Search Results (3,026)

Indoor air pollution caused by volatile organic compounds (VOCs) is a major environmental and public health concern. Ethanol is a common indoor VOC released from cleaning products, disinfectants, and industrial activities. This study evaluated the capacity of Ficus elastica Roxb. to remove airborne ethanol under controlled chamber conditions. Response Surface Methodology was applied to optimise the effects of initial ethanol concentration, relative humidity, and exposure time on removal efficiency. The model predicted a maximum removal efficiency of 97.16%, which was experimentally validated with an average efficiency of 96.2%, confirming the model’s reliability. Analysis of variance identified exposure time as the most influential factor affecting ethanol removal. Desorption experiments showed only limited and transient ethanol re-emission, indicating that ethanol was not merely adsorbed but also partially metabolised by the plant. Scanning electron microscopy revealed structural changes in stomatal morphology after prolonged exposure. Biochemical analyses demonstrated increased total phenolic content, flavonoid content, and antioxidant capacity, whereas a moderate decline in total chlorophyll reflected physiological stress accompanied by enhanced defence responses, indicating adaptive tolerance to prolonged ethanol exposure. These findings demonstrate the potential of F. elastica as an effective and sustainable botanical biofiltration system for improving indoor air quality. Full article

To reveal the chemical composition and concentration distribution, spatial distribution characteristics, source composition, and health impacts of volatile organic compounds (VOCs) in the two multi-industry industrial parks in Tianjin, 57 VOC species were determined by using SUMMA canister sampling with preconcentration gas chromatography/mass spectrometry. Based on these measurements, the Positive Matrix Factorization (PMF) model was used for source analysis to achieve quantitative identification and contribution analysis of different source factors. The health risks of VOC concentrations were analyzed based on the assessment framework recommended by the United States Environmental Protection Agency (USEPA). The results showed that the average concentrations of TVOCs in A-1 (Industrial Park and Cluster A, 5 m), A-2 (Industrial Park and Cluster A, 10 m), B-1 (Industrial Park and Cluster B, 5 m), and B-2 (Industrial Park and Cluster B, 10 m) were 59.72 ppbv, 45.35 ppbv, 32.44 ppbv, and 21.65 ppbv, respectively. TVOC concentrations were higher at A-1 and B-1 than at A-2 and B-2, and were generally higher at site A than at site B. The VOC components were mainly alkanes (53.5%–71.4%), followed by aromatic hydrocarbons (15.6%–36.2%), alkenes (4.6%–9.9%), and alkynes (3.1%–7.6%). The proportion of aromatic hydrocarbons in A was higher (22.13% and 36.22%), while alkanes dominated absolutely in B (71.4% and 66.9%). n-Hexane was the key species driving the spatial differences (a typical source of VOCs in solvent usage). The concentration in A-1 was 3.1 times that of A-2, and B-1 was 3.3 times that of B-2. It was mainly controlled by local solvent unorganized emissions. The differences in species between the two points at site A for toluene, xylene, etc., were relatively gentle, while at site B, the concentration of the same aromatic hydrocarbons at B-1 was significantly higher than that at B-2, presenting a clearer spatial characteristic, indicating differences in the spatial distribution of organic solvent-related industrial activities in different sites. The source analysis showed that A-1 was dominated by solvent usage (38.64%) and natural gas/LPG sources (36.96%); A-2 by vehicle exhaust (40.20%) and natural gas/LPG sources (36.15%); B-1 by cleaning-agent usage (38.81%) and fuel combustion (30.33%); and B-2 by plastic and rubber production (36.90%) and fuel combustion (31.84%). The health risk assessment showed that benzene, n-hexane, and xylene dominated the non-carcinogenic risks, but the overall non-carcinogenic (HI < 1) and carcinogenic (CR < 1 × 10⁻⁶) risks were both below the threshold. This study reveals inter-site differences in VOC concentrations, compositions, and source contributions across two mixed industrial parks, providing a basis for site-specific VOC control priorities, source-targeted monitoring strategies, and risk management in mixed industrial areas. Full article

