiratory disease, how it can be affected during childhood, and which changes over time can be associated with diseases' onset in adulthood.


Assuntos
Poluição do Ar , Praguicidas , Adulto , Criança , Humanos , Poluição do Ar/efeitos adversos , Biomarcadores , Fuligem , Telômero , Carbono
17.
Sensors (Basel) ; 22(24)2022 Dec 14.
Artigo em Inglês | MEDLINE | ID: mdl-36560182

RESUMO

This paper proposes a flexible sensor for detecting cracks on bridges. Strain and deflection sensing modules are integrated on the film that is made of composite conductive materials. By optimizing the preparation ratio and internal structure, the strain detection accuracy and sensitivity of the sensor have been improved. The bridge crack detection accuracy reached 91%, which is higher than current sensors. Experimental results show that the composite material containing 2.23 wt% carbon black (CB) mixed hybrid filler has good linearity, higher accuracy than sensors in use, excellent stretchability (>155%), high gauge factor (GF ~ 43.3), and excellent durability over 2000 stretching-releasing cycles under 10 N. The designed flexible sensor demonstrates the practicality and effectiveness of bridge crack detection and provides a feasible solution for accurate bridge health monitoring in the future.


Assuntos
Fuligem , Dispositivos Eletrônicos Vestíveis , Condutividade Elétrica
18.
Sensors (Basel) ; 22(23)2022 Dec 02.
Artigo em Inglês | MEDLINE | ID: mdl-36502122

RESUMO

The present paper describes an alternative approach to the traditionally used covalent immobilization methods that require cost-intensive and complicated chemistry modification of a single-stranded DNA (ssDNA) capture probe. The low-cost pencil graphite electrode (PGE) modified with carbon black (CB) and gold nanoparticles (AuNPs) was used as an electrochemical platform and the non-modified ssDNA was immobilized on a self-assembled cysteamine modified AuNPs/CB-PGE through a phosphoramidate bond between the 5'-terminal phosphate group of ssDNA and the primary amine group of cysteamine. The microRNA-21 was used as a target model in the fabrication of this electrochemical DNA biosensor and the hybridization process with the complementary probe was monitored by differential pulse voltammetry using methylene blue (MB) as an electrochemical hybridization indicator. The decreased reduction peak current of MB shows a good linear correlation with the increased concentration of microRNA-21 target sequences because the MB signal is determined by the amount of exposed guanine bases. The linear range of the fabricated DNA biosensor was from 1.0 × 10-8 to 5.0 × 10-7 M with a detection limit of 1.0 × 10-9 M. These results show that the covalent immobilization of a non-modified ssDNA capture probe through a phosphoramidate-bonding strategy could serve as a cost-effective and versatile approach for the fabrication of DNA biosensors related to a wide range of applications that cover the fields of medical diagnostic and environmental monitoring. The fabricated electrochemical DNA biosensor was used to analyze microRNA-21 in a (spiked) human serum sample and it showed satisfactory and encouraging results as an electrochemical DNA biosensor platform.


Assuntos
Técnicas Biossensoriais , Grafite , Nanopartículas Metálicas , MicroRNAs , Humanos , Ouro/química , Grafite/química , DNA de Cadeia Simples , Fuligem , Sondas de DNA/química , Cisteamina , Técnicas Biossensoriais/métodos , Eletrodos , DNA/química , Azul de Metileno/química , Técnicas Eletroquímicas/métodos
19.
Nature ; 612(7941): E20-E21, 2022 12.
Artigo em Inglês | MEDLINE | ID: mdl-36543950
20.
Artigo em Inglês | MEDLINE | ID: mdl-36554946

RESUMO

BACKGROUND: The SARS-CoV-2 pandemic has temporarily decreased black carbon emissions worldwide. The use of multi-wavelength aethalometers provides a quantitative apportionment of black carbon (BC) from fossil fuels (BCff) and wood-burning sources (BCwb). However, this apportionment is aggregated: local and non-local BC sources are lumped together in the aethalometer results. METHODS: We propose a spatiotemporal analysis of BC results along with meteorological data, using a fuzzy clustering approach, to resolve local and non-local BC contributions. We apply this methodology to BC measurements taken at an urban site in Santiago, Chile, from March through December 2020, including lockdown periods of different intensities. RESULTS: BCff accounts for 85% of total BC; there was up to an 80% reduction in total BC during the most restrictive lockdowns (April-June); the reduction was 40-50% in periods with less restrictive lockdowns. The new methodology can apportion BCff and BCwb into local and non-local contributions; local traffic (wood burning) sources account for 66% (86%) of BCff (BCwb). CONCLUSIONS: The intensive lockdowns brought down ambient BC across the city. The proposed fuzzy clustering methodology can resolve local and non-local contributions to BC in urban zones.


Assuntos
Poluentes Atmosféricos , COVID-19 , Humanos , Poluentes Atmosféricos/análise , SARS-CoV-2 , Chile , COVID-19/epidemiologia , Monitoramento Ambiental/métodos , Controle de Doenças Transmissíveis , Aerossóis e Gotículas Respiratórios , Fuligem/análise , Análise Espaço-Temporal , Carbono/análise , Material Particulado/análise
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