Components Of Volatile Organic Compounds Research Articles

High ratio of Ce3+/(Ce3++Ce4+) enhanced the plasma catalytic degradation of n-undecane on CeO2/γ-Al2O3

n-Undecane (C11) is the main component of volatile organic compounds (VOCs) emitted from the printing industry, and its emission to the atmosphere should be controlled. In this study, a dielectric barrier discharge reactor coupled with CeO2/γ-Al2O3 catalysts was used to degrade C11. The effect of the chemical state of CeO2 on C11 degradation was evaluated by varying the CeO2 loading on γ-Al2O3. The C11 conversion and COx selectivity were as high as 92% and 80%, respectively, under mild reaction conditions of energy density 34 J/L and 423 K to degrade 134 mg/m3 C11 in a simulated air using 10 wt%CeO2 impregnated on γ-Al2O3. After analyses using in-situ plasma diffuse reflectance Fourier transform infrared spectroscopy and gas chromatography-mass spectrometry, it was found that most of C11 were degraded to CO2, and the main by-products on catalyst surfaces were alcohols and ketones. It was concluded from X-ray photoemission spectroscopy that the good performance of the 10 wt%CeO2/γ-Al2O3 catalyst was due to its high Ce3+/(Ce3++Ce4+) ratio as well as the oxygen vacancies. The Ce3+/(Ce3++Ce4+) ratio of CeO2 on γ-Al2O3 is crucial for the degradation of C11, providing a further roadmap for the plasma catalytic oxidation of alkanes.

Insight into the environmental monitoring and source apportionment of volatile organic compounds (VOCs) in various functional areas

Atmospheric aerosol contamination has caused widespread concern about human and environmental health. However, research about VOCs as an important precursor of secondary aerosols in ambient air is still limited. In this study, VOCs at sites from three typical functional areas in Hefei, China, were monitored using GC–MS/FID. The VOCs in ambient air from different functional areas showed significantly different characteristics. The highest concentrations and the biggest diurnal difference of VOCs were found in the High-tech Zone (industrial area) with serried emission sources. Additionally, lower VOC concentration was observed in Changjiang West Road, the center area of studied city. The VOC concentration in this area is strongly related to other pollutants. The composition of VOCs at all sampling sites showed certain common characteristics, i.e., alkanes, OVOCs, and halogenated hydrocarbons account for more than 75% of the total VOCs’ quality. The High-tech Zone with the highest concentration of VOCs also has the highest proportion of alkanes. Besides, the positive matrix factorization analysis results revealed that vehicle exhaust, LPG volatilization sources, and chemical solvents were the most important VOC emission sources in Hefei. In terms of the contribution of VOC components to the OFP at the three sites, the olefins and alkynes at the Changjiang West Road site and the Science Island site contribute the most significant proportion. In contrast, the OVOCs at the High-tech Zone site contribute the largest proportion.

PM2.5-bound silicon-containing secondary organic aerosols (Si-SOA) in Beijing ambient air

Volatile methyl siloxanes (VMS) have been widely used in personal care products and industrial applications, and are an important component of VOCs (volatile organic compounds) indoors. They have sufficiently long lifetimes to undergo long-range transport and to form secondary aerosols through atmospheric oxidation. To investigate these silicon-containing secondary organic aerosols (Si-SOA), we collected PM2.5 samples during 8th-21st August 2018 (summer) and 3rd-23rd January 2019 (winter) at an urban site of Beijing. As the oxidation of VMS mainly results in hydrophilic polar semi-volatile and non-volatile oxidation products, the differences between total water-soluble Si and total water-soluble inorganic Si were used to estimate water-soluble organic Si, considered to be secondary organic Si (SO–Si). The average concentrations of SO–Si during the summer and winter campaigns were 4.6 ± 3.7 and 13.2 ± 8.6 ng m−3, accounting for approximately 80.1 ± 10.1% and 80.2 ± 8.7% of the total water-soluble Si, and 1.2 ± 1.2% and 5.0 ± 6.9% of total Si in PM2.5, respectively. The estimated Si-SOA concentrations were 12.7 ± 10.2 ng m−3 and 36.6 ± 23.9 ng m−3 on average in summer and winter, which accounted for 0.06 ± 0.07% and 0.16 ± 0.22% of PM2.5 mass, but increased to 0.26% and 0.92% on certain days. We found that net solar radiation is positively correlated with SO–Si levels in the summer but not in winter, suggesting seasonally different formation mechanisms.