The growing demand for clean-label and low-sulphite wines has increased interest in alternative preservation strategies capable of reducing sulphur dioxide (SO₂) usage while maintaining wine quality and stability. In this study, the effectiveness of Vitis vinifera leaf extract as a natural alternative to sulphur dioxide was evaluated in High Hydrostatic Pressure (HHP)-treated Fiano wines. Three experimental wines were produced: CW (control wine), SW (sulphited wine), and LW (leaf-extract wine). Following alcoholic fermentation, all wines were subjected to HHP treatment (600 MPa for 5 min) and stored at 4 °C for 60 days. Physicochemical parameters, volatile organic compounds (VOCs), and sensory characteristics were evaluated immediately after alcoholic fermentation and after HHP treatment followed by refrigerated storage. Compared with the control wine, LW exhibited approximately 20% higher total polyphenol concentrations, whereas SW showed the greatest preservation of fermentation-derived esters. HHP treatment induced only moderate changes in the volatile fraction, confirming the suitability of this non-thermal technology for wine stabilization. LW wines were characterized by higher abundances of terpene-related compounds, C6 alcohols, medium-chain fatty acids, and phenolic-associated volatiles, resulting in more pronounced floral, balsamic, herbaceous, and vegetal sensory attributes. Principal Component Analysis (PCA) explained 79.0% of the total VOC variability and clearly differentiated LW wines from CW and SW according to their volatile profiles, while sensory analysis confirmed the development of a distinctive aromatic identity associated with grapevine leaf extract. Overall, the results indicate that the combined application of V. vinifera leaf extract and HHP represents a promising strategy for the partial replacement of sulphur dioxide in white winemaking. This integrated approach contributes to wine stabilization while promoting the valorization of grapevine leaves as a sustainable winery by-product within a circular economy framework. Full article

Liupao tea (LPT), one of China’s representative fermented dark teas, develops its unique “red, heavy, aged, and mellow” flavor characteristics. This review provides a comprehensive update on LPT aroma, integrating analyses of volatile organic compounds (VOCs), associated microorganisms, odor-active compounds (OACs), and metabolic pathways of key odor-active compounds (KOACs). With over 2000 VOCs documented, predominated by alcohols (368), hydrocarbons (357), and ketones (351), the total for LPT substantially exceeds the approximately 1000 compounds typically reported for other dark teas. By combining sensory evaluation with techniques such as gas chromatography–olfactometry (GC-O) and odor activity value (OAV), KOACs, predominantly comprising alcohols, aldehydes, and methoxybenzene derivatives, were identified as key contributors to the floral, fruity, aged, stale and other notes that define LPT’s characteristic aroma. The formation of the aroma compounds is closely linked to microbial metabolism and the enzymatic activities generated by microorganisms. Fungi, including Aspergillus, Rhodotorula, Geosmithia, Wallemia, Penicillium, Blastobotrys, Fusarium, and Xeromyces, and bacteria, including Burkholderia, Ralstonia, and Achromobacter, serve as the primary functional microorganisms driving fermentation and aging. This review provides a comprehensive framework for understanding the chemical and microbial complexity of LPT aroma. Full article

Conventional solvent-based and hot-melt road marking paints face significant challenges regarding high volatile organic compound (VOC) emissions and limited durability, necessitating the development of eco-friendly, high-performance alternatives. In this study, a waterborne acrylic road marking paint was systematically formulated and optimized using an L₁₆(4⁵) orthogonal experimental design coupled with a comprehensive weighted scoring method integrating subjective and objective (entropy) weights. Four key formulation parameters (pigment-to-binder ratio, titanium dioxide content, ground calcium carbonate content, and coalescing agent dosage) were investigated, with abrasion resistance, hiding power, luminance factor, and stain resistance as evaluation criteria. The optimized formulation was identified through range analysis of comprehensive scores and subsequently subjected to rigorous performance characterization, including retroreflectivity optimization, Taber and accelerated abrasion testing, UV-accelerated weathering, skid resistance, and VOC emissions measurement using a self-designed sealed chamber system. Benchmark comparisons against commercial waterborne and hot-melt paints demonstrated that the developed formulation achieves superior abrasion resistance, exceptional weatherability, and meaningfully lower VOC emissions. Field application on an operational highway section in Liaoning Province, China, confirmed the practical constructability and performance reliability of the optimized paint under real-world construction conditions. This research provides both theoretical guidance and practical validation for the design of sustainable, durable, and highly visible road marking materials, contributing to the advancement of environmentally responsible transportation infrastructure. Full article

