Search Results (507)

This study introduces a simple, sensitive, efficient, and low-cost gas detection method in the terahertz range. A mode-adjustable Fabry–Pérot cavity is proposed to enhance detection by tuning the cavity length to match the cavity’s resonant frequency with the gas absorption peak. Terahertz frequency domain spectroscopy (THz-FDS), offering MHz-level resolution, provides stronger applicability than other spectral systems. Carbon monoxide (CO) is used as the test gas, with its 465 GHz absorption peak validating the coupling enhancement. The experiment measures CO absorption spectra from 0.02 to 1.5 THz, achieving a detection limit of 7%. Using a vacuum cavity to eliminate water vapor interference, low concentrations are detected, with a mode number of m = 10 yielding a detection limit of 3500 ppm, 20 times better than previous results. The impact of different modes on coupling was analyzed, showing more effective coupling when the Q-value of the resonant peak closely matches that of the gas absorption peak. This method demonstrates high sensitivity and applicability for detecting low concentrations of toxic and harmful gases. Full article

Urban underground spaces, including tunnels, subways, and underground commercial buildings, have grown quickly as urbanization has progressed. Fires frequently break out following industrial accidents and multi-hazard natural disasters, and they can severely damage human health. Fire smoke is a major contributor and a major hazard to public safety. The flow patterns of fire smoke in underground spaces, the risks to human casualties, and engineering and personal protective technologies are all thoroughly reviewed in this work. First, it analyzes the diffusion characteristics of fire smoke in underground spaces and summarizes the coupling effects between human behavior and smoke spread. Then, it examines the risks of casualties caused by toxic gases, particulate matter, and thermal effects in fire smoke from both macroscopic case studies and microscopic toxicological viewpoints. It summarizes engineering protection strategies, such as optimizing ventilation systems, intelligent monitoring and early warning systems, and advances in the application of new materials in personal respiratory protective equipment. Future studies should concentrate on interdisciplinary collaboration, creating more precise models of the interactions between people and fire smoke and putting life-cycle management of underground fires into practice. This review aims to provide theoretical and technical support for improving human safety in urban underground space fires, thereby promoting sustainable urban development. Full article

European energy and climate policies have enabled reductions in greenhouse gas emissions across many sectors, with transport standing out as an exception. In this area, one of the most promising solutions is the electrification of vehicles. In urban contexts, the shift towards electrifying transport—particularly local public transport (LPT)—can yield significant benefits, especially when paired with an increasingly decarbonized electricity mix, effectively reducing tailpipe emissions of both greenhouse gases and other pollutants. Nevertheless, it is essential to assess whether eliminating tailpipe emissions simply shifts environmental impacts to other stages of a vehicle’s life cycle. The Life Cycle Assessment (LCA), employing a comprehensive cradle-to-grave approach, serves as the principal tool for such evaluations. In this framework, this study focuses on the Italian situation by using a dynamic LCA for the electricity mix. Results show that the electric bus reduces the impact on climate change (28.5 gCO₂eq/pkm vs. 66.7 gCO₂eq/pkm for Diesel, −57%), acidification, photochemical ozone formation, particulate matter, and the use of fossil resources. However, it presents higher impacts in terms of human toxicity (both carcinogenic and non-carcinogenic) and the use of mineral and metal resources, mainly due to battery production and the use of metals such gold, silver, and copper. Full article

Eco-friendly flame retardants are becoming a popular alternative to traditional fire retardants, many of which contain toxic halogens. These modern additives, which are based on phosphorus, nitrogen, or silicon compounds, minimize the emission of harmful gases during combustion, making them safer for the environment and human health. This study aimed to synthesize and analyze poly(vinyl chloride) (PVC) composites using a newly synthesized hybrid fire retardant, boehmite derivative (aluminium dibutyl phosphonate), as an environmentally friendly additive. The fire-retardant properties of chitosan, which is derived from the natural biopolymer chitin, have also been tested. The chemical structure of the synthesized compounds was confirmed using ATR/FTIR spectroscopy and SEM-EDX analysis. Next, PVC-based dry blends were prepared with the addition of a stabilizer, plasticiser, chalk, and selected flame retardants (aluminium dibutyl phosphonate or chitosan) at concentrations of 10 wt%, 30 wt%, and 50 wt%, resulting in homogeneous materials intended for evaluating fire performance, thermal stability (DSC, TGA), and mechanical resistance. Full article

