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2.
Sensors (Basel) ; 23(1)2023 Jan 02.
Artigo em Inglês | MEDLINE | ID: mdl-36617078

RESUMO

This article deals with a unique, new powertrain diagnostics platform at the level of a large number of EU25 inspection stations. Implemented method uses emission measurement data and additional data from significant sample of vehicles. An original technique using machine learning that uses 9 static testing points (defined by constant engine load and constant engine speed), volume of engine combustion chamber, EURO emission standard category, engine condition state coefficient and actual mileage is applied. An example for dysfunction detection using exhaust emission analyses is described in detail. The test setup is also described, along with the procedure for data collection using a Mindsphere cloud data processing platform. Mindsphere is a core of the new Platform as a Service (Paas) for data processing from multiple testing facilities. An evaluation on a fleet level which used quantile regression method is implemented. In this phase of the research, real data was used, as well as data defined on the basis of knowledge of the manifestation of internal combustion engine defects. As a result of the application of the platform and the evaluation method, it is possible to classify combustion engine dysfunctions. These are defects that cannot be detected by self-diagnostic procedures for cars up to the EURO 6 level.


Assuntos
Aprendizado de Máquina , Emissões de Veículos , Emissões de Veículos/análise , Computação em Nuvem , Gasolina/análise
3.
Environ Pollut ; 316(Pt 1): 120526, 2023 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-36341831

RESUMO

The emissions of marine diesel engines have gained both global and regional attentions because of their impact on human health and climate change. To reduce ship emissions, the International Maritime Organization capped the fuel sulfur content of marine fuels. Consequently, either low-sulfur fuels or additional exhaust gas cleaning devices for the reduction in sulfur dioxide (SO2) emissions became mandatory. Although a wet scrubber reduces the amount of SO2 significantly, there is still a need to consider the reduction in particle emissions directly. We present data on the particle removal efficiency of a scrubber regarding particle number and mass concentration with different marine fuel types, marine gas oil, and two heavy fuel oils (HFOs). An open-loop sulfur scrubber was installed in the exhaust line of a marine diesel test engine. Fine particulate matter was comprehensively characterized in terms of its physical and chemical properties. The wet scrubber led up to a 40% reduction in particle number, whereas a reduction in particle mass emissions was not generally determined. We observed a shift in the size distribution by the scrubber to larger particle diameters when the engine was operated on conventional HFOs. The reduction in particle number concentrations and shift in particle size were caused by the coagulation of soot particles and formation/growing of sulfur-containing particles. Combining the scrubber with a wet electrostatic precipitator as an additional abatement system showed a reduction in particle number and mass emission factors by >98%. Therefore, the application of a wet scrubber for the after-treatment of marine fuel oil combustion will reduce SO2 emissions, but it does not substantially affect the number and mass concentration of respirable particulate matters. To reduce particle emission, the scrubber should be combined with additional abatement systems.


Assuntos
Poluentes Atmosféricos , Óleos Combustíveis , Aerossóis , Poluentes Atmosféricos/análise , Gasolina/análise , Material Particulado/análise , Enxofre/análise , Emissões de Veículos/análise
4.
Environ Res ; 216(Pt 4): 114742, 2023 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-36347393

RESUMO

The main focus of the study was to witness the effects of chicken waste-based biodiesel blends along with constant hydrogen injection in a modified diesel engine. Furthermore, the nanoparticle multiwall carbon nanotubes (MWCNT) effects on the engine efficiency were also examined. A series of tests was conducted in the single cylinder, water cooled engine fuelled with diesel, CB100N, CB10N, CB30N, and CB50N. Throughout the entire run, constant hydrogen injection of 5 LPM has been maintained. The parameters such as brake thermal efficiency, brake specific fuel consumption, heat release rate and the emissions of different pollutants were determined for a variety of engine speeds. ASTM standards were applied to measure the viscosity, density and calorific value. From the reported findings, it was clear that the addition of the chicken waste biodiesel could be a sustainable substitute for the existing fossil fuels. Although the emission of the pollutants was dropped significantly, there was a massive drop in the BTE values. To compensate such shortage of power, the biodiesel was dispersed with MWCNT at the concentration of 80 ppm. Compared to the regular biodiesel, MWCNT inclusion increased the BTE by 14%. Further, the consumption of the fuel was also reduced marginally. Considering the pollutants, the catalytic activity of the MWCNT reduced the emissions of CO, NOx, and HC at various engine speeds. Besides, 10% reduction in NOx had been reported at lower engine speeds and was reduced to 8% at higher speed regimes. Compiling all together, increasing the concentration of the biodiesel blends obviously reduced the performance values and however, there was a great advantage in terms of the emission magnitudes irrespective of the engine operating conditions.