This study explored disease symptom development and changes in relative volatile organic compound (VOC) profiles after inoculation of Trichoderma atroviride onto Lentinula edodes pilei. Phylogenetic analyses based on ITS and tef1 sequences supported identification of the inoculated strain as T. atroviride. Inoculation caused surface depression and browning, while discoloration extended from the surface into internal tissues. At 3 days after inoculation, the inoculated strain was re-isolated from T1–T3 tissues, confirming the presence of viable fungi at all sampling positions. Relative VOC profiles were compared among untreated pilei, wound-treated samples, T. atroviride cultures (TA), and samples collected from different positions after inoculation (T1–T3). PCA and heatmap analyses revealed descriptive VOC variation among treatment groups and T1–T3, although no individual VOCs differed significantly among T1–T3 after FDR correction. 6-Pentyl-2H-pyran-2-one showed the highest relative peak area percentage in TA, whereas 2(3H)-naphthalenone was consistently detected only in TA. In inoculated pilei, ylangene was detected at all positions, whereas γ-muurolene, α-muurolene, 1-naphthalenol, 3-octanone, and 1,2,4-trithiolane showed different detection patterns and relative peak area percentages among T1–T3. These findings provide a basis for quantitative validation of inoculation-associated VOC changes and potential spatial variation within the pileus. Full article

Food security faces significant challenges due to the growing threat of insect pests and global climate change, making it essential to adopt sustainable agricultural strategies. Plants possess intrinsic defense systems that are activated in response to herbivore attack, including the emission of specialized volatile organic compounds (VOC) known as herbivore-induced plant volatiles (HIPVs). These volatiles aid the foraging of natural enemies (predators and parasitoids), thereby contributing to biological control of pest populations. Harnessing these chemical defense mechanisms offers a promising avenue for pest management, although natural enemy attraction does not necessarily result in pest suppression or increased crop yield. This review synthesizes plant and insect-derived chemical signaling mechanisms with direct relevance to biological control in crop agroecosystems, including field crops, orchards, vegetable systems, and protected cultivation. We emphasize recent applied research while retaining selected foundational studies that established the principal concepts and mechanisms underlying chemically mediated pest management. Considering the importance of chemical signaling in sustainable agriculture, we propose four key research directions: (1) optimizing plant defense induction mechanisms; (2) integrating HIPVs with natural enemy pheromone-based attractants; (3) combining habitat management with the provision of plant-derived food resources; and (4) harnessing plant defenses through breeding and infochemical-based genetically modified crops. Additionally, we examine the potential impacts of environmental stressors on plant–herbivore chemical communication, underscoring their importance for resilient and environmentally sustainable agricultural systems. Full article

Background: Type 2 diabetes (T2D) and insulin resistance (IR) are major global health challenges. Volatile organic compounds (VOCs) in exhaled breath offer a non-invasive window into metabolic dysregulation. This study aimed to predict HOMA-IR using machine learning (ML) by integrating biochemical markers and VOC profiles in a male cohort. Methods: This cross-sectional study included 1258 male participants from the Taiwan MJ cohort. Four ML algorithms (Elastic Net, MARS, Random Forest, and XGBoost) were trained to predict HOMA-IR. Model performance was evaluated using R², RMSE, and MAE. SHAP analysis was used to interpret feature contributions. Results: Ensemble tree-based approaches (Random Forest and XGBoost) demonstrated better predictive performance than Elastic Net and MARS. Random Forest achieved the highest predictive performance on the test set (R² = 0.323). SHAP analysis identified BMI (mean |SHAP| = 1.326) as the strongest predictor, followed by TG (1.005) and HDL-C (0.445). Notably, specific breath VOCs, including methanol and formic acid, ranked among the top 20 predictors, capturing distinct aspects of metabolic dysregulation orthogonal to standard blood tests. Conclusions: Integrating VOC profiles with clinical markers provides acceptable predictive performance for IR in men. While traditional metabolic markers dominate the prediction, specific VOCs capture distinct metabolic information, highlighting the potential of breath analysis as a complementary early screening tool. Full article

Tea quality is fundamentally determined by the complex biochemical transformations occurring during manufacturing. Traditional sensory evaluation, while essential, suffers from inherent subjectivity and cannot meet the demands of modern, industrial-scale production monitoring. This review critically examines the application of electronic nose (E-nose) technology throughout the tea-processing pipeline, covering multiple transducer technologies including metal oxide semiconductor (MOS) sensors, quartz crystal microbalance (QCM) sensors, conducting polymer (CP) sensors, and emerging chemiresistive platforms. Particular emphasis is placed on the E-nose’s capacity for real-time, non-destructive monitoring of key processing stages, including withering, rolling, fermentation, and drying. We analyze how optimized sensor arrays capture dynamic volatile organic compound (VOC) evolution, enabling the precise identification of optimal processing endpoints, especially in black tea fermentation control. Furthermore, this review evaluates how advanced pattern recognition algorithms (such as deep learning models) and multi-sensor data fusion strategies enhance the robustness and accuracy of process monitoring. By correlating E-nose response patterns with critical biochemical markers and traditional taster metrics, this paper demonstrates the technology’s pivotal role in transitioning tea manufacturing from experience-based craftsmanship to data-driven automation, ultimately ensuring superior product consistency and efficiency. Full article

