Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 77
Filtrar
Más filtros

Tipo del documento
Intervalo de año de publicación
1.
Environ Res ; 260: 119630, 2024 Nov 01.
Artículo en Inglés | MEDLINE | ID: mdl-39019137

RESUMEN

Although many studies have discussed the impact of Europe's air quality, very limited research focused on the detailed phenomenology of ambient trace elements (TEs) in PM10 in urban atmosphere. This study compiled long-term (2013-2022) measurements of speciation of ambient urban PM10 from 55 sites of 7 countries (Switzerland, Spain, France, Greece, Italy, Portugal, UK), aiming to elucidate the phenomenology of 20 TEs in PM10 in urban Europe. The monitoring sites comprised urban background (UB, n = 26), traffic (TR, n = 10), industrial (IN, n = 5), suburban background (SUB, n = 7), and rural background (RB, n = 7) types. The sampling campaigns were conducted using standardized protocols to ensure data comparability. In each country, PM10 samples were collected over a fixed period using high-volume air samplers. The analysis encompassed the spatio-temporal distribution of TEs, and relationships between TEs at each site. Results indicated an annual average for the sum of 20 TEs of 90 ± 65 ng/m3, with TR and IN sites exhibiting the highest concentrations (130 ± 66 and 131 ± 80 ng/m3, respectively). Seasonal variability in TEs concentrations, influenced by emission sources and meteorology, revealed significant differences (p < 0.05) across all monitoring sites. Estimation of TE concentrations highlighted distinct ratios between non-carcinogenic and carcinogenic metals, with Zn (40 ± 49 ng/m3), Ti (21 ± 29 ng/m3), and Cu (23 ± 35 ng/m3) dominating non-carcinogenic TEs, while Cr (5 ± 7 ng/m3), and Ni (2 ± 6 ng/m3) were prominent among carcinogenic ones. Correlations between TEs across diverse locations and seasons varied, in agreement with differences in emission sources and meteorological conditions. This study provides valuable insights into TEs in pan-European urban atmosphere, contributing to a comprehensive dataset for future environmental protection policies.


Asunto(s)
Contaminantes Atmosféricos , Ciudades , Monitoreo del Ambiente , Material Particulado , Oligoelementos , Material Particulado/análisis , Contaminantes Atmosféricos/análisis , Oligoelementos/análisis , Monitoreo del Ambiente/métodos , Europa (Continente) , Atmósfera/química , Estaciones del Año , Contaminación del Aire/análisis
2.
Int J Mol Sci ; 24(23)2023 Nov 29.
Artículo en Inglés | MEDLINE | ID: mdl-38069233

RESUMEN

Atmospheric particulate matter (PM) with diameters below 10 µm (PM10) may enter the lungs through inhalation and are linked to various negative health consequences. Emergent evidence emphasizes the significance of cell metabolism as a sensitive target of PM exposure. However, the current understanding of the relationship between PM composition, conventional toxicity measures, and the rewiring of intracellular metabolic processes remains limited. In this work, PM10 sampled at a residential area (urban background, UB) and a traffic-impacted location (roadside, RS) of a Portuguese city was comprehensively characterized in terms of polycyclic aromatic hydrocarbons and plasticizers. Epithelial lung cells (A549) were then exposed for 72 h to PM10 organic extracts and different biological outcomes were assessed. UB and RS PM10 extracts dose-dependently decreased cell viability, induced reactive oxygen species (ROS), decreased mitochondrial membrane potential, caused cell cycle arrest at the G0/G1 phase, and modulated the intracellular metabolic profile. Interestingly, the RS sample, richer in particularly toxic PAHs and plasticizers, had a greater metabolic impact than the UB extract. Changes comprised significant increases in glutathione, reflecting activation of antioxidant defences to counterbalance ROS production, together with increases in lactate, NAD+, and ATP, which suggest stimulation of glycolytic energy production, possibly to compensate for reduced mitochondrial activity. Furthermore, a number of other metabolic variations hinted at changes in membrane turnover and TCA cycle dynamics, which represent novel clues on potential PM10 biological effects.