Emission Characteristics and Atmospheric Chemical Reactivity of Volatile Organic Compounds(VOCs) in Automobile Repair Industry

Volatile organic compounds (VOCs) emitted by the automobile repair industry are an important source of ozone precursors. However, the current reduction policy generally focuses on the emissions of VOCs, without considering their chemical reactivity. Based on an investigation of the development status of China's automobile repair industry, this study analyzes VOCs emission nodes in different sections of automobile repair enterprises. The amount and VOCs content of paint in each section was determined, and a material balance algorithm was used for sections with different VOCs quantities and compositions to analyze the emission characteristics of exhaust VOCs. The atmospheric reactivity of VOCs components was evaluated by calculating ozone generation potential (OFP). The results show that VOCs components produced by automobile repair paint are mainly benzene homologues, with butyl acetate and xylene the highest. Varnish is the largest contributor to VOCs emissions in automobile repair industries (92%), due to its high VOCs content and high dosage. The VOCs content of solvent-based coatings (22%) is higher than that of water-based coatings (3%). The application of water-based coatings leads to a remarkable reduction in VOCs emissions in automobile repair industries. A total of 49 VOCs components have been detected in gas from exhaust cylinders, with the top 10 VOCs components accounting for 97.9% of the total emissions. The main pollutants are aromatic hydrocarbons (10 types, 30.90%-69.30%), and OVOC (12 types) and halogenated hydrocarbons (22 types) were the second-highest contributors, with contribution rates of 8.82%-43.71% and 2.40%-25.00%, respectively. Aromatic hydrocarbon is the largest VOCs component emitted by automobile repair industries, but the main types of VOCs vary greatly in different studies. VOCs discharged by automobile repair industries have an average OFP value of 194.04 mg ·m-3 and an average SR value of 3.37 g ·g-1. The m/p-xylene component contributes the most to OFP (70.24%) and is the preferred pollutant in automobile repair industry. Aromatic hydrocarbons contribute a maximum of 99.29% to the OFP value and are also the most chemically reactive component. Although esters account for a large proportion of VOCs, their contribution to OFP is relatively low. Therefore, the automobile repair industry should focus on controlling the emission of aromatic hydrocarbons.

Pollution Characteristics and Source Apportionment of Atmospheric VOCs During Ozone Pollution Period in the Main Urban Area of Chongqing

In late August 2020, a period of O3 pollution occurred in the main urban area of Chongqing and lasted for approximately 2 weeks (till early September). Ambient air samples, collected using Summa Canisters and DNPH sampling columns at three observation sites in the main urban area, were used to study the composition, photochemical reaction activity, and source apportionment of volatile organic compounds (VOCs) during the period of O3 pollution. The results showed that the mean volume fraction of TVOCs in the main urban area of Chongqing during the observation period was 45.08×10-9, and the components were ranked by volume fraction in the following order:OVOCs, alkanes, halohydrocarbons, alkenes, aromatics, and alkynes. Formaldehyde, ethylene, and acetone made up the higher volume fraction of VOCs, together accounting for more than 30% of TVOCs. OVOCs and alkenes contributed more to · OH loss rate (Li·OH) and ozone formation potential (OFP) and were the key VOCs components for ozone generation. The main active species in the OVOCs component were formaldehyde, acetaldehyde, and acrolein; the main active species in the alkene component were isoprene, ethylene, and n-butene. The ratio of xylene to ethylbenzene in VOCs was low, and they showed a significant correlation, indicating that the VOCs air mass in the main urban area was highly aging and affected by long-distance transmission from other areas. The source apportionment results of the PMF model showed five main sources of VOCs, namely secondary generation (27.67%), vehicle exhaust (26.56%), industrial emission (17.86%), plant (14.51%), and fossil fuel combustion (13.4%).