Volatile organic compounds (VOCs) have adverse effects on both humans and the environment. Catalytic abatement of VOC emissions is regarded as an efficient solution, and transition metal oxides, like Co₃O₄, are promising catalysts due to their high activity, abundance and low cost. Previous studies have correlated catalytic activity with the Co³⁺/Co²⁺ ratio, absorbed oxygen species and specific exposed facets. However, the reaction mechanism and the active oxygen species remain unclear. This work focuses on propene oxidation over Co₃O₄ catalysts that were synthesized by four different methods, leading to significant morphological differences. Despite variability in specific surface area, particle size/geometry and population of oxygen species, catalytic experiments showed similar specific rates but different apparent activation energies (E_app). Propene-TPD/TPSR experiments confirmed the participation of lattice oxygen and indicated that chemisorbed oxygen is used at low reaction temperatures, while lattice oxygen is activated at higher temperatures. Detailed kinetic experiments revealed complex kinetic behavior that can be explained by the simultaneous operation of two pathways: a competitive Langmuir–Hinshelwood (LH) mechanism and a redox, Mars–van Krevelen (MvK) mechanism. Catalytic and kinetic data suggest that any structural differences observed in the prepared catalysts did not affect the intrinsic activity nor the mechanism of propene oxidation. Full article

Huangshui (HS), fermented grains (FG), and pit mud (PM) are closely connected during the fermentation of Nongxiangxing baijiu (NXB); however, the contribution of HS to the differences in flavor profiles across PM, FG, and distilled baijiu has not been fully elucidated. Herein, instrumental techniques of electronic nose (E-nose), headspace gas chromatography–ion mobility spectrometry (HS-GC-IMS), and headspace solid-phase microextraction coupled with gas chromatography–mass spectrometry (HS-SPME-GC-MS) were used to compare the volatile profiles of HS, FG, PM, and two quality grades of NXB. E-nose analysis revealed that PM exhibited stronger signals related to sulfur-containing, organic, and terpene-associated compounds. Gas chromatography indicated that special-grade baijiu had a more favorable ethyl caproate/ethyl lactate ratio than superior-grade baijiu. Furthermore, HS-GC-IMS revealed different volatile profiles of the samples. Up to 183 volatile organic compounds (VOCs) were identified via HS-SPME-GC-MS, with esters and acids being the dominant classes. Multivariate analysis showed close relationships among HS, FG, and PM, and 35 VOCs were identified as important discriminatory compounds. These results suggest the differences and similarities in VOCs among the HS, FG, PM, and NXB samples, indicating that HS is chemically associated with both FG and PM. This study provides useful insights into HS utilization and quality regulation of NXB through the effective management of HS. Full article

The emission of odorous gases has become a critical environmental challenge in livestock and poultry farming, organic solid waste treatment, and wastewater and sludge management, with typical pollutants including NH₃, H₂S, and various volatile organic compounds (VOCs). Conventional physicochemical deodorization methods are limited by complex equipment, high energy consumption, and secondary pollution, whereas microbial deodorization has attracted increasing attention because of its low energy demand, environmental friendliness, and environmentally safe end products. At present, comprehensive reviews of microbial deodorization technology remain limited, particularly those addressing the differences in microbial removal mechanisms for odorous gases and their components originating from different sources. The major components, characteristics, and emission patterns of odorous gases from different sources are summarized in this paper. Recent advances in the screening and consortium construction of highly efficient deodorizing microorganisms, together with their practical applications in odor treatment, are further summarized. Furthermore, emerging metabolic engineering strategies based on genetic modification, enzyme regulation, and metabolic pathway reconstruction are discussed, highlighting their potential for enhancing microbial degradation capacity and facilitating the rational design of next-generation deodorization systems. Future research directions are also proposed to address existing challenges, thereby providing insights for the rational design and engineering application of microbial deodorization systems. Full article