Assuntos
Poluentes Ambientais , Nanotubos de Carbono , Animais , Biocombustíveis , Monóxido de Carbono/análise , Galinhas , Gasolina , Hidrogênio , Emissões de Veículos , Gorduras
5.
J Environ Sci (China) ; 123: 15-29, 2023 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-36521980

RESUMO

Diesel vehicles have caused serious environmental problems in China. Hence, the Chinese government has launched serious actions against air pollution and imposed more stringent regulations on diesel vehicle emissions in the latest China VI standard. To fulfill this stringent legislation, two major technical routes, including the exhaust gas recirculation (EGR) and high-efficiency selective catalytic reduction (SCR) routes, have been developed for diesel engines. Moreover, complicated aftertreatment technologies have also been developed, including use of a diesel oxidation catalyst (DOC) for controlling carbon monoxide (CO) and hydrocarbon (HC) emissions, diesel particulate filter (DPF) for particle mass (PM) emission control, SCR for the control of NOx emission, and an ammonia slip catalyst (ASC) for the control of unreacted NH3. Due to the stringent requirements of the China VI standard, the aftertreatment system needs to be more deeply integrated with the engine system. In the future, aftertreatment technologies will need further upgrades to fulfill the requirements of the near-zero emission target for diesel vehicles.


Assuntos
Poluentes Atmosféricos , Poluição do Ar , Poluentes Atmosféricos/análise , Emissões de Veículos/prevenção & controle , Emissões de Veículos/análise , Poluição do Ar/prevenção & controle , Poluição do Ar/análise , Catálise , China , Gasolina , Material Particulado/análise , Veículos Automotores
6.
J Environ Sci (China) ; 123: 30-40, 2023 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-36521993

RESUMO

China's emission control for nonroad diesel mobile machinery (NDMM) must deal with a fast increase in stock as well as regulations that are two decades behind those for on-road vehicles. This study provides the first large-scale review and evaluation of China's NDMM policies, along with emission measurements and an investigation on diesel fuel quality. The sulfur contents of the investigated diesel declined from 430 ppm (median value) in 2011 to 6-8 ppm during the 2017-2018 period. The emission control of NOx and PM greatly improved with the shift from the China II to China IV standards, as demonstrated by engine tests and field NOx measurements. However, the NOx emission factors for non-type-approved engines were approximately twice the limits of the China II standards. Emission compliance based on bench tests was not sufficient to control actual emissions because the field-measured NOx emission factors of all machinery ranged from 24% to 225% greater than the respective emission limits for the engines. These circumstances adversely affected the effectiveness of the regulations and policies for China's emission control of NDMM. Nevertheless, the policies on new and in-use NDMM, as well as diesel fuel quality, prevented NOx and PM emissions amounting to 4.4 Tg and 297.8 Gg during the period 2008-2017, respectively. The emission management strategy contributed to enhancing the international competitiveness of China's NDMM industries by promoting advanced technologies. For effective NDMM emission control in the future, portable testing and noncontact remote supervision should be strengthened; also, the issue of noncompliant diesel should be addressed through rigorous control measures and financial penalties.


Assuntos
Poluentes Atmosféricos , Emissões de Veículos , Poluentes Atmosféricos/análise , China , Gasolina , Enxofre , Emissões de Veículos/análise
7.
Environ Res ; 216(Pt 2): 114523, 2023 01 01.
Artigo em Inglês | MEDLINE | ID: mdl-36270534