Asunto(s)
Contaminantes Atmosféricos , Hidrocarburos Policíclicos Aromáticos , Material Particulado/toxicidad , Material Particulado/análisis , Contaminantes Atmosféricos/análisis , Especies Reactivas de Oxígeno/farmacología , Plastificantes/farmacología , Pulmón/metabolismo , Hidrocarburos Policíclicos Aromáticos/farmacología , Monitoreo del Ambiente
3.
J Environ Sci (China) ; 124: 860-874, 2023 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-36182189

RESUMEN

Particulate matter (PM2.5) samples were collected in the vicinity of an industrial chemical pole and analysed for organic and elemental carbon (OC and EC), 47 trace elements and around 150 organic constituents. On average, OC and EC accounted for 25.2% and 11.4% of the PM2.5 mass, respectively. Organic compounds comprised polycyclic aromatic hydrocarbons (PAHs), alkylated PAHs, anhydrosugars, phenolics, aromatic ketones, glycerol derivatives, aliphatic alcohols, sterols, and carboxyl groups, including aromatic, carboxylic and dicarboxylic acids. Enrichment factors > 100 were obtained for Pb, Cd, Zn, Cu, Sn, B, Se, Bi, Sb and Mo, showing the contribution of industrial emissions and nearby major roads. Principal component analysis revealed that vehicle, industrial and biomass burning emissions accounted for 66%, 11% and 9%, respectively, of the total PM2.5-bound PAHs. Some of the detected organic constituents are likely associated with plasticiser ingredients and thermal stabilisers used in the manufacture of PVC and other plastics in the industrial complex. Photooxidation products of both anthropogenic (e.g., toluene) and biogenic (e.g., isoprene and pinenes) precursors were also observed. It was estimated that biomass burning accounted for 13.8% of the PM2.5 concentrations and that secondary OC represented 37.6% of the total OC. The lifetime cancer risk from inhalation exposure to PM2.5-bound PAHs was found to be negligible, but it exceeded the threshold of 10-6 for metal(loi)s, mainly due to Cr and As.


Asunto(s)
Contaminantes Atmosféricos , Hidrocarburos Policíclicos Aromáticos , Oligoelementos , Contaminantes Atmosféricos/análisis , Alcoholes , Cadmio/análisis , Carbono/análisis , Ácidos Dicarboxílicos/análisis , Monitoreo del Ambiente , Cetonas , Plomo/análisis , Material Particulado/análisis , Hidrocarburos Policíclicos Aromáticos/análisis , Cloruro de Polivinilo/análisis , Estaciones del Año , Esteroles/análisis , Tolueno/análisis , Oligoelementos/análisis , Emisiones de Vehículos/análisis
4.
J Environ Sci (China) ; 115: 215-226, 2022 May.
Artículo en Inglés | MEDLINE | ID: mdl-34969449

RESUMEN

Particulate matter emissions (PM10) from the combustion, in a residential stove, of two commercial brands of certified (ENplus A1) pellets, a non-certified brand and laboratory made pellets of acacia were tested for their ability to induce ecotoxic, cytotoxic, and mutagenic responses in unicellular organisms and a human cell line. Ecotoxicity was evaluated through the Vibrio fischeri bioluminescence inhibition assay. Moreover, cytotoxicity was assessed at two time points (24- and 48-hr) through two complementary techniques in order to evaluate the cellular metabolic activity and membrane integrity of human lung epithelial cells A549. The Ames test using two Salmonella typhimurium strains (TA100 and TA98) was employed to assess the mutagenic potential of the polycyclic aromatic hydrocarbon fraction extracted from the PM10 samples. Results obtained with the bioluminescent bacteria indicated that only particles from the combustion of acacia pellets were toxic. All samples induced impairment on the A549 cells metabolic activity, while no significant release of lactate dehydrogenase was recorded. PM10 emissions from acacia pellets were the most cytotoxic, while samples from both certified pellets evoked significant cytotoxicity at lower doses. Cytotoxicity time-dependency was only observed for PM10 from the combustion of acacia pellets and one of the brands of certified pellets. Mutagenic activity was not detected in both S. typhimurium strains. This study emphasises the role of the raw material for pellet manufacturing on the toxicological profile of PM emissions. Alternative raw materials should be deeply investigated before their use in pelletisation and combustion in residential appliances.


Asunto(s)
Contaminantes Atmosféricos , Hidrocarburos Policíclicos Aromáticos , Contaminantes Atmosféricos/análisis , Contaminantes Atmosféricos/toxicidad , Humanos , Pruebas de Mutagenicidad , Mutágenos , Material Particulado/análisis , Material Particulado/toxicidad , Hidrocarburos Policíclicos Aromáticos/análisis , Hidrocarburos Policíclicos Aromáticos/toxicidad , Emisiones de Vehículos , Madera/química
5.
Environ Monit Assess ; 191(11): 659, 2019 Oct 19.
Artículo en Inglés | MEDLINE | ID: mdl-31630273

RESUMEN

A major campaign was carried out in indoor and outdoor environments in a school located in the university campus of the city of São Paulo. Elements, PAH, oxy-PAH, water-soluble ions and black carbon were determined and compared with preliminary campaigns. The results indicated that the concentrations of particles and organic compounds were higher indoors. Some high molecular weight compounds, attributed to vehicular emissions, were more abundant outdoors. The associated health risk was found to be low. 2-Methylanthraquinone and benzo(a)anthracene-7,12-dione were detected in the indoor samples, denoting the infiltration of vehicle exhaust. The observation of black carbon also corroborates the contribution of traffic emissions. For most of the elements, except for chromium, iron and manganese, the concentrations obtained in indoors were higher than outdoors, mainly due to soil resuspension. Chromium and manganese likely derived from emissions of the vehicle powered by mixtures of ethanol and gasoline. Water-soluble inorganic ions species denoted the influence of soil resuspension and human activities.