Simultaneous annihilation of microorganisms and volatile organic compounds from municipal solid waste storage rooms with slightly acidic electrolyzed water

Great deal pathogenic bacteria and malodorous gases are hidden in municipal solid waste (MSW), which poses excellent environmental sanitation risks for sanitation workers and residents, and preventive measures should be implemented. In this study, the simultaneous annihilation of microorganisms and volatile organic compounds (VOCs) with slightly acidic electrolyzed water (SAEW) was investigated in an MSW storage room of a residential community in Shanghai, China. The microbial population of airborne, surfaces and handles of waste bins, hands of sanitation workers and the main components of VOCs were measured. The results indicated that the bacterial reduction efficiencies of SAEW with an available chlorine concentration (ACC) of 50–100 mg/L on surfaces and handles of waste bins and sanitation workers’ hands were 22.7%–84.1%. Also, SAEW effectively reduced the average population of airborne bacteria and fungi by 358 and 378 colony-forming units (CFU)/m3 and decreased the detection rates of coliforms by 14.2%–51.9%. The concentrations of most VOCs were reduced by 21.4%–88.3% after spraying SAEW. And the accumulated values of carcinogenic and noncarcinogenic risks also tended to decrease with spraying SAEW. These findings imply that SAEW has significant application potential to control environmental sanitation risks in MSW storage rooms.

On-line fast analysis of light hydrocarbons, PAH and radicals by molecular-beam time of flight mass spectrometry

Volatile organic compounds (VOC) and polycyclic aromatic hydrocarbons (PAH), emitted in the environment from a wide range of combustion sources, are hazardous to human health and considered important precursors of both primary and secondary particulate pollutants. In the present work, light hydrocarbons up to C9, as main components of combustion-derived VOC, and PAH produced in fuel-rich conditions of premixed ethylene flames were analyzed by implementing a molecular-beam time of flight mass spectrometer (MB-TOFMS), purposely built for on-line fast monitoring of the environmental impact of combustion systems. The reliability of the MB-TOFMS was preliminarily verified on a slightly-sooting flame, comparing the results with those obtained by batch sampling and gas chromatographic techniques. Electron ionization (EI) and multi-photon ionization (MPI) were used as MB-TOFMS sources and tested on combustion gases of a no-sooting premixed ethylene flame where VOC and PAH are present in traces not detectable with batch sampling and conventional analytical techniques. The mass identification accuracy was improved and guaranteed by systematically performing internal mass calibration, exploiting the formation of “in situ” clusters from combustion water in the molecular beam apparatus. Selective and sensitive monitoring of light hydrocarbons and PAH, derived from oxidation and pyrolysis reactions featuring combustion, was shown to be especially effective when using the MB-TOFMS equipped with MPI source. This technique showed to be effective also for the detection of radical species that are important for the risk assessment of aerosol and fundamental understanding of aerosol chemistry at a molecular level.

Analysis on aroma components of flowers of five Magnolia denudata cultivars

Aroma components in fresh flowers fromfive Magnolia denudata Desr are analyzed with Head Space Solid PhaseMicro-extraction (HS-SPME) and Gas Chromatograph-Mass Spectrometer (GC-MS) technology. The results show that 45 compounds are detected in the flowers offive germplasm of genus Magnolia denudata Desr, including 19 alkenes, 5 alcohols, 5 benzenes, 4 ketones, 3 esters, 2 ethers, 1 acid, 5 alkanes and 1 other compound. The type number of volatile organic compounds (VOCs)from more to less in order are: Yulania denudata ‘5#’ (22 species), Yulania denudata ‘Fei Huang’ (21 species), Yulania stellata (15 species), Magnolia liliflora Desr(12 species), Magnolia liliiflora ‘Hong Yuanbao’ (10 species);The content of volatile organic compounds from high to low areYulania stellata (28%), Yulania denudata ‘Fei Huang’ (26%), Magnolia liliflora Desr (17%), Magnolia liliiflora ‘Hong Yuanbao’ (15%) and Yulania denudata ‘5#’(14%). The type and content differences of volatile organic compounds (VOCs) in the flowers offive germplasm of genus Magnolia denudata Desr are comparatively big. There has been no research reports about the contents of volatile organic compounds in the flowers of Yulania stellata, Magnolia liliiflora ‘Hong Yuanbao’ and Yulania denudata ‘5#’. In conclusion, this study is expected to better clarify the component and content of VOCs from the flowers of different Magnolia denudata Desrcultivars, and provide the scientific basis for the health-care type garden green space building.