Gas Detection Systems (GDSs) are critical safety technologies deployed in semiconductor wafer fabrication facilities to monitor the presence of hazardous gases. A GDS receives input from gas detectors equipped with consumable gas sensors, such as electrochemical (EC) and metal oxide semiconductor (MOS) types, which are used to detect toxic, flammable, or reactive gases. However, over time, sensors degradations, accuracy drift, and cross-sensitivity to interference gases compromise their intended performance. To maintain sensor accuracy and reliability, routine manual calibration is required—an approach that is resource-intensive, time-consuming, and prone to human error, especially in facilities with extensive networks of gas detectors. This systematic review (PROSPERO on 11th October 2025 Registration number: 1166004) explored minimizing or eliminating the dependency on manual calibration. Findings indicate that using properly calibrated gas sensor data can support advanced data analytics and machine learning algorithms to correct accuracy drift and improve gas selectivity. Techniques such as Principal Component Analysis (PCA), Support Vector Machines (SVMs), multivariate regression, and calibration transfer have been effectively applied to differentiate target gases from interferences and compensate for sensor aging and environmental variability. The paper also explores the emerging potential for integrating calibration-free or self-correcting gas sensor systems into existing GDS infrastructures. Despite significant progress, key research challenges persist. These include understanding the dynamics of sensor response drift due to prolonged gas exposure, synchronizing multi-sensor data collection to minimize time-related drift, and aligning ambient sensor signals with gas analytical references. Future research should prioritize the development of application-specific datasets, adaptive environmental compensation models, and hybrid validation frameworks. These advancements will contribute to the realization of intelligent, autonomous, and data-driven gas detection solutions that are robust, scalable, and well-suited to the operational complexities of modern industrial environments. Full article

Effective management of municipal solid waste is crucial for achieving sustainable development and maintaining a healthy ecological environment. Municipal solid waste incineration (MSWI) processes are highly nonlinear and exhibit strong coupling characteristics, which makes long-term stable control challenging. Accurate prediction of the various toxic and harmful acidic gases that will be generated during this process is crucial for supporting optimization and control research. This study proposes a predictive model for acidic gases using Random Forest (RF) and Inverted Transformer (ITransformer). First, the RF algorithm is used to identify feature variables that strongly correlate with the target variables, thereby facilitating the shared feature selection process for multiple acidic gases. These selected features are then fed into a multi-output ITransformer model, which predicts the target variables and generates multiple evaluation metrics. Finally, the model’s hyperparameters are optimized based on these metrics and the threshold ranges of the acidic gases. The experimental results using real data from a specific incineration plant show that 13 features remain after the shared feature selection process. Compared to other models, the proposed approach uses the fewest shared features while reducing computational costs. Moreover, the R² values for NO_x, SO₂, and HCl are 0.9791, 0.9793, and 0.9838, respectively. Full article

The utilization of oil sludge for the creation of value-added petroleum products represents an important research direction, as certain processing routes do not incur the additional costs that are associated with more complex refining operations. The selection of the most appropriate treatment method is therefore critical for achieving cost-effective processing outcomes. The economic feasibility of a particular technology is largely determined by the physical–chemical properties and potential toxicity of oil sludge, and thus, it is essential to comprehensively characterize and assess the toxicity of this substance. In this study, the physical–chemical composition and principal characteristics of oil sludge obtained from a Kazakhstan oil company were examined. To clean the oil sludge, an alkaline solution was used as a surfactant with a solid–liquid ratio of 1:3. The solid content in the sludge was reduced from 23% to 0.76%. The results revealed that the hydrocarbon fraction of the oil sludge was predominantly composed of heavy fractions. In addition, the effects of thermal parameters on treatment efficiency were found to contribute to the secondary products present in high oil fractions. Treatment with inert gases improved processing efficiency rates by over 57%. The most efficient results included the pyrolysis of cleaned oil sludge with minimum solid residues (5.8% under CO₂) and maximum gas products (37.8% under N₂). Full article

Environmental pollution is a global issue presenting risks to ecosystems and human health through release of toxic gases, existence of volatile organic compounds (VOCs) in the environment, and heavy metal contamination of waters and soils. To effectively address this issue, reliable and real-time monitoring technology is imperative. Metal–organic frameworks (MOFs) are a disruptive set of materials with high surface area, tunable porosity, and abundant chemistry to design extremely sensitive and selective pollutant detection. This review article gives an account of recent advances towards sensor technology for MOFs with application specificity towards gas and environment monitoring. We critically examine optical, electrochemical, and resistive platforms and their interfacing with embedded electronics and edge artificial intelligence (edge-AI) to realize smart, compact, and energy-efficient monitoring tools. We also detail critical challenges such as scalability, reproducibility, long-term stability, and secure data management and underscore transforming MOF-based sensors from lab prototype to functional instruments to ensure safe coverage of human health and to bring about sustainable environmental management. Full article

