Kinds Of Volatile Organic Compounds Research Articles

HS-GC-IMS Analysis of Volatile Organic Compounds in Six Spicy Spices and Their Effects on Ulcerative Colitis.

The volatile organic compounds of six spices, including black pepper, dried ginger, cinnamon, fennel, clove, and zanthoxylum, were analyzed by gas chromatography-ion mobility spectrometry (HS-GC-IMS) combined with principal component analysis (PCA) and Euclidean distance. In further analyses, the effects of volatile oils in six spices on ulcerative colitis were assayed in a zebrafish model induced by 3-nitrobenzenesulfonic acid. A total of 120 kinds of volatile organic compounds were detected and 80 among them were identified, which included 10 common components and 3 to 24 characteristic components belonging to different spices. The major VOCs in six spices were estimated to be terpenes with the contents of 45.02%, 56.87%, 36.68%, 58.19%, 68.68%, and 30.62%, respectively. Meanwhile, the volatile components of fennel, dried ginger, black pepper, and cinnamon are quite similar, but differ from clove and zanthoxylum. The volatile oils in six spices presented efficient activity to improve ulcerative colitis which can decrease the number of neutrophils, restore the structure of intestinal epithelial and the morphology of the epithelial cells. Our study achieved rapid analysis of the volatile organic compounds and flavors in six spices and further revealed the potential health benefits of their volatile oils on ulcerative colitis, especially for clove and zanthoxylum. This study is expected to provide certain data support for the quality evaluation and the potential use in functional foods of six spices.

An absorption model of volatile organic compound by plant leaf: The most influential site in the absorption pathway

Plant leaves absorb some kinds of volatile organic compounds (VOCs) and can contribute to air purification, as revealed by recent exposure experiments conducted at environmentally realistic concentrations in ppb (v/v). However, the mechanisms underlying VOC absorption by plants remain unclear. In this study, we applied Fick's first law of diffusion to a VOC absorption model for plant leaves to account for the VOC diffusion process via stomata, air-liquid partitioning, partitioning into the plasma membrane, and metabolic conversion of the VOC in plant cells. The resistance and concentration of VOCs at individual sites were determined using previously reported absorption data for aliphatic aldehydes and ketones in three plant species and the leaf morphology parameters obtained from leaf cross-section micrographs. The highest resistance occurred at the metabolic site (rmet), suggesting that VOC metabolic capacity is the most influential factor in VOC absorption. The resistance of stomata (rs) or plasma membrane (rpl) was the second highest, depending on compound family. Using the absorption rate data of Q. acutissima, it is revealed that metabolic site resistance rmet for methyl vinyl ketone is affected by light intensity. Thus, our VOC absorption model can determine the most influential site in the absorption pathway both for different VOCs and plant species. Our model can contribute to the development of plant-based strategies for controlling air pollution.

Molecular simulation of different VOCs adsorption on nitrogen-doped biochar

Nitrogen-doped biochar has potential application in the removal of volatile organic compounds (VOCs) from coal-fired flue gas. To explore the adsorption characteristics of different VOCs on nitrogen-doped biochar by molecular simulation, in this study, six typical aromatic VOCs (benzene, toluene, phenol, naphthalene, p-xylene, and chlorobenzene), and an amorphous carbon model with nitrogen/oxygen groups were selected and constructed. Grand Canonical Monte Carlo (GCMC) simulations were performed to evaluate the adsorption capacities of VOCs on nitrogen-doped biochar. The results showed that the optimized carbon model was in good agreement with the pore structure parameters of nitrogen-doped biochar, and the agreement of toluene adsorption capacities was more than 80 % at room temperature. The adsorption capacity of nitrogen-doped biochar for different VOCs was 184 − 317 mg/g with the order of phenol > naphthalene > p-xylene > toluene ≈ benzene ≈ chlorobenzene (single-component adsorption). Among them, the phenol molecule is more easily adsorbed due to its strong polarity, resulting in stronger electrostatic interaction with the adsorbent. The decrease rate of benzene adsorption capacity is the lowest with increasing adsorption temperature because of its low molecular weight. As gas concentration increases, van der Waals interactions between molecules and between molecules and porous carbon also increase, leading to an increase in VOCs adsorption capacity. Nitrogen-doped biochar not only has the highest VOCs/N2 selective adsorption coefficient for phenol (up to 36) but also has the highest adsorption capacity of 63 mg/g when 6 kinds of VOCs are multi-component adsorption at 25 °C. This study can provide references for the practical application of adsorption method in the removal of VOCs from coal-fired flue gas.