Potential of Volatile Organic Compounds Emitted by Pseudomonas fluorescens ZX as Biological Fumigants to Control Citrus Green Mold Decay at Postharvest.

In this study, volatile organic compounds (VOCs) were generated by Pseudomonas fluorescens ZX with incubation in nutrient broth (NB), on NA (NB with agar), and on healthy orange fruits, and pure individual components of VOCs were used to manage citrus green mold infected by Penicillium digitatum. At a concentration of 1 × 1010 cfu/mL, the VOCs from antagonist-containing NA plates inhibited P. digitatum conidial germination and mycelial growth by about 60%, while the VOCs from bacterial fluid exhibited approximately 75% inhibitory effect. Biofumigation by VOCs significantly reduced the disease index, with a higher biocontrol efficacy by VOCs from bacterial fluid (about 51%) than from antagonist-containing NA plates (around 40%) or from antagonist-infested fruit (approximately 24%). Exposure to VOCs led to morphological abnormalities of P. digitatum conidia and hyphae. However, VOCs exhibited poor preventative and curative action against P. digitatum. The storage test showed that biofumigation had no negative effects on fruit quality. Antifungal assays suggested that dimethyl disulfide and dimethyl trisulfide exhibited the highest inhibitory effects, which afforded complete inhibition at the lowest concentrations. In addition, organic acids were also promising in controlling green mold, but only at suitable low concentrations to avoid eliciting fruit's physiological diseases.

Volatile 1-octanol of tea (Camellia sinensis L.) fuels cell division and indole-3-acetic acid production in phylloplane isolate Pseudomonas sp. NEEL19

Tea leaves possess numerous volatile organic compounds (VOC) that contribute to tea’s characteristic aroma. Some components of tea VOC were known to exhibit antimicrobial activity; however, their impact on bacteria remains elusive. Here, we showed that the VOC of fresh aqueous tea leaf extract, recovered through hydrodistillation, promoted cell division and tryptophan-dependent indole-3-acetic acid (IAA) production in Pseudomonas sp. NEEL19, a solvent-tolerant isolate of the tea phylloplane. 1-octanol was identified as one of the responsible volatiles stimulating cell division, metabolic change, swimming motility, putative pili/nanowire formation and IAA production, through gas chromatography-mass spectrometry, microscopy and partition petri dish culture analyses. The bacterial metabolic responses including IAA production increased under 1-octanol vapor in a dose-dependent manner, whereas direct-contact in liquid culture failed to elicit such response. Thus, volatile 1-octanol emitting from tea leaves is a potential modulator of cell division, colonization and phytohormone production in NEEL19, possibly influencing the tea aroma.

Characteristics and Source Apportionment of Ambient VOCs in Spring in Liuzhou

The objective was to investigate the characteristics and sources of ambient volatile organic compounds (VOCs) in the karst region in southwestern China. We monitored atmospheric VOCs in Liuzhou by the GC955 VOCs Online Monitoring System and analyzed the pollution characteristics, ozone formation potential (OFP), aerosol formation potential (AFP), and the positive matrix factorization (PMF) model in March 2019. The results show that ① 50 kinds of VOC components were detected during the supervised period, with an average daily concentration of 25.52×10-9 mol·mol-1, which was composed of alkanes (56.08%), alkenes (19.63%), alkynes (14.25%), and aromatics (10.04%), respectively. ② The concentration of VOCs was lower during the day and higher at night, with the highest value at 23:00. The VOC concentration was low in daytime and high at night. The peak value of VOCs with regard to diurnal variation was correlated with the time of morning and the evening traffic peak and may be influenced by various factors. ③ The contribution of alkenes, aromatics, and alkanes to OFP was 44.30%, 33.03%, and 19.96%, respectively. This indicates that the control of aromatic and olefin should prioritize alkanes. In addition, Liuzhou city is in the VOC sensitive area of O3 generation, and the reduction of VOCs had a controlling effect on O3 generation. ④ The contribution of aromatic hydrocarbons to AFP was up to 95.27%. Therefore, the improvement and control of the processes in motor vehicle exhaust emissions, solvent use, and the automobile industry and the chemical industry could effectively suppress ozone and haze pollution. ⑤ The emission sources of VOCs in spring were mainly industrial emission sources (28.34%), motor vehicle sources (25.47%), combustion sources (24.37%), solvent sources (13.28%), and plant emission sources (8.54%), respectively. This indicates that the control of industrial emission sources, motor vehicle sources, and combustion sources is the main way to control VOC pollution in Liuzhou City. Meanwhile, the olefin and aromatic hydrocarbons emitted by these emission sources should be mainly considered.