The detection of volatile organic compounds (VOCs) is critical for ensuring food safety, particularly for identifying spoilage gases and food adulterants. Surface Enhanced Raman Spectroscopy (SERS) has traditionally relied on noble metals such as gold and silver for strong electromagnetic enhancement. However, these substrates present challenges in terms of cost, stability, and integration into real-world applications. In this study, we explore a hybrid metal–organic framework (MOF) with reduced graphene oxide (rGO) as a SERS active substrate. The developed material showed a good sensitivity for VOC formaldehyde (FA), easily detectable at peak 1452 cm⁻¹ and offering an RSD of 16.95%. Since the substrate did not rely on any noble metals for SERS enhancement, this low cost and easy material could be fine-tuned, creating alternative less-toxic materials for detection in industries such as food safety. Full article

With the enlargement of underground parking lots, the risk of massive smoke and toxic gases generated during a fire will be increased, resulting in significant casualties, property damage, and difficulties in firefighting operations. To address these issues, installation of ventilation fans and inducer fans together has been proposed to extract smoke and hazardous gases more efficiently to the outside. However, the disturbance of ventilation caused by simultaneous operation of inducer fans and ventilation fans limits smoke extraction efficiency. In some worst cases, smoke disturbance may even lead to further smoke spread. Therefore, this study aims to suggest an efficient smoke extraction strategy for underground parking lots equipped with ventilation and inducer fans by optimizing the orientation of ventilation fans in the event of vehicle fires. Computational fluid dynamics-based simulation results showed that installing ventilation fan intakes and exhausts perpendicularly (PE, 90° apart) was more effective in controlling smoke than installing them in parallel (PA, horizontally facing each other). In the case of PE, the smoke stagnation area around the intakes decreased markedly from 38.18% to 3.68%. Although the smoke area near the exhausts increased in the PE configuration (53.66%) compared with the PA configuration (26.13%), this indicates that smoke was being effectively transported from the intakes to the exhausts. Furthermore, the overall smoke distribution across the entire space decreased by 4.5% under the PE setup compared with the PA setup. As the intake and exhaust flow rates of the fans increased, the efficiency of smoke removal was enhanced under the PE configuration. Consequently, in environments equipped with both ventilation and inducer fans with given conditions, perpendicular installation of fan intakes and exhausts is more efficient. These results are expected to provide practical design guidelines for ensuring effective smoke extraction in underground parking facilities. Full article

The rapid growth of the human population and industrialization has intensified anthropogenic activities, leading to the release of various toxic chemicals into the environment, triggering significant risks to human health and ecosystem stability. One sustainable solution to remove toxic chemicals from various environmental matrices, such as water, air, and soil, is bioremediation, an approach utilizing biological agents. Microalgae, as the primary producers of the aquatic environment, offer a versatile bioremediation platform, where their metabolic processes break down and convert pollutants into less harmful substances, thereby mitigating the negative ecological impact. Besides the CO₂ sequestration potential, microalgae are a source of renewable energy and numerous high-value biomolecules. Additionally, microalgae can mitigate various toxic chemicals through biosorption, bioaccumulation, and biodegradation. These remediation strategies propose a sustainable and eco-friendly approach to address environmental pollution. This review evaluates the microalgal mitigation of major environmental contaminants—heavy metals, pharmaceuticals and personal care products (PPCPs), persistent organic pollutants (POPs), flue gases, microplastics, and nanoplastics—linking specific microalgae removal mechanisms to pollutant-induced cellular responses. Each section explicitly addresses the effects of these pollutants on microalgae, microalgal bioremediation potential, bioaccumulation process, the risks of trophic transfer, and biomagnification in the food web. Herein, we highlight the current status of the microalgae-based bioremediation prospects, pollutant-induced microalgal toxicity, bioaccumulation, and consequential biomagnification. The novelty of this review lies in integrating biomagnification risks with the bioremediation potential of microalgae, providing a comprehensive perspective not yet addressed in the existing literature. Finally, we identify major research gaps and outline prospective strategies to optimize microalgal bioremediation while minimizing the unintended trophic transfer risks. Full article