Asunto(s)
Contaminantes Atmosféricos/análisis , Contaminación del Aire Interior/análisis , Contaminación del Aire/análisis , Monitoreo del Ambiente/métodos , Instituciones Académicas/normas , Brasil , Ciudades , Humanos , Compuestos Orgánicos/análisis , Material Particulado/análisis , Suelo/química , Emisiones de Vehículos/análisis
6.
J Environ Sci (China) ; 53: 122-131, 2017 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-28372736

RESUMEN

In summer 2010, twenty eight (14 PM2.5 samples plus 14 samples PM2.5-10) smoke samples were collected during wildfires that occurred in central Portugal. A portable high-volume sampler was used to perform the sampling, on quartz fibre filters of coarse (PM2.5-10) and fine (PM2.5) smoke samples. The carbonaceous content (elemental and organic carbon) of particulate matter was analysed by a thermal-optical technique. Subsequently, the particulate samples were solvent extracted and fractionated by vacuum flash chromatography into three different classes of organic compounds (aliphatics, polycyclic aromatic hydrocarbons (PAHs) and carbonyl compounds). The organic speciation was performed by gas chromatography-mass spectrometry (GC-MS). Emissions were dominated by the fine particles, which represented around 92% of the PM10. A clear predominance of carbonaceous constituents was observed, with organic to elemental carbon (OC/EC) ratios ranging between 1.69 and 245 in both size fractions. The isoprenoid ketone 6,10,14-trimethyl-2-pentadecanone, a tracer for secondary organic aerosol formation, was one of the dominant constituents in both fine and coarse particles. Retene was the most abundant compound in all samples. Good correlations were obtained between OC and both aliphatic and PAH compounds. Pyrogenic processes, thermal release of biogenic compounds and secondary processing accounted for 97% of the apportioned PM2.5 levels.


Asunto(s)
Contaminantes Atmosféricos/análisis , Monitoreo del Ambiente , Incendios , Hidrocarburos/análisis , Material Particulado/análisis , Aerosoles/análisis , Hidrocarburos Policíclicos Aromáticos , Portugal , Estaciones del Año
7.
Environ Res ; 146: 35-46, 2016 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-26717078

RESUMEN

Sampling campaigns using the same equipment and methodology were conducted to assess and compare the air quality at three South European subway systems (Barcelona, Athens and Oporto), focusing on concentrations and chemical composition of PM2.5 on subway platforms, as well as PM2.5 concentrations inside trains. Experimental results showed that the mean PM2.5 concentrations widely varied among the European subway systems, and even among different platforms within the same underground system, which might be associated to distinct station and tunnel designs and ventilation systems. In all cases PM2.5 concentrations on the platforms were higher than those in the urban ambient air, evidencing that there is generation of PM2.5 associated with the subway systems operation. Subway PM2.5 consisted of elemental iron, total carbon, crustal matter, secondary inorganic compounds, insoluble sulphate, halite and trace elements. Of all metals, Fe was the most abundant, accounting for 29-43% of the total PM2.5 mass (41-61% if Fe2O3 is considered), indicating the existence of an Fe source in the subway system, which could have its origin in mechanical friction and wear processes between rails, wheels and brakes. The trace elements with the highest enrichment in the subway PM2.5 were Ba, Cu, Mn, Zn, Cr, Sb, Sr, Ni, Sn, Co, Zr and Mo. Similar PM2.5 diurnal trends were observed on platforms from different subway systems, with higher concentrations during subway operating hours than during the transport service interruption, and lower levels on weekends than on weekdays. PM2.5 concentrations depended largely on the operation and frequency of the trains and the ventilation system, and were lower inside the trains, when air conditioning system was operating properly, than on the platforms. However, the PM2.5 concentrations increased considerably when the train windows were open. The PM2.5 levels inside the trains decreased with the trains passage in aboveground sections.