Anisotropic sensing based on single ReS2 flake for VOCs discrimination

Selective and sensitive detection of volatile organic compounds (VOCs) holds paramount importance in real-world applications. This study proposes an innovative approach utilizing a single ReS2 field-effect transistor (FET) characterized by distinct in-plane anisotropy, specifically tailored for VOC recognition. The unique responses of ReS2, endowed with robust in-plane anisotropic properties, demonstrate significant difference along the a-axis and b-axis directions when exposed to four kinds of VOCs: acetone, methanol, ethanol, and IPA. Remarkably, the responses of ReS2 were significantly magnified under ultraviolet (UV) illumination, particularly in the case of acetone, where the response amplified by 10–15 times and the detection limit decreasing from 70 to 4 ppm compared to the dark conditions. Exploiting the discernible variances in responses along the a-axis and b-axis under both UV and dark conditions, the data points of acetone, ethanol, methanol and IPA gases were clearly separated in the principal component space without any overlap through principal component analysis, indicating that the single ReS2 FET has a high ability to distinguish various gas species. The exploration of anisotropic sensing materials and light excitation strategies can be applied to a broad range of sensing platforms based on two-dimensional materials for practical applications.

Engineering porosity of MIL-101(Cr) using solvation effect

Toluene, a kind of volatile organic compounds (VOCs), serves as a vital constituent of PM2.5 and acts as a notable precursor to ozone. To improve the adsorption performance of adsorbents for toluene, MIL-101(Cr)-XmM with high porosity were synthesized using an in-situ growth restriction strategy. This research reveals that the solvation effect influences the rate of crystal nucleation and growth, leading to variations in the ratio of micropores to mesopores and overall porosity in MIL-101(Cr)-XmM. The high porosity of MIL-101(Cr)-1.6 mM facilitates a higher diffusion rate of particles and exposes a greater number of alkaline sites. Consequently, the adsorption performance of MIL-101(Cr)-1.6 mM for toluene demonstrates a remarkable 240% improvement compared to that of MIL-101(Cr)-1.2 mM. Molecular simulations unveils the impact of adsorption temperature, demonstrating the crucial role of van der Waals interactions in the adsorption of toluene, with a noteworthy inhibition of van der Waals interactions observed upon heating. Density functional theory(DFT) simulations show that toluene molecules tend to preferentially adsorb near the benzene ring of the ligand, primarily due to π-π stacking interactions. Simultaneously, the electrophilic channel with greater porosity can gather more nucleophilic groups, thereby enhancing the adsorption performance of toluene.

Health Risk Assessment from Exposure to Ambient Volatile Organic Compounds (VOCs) at a Truck Tire Factory in the Yangtze River Delta, China