Hydrogen sulfide (H₂S), nitric oxide (NO), and carbon monoxide (CO) are now recognized as key gasotranmitters that regulate vascular function, contributing to vasodilation, angiogenesis, inflammation control, and oxidative balance. Initially regarded as toxic gases, they are produced on demand by specific enzymes, including cystathionine γ-lyase (CSE), endothelial nitric oxide synthase (eNOS), and heme oxygenase-1 (HO-1). Their activity is tightly controlled by redox-sensitive pathways. Reactive oxygen species (ROS), particularly superoxide and hydrogen peroxide, modulate gasotransmitter biosynthesis at the transcriptional and post-translational levels. Moreover, ROS affect gasotransmitter availability through oxidative modifications, including thiol persulfidation, nitrosative signaling, and carbonylation. This redox regulation ensures a tightly coordinated response to environmental and metabolic cues within the vascular system. This review synthesizes the current understanding of redox–gasotransmitter interactions, highlighting how ROS modulate the vascular roles of H₂S, NO, and CO. Understanding these interactions provides critical insights into the pathogenesis of cardiovascular diseases and offers potential redox-targeted therapies. Full article

Insulin resistance is a condition of impaired tissue reactivity to insulin. This state is primarily associated with obesity and the lifestyle of modern Western societies, which favors abnormalities of glucose and lipid homeostasis. As a result, more and more people suffer from illnesses that develop because of the disturbed metabolic function of insulin, including type 2 diabetes, nonalcoholic fatty liver disease and polycystic ovarian syndrome. There are many studies describing the relationship between declining sensitivity to insulin and insufficient physical activity or unhealthy dietary habits. However, there is a vast number of other factors that may contribute to the development of this condition. In recent years, more attention has been paid to environmental pollutants as promoters of insulin resistance. As the overall grade of waste accumulation in the environment rises, factors like toxic metals, pesticides, dust, harmful gases and micro- or nanoplastics are starting to pose an increasingly serious threat in the context of metabolic disorder development. This review gathers data concerning the influence of the mentioned pollutants on the metabolic health of living organisms, with particular emphasis on the impact on carbohydrate processing, insulin resistance and molecular pathways associated with these processes. Full article

This study describes the modification of polyamide fabric with the commercial name Cordura to create a material that is more resistant to the permeation of toxic gases and compound vapors while remaining permeable to water vapor and air. The surface of Cordura was modified by applying a very thin film, deposited from a vapor organic phase at room temperature under the influence of γ-radiation. The permeability of the modified fabric to water vapor, organic vapors, organic dyes, and toxic substances (sulfur mustard gas) was determined and compared to the properties of the unmodified fabric. Full article

With the development of the mining industry, safety issues in underground operations are becoming increasingly relevant. Complex gas conditions in mines, including the presence of explosive and toxic gases, pose a serious threat to the lives of miners and the stability of production processes. This paper describes the development and modeling of an integrated fire monitoring and automatic extinguishing system that combines gas collection, concentration analysis, and rapid response to emergencies. The main components of the system include the following: a gas collection module that uses an array of highly sensitive sensors to continuously measure the concentrations of methane (CH₄), carbon monoxide (CO), and hydrogen sulfide (H₂S) with an accuracy of up to 95%; a gas analysis module that uses data processing algorithms to identify gas concentration threshold exceedances (e.g., CH₄ > 5% vol. or CO > 20 ppm); and an automatic fire extinguishing module that activates nitrogen supply, ventilation, and aerosol/powder fire extinguishers when a threat is detected. Simulation results in MATLAB/Simulink showed that the system reduces the concentration of hazardous gases by 30% within the first 2 s after activation, which significantly increases safety. Additionally, scenarios with various types of fires were analyzed, confirming the effectiveness of the extinguishing modules in mines up to 500 m deep. The integrated system achieves 95% gas detection accuracy, 90 ms response latency, and 40% hazard reduction within 3 s of activation, verified in 500 m deep mine simulations. Quantitative comparison shows a 75% faster response time and 10% higher detection accuracy than conventional systems. The proposed system demonstrates high reliability in difficult conditions, reducing the risk of fires by 75% compared to traditional methods. This work opens up prospects for practical application in the coal industry, especially in regions with a high risk of spontaneous coal combustion, such as India and Germany. Full article