Asunto(s)
Contaminantes Atmosféricos/análisis , Contaminación del Aire Interior/análisis , Material Particulado/análisis , Vías Férreas , Monitoreo del Ambiente , Grecia , Tamaño de la Partícula , Portugal , España , Análisis Espacial , Factores de Tiempo
8.
Clin Oral Implants Res ; 26(9): 983-91, 2015 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-24735458

RESUMEN

OBJECTIVE: The effect on the marginal peri-implant tissues following repeated platform switching abutment removal and subsequent reconnection was studied. MATERIAL AND METHODS: Six adult female Beagle dogs were selected, and Pm3 and Pm4 teeth, both left and right sides, were extracted and the sites healed for 3 months. At this time, 24 bone level (BL) (Straumann, Basel, Switzerland) Ø 3.3/8 mm implants were placed, 2 in each side on Pm3 and Pm4 regions. In one side (control group), 12 bone level conical Ø 3.6 mm healing abutments and, on the other side (test group), 12 Narrow CrossFit (NC) multibase abutments (Straumann) , Basel, Switzerland) were connected at time of implant surgery. On test group, all prosthetic procedures were carried out direct to multibase abutment without disconnecting it, where in the control group, the multibase abutment was connected/disconnected five times (at 6/8/10/12/14 weeks) during prosthetic procedures. Twelve fixed metal bridges were delivered 14 weeks after implant placement. A cleaning/control appointment was scheduled 6 months after implant placement. The animals were sacrificed at 9 months of the study. Clinical parameters and peri-apical x-rays were registered in every visit. Histomorphometric analysis was carried out for the 24 implants. The distance from multibase abutment shoulder to the first bone implant contact (S-BIC) was defined as the primary histomorphometric parameter. RESULTS: Wilcoxon comparison paired test (n = 6) found no statistically significant differences (buccal P = 0.917; Lingual P = 0.463) between test and control groups both lingually and buccally for S-BIC distance. Only Pm3 buccal aBE-BC (distance from the apical end of the barrier epithelium to the first bone implant contact) (P = 0.046) parameter presented statistically significant differences between test and control groups. Control group presented 0.57 mm more recession than test group, being this difference statistically significant between the two groups (P < 0.001). CONCLUSION: It can be conclude, within the limits of this animal study, that the connection/disconnection of platform switching abutments during prosthetic phase of implant treatment does not induce bone marginal absorption. Furthermore, it may present a negative influence in the buccal connective tissue attachment that becomes shorter anyway preventing marginal hard tissue resorption, especially in thin biotypes.


Asunto(s)
Pilares Dentales , Implantes Dentales/efectos adversos , Prótesis Dental de Soporte Implantado/efectos adversos , Encía/patología , Maxilares/patología , Animales , Biometría , Perros , Femenino , Histocitoquímica , Modelos Animales , Radiografía Dental , Suiza , Resultado del Tratamiento
9.
Environ Pollut ; 362: 125015, 2024 Sep 23.
Artículo en Inglés | MEDLINE | ID: mdl-39322112

RESUMEN

An air quality monitoring campaign for gaseous pollutants using passive sampling techniques was carried out, for the first time, at 25 locations in the metropolitan area of Luanda, Angola, in June 2023. Concentrations of benzene, toluene, ethylbenzene, xylenes, trimethylbenzenes, SO2 and NO2 were generally higher in locations more impacted by traffic. Benzene, SO2 and NO2 levels did not exceed the World Health Organisation guidelines. Ozone concentrations surpassed those documented for other African regions. Higher O3 formation potential values were recorded at heavy-trafficked roads. The top 5 species with potential for ozone formation were m,p-xylene, toluene, formaldehyde, propionaldehyde and butyraldehyde. The Mulenvos landfill presented a distinctive behaviour with a very low toluene/benzene ratio (0.47), while values close to 5 were obtained at traffic sites. The maximum levels of α-pinene, D-limonene, formaldehyde, acetaldehyde, acetone, acrolein, propionaldehyde, butyraldehyde, benzaldehyde, valeraldehyde, hexaldehyde and crotonaldehyde were recorded at the landfill. The formaldehyde/acetaldehyde ratio ranged from 0.40 at the Mulenvos landfill to 3.0, averaging 1.8, which is a typical value for urban atmospheres. Acetaldehyde/propionaldehyde ratios around 0.4-0.6 were found in locations heavily impacted by traffic, whereas values between 0.7 and 1.2 were observed in green residential areas and in places with more rural characteristics. All hazard quotient (HQ) values were in the range from 1 to 10, indicating moderate risk of developing non-cancer diseases. The exception was the Mulenvos landfill for which a HQ of 11 was obtained (high risk). The cancer risks exceeded the tolerable level of 1 × 10-4, with special concern for the landfill and sites most impacted by traffic. A mean lifetime cancer risk of 9 × 10-4 was obtained. The cancer risk was mainly due to naphthalene, which accounted, on average, for 94.6% of the total.