RESUMO

Acute exposure to fresh traffic-related air pollutants (TRAPs) can be high for road users, including motorbike drivers, cyclists, and pedestrians. However, evaluating the toxicity of fresh traffic emissions from on-road vehicles is challenging since pollution properties can change dynamically within a short distance and time. This study demonstrated a mobile platform equipped with an On-Board Diagnostic II (OBDII) system, a tailor-made portable emission measurement system, and an electrostatic air-liquid interface exposure system with human monocytic THP-1 cells to characterize on-road tailpipe emissions under real driving conditions. High number concentrations up to 106-107 # cm-3 of ultrafine particles (UFPs) were observed for a gasoline engine at the cold-start stage and a diesel engine during particulate filter regeneration. In particular, a substantial fraction of freshly emitted UFPs within the size less than 23 nm were observed and should be cautioned. The potential toxicity of fresh TRAPs was quantified by cell viability, cytotoxicity, oxidative stress, and inflammatory biomarkers. Results show that the decreased cell viability, increased lactate dehydrogenase (LDH) activity, and high oxidative stress induced by the fresh TRAPs were potentially contributed by gaseous pollutants as well as particles, especially driving with the high idling frequency. Moreover, the dominant contributor to the toxicity is different for gasoline's and diesel's TRAPs. Characterizing on-road air pollutant toxicity as well as physicochemical properties using an innovative mobile platform can fill this knowledge gap.


Assuntos
Poluentes Atmosféricos , Poluição do Ar , Humanos , Material Particulado/análise , Gasolina/análise , Tamanho da Partícula , Monitoramento Ambiental/métodos , Emissões de Veículos/toxicidade , Emissões de Veículos/análise , Poluentes Atmosféricos/toxicidade , Poluentes Atmosféricos/análise , Poluição do Ar/análise , Veículos Automotores
8.
Environ Sci Pollut Res Int ; 29(5): 7793-7810, 2022 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-34480315

RESUMO

Promoting the development of electric vehicles (EVs) is regarded as an important measure to ensure energy security, mitigate climate change, and solve the transport sector's air pollution problems. Nowadays, compared to gasoline vehicles, whether the EVs are more competitive in terms of cost is still a question. There is no consensus achieved since the total cost depends on the development stage of the automobile industry and power generation structure as well as the cost accounting boundary. Many of existing studies did not include the costs occurred in all the stages. In response to this concern, this study estimates the lifecycle cost covering the whole process of production, use, disposal, and infrastructure construction as well as externalities for passenger battery electric vehicle (BEV), fuel cell vehicle (FCV), and gasoline vehicle (GV) by applying the comprehensive lifecycle cost model to China. The results indicate that in 2018, BEV and FCV were more expensive than GV (1.2-5.3 times), but that BEV will become cheaper after 2025, and its cost advantage will be enlarged to $419 (5%) compared to GV by 2030. The lifecycle cost of FCV will be $527 (or 5%) lower than that of GV by 2030. These results clarify that the costs of vehicle production account for the largest proportion in the total lifecycle cost.


Assuntos
Poluição do Ar , Emissões de Veículos , China , Eletricidade , Gasolina/análise , Veículos Automotores , Emissões de Veículos/análise
9.
Sci Rep ; 12(1): 21719, 2022 12 15.
Artigo em Inglês | MEDLINE | ID: mdl-36522376

RESUMO

There is a growing amount of plastic waste that needs to be properly disposed of in order to protect the environment from the negative effects of increasing reliance on plastic products. Recent interest has focused on chemical recycling as a means of reducing plastic's negative environmental effects. Converting waste plastics into basic petrochemicals allows them to serve as hydrocarbon feedstock or fuel oil through pyrolysis operations. Scientists have taken a keen interest in the production of bioethanol from renewable feedstocks due to its potential as a source of energy and alternative fuel. Due to its beneficial effects on the environment, ethanol has emerged as a promising biofuel. In this paper, energy recovered from low-density polyethylene and high-density polyethylene waste was converted into an alternative plastic fuel and evaluated for its environmental impact with the blending of ethanol in a diesel engine. Ternary fuel blends with 20%, 30%, and 40% waste plastic fuel and 10%, 15%, and 20% ethanol with standard diesel were tested. The study found that blending 10% ethanol with 20% plastic fuel decreased fuel consumption by around 7.9% compared to base diesel. Carbon monoxide emissions are reduced by about 10.2%, and hydrocarbon emissions are reduced by about 13.43% when using the same ternary blend. The optimum values of fuel consumption and emissions were obtained by full factorial design for a ternary fuel blend of 10% ethanol and 20% plastic fuel at the full load condition.