Sources and components of volatile organic compounds in breast surgery operating rooms

ObjectivesThe composition and concentration distribution of volatile organic compounds (VOCs) in surgical smoke had seldomly been reported. This study aimed to investigate the profile of VOCs and their concentration in surgical smoke from breast surgery during electrocautery in different tissues, electrosurgical units, and electrocautery powers. MethodsThirty-eight surgical smoke samples from 23 patients performed breast surgery were collected using evacuated stainless steel canisters. The concentrations of 87 VOCs in surgical smoke samples were analyzed by gas chromatography-mass spectrometry. The human tissues, electrosurgical units, and electrocautery power were recorded. ResultsThe median level of total VOCs concentrations in surgical smoke samples from mammary glands (total VOCs: 9953.5 ppb; benzene: 222.7 ppb; 1,3-butadiene: 856.2 ppb; vinyl chloride: 3.1 ppb) using conventional electrosurgical knives were significantly higher than that from other tissues (total VOCs: 365.7–4266.8 ppb, P < 0.05; benzene: 26.4–112 ppb, P < 0.05; 1,3-butadiene: 15.6–384 ppb, P < 0.05; vinyl chloride: 0.6–1.8 ppb, P < 0.05) using different electrosurgical units. A high methanol concentration was found in surgical smoke generated during breast surgery (641.4–4452.5 ppb) using different electrosurgical units. An electrocautery power of ≥ 27.5 watts used for skin tissues produced a higher VOCs concentration (2905.8 ppb). ConclusionsThe surgical smoke samples collected from mammary glands using conventional electrosurgical knives had high VOCs concentrations. The carcinogens (including benzene, 1,3-butadiene, and vinyl chloride) and methanol were found in the surgical smoke samples from different electrosurgical units. The type of electrosurgical unit and electrocautery power used affected VOCs concentrations in surgical smoke.

Relationships between the bacterial diversity and metabolites of a Chinese fermented pork product, sour meat

SummaryThe present study evaluated the relationship between the bacterial diversity and metabolites of various sour meats, a traditional fermented meat product. The results showed that sour meats had a low pH (average of 4.34), low water activity (aw, an average of 0.917), and high lactic acid (~19 177.48 mg kg−1) and free amino acid (FAA) (~4047.65 mg kg−1) concentrations. The lactic acid bacteria (LAB), especiallyLactobacillusandWeissella, were predominated in the samples. The alcohols, aldehydes and esters accounted for the major components of volatile organic compounds (VOCs). Of which, (E)‐2‐octenal, nerol, cis‐4‐decenal, tetradecanal, linalyl acetate, linalool, 1‐octen‐3‐ol, hexanal, 1‐heptanol, benzaldehyde and (E)‐2‐decenal were considered as the key VOCs of sour meats. The redundancy analysis (RDA) and Pearson’s correlation analysis revealed that LAB (LactobacillusandWeissella) and salt were positively correlated with most FAAs and VOCs. Overall, higher salinity, lowerawand abundant LAB might be the indicators of good sour meat quality.