10.
IDCases ; 37: e02002, 2024.
Artículo en Inglés | MEDLINE | ID: mdl-38966283

RESUMEN

This case report describes a rare fungal infection, piedra alba, in a 5-year-old female initially misdiagnosed. Treatment with 2 % ketoconazole shampoo led to significant regression within a week, without the need for hair cutting. We discuss the importance of early and accurate diagnosis, highlighting potential hair damage and complications in immunocompromised cases. Dermatoscopy aided diagnosis, and 2 % ketoconazole demonstrated efficacy, emphasizing the need for a multidisciplinary approach and dermatological follow-up.

11.
Sci Total Environ ; 918: 170598, 2024 Mar 25.
Artículo en Inglés | MEDLINE | ID: mdl-38340837

RESUMEN

Indoor air quality is crucial for human health due to the significant time people spend at home, and it is mainly affected by internal sources such as solid fuel combustion for heating. This study investigated the indoor air quality and health implications associated with residential coal burning covering gaseous pollutants (CO, CO2 and total volatile organic compounds), particulate matter, and toxicity. The PM10 chemical composition was obtained by ICP-MS/OES (elements), ion chromatography (water-soluble ions) and thermal-optical analysis (organic and elemental carbon). During coal combustion, PM10 levels were higher (up to 8.8 times) than background levels and the indoor-to-outdoor ratios were, on average, greater than unity, confirming the existence of a significant indoor source. The chemical characterisation of PM10 revealed increased concentrations of organic carbon and elemental carbon during coal combustion as well as arsenic, cadmium and lead. Carcinogenic risks associated with exposure to arsenic exceeded safety thresholds. Indoor air quality fluctuated during the study, with varying toxicity levels assessed using the Aliivibrio fischeri bioluminescence inhibition assay. These findings underscore the importance of mitigating indoor air pollution associated with coal burning and highlight the potential health risks from long-term exposure. Effective interventions are needed to improve indoor air quality and reduce health risks in coal-burning households.


Asunto(s)
Contaminantes Atmosféricos , Contaminación del Aire Interior , Arsénico , Contaminantes Atmosféricos/análisis , Contaminación del Aire Interior/análisis , Arsénico/análisis , Carbono/análisis , Carbón Mineral/análisis , Monitoreo del Ambiente , Material Particulado/análisis
12.
J Oral Implantol ; 39(2): 198-205, 2013 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-21767202

RESUMEN

The aim of this article is to present a novel approach to preserve the buccal wall when performing immediate implants. After immediate implant site preparation, the socket is filled with Bio-Oss collagen and trimmed in a cone form to closely adapt to the buccal wall. Then, the implant is placed with low-rotation-speed condensing Bio-Oss collagen buccally. With this technique, the remodeling of buccal wall after immediate implant placement may be reduced.


Asunto(s)
Aumento de la Cresta Alveolar/métodos , Sustitutos de Huesos/uso terapéutico , Carga Inmediata del Implante Dental/métodos , Maxilar/cirugía , Alveolo Dental/cirugía , Pérdida de Hueso Alveolar/cirugía , Matriz Ósea/trasplante , Regeneración Ósea/fisiología , Periodontitis Crónica/complicaciones , Colágeno/uso terapéutico , Tomografía Computarizada de Haz Cónico/métodos , Estudios de Seguimiento , Humanos , Masculino , Persona de Mediana Edad , Minerales/uso terapéutico , Oseointegración/fisiología , Planificación de Atención al Paciente
13.
Toxics ; 11(6)2023 Jun 03.
Artículo en Inglés | MEDLINE | ID: mdl-37368605

RESUMEN

People spend most of their time indoors, particularly in their houses where daily activities are carried out, enhancing particulate matter (PM) emissions with consequent adverse health impacts. This study intended to appraise the toxicological and mutagenic responses of particulate matter with a diameter less than 10 µm (PM10) released from cooking and ironing activities under different conditions. The cytotoxicity of the PM10 total organic extracts was tested in A549 cells using the WST-8 and the lactate dehydrogenase (LDH) assays, while the interference in cell cycle dynamics and reactive oxygen species (ROS) production was analysed by flow cytometry. The S. typhimurium TA98 and TA100 Ames tester strains with and without metabolic activation were employed to determine the mutagenic potential of the PM10-bound polycyclic aromatic hydrocarbons (PAHs). PM10 organic extracts decreased the metabolic activity of A549 cells; however, no effects in the LDH release were observed. An increase in ROS levels was registered only for cells treated with PM10 at IC20 from steam ironing, in low ventilation conditions, while cell cycle dynamics was only affected by exposure to PM10 at IC20 from frying horse mackerel and grilling boneless pork strips. No mutagenic effects were observed for all the PM10-bound PAHs samples.