Assuntos
Gasolina , Plásticos , Emissões de Veículos/análise , Etanol/análise , Biocombustíveis , Hidrocarbonetos/análise , Polietileno
10.
Environ Health ; 21(1): 138, 2022 Dec 27.
Artigo em Inglês | MEDLINE | ID: mdl-36572887

RESUMO

BACKGROUND: Millions of tons of lead were added to gasoline worldwide beginning in 1922, and leaded gasoline has been a major source of population lead exposure. In 1960s, lead began to be removed from automotive gasoline. Removal was completed in 2021. OBJECTIVES: To determine whether removal of lead from automotive gasoline is associated with declines in population mean blood lead levels (BPb). METHODS: We examined published studies that reported population blood leaded levels for two or more years, and we calculated average concentrations of lead in gasoline corresponding to the years and locations of the blood lead level measurements. RESULTS: Removal of lead from gasoline is associated with declines in BPb in all countries examined. In some countries, BPb continues to fall after lead has been eliminated from gasoline. Following elimination of lead from gasoline, BPb less than 1 µg/dL have been observed in several European and North American countries, and BPb less than 3 µg/dL have been documented in several studies from South America. DISCUSSION: There remain many countries for which no multi-year studies of populations BPb have been identified, including all of Central America, high population countries including Pakistan and Indonesia, and major lead producers including Australia and Russia. CONCLUSION: Removal of lead from gasoline has been a public health success. Elimination of lead from gasoline has enabled many countries to achieve population mean BPb levels of 1 µg/dL or lower. These actions have saved lives, increased children's intelligence and created great economic benefit in countries worldwide.


Assuntos
Intoxicação por Chumbo , Chumbo , Criança , Humanos , Exposição Ambiental , Gasolina , Hidrocarbonetos
11.
Artigo em Inglês | MEDLINE | ID: mdl-36361013

RESUMO

Legal restrictions on vehicle engine exhaust gas emission control do not always go hand in hand with an actual reduction in the emissions of toxins into the atmosphere. Moreover, the methods currently used to measure exhaust gas emissions do not give unambiguous results on the impact of the tested gases on living organisms. The method used to assess the actual toxicity of gases, BAT-CELL Bio-Ambient-Tests using in vitro tests, takes into account synergistic interactions of individual components of a mixture of gases without the need to know its qualitative and quantitative composition and allows for determination of the actual toxicity of the gas composition. Using the BAT-CELL method, exhaust gases from passenger vehicles equipped with spark-ignition engines complying with the Euro 3 and Euro 6 emission standards were tested. The results of toxicological tests were correlated with the results of chromatographic analysis. It was shown that diverse qualitative composition of the mixture of hydrocarbons determining the exhaust gases toxicity may decrease the percentage value of cell survival. Additionally, it was proven that the average survival of cells after exposure to exhaust gases from tested vehicles meeting the more restrictive Euro 6 standard was lower than for vehicles meeting the Euro 3 standard thus indicating the higher toxicity of exhaust gases from newer vehicles.


Assuntos
Poluentes Atmosféricos , Emissões de Veículos , Emissões de Veículos/toxicidade , Emissões de Veículos/análise , Gasolina/análise , Gases/toxicidade , Gases/análise , Hidrocarbonetos/toxicidade , Hidrocarbonetos/análise , Técnicas In Vitro , Poluentes Atmosféricos/toxicidade , Poluentes Atmosféricos/análise , Veículos Automotores
12.
Sci Rep ; 12(1): 18963, 2022 Nov 08.
Artigo em Inglês | MEDLINE | ID: mdl-36347886

RESUMO

This research endeavored to boost the applicability of methanol in CI engines utilizing n-decanol as cosolvents. The work was split into binary phases. Firstly, the stabilities of pure methanol (M100) and hydrous-methanol (MH10), with diesel as a reference fuel, were examined applying various temperatures: 10 °C, 20 °C, and 30 °C. The findings showed that the M100-diesel and MH10-diesel combinations were unstable. Thus, n-decanol was utilized as a cosolvent. Following by the engine combustion and emissions characteristics were evaluated by manipulating three proportions of M100-diesel mixtures with n-decanol. Three mixtures comprised of 5, 10, and 15% M100 with 20% n-decanol, which are denoted as M5, M10, and M15, correspondingly. These combinations were assessed via thermogravimetric assessment, and their physicochemical properties were assessed corresponding to the ASTM. The maximum in-cylinder pressure, heat release rate, and pressure rise rate diminished by 10, 11, and 10%, respectively, for the M100/diesel/n-decanol combinations compared with the diesel oil. The brake thermal efficiency lowered by 10%, whereas the brake specific fuel consumption enlarged by 10% for the combinations compared with the diesel. NOx and smoke opacity levels diminished by about 30 and 50%, respectively, whereas the CO and UHC enlarged by about 50 and 60% for the blends compared with the diesel oil.