Occupational health risk assessments of exposure to VOCs still need to be extensively studied to improve the safety standards in the industry. Based on the monitoring of organic pollutants at various workstations in a truck tire factory in Jiangsu Province, both semi-quantitative and quantitative health risk assessment methods were employed to assess health risk levels. The findings indicated that VOCs were categorized into five classes, which included alkanes, aromatics, halocarbons, carbon disulfide, and oxygenated volatile organic compounds (OVOCs). The highest concentration of total volatile organic compounds (TVOCs) was found in shaping workshop; alkanes were the most abundant class (74.2%), followed by aromatics (24.02%) and OVOCs (1.96%). Although the results of the semi-quantitative risk assessment showed that most of the organic compounds had low R values, various kinds of VOCs were detected; particularly, many harmful organic compounds (such as toluene, ethyl benzene) were detected in all the sampling sites. The quantitative risk in the calendering and vulcanizing workshop exceeded the acceptable level; both the carcinogenic risk of ethylbenzene in the tire-strip storage room, and trichloroethylene and perchloroethylene in the calendering workshop were unacceptable. Thus, the calendering and vulcanizing processes in rubber tire manufacturing should be priority-controlled processes.

Selection Behavior and OBP-Transcription Response of Western Flower Thrips, Frankliniella occidentalis, to Six Plant VOCs from Kidney Beans.

Plant volatile organic compounds (VOCs) are an important link that mediates chemical communication between plants and plants, plants and insects, and plants and natural enemies of insect pests. In this study, we tested the response in the selective behavior of western flower thrips, Frankliniella occidentalis, to the VOCs of kidney bean, Phaseolus vulgaris L., to explore their "attraction" or "repellent" effects regarding their application in integrated pest management (i.e., IPM). The results indicated that 12.7 μL/mL (E, E, E, E)-squalene, 3.2 μL/mL dioctyl phthalate, and 82.2 μL/mL ethyl benzene had a significantly attractive effect on the selective behavior of F. occidentalis, while 10.7 μL/mL and 21.4 μL/mL 2,6-ditert-butyl-4-methyl phenol had a significantly repulsive effect on the selective behavior of F. occidentalis, showing that F. occidentalis responds differently to specific concentrations of VOCs from P. vulgaris plant emissions. Interestingly, the three compounds with the specific above concentrations, after being mixed in pairs, significantly attracted F. occidentalis compared to the control treatment; however, the mixture with the three above compounds had no significant different effect on F. occidentalis compared to the control treatment. It can be seen that the effect with the mixtures of three kinds of VOCs had the same function and may not get better. Simultaneously, the reasons for this result from the transcription levels of odorant-binding protein genes (OBPs) were determined. There were differences in the types and transcription levels of OBPs, which played a major role in the host selection behavior of F. occidentalis under the mixed treatment of different VOCs. It is presumed that there are specific VOCs from P. vulgaris plants that have a good repellent or attracting effect on the selective behavior of F. occidentalis, which can be used for the development of plant-derived insect attractants and repellents to serve as IPM in fields. But attention should be paid to the antagonism between plant-derived preparations and VOCs produced by plants themselves after application.

Recent Advances of VOCs Catalytic Oxidation over Spinel Oxides: Catalyst Design and Reaction Mechanism.

Volatile organic compounds (VOCs) harm the environment and human health and have been of wide concern and purified efficiently by catalytic oxidation. Spinel oxides, mainly composed of transition metal elements with low price and extensive sources, have been widely investigated as efficient and stable catalysts for VOCs oxidation due to their adjustable element composition, flexible structure, and high thermal/chemical stability. However, it is necessary to dissect the design of the spinel in a targeted way to satisfy the removal of different types of VOCs. This article systematically summarizes the recent advances regarding the application of spinel oxides for VOCs catalytic oxidation. Specifically, the design strategies of spinel oxides were first introduced to clarify their effect on the structure and properties of the catalyst. Then the reaction mechanism and degradation pathway of different kinds of VOCs on the spinel oxides were in detail summarized, and the characteristic requirements of the spinel oxides for various VOCs purification were analyzed. Furthermore, the practice applications were also discussed. Finally, the prospects were proposed to guide the rational design of spinel-based catalysts for VOCs purification and intensify the understanding of reaction mechanisms.