14.
Environ Sci Pollut Res Int ; 30(23): 63738-63753, 2023 May.
Artículo en Inglés | MEDLINE | ID: mdl-37059947

RESUMEN

This study assessed the emissions of gaseous pollutants and particle size distributed water-soluble organics (WSO) from a diesel vehicle fuelled with ultralow sulphur diesel (B0) and 10 (B10), 20 (B20), and 30% (B30) biodiesel blends in a chassis dynamometer tested under transient mode. Particulate emission sampling was carried out in an ultraviolet (UV) test chamber using a 10-stage impactor. Samples were grouped into three size fractions and analysed by gas chromatography-mass spectrometry. Increasing the biofuel ratio up to 30% in the fuel reduced WSO emissions by 20.9% in comparison with conventional diesel. Organic acids accounted for 82-89% of WSO in all tested fuels. Dicarboxylic acids were the most abundant compound class, followed by hydroxy, aromatic, and linear alkanoic acids. Correlations between compounds demonstrated that adding biodiesel to diesel fuel reduces the emissions of nitrogen oxides (NOx), benzene, toluene, ethylbenzene and xylenes (BTEX), methane (CH4), total and nonmethane hydrocarbons (THC and NMHC), and dicarboxylic and hydroxy acids, but increases emissions of carbon dioxide (CO2) and alkanoic and aromatic acids. Emissions of dicarboxylic and hydroxy acids were strongly correlated with the biodiesel content. WSO emissions of coarse and fine (1.0-10 µm) particles decreased with the increasing biofuel content in fuel blend. The total share of ultrafine (0.18-1.0 µm) and nanoparticles (< 0.18 µm) increased in WSOs emissions from B20 and B30 blends, when compared with petrodiesel. The biodiesel content also affected the chemical profile of WSO size fractions.


Asunto(s)
Contaminantes Atmosféricos , Gases , Gases/análisis , Biocombustibles/análisis , Tamaño de la Partícula , Agua/análisis , Emisiones de Vehículos/análisis , Gasolina/análisis , Compuestos Orgánicos/análisis , Contaminantes Atmosféricos/análisis
15.
Urban Clim ; 49: 101446, 2023 May.
Artículo en Inglés | MEDLINE | ID: mdl-36820273

RESUMEN

The lockdowns held due to the COVID-19 pandemic conducted to changes in air quality. This study aimed to understand the variability of PM2.5 levels and composition in an urban-industrial area of the Lisbon Metropolitan Area and to identify the contribution of the different sources. The composition of PM2.5 was assessed for 24 elements (by PIXE), secondary inorganic ions and black carbon. The PM2.5 mean concentration for the period (December 2019 to November 2020) was 13 ± 11 µg.m-3. The most abundant species in PM2.5 were BC (19.9%), SO4 2- (15.4%), NO3 - (11.6%) and NH4 + (5.3%). The impact of the restrictions imposed by the COVID-19 pandemic on the PM levels was found by comparison with the previous six years. The concentrations of all the PM2.5 components, except Al, Ba, Ca, Si and SO4 2-, were significantly higher in the winter/pre-confinement than in post-confinement period. A total of seven sources were identified by Positive Matrix Factorisation (PMF): soil, secondary sulphate, fuel-oil combustion, sea, vehicle non-exhaust, vehicle exhaust, and industry. Sources were greatly influenced by the restrictions imposed by the COVID-19 pandemic, with vehicle exhaust showing the sharpest decrease. Secondary sulphate predominated in summer/post-confinement. PM2.5 levels and composition also varied with the types of air mass trajectories.

16.
Environ Toxicol Pharmacol ; 101: 104170, 2023 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-37295738

RESUMEN

In the vicinity of a petrochemical industrial region in São Paulo, Brazil, PM2.5-bound organic carbon (OC), elemental carbon (EC), polycyclic aromatic hydrocarbons (PAHs), nitro-PAHs, oxy-PAHs, hopanes, and inorganic species were evaluated. Oxidative potential (OP), burden (OB), and Alivibrio fischeri bioluminescence inhibition (AFBIA) assays were conducted to determine the potential health effects of exposure to these compounds. The PM2.5 mean concentration was 32.0 ± 18.2 µg m-3, and benzo (a)pyrene was found to exceed recommended levels by at least four times. Secondary sources and vehicular emissions were indicated by nitro-PAHs, oxy-PAHs, and inorganic species. The OP and OB results revealed that secondary compounds favored antioxidant depletion. The AFBIA results showed that 64 % of the samples were toxic. These findings emphasize the need to reduce the exposure risk and take measures to protect human health.