Assuntos
Metanol , Emissões de Veículos , Metanol/química , Gasolina , Álcoois Graxos , Biocombustíveis
13.
Environ Monit Assess ; 195(1): 141, 2022 Nov 23.
Artigo em Inglês | MEDLINE | ID: mdl-36416984

RESUMO

With the use of vehicles, large amounts of carbon dioxide are emitted by combustion of gasoline and energy consumes in their lifecycle. Therefore, the objective of this study is to evaluate the lifecycle carbon emission and primary energy input of a widely used sport utility vehicle (SUV) in China with the lifecycle assessment method. The results show that total petrol consumption of an SUV in lifetime is 21,300 kg; the CO2 emissions and primary energy input in the manufacturing, assembly, operation, and decommissioning phase are respectively 8857, 443, 54,925, and 443 kg and 123,413, 6171, 12,341, and 6171 MJ. The average CO2 emission intensity and energy input intensity of materials are respectively 2.74 kg/kg and 64.9 MJ/kg. The primary energy input of materials in manufacturing phase occupies 83.3%, and CO2 emission in use phase is 64,267.3 kg (occupied 92.62%), mainly attributed to the combustion of petrol.


Assuntos
Gasolina , Emissões de Veículos , Gasolina/análise , Emissões de Veículos/análise , Dióxido de Carbono , Monitoramento Ambiental , Veículos Automotores
14.
Proc Natl Acad Sci U S A ; 119(47): e2208024119, 2022 Nov 22.
Artigo em Inglês | MEDLINE | ID: mdl-36375060

RESUMO

For countries to rapidly decarbonize, they need strong leadership, according to both academic studies and popular accounts. But leadership is difficult to measure, and its importance is unclear. We use original data to investigate the role of presidents, prime ministers, and monarchs in 155 countries from 1990 to 2015 in changing their countries' gasoline taxes and subsidies. Our findings suggest that the impact of leaders on fossil fuel taxes and subsidies is surprisingly limited and often ephemeral. This holds true regardless of the leader's age, gender, education, or political ideology. Rulers who govern during an economic crisis perform no better or worse than other rulers. Even presidents and prime ministers who were recognized by the United Nations for environmental leadership had no more success than other leaders in reducing subsidies or raising fuel taxes. Where leaders appear to play an important role-primarily in countries with large subsidies-their reforms often failed, with subsidies returning to prereform levels within the first 12 mo 62% of the time, and within 5 y 87% of the time. Our findings suggest that leaders of all types find it exceptionally hard to raise the cost of fossil fuels for consumers. To promote deep decarbonization, leaders are likely to have more success with other types of policies, such as reducing the costs and increasing the availability of renewable energy.


Assuntos
Combustíveis Fósseis , Liderança , Impostos , Energia Renovável , Gasolina
15.
Sensors (Basel) ; 22(21)2022 Oct 24.
Artigo em Inglês | MEDLINE | ID: mdl-36365825

RESUMO

Regarding the problem of the valve gap health status being difficult to assess due to the complex composition of the condition monitoring signal during the operation of the diesel engine, this paper proposes an adaptive noise reduction and multi-channel information fusion method for the health status assessment of diesel engine valve clearance. For the problem of missing fault information of single-channel sensors in condition monitoring, we built a diesel engine valve clearance preset simulation test bench and constructed a multi-sensor acquisition system to realize the acquisition of diesel engine multi-dimensional cylinder head signals. At the same time, for the problem of poor adaptability of most signal analysis methods, the improved butterfly optimization algorithm by the bacterial foraging algorithm was adopted to adaptively optimize the key parameter for variational mode decomposition, with discrete entropy as the fitness value. Then, to reduce the uncertainty of artificially selecting fault characteristics, the characteristic parameters with a higher recognition degree of diesel engine signal were selected through characteristic sensitivity analysis. To achieve an effective dimensionality reduction integration of multi-channel features, a stacked sparse autoencoder was used to achieve deep fusion of the multi-dimensional feature values. Finally, the feature samples were entered into the constructed one-dimensional convolutional neural network with a four-layer parameter space for training to realize the health status assessment of the diesel engine. In addition, we verified the effectiveness of the method by carrying out valve degradation simulation experiments on the diesel engine test bench. Experimental results show that, compared with other common evaluation methods, the method used in this paper has a better health state evaluation effect.