Nitrogen-doped ZnO microspheres with a yolk-shell structure for high sensing response of triethylamine

Triethylamine is a kind of volatile organic compounds, which is harmful and toxic to the environment and people. Therefore, triethylamine gas sensors are increasingly demanded in practical applications. In this work, we synthesized the nitrogen-doped ZnO yolk-shell microspheres with mesoporous distribution by a facile strategy of hydrothermal-annealing. The influence of the amount of hexamethylene tetramine on the morphology of yolk-shell ZnO was studied and the yolk-shell ZnO (YSZ-3) prepared with 0.3 g hexamethylene tetramine showed the best gas sensing performances for triethylamine at 370 ℃. The response to 100 ppm triethylamine was 133. Moreover, a low triethylamine detection limit was achieved (1 ppm), with a response value of 2.6. The prepared yolk-shell ZnO showed an excellent selectivity to triethylamine, over ethanol, methanol, acetone, formaldehyde, ammonia, and toluene. Furthermore, YSZ-3 offered a low theoretical detection limit (42.4 ppb) and a fast response and recovery (20 s/5 s). Finally, the growth mechanism and gas sensing mechanism of yolk-shell ZnO were discussed.

Biodegradation of isobutyraldehyde with high removal efficiency by using a modified biotrickling filter

Isobutyraldehyde is a kind of Volatile organic compounds (VOCs) released by the butanol industry, which has a low olfactory threshold and high hydrophobicity, causing harm to the environment. Biotrickling filters have been widely used for VOCs treatment. Herein, a biotrickling filter (BTF-1) inoculated with the domesticated bacteria was used to degrade isobutyraldehyde. However, low dissolved oxygen, unstable temperature, high-pressure drop, and excessive foams were observed due to structural and technical problems. Hence, a modified BTF-2 was established to revise these problems by adding an oxygenation device, separating the tower kettle, and adding a recirculating water layer. Finally, the maximum elimination capacity (EC) (195 g/(m3·h)) and average removal efficiency (RE) (90%) were achieved at an empty bed residence time (EBRT) of 46 s and inlet flow rate of 500 L/h. Furthermore, 16S rDNA analysis identified Clostridiales as the prominent bacteria group in charge of isobutyraldehyde degradation. Overall, the feasibility and efficiency of using a biotrickling filter for isobutyraldehyde treatment were confirmed in this investigation, which would provide technical support for the industrial scale-up of BTF to biodegrade isobutyraldehyde.

Designing a Coupling Agent with Aliphatic Polyether Chain and Exploring Its Effect on Silica/Natural Rubber Nanocomposites under the Action of Non-Rubber Contents.

In order to prepare engineering tires with lower rolling resistance and better wet slip resistance in a more environmentally friendly way. In this study, a series of low volatile organic compound (VOC) Mx-Si69 coupling agents (x = 1, 2, 3, 4, 5, 6, which means the number of ethoxy group in bis-(γ-triethoxysilylpropyl)-tetrasulfide (Si69) substituted by the aliphatic polyether chain) were applied to silica/NR nanocomposites to prepare tire tread with excellent performance. Firstly, M1-Si69 was substantiated as the best choice of Mx-Si69 and Si69 to achieve comprehensive optima in the mechanical properties of silica/NR nanocomposites characterized by dynamic and static mechanical properties. Afterwards, the modification of silica with M1-Si69 induced by Non-Rubber Contents (NRCs) in silica/NR nanocomposites was revealed by comparing the filler network, micromorphology, and mechanical properties of isoprene rubber (IR) and NR nanocomposites. Furthermore, compared with Si69, the M1-Si69 coupling agent was found to conspicuously reduce the energy loss and improve the safety performance of engineering tires according to evaluations of the rolling resistance and dynamic thermomechanical properties of the silica/NR nanocomposites. Finally, the critical function of M1-Si69 in reducing ethanol (a kind of volatile organic compound (VOC)) emissions from the reaction of coupling agent and silica was disclosed by gas chromatography-mass spectrometry.