Asunto(s)
Contaminantes Atmosféricos , Neoplasias , Hidrocarburos Policíclicos Aromáticos , Humanos , Material Particulado/toxicidad , Material Particulado/análisis , Contaminantes Atmosféricos/toxicidad , Contaminantes Atmosféricos/análisis , Monitoreo del Ambiente/métodos , Brasil , Hidrocarburos Policíclicos Aromáticos/análisis , Carbono
17.
Sci Total Environ ; 900: 165860, 2023 Nov 20.
Artículo en Inglés | MEDLINE | ID: mdl-37516189

RESUMEN

This paper presents a source apportionment study performed on a dataset collected at a trafficked site in Coimbra (Portugal) during the period December 2018-June 2019. The novelty of this work consists in the methodological approach used and the sensitivity study carried out to give hints to potential future applications. Indeed, a multi-time resolution and multi-parameter study was performed joining together aerosol data from 24-h chemically characterized samples and high-time resolution multi-wavelength absorption coefficients retrieved by an Aethalometer. A detailed sensitivity study on the most suitable combination of time resolution and uncertainties was carried out to obtain reliable physical and stable solutions over all analyses. In parallel, a regular EPA-PMF source apportionment study using chemical and optical variables averaged on 24 h is presented and discussed in comparison to the more complex multi-time and multi-parameter approach. Apart from results pertaining to the identification and relevance of different sources in Coimbra, the methodological results shown here can give guidance for readers who want to implement optical variables jointly with chemical ones in the same model run.

18.
J Neurosurg ; : 1-8, 2023 Nov 10.
Artículo en Inglés | MEDLINE | ID: mdl-37948693

RESUMEN

OBJECTIVE: Evidence on timing for mobilization after chronic subdural hematoma (cSDH) surgery is heterogeneous, and practices differ considerably among neurosurgical centers. The Impact of an Early Out-of-Bed Paradigm in Postoperative Outcomes of Chronic Subdural Hematomas: GET-UP Randomized Prospective Trial (GET-UP Trial) is a randomized clinical trial comparing a postoperative early mobilization protocol to bed rest. Previously reported results at clinical discharge and 1 month after surgery indicated a decreased risk of medical complications in the early mobilization group. Herein, the authors report outcomes at the 1-year follow-up. METHODS: The GET-UP Trial is a prospective, randomized, unicentric, open-label study with an intention-to-treat primary analysis designed to evaluate the impact of an early mobilization protocol after burr hole craniostomy for cSDH on the occurrence of medical complications and functional outcomes. Between January 2019 and August 2021, a total of 208 patients were recruited and randomized to either an early mobilization group, in which patients began elevation of the head of the bed within the first 12 hours after surgery, or to a bed rest group, in which patients remained recumbent for 48 hours. Outcomes assessed at the 1-year follow-up included functional status as measured by the Glasgow Outcome Scale-Extended (GOSE) and repeat surgery for hematoma recurrence (surgical recurrence). RESULTS: A total of 203 patients completed 1 year of follow-up: 101 in the bed rest group and 102 in the early mobilization group. No significant baseline pre-randomization clinical differences were observed between the two management groups. At 1 year after surgery, a favorable functional outcome, defined as a GOSE score ≥ 5, was observed in 59 patients (58.4%) in the bed rest group and 78 (76.5%) in the early mobilization group (p = 0.006). Death occurred in 25 patients (24.8%) in the bed rest group and 16 (15.7%) in the early mobilization group (p = 0.108). Surgical recurrence was noted in 6 patients (5.9%) in the bed rest group and 7 (6.9%) in the early mobilization group (p = 0.788). Multivariate analysis showed an independent association between early mobilization and an increase in favorable functional outcomes (OR 2.006, 95% CI 1.076-3.739, p = 0.028). CONCLUSIONS: The GET-UP Trial is the first randomized clinical trial assessing the impact of mobilization strategies on medical complications after burr hole craniostomy for cSDH. Regarding functional results 1 year after surgery, early mobilization was associated with an improvement in functional outcomes without an increase in surgical recurrence. These findings support the preference for an early mobilization protocol in cSDH patients over mandatory bed rest strategies.