Assuntos
Gasolina , Emissões de Veículos , Gasolina/análise , Emissões de Veículos/análise , Redes Neurais de Computação , Cinética , Nível de Saúde
16.
Molecules ; 27(22)2022 Nov 15.
Artigo em Inglês | MEDLINE | ID: mdl-36431989

RESUMO

For ultra-deep desulfurization of diesel fuel, this study applied the ultrasound-assisted catalytic ozonation process to the dibenzothiophene (DBT) removal process with four Keggin-type heteropolyacids (HPA) as catalysts and acetonitrile as extractant. Through experimental evaluations, H3PMo12O40 was found to be the most effective catalyst for the oxidative removal of DBT. Under favorable operating conditions with a temperature of 0 °C, H3PMo12O40 dosage of 2.5 wt.% of n-octane, and ultrasonic irradiation, DBT can be effectively removed from simulated diesel. Moreover, the reused catalyst exhibited good catalytic activity in recovery experiments. This desulfurization process has high potential for ultra-deep desulfurization of diesel.


Assuntos
Ozônio , Ultrassom , Oxirredução , Catálise , Gasolina
17.
Chemosphere ; 309(Pt 1): 136629, 2022 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-36181851

RESUMO

In order to keep high fuel economy of diesel passenger cars, Diesel particulate filter (DPF) is periodically regenerated. In the regeneration process, extra fuel is injected into combustion chambers to achieve high exhaust temperature for the purpose of oxidizing particles accumulating on DPF substrate. It generates significant impacts on passenger car performance and exhaust emissions. In this paper, real-driving performance and exhaust emissions of a diesel car were tested over sixteen drivers under real-world conditions. DPF regeneration events were identified via exhaust temperature. Vehicle power output, fuel economy, and exhaust emissions in the trips both with and without DPF regeneration were analyzed. The results indicated that DPF regeneration events occurred in three of thirty-two test trips, and the maximum exhaust temperature was 250 °C during DPF regeneration. The DPF regeneration event led to the decrease of fuel economy and the increase of particle number, nitrogen oxides and carbon dioxides emission. Particle number emission factors were increased from approximately 109 #/km to 5 × 1010 #/km during DPF regeneration. The average power output of the car was in the range of 14.5 kW-15.6 kW and 15.8 kW-18.4 kW for the trips with and without DPF regeneration, respectively. However, Carbon monoxide emission factors were insensitive to DPF regeneration in the test trips.


Assuntos
Poluentes Atmosféricos , Automóveis , Monóxido de Carbono , Emissões de Veículos/análise , Óxidos de Nitrogênio/análise , Poeira , Gasolina/análise , Poluentes Atmosféricos/análise
18.
JAMA Netw Open ; 5(10): e2237545, 2022 10 03.
Artigo em Inglês | MEDLINE | ID: mdl-36264577

RESUMO

Importance: There is a growing focus on environmental sustainability in health care. Objective: To estimate the environmental and patient-level financial benefits associated with the widespread adoption of virtual care during the COVID-19 pandemic. Design, Setting, and Participants: This population-based cross-sectional study obtained data from linked administrative databases in the universal health care system of Ontario, Canada, from March 2020 to December 2021. Participants included all people with a physician claim for at least 1 episode of virtual care. Exposures: Patients were stratified by age, socioeconomic status quintiles, Charlson Comorbidity Index, and area of residence (rural or urban). Main Outcomes and Measures: The primary outcomes were total travel distance and estimated travel-related carbon dioxide emissions avoided owing to virtual care visits. Different model assumptions were used to account for electric and hybrid vehicles and public transit use. The secondary outcomes were estimated patient costs (gasoline, parking, or public transit expenses) avoided. Results: During the 22-month study period, 10 146 843 patients (mean [SD] age, 44.1 [23.1] years; 5 536 611 women [54.6%]) had 63 758 914 physician virtual care visits. These visits were associated with avoidance of 3.2 billion km of travel distance and between 545 and 658 million kg of carbon dioxide emissions. Patients avoided an estimated total of $569 to $733 million (Canadian [US $465-$599 million]) in parking, public transit, and gasoline costs. Carbon dioxide emission avoidance and patient cost savings were more apparent in patients living in rural areas, those with higher comorbidity, and those who were older than 65 years. Conclusions and Relevance: Results of this study suggest that virtual care was associated with a large amount of carbon dioxide emissions avoided owing to reduced patient travel and with millions of dollars saved in parking, gasoline, or public transit costs. These benefits are likely to continue as virtual care is maintained as part of the health care system.