Efficient Degradation of Toluene over MnO2/TiO2 Nanobelts under Vacuum Ultraviolet Irradiation

Toluene, as a kind of volatile organic compounds, not only causes pollution to the atmosphere and water but also damages human health. Although vacuum ultraviolet (VUV) can effectively promote the degradation of toluene, it will produce a large amount of O3, which will cause secondary pollution. Therefore, it is very important to study catalysts that can promote both toluene degradation and ozone decomposition. In this work, a MnO2/TiO2 catalyst with uniformly dispersed MnO2 was prepared using the immersion reduction method, which was used to degrade toluene under VUV. The toluene removal efficiency was improved by the utilization and elimination of O3. The toluene removal efficiency over the prepared MnO2/TiO2 catalyst was 88%, and the O3 removal rate was 97%. The toluene removal efficiency under VUV was 4.9 times that of UV. The synergistic effect of VUV and multifunctional catalyst effectively improved the toluene removal efficiency.

Highly selective gas sensor for rapid detection of triethylamine using PdRu alloy nanoparticles functionalized SnO2

Triethylamine is a kind of volatile organic compound, which is flammable and toxic. Here, PdRu alloy nanoparticles (NPs) were used for modifying SnO2 to make it more selective for triethylamine. Monodisperse PdRu alloy NPs were produced through coreduction in polyol solution, while the SnO2 nanoparticles with a small particle size were generated by a hydrothermal method. The sensor based on 0.5 wt% PdRu-SnO2 exhibited a high response (S = 256) to 100 ppm triethylamine when the temperature was 220 °C. The response was 12 times more than trimethylamine and 10 times higher than that to NH3. Moreover, it showed rapid response speed (2 s) to triethylamine. SnO2 with small particle size had many acid sites, which showed selective detection of triethylamine due to acid-base reaction. Besides, the catalytic property of PdRu NPs also played a role in improving performance. This work provides a new method for the fast identification of triethylamine in chemical industry plant.

Molecular and metabolic insights into floral scent biosynthesis during flowering in Dendrobium chrysotoxum.

Dendrobium chrysotoxum is considered as an important ornamental dendrobium because of its strong and long-lasting floral scent. Nevertheless, few information is known about the dynamic changes and related formation mechanism of dendrobium floral scent at different flowering stages. In this study, the characteristics and biosynthetic mechanism of floral scent in D. chrysotoxum during flowering was revealed by using widely-targeted volatilomics (WTV) combined with transcriptome analysis. Over 500 kinds of volatile organic compounds (VOCs) were detected in the floral scents of D. chrysotoxum, which improved the knowledge about floral scent components of dendrobium. A total of 153 differential VOCs and 4,487 differentially expressed genes (DEGs) were identified between flowers of different flowering stages, respectively. The results for both volatilomics and transcriptomics data indicated that terpenes and related genes played an important role in the formation of floral characteristics of D. chrysotoxum. But in general, the expression of genes showed an opposite trend to the accumulation of metabolites during flowering, suggesting that the regulation of floral scent biosynthesis might have started at the budding stage in D. chrysotoxum. Additionally, a transcriptional metabolic regulatory network consisting of terpenes, terpene synthases and candidate transcription factors was established. This research is the first systematic and comprehensive exploration of floral characteristics and related mechanisms during flowering in D. chrysotoxum. It provides basis for exploration of mechanisms on the floral scents and the breeding of aromatic dendrobium.