19.
Sci Total Environ ; 856(Pt 2): 159006, 2023 Jan 15.
Artículo en Inglés | MEDLINE | ID: mdl-36162571

RESUMEN

This study characterized the chemical composition of particulate matter (PM) from light- (LDV) and heavy-duty (HDV) vehicles based on two traffic tunnel samplings carried out in the megacity of São Paulo (Brazil), which has >7 million vehicles and intense biofuel use. The samples were collected with high-volume samplers and analyzed using chemical characterization techniques (ion and gas chromatography, thermal-optical analysis, and inductively coupled plasma mass spectroscopy). Chemical source profiles (%) were calculated based on the measurements performed inside and outside the tunnels. Identifying a high abundance of Fe and Cu for traffic-related PM in the LDV-impacted tunnel was possible, linked with the emission of vehicles powered by ethanol and gasohol (gasoline and ethanol blend). We calculated diagnostic ratios (e.g., EC/Cu, Fe/Cu, pyrene/benzo[a]pyrene, pyrene/benzo[b]fluoranthene, and fluoranthene/benzo[b]fluoranthene) characteristic of fuel exhausts (diesel/biodiesel and ethanol/gasohol), allowing their use in the assessment of the temporal variation of the fuel type used in urban sites. Element diagnostic ratios (Cu/Sb and Fe/Cu) pointed to the predominance of LDVs exhaust-related copper and can differentiate LDVs exhaust from brake wear emissions. The carbonaceous fraction EC3 was suggested as an HDV emission tracer. A higher total polycyclic aromatic hydrocarbons (PAHs) fraction of traffic-related PM2.5 was observed in the HDV-impacted tunnel, with a predominance of diesel-related pyrene and fluoranthene, as well as higher oxy-PAHs (e.g., 9,10-anthraquinone, associated with biodiesel blends) abundances. However, carcinogenic species presented higher abundances for the LDV-impacted tunnel (e.g., benzo[a]pyrene). These findings highlighted the impact of biofuels on the characteristic ratios of chemical species and pointed to possible markers for LDVs and HDVs exhausts.


Asunto(s)
Contaminantes Atmosféricos , Hidrocarburos Policíclicos Aromáticos , Material Particulado/análisis , Biocombustibles/análisis , Contaminantes Atmosféricos/análisis , Benzo(a)pireno/análisis , Monitoreo del Ambiente/métodos , Brasil , Emisiones de Vehículos/análisis , Hidrocarburos Policíclicos Aromáticos/análisis , Etanol/análisis
20.
Environ Pollut ; 331(Pt 2): 121826, 2023 Aug 15.
Artículo en Inglés | MEDLINE | ID: mdl-37196840

RESUMEN

The Metropolitan Area of São Paulo (MASP) is among the largest urban areas in the Southern Hemisphere. Vehicular emissions are of great concern in metropolitan areas and MASP is unique due to the use of biofuels on a large scale (sugarcane ethanol and biodiesel). In this work, tunnel measurements were employed to assess vehicle emissions and to calculate emission factors (EFs) for heavy-duty and light-duty vehicles (HDVs and LDVs). The EFs were determined for particulate matter (PM) and its chemical compounds. The EFs obtained for 2018 were compared with previous tunnel experiments performed in the same area. An overall trend of reduction of fine and coarse PM, organic carbon (OC), and elemental carbon (EC) EFs for both LDVs and HDVs was observed if compared to those observed in past years, suggesting the effectiveness of vehicular emissions control policies implemented in Brazil. A predominance of Fe, Cu, Al, and Ba emissions was observed for the LDV fleet in the fine fraction. Cu presented higher emissions than two decades ago, which was associated with the increased use of ethanol fuel in the region. For HDVs, Zn and Pb were mostly emitted in the fine mode and were linked with lubricating oil emissions from diesel vehicles. A predominance in the emission of three- and four-ring polycyclic aromatic hydrocarbons (PAHs) for HDVs and five-ring PAHs for LDVs agreed with what was observed in previous studies. The use of biofuels may explain the lower PAH emissions for LDVs (including carcinogenic benzo[a]pyrene) compared to those observed in other countries. The tendency observed was that LDVs emitted higher amounts of carcinogenic species. The use of these real EFs in air quality modeling resulted in more accurate simulations of PM concentrations, showing the importance of updating data with real-world measurements.


Asunto(s)
Contaminantes Atmosféricos , Hidrocarburos Policíclicos Aromáticos , Contaminantes Atmosféricos/análisis , Emisiones de Vehículos/análisis , Biocombustibles , Serina Proteasas Asociadas a la Proteína de Unión a la Manosa , Monitoreo del Ambiente/métodos , Brasil , Material Particulado/análisis , Carbono/análisis , Hidrocarburos Policíclicos Aromáticos/análisis , Etanol
SELECCIÓN DE REFERENCIAS
DETALLE DE LA BÚSQUEDA