Assuntos
COVID-19 , Viagem , Adulto , Feminino , Humanos , Dióxido de Carbono , COVID-19/epidemiologia , Estudos Transversais , Gasolina , Ontário/epidemiologia , Pandemias
19.
J Environ Manage ; 323: 116217, 2022 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-36261979

RESUMO

Once installed, underground concrete pipes with rubber gaskets might be exposed to contaminated soil and groundwater. A pipe material monitoring capsule (PMMC) has been developed to evaluate volatile organic compounds (VOCs) breaking through three types of pipe gaskets; Neoprene, Buna-N, and Viton. The PMMCs were deployed in three contaminated sites: two with gasoline and one with chlorinated solvent (CS). A 3-D field-domain numerical model has been developed for each site to calibrate equivalent hydraulic parameters of each gasket material (ke, D) against benzene and PCE diffusion. The calibrated parameters were then used to compute the concentrations as well as rate of breakthrough of the two study contaminants. A protocol was developed for installing/retrieval of PMMCs to monitor PCE and benzene mass breaking through the gasket material with time. Employing PMMC, benzene concentrations breaking through the Neoprene and Buna-N after 4 months were approximately 70% and 60% respectively of the monitoring wells concentration. The corresponding value for PCE breakthrough after 4 months was 60% for both the Neoprene and Buna-N. Both gasket materials of Neoprene and Buna-N yielded similar performances, including higher rate of contaminant breakthrough compared to Viton. A nonlinear relationship of mass breaking through the gaskets of benzene and PCE with time was discerned from the modeling and field data.


Assuntos
Gasolina , Compostos Orgânicos Voláteis , Benzeno , Neopreno , Borracha , Solventes , Solo
20.
Arch Microbiol ; 204(11): 672, 2022 Oct 17.
Artigo em Inglês | MEDLINE | ID: mdl-36251102

RESUMO

The growing population increases the need to develop advanced biological methods for utilizing renewable and sustainable resources to produce environmentally friendly biofuels. Currently, energy resources are limited for global demand and are constantly depleting and creating environmental problems. Some higher chain alcohols, like butanol and ethanol, processing similar properties to gasoline, can be alternate sources of biofuel. However, the industrial production of these alcohols remains challenging because they cannot be efficiently produced by microbes naturally. Therefore, butanol is the most interesting biofuel candidate with a higher octane number produced naturally by microbes through Acetone-Butanol-Ethanol fermentation. Feedstock selection as the substrate is the most crucial step in biobutanol production. Lignocellulosic biomass has been widely used to produce cellulosic biobutanol using agricultural wastes and residue. Specific necessary pretreatments, fermentation strategies, bioreactor designing and kinetics, and modeling can also enhance the efficient production of biobutanol. The recent genetic engineering approaches of gene knock in, knock out, and overexpression to manipulate pathways can increase the production of biobutanol in a user friendly host organism. So far various genetic manipulation techniques like antisense RNA, TargeTron Technology and CRISPR have been used to target Clostridium acetobutylicum for biobutanol production. This review summarizes the recent research and development for the efficient production of biobutanol in various aspects.


Assuntos
Clostridium acetobutylicum , 1-Butanol/metabolismo , Acetona/metabolismo , Anaerobiose , Biocombustíveis , Biomassa , Butanóis/metabolismo , Clostridium acetobutylicum/genética , Clostridium acetobutylicum/metabolismo , Etanol/metabolismo , Fermentação , Gasolina , Octanos/metabolismo , RNA Antissenso/metabolismo
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