Selecting interior wood materials requires balancing functional and aesthetic demands with indoor air quality, as wood can emit volatile organic compounds (VOCs) and very volatile organic compounds (VVOCs) that either peak shortly after installation or persist over time. This study investigated time-resolved VOC and VVOC accumulation concentrations from untreated pine, spruce, aspen, and oak, representing wood species commonly used in Norway. Concentrations of VOCs and VVOCs were monitored for 25–28 days under low-ventilation, worst-case chamber conditions using Proton Transfer Reaction–Time-of-Flight Mass Spectrometry (PTR-TOF-MS). Emission behaviour was assessed using peak concentration, decay rate, half-time, stabilised concentration, cumulative exposure (AUC₂₈), and available health-based thresholds. Clear species-dependent differences were observed. Pine was the dominant VOC source, with the highest peak concentration, stabilised concentration, and AUC₂₈, mainly due to monoterpenes, which remained above the health-based threshold throughout the test period. Oak showed the second-highest VOC burden and a distinct acetate-dominated profile, with acetic acid showing the longest predicted exceedance duration. Aspen and spruce had lower VOC burdens, but their cumulative VVOC exposure exceeded VOC exposure. VVOCs generally peaked earlier than VOCs, although persistence varied by species. Overall, the concentration of VOCs and VVOCs was controlled by species, compound chemistry, volatility, and internal transport, supporting species- and compound-specific ventilation and material-selection strategies. Full article

Accurate classification of volatile organic compounds (VOCs) is important for environmental monitoring and industrial safety via electronic nose (E-nose) systems. However, extracting discriminative features from dynamic one-dimensional sensor responses remains challenging, especially when the recognition model is expected to maintain low computational complexity. This study introduces MSD-GasNet, a lightweight multi-scale depthwise convolutional network combined with Gramian Angular Summation Field (GASF) encoding, for VOC classification using E-nose response signals. The gas-sensing response curves are first transformed into two-dimensional GASF images to preserve temporal correlation information and provide structured inputs for convolutional feature learning. MSD-GasNet further adopts parallel 3 × 3 and 5 × 5 depthwise convolutional branches with feature fusion to capture local response details and broader morphology-related patterns while reducing parameter redundancy. Evaluated on Dataset 1, which contains five representative VOC categories including 1-butanol, acetone, benzaldehyde, butyl acetate, and dimethylbenzene, MSD-GasNet achieves an accuracy of 96.80 ± 0.78%, with 796.6 K parameters and 2.54 ms inference time per sample. Compared with traditional machine learning classifiers, conventional CNN baselines, recent lightweight networks, and a single-scale ablation model, MSD-GasNet shows better classification performance under the current five-class setting. An additional independent validation on Dataset 2 achieves an accuracy of 95.12 ± 1.11% under a chronological train/test split, further supporting the generalization potential of the proposed method. This work provides a GASF-based lightweight multi-scale framework with potential for efficient VOC recognition in portable or resource-limited E-nose applications. Full article

This study investigated quality traits and volatile organic compounds (VOCs) in two winter wheat varieties with different gluten types (Xinliang 169, medium-strong gluten, and Xinliang 607, medium-weak gluten) across five grain-filling stages (5, 10, 20, 30, and 40 days after anthesis, DAA) under heated headspace conditions (80 °C). During grain filling, moisture and total soluble sugar (TSS) decreased significantly, whereas hardness, thousand-kernel weight (TKW), and starch content increased significantly. Protein followed a typical “high–low–high” pattern. Using headspace gas chromatography–ion mobility spectrometry (HS-GC-IMS) and headspace solid-phase microextraction gas chromatography–mass spectrometry (HS-SPME-GC-MS), 80 and 125 VOCs were detected, respectively. A total of 19 preliminarily prioritized candidate odorants (e.g., 1-penten-3-one, 2,3-butanedione, and 3-methylbutanal) were screened using orthogonal partial least squares discriminant analysis (OPLS-DA, VIP > 1) and relative odor activity value (ROAV ≥ 1). Based on literature odor descriptors, the aroma profile shifted from green, malty notes during early grain filling to waxy, fatty, and grain-like notes during late grain filling. XL169 was characterized by grassy-green, malty, and fatty grain-like notes, whereas XL607 was dominated by creamy, buttery, and sweet-fruity woody notes. Correlation analysis revealed significant correlations between high-priority candidate odorants (2,3-butanedione, (E)-2-octenal, and 3-hydroxy-4,5-dimethyl-2(5H)-furanone) and quality traits (starch, TSS, and protein). These exploratory findings provide a preliminary reference profile for understanding how grain filling affects wheat VOCs. Full article