Systematic Review on Respiratory Toxicology Caused by Synthetic Air Fresheners

Abstract: The main objective of this comprehensive review research on the various kinds of respiratory illness caused by the synthetic air fresheners. Air fresheners are widely used in indoor built environmental settings such as businesses, schools, residences, transit, hotels, hospitals, care facilities, and a variety of private and governmental structures. In order to create a comfortable indoor atmosphere, air fresheners are made to add aroma to the air or to cover up odours. Air fresheners, however, can produce and emit a variety of potentially toxic air pollutants that can deteriorate air quality, regardless of their intended use. Volatile organic compounds (VOCs) found in air fresheners include ones that may be harmful air pollutants, carcinogens, or substances linked to adverse health consequences including asthma, COPD and so on. Air fresheners have been identified as a major source of volatile organic compounds in buildings from the perspective of indoor air quality. Air fresheners have been linked to negative health impacts include neonatal illness, asthma symptoms, mucosal symptoms, migraine headaches, and breathing problems. In this research review we mainly focused on synthetic air freshener, emits various kinds of VOC’s that caused different types of respiratory illness. This review also investigates a paradoxical effect that the synthetic air fresheners meant to enhance indoor environments may also present unanticipated & unidentified risk. Finally, we discussed about the International and National market size of the air freshener.

A Closure Study of Secondary Organic Aerosol Estimation at an Urban Site of Yangtze River Delta, China

Secondary organic aerosols (SOA) are crucial components of ambient particulate matters. However, their composition and formation mechanisms remain uncertain. To investigate the SOA formation and evaluate various SOA estimation approaches, a comprehensive measurement was conducted at an urban site, Changzhou, in Yangtze River Delta (YRD) region. 98 kinds of volatile organic compounds (VOCs) were measured by an online gas chromatography-mass spectrometer/flame ionization detector (GC-MS/FID). Non-refractory submicron particulate matters (NR-PM1) were measured by an Aerodyne Aerosol Chemical Speciation Monitor (ACSM). Both bottom-up approaches, i.e., VOCs oxidation yield method, and top-down approaches, i.e., elemental carbon (EC) tracer method and ACSM, combined with positive matrix factorization (PMF) method, were utilized to estimate SOA. ACSM-PMF method estimated the highest SOA concentration, followed by EC tracer method. SOA from VOCs oxidation yield method accounted for 43.2 ± 41.9% of that from EC tracer method, suggesting the existence of missing SOA precursors, e.g., semivolatile organic compounds. The influencing factors of SOA formation were investigated and a good correlation of SOA with odd oxygen rather than aerosol liquid water content was found, suggesting the importance of photochemical formation of SOA.

Uncertainty evaluation for nine VOC gas certified reference materials used for indoor air testing

9 kinds of volatile organic compounds (VOC) gas certified reference materials (CRM) for indoor air quality testing were developed at nominal 1 µmol/mol in nitrogen. The property value was assigned gravimetrically and its uncertainty was evaluated by combining different contributions to uncertainty. The resources of uncertainty were discerned as the preparation process, homogeneity and stability and the evaluation method of each uncertainty component was proposed, especially the uncertainty calculation method of raw material’s purity encountered with “interference impurity” was discussed. The relative expanded uncertainties (k = 2) of the nine VOC CRM were in the range from 1.63 % to 2.32 %. The experimental results show: (1) the uncertainty component has basically the similar contribution to the gross uncertainty of its property value; (2) the uncertainty associated with the mass weighing of nine VOC mixed intermediate liquid has the greatest influence on the uncertainty caused by the preparation process; (3) the nine VOC CRM was stable for minimum 12 month with pressure above 2 MPa but their uncertainties should be assessed and combined; (4) more attention should be attached to the uncertainly connected with stability to study its long-time stability.

A Methyl-Modified Silica Layer Supported on Porous Ceramic Membranes for the Enhanced Separation of Methyl Tert-Butyl Ether from Aqueous Solution.

As a kind of volatile organic compound (VOC), methyl tert-butyl ether (MTBE) is hazardous to human health and destructive to the environment if not handled properly. MTBE should be removed before the release of wastewater. The present work supported the methyl-modified silica layer (MSL) on porous α-Al2O3 ceramic membranes with methyltrimethoxysilane (MTMS) as a precursor and pre-synthesized mesoporous silica microspheres as dopants by the sol-gel reaction and dip-coating method. MTMS is an environmentally friendly agent compared to fluorinated alkylsilane. The MSL-supported Al2O3 ceramic membranes were used for MTBE/water separation by pervaporation. The NMR spectra revealed that MTMS evolves gradually from an oligomer to a highly cross-linked methyl-modified silica species. Methyl-modified silica species and pre-synthesized mesoporous silica microspheres combine into hydrophobic mesoporous MSL. MSL makes the α-Al2O3 ceramic membranes transfer from amphiphilic to hydrophobic and oleophilic. The MSL-supported α-Al2O3 ceramic membranes (MSL-10) exhibit an MTBE/water separation factor of 27.1 and a total flux of 0.448 kg m−2 h−1, which are considerably higher than those of previously reported membranes that are modified by other alkylsilanes via the post-grafting method. The mesopores within the MSL provide a pathway for the transport of MTBE molecules across the membranes. The presence of methyl groups on the external and inner surface is responsible for the favorable separation performance and the outstanding long-term stability of the MSL-supported porous α-Al2O3 ceramic membranes.

Discriminative Detection of Aliphatic, Electron‐Rich and Electron‐Deficient Aromatic Volatile Organic Contaminants Using Conjugated Polymeric Fluorescent Nanoaggregates with Aggregation Induced Emission Characteristics

AbstractDiscrimination of aromatic, aliphatic volatile organic compounds (VOCs) with high sensitivity and easy operational techniques is important due to related environmental implications. Herein the development of fluorescent conjugated polymers is reported, consisting of donor–acceptor pairs and their nanoaggregates as fluorophores with differential emission behavior in the presence of aromatic, aliphatic VOCs and electron‐deficient VOCs both in aqueous solution and solid state. The polymeric network consists of fluorene moiety with dangling alkyl groups as donors and aggregation‐induced emission (AIE) active tetraphenylethylene (TPE) unit as an acceptor. The corresponding fluorescent nanoaggregates exhibit enhancement in the emission intensity owing to restriction in intramolecular motion of AIE unit in the presence of aliphatic VOCs, whereas the fluorescence enhancement is accompanied by a bathochromic shift in emission maxima in the case of aromatic VOCs owing to the conformational change in the phenyl rings of TPE unit. On the other hand, the fluorescence of nanoaggregates quenches in the presence of an electron‐deficient VOC through a possible nonradiative electron transfer. Detailed mechanistic studies are corroborated through a variety of spectroscopic, density functional theory calculations, and theoretical simulations. The discriminatory response of the polymeric nanoaggregates toward a different kind of VOCs can also be observed visually in the thin‐film state.

Seasonal dynamics of VOCs released from Cinnamomun camphora forests and the associated adjuvant therapy for geriatric hypertension

Cinnamomun camphora is an important species for afforestation in southern China and is widely used in landscaping. To explore the seasonal dynamics of the volatile organic compounds (VOCs) released from Cinnamomun camphora forests and the adjuvant therapeutic effect of forest bathing on elderly patients with hypertension (HTN), the components and relative contents of VOCs released by a Cinnamomun camphora forest were analysed, and the blood pressure and inflammation of elderly patients with HTN experiencing forest bathing were studied. Variations in the components and relative contents of VOCs released by the Cinnamomun camphora forest were detected among the seasons, and the alkanes varied more widely than the other kinds of VOCs. The relative contents of alkanes and organic acids were greater than those of the other kinds of VOCs in spring and winter, while the VOCs released in autumn and summer contained higher proportions of terpenes. Forest bathing in Cinnamomun camphora forests in autumn, summer and spring had a high auxiliary regulatory effect on blood pressure and inflammation in elderly patients with HTN, which may be closely related to terpenes and negative oxygen ions. However, forest bathing in Cinnamomun camphora forests in winter was not conducive to the therapy of elderly patients with HTN. The results not only lay the foundation for research on the release of VOCs from Cinnamomun camphora forests but also provide a reference for studies on the influences of forest bathing on human health.