Simultaneous removal of ammonia and volatile organic compounds from composting of dead pigs and manure using pilot-scale biofilter

ABSTRACT Odor emission is one of the most common problems associated with dead animals composting. Biofiltration treatment for eliminating exhaust odors formed during dead pigs and manure composting has been studied. The composting and biofiltration process consisted of two series of tests. Composting experimental trials lasted 6 weeks, and composting was performed using six pilot-scale reactor vessels. A total of 37 kinds of volatile organic compounds (VOCs) present in the air were identified, and temporal variations were determined during the 42 days of composting. Dimethyl sulfide (DMS), dimethyl disulfide (DMDS), dimethyl trisulfide (DMTS), and trimethylamine (TMA) were identified as the main odors VOCs component according to odor active values (OAVs). Nine biofilter vessels containing mature compost were used in studying the effect of different (30, 60, and 100 s) empty bed retention times (EBRT) on the simultaneous removal efficiencies (REs) of NH3, DMS, DMDS, DMTS, and TMA. Results indicated that the inlet concentration of NH3 applied was 12–447 mg m−3, and the average removal efficiencies were 85.4%, 88.7%, and 89.0% for EBRTs of 30, 60, and 100 s, respectively. The average REs of DMS, DMDS, DMTS, and TMA were 79.2%–95.4%, 81.9%–94.0%, 76.7%–99.1%, and 92.9%–100%, respectively, and their maximum elimination capacity (ECs) were 220, 1301, 296, and 603 mg m−3 h−1, respectively. The optimal EBRT for the stimulation removal of NH3, DMS, DMDS, DMTS, and TMA was 60 s. Implications: Dimethyl sulfide (DMS), dimethyl disulfide (DMDS), dimethyl trisulfide (DMTS), and trimethylamine (TMA) were identified as the main odors VOCs component during dead pigs and manure composting. Biofilter with mature as media can be used to stimulation remove NH3, DMS, DMDS, DMTS, and TMA, the optimal empty bed retention times EBRT was 60 s.

Effects of hexanal fumigation on fungal spoilage and grain quality of stored wheat

The prevention of fungal spoilage is an essential consideration in wheat storage. Recent studies have revealed that volatile organic compounds (VOCs), possibly with natural fungicidal properties, could be produced from stored wheat grains. In this study, the antifungal effect of hexanal, a main component of VOCs from stored wheat, against spoilage fungi on agar plate and in high-moisture wheat grains were investigated via the gas fumigation method. And the impact of hexanal fumigation on grain quality was evaluated through analysis of the malondialdehyde content, fatty acid values, germination percentages and vigor of 16% and 18% moisture wheat grains fumigated with 1.66, 2.49, and 3.31 mmol/L hexanal vapor. The results of in vitro antifungal experiments on agar plates revealed that the minimum inhibitory concentration and minimum fungicidal (fatal) concentration of hexanal against the five fungi were 4–14 folds and 4–7 folds lower than those of propionic acid, respectively. The fungal spoilage of high-moisture wheat grains inoculated with pure fungal spores and with naturally occurring fungi could be completely inhibited by 1.66 mmol/L hexanal vapor. During 5-week storage of high-moisture wheat grains fumigated with 1.66, 2.49, and 3.31 mmol/L hexanal vapor, the malondialdehyde content in high-moisture wheat grains did not change significantly in all samples, and fatty acid values were slightly higher in 18% moisture wheat than in 16% moisture wheat. The germination percentages and vigor of wheat samples decreased with increased hexanal vapor concentrations and moisture content. These results indicated that hexanal fumigation could be used as an alternative chemical control method to prevent the fungal spoilage of postharvest wheat.

Ambient volatile organic compounds at Wudang Mountain in Central China: Characteristics, sources and implications to ozone formation

A continuous measurement of ambient volatile organic compounds (VOCs) was carried out from May to June 2018 at a background site, the Wudang Mountain (Mt. Wudang) in Central China. The characteristics, sources of VOCs and their contributions to ozone formation were investigated for the first time in this area. Based on the National Ambient Air Quality Standard, 29 O3 non-attainment days were identified. The average mixing ratio of 82 total VOCs (∑VOCs) was 12.17 ± 3.66 ppb. Higher mixing ratios of individual species were found compared with those measured at global baseline sites. The results revealed that the dominant VOCs components were alkanes and OVOCs, accounting for 79.92%. Five sources, i.e. industrial processes, fuel evaporation, vehicular exhaust, solvent utilization and biogenic emission were identified by the positive matrix factorization (PMF) model. From potential source contribution function (PSCF) analysis, local area and the adjacent provinces especially Shaanxi province, had some extent influence on Mt. Wudang. The OH radical loss rate (LOH) and ozone formation potential (OFP) calculations revealed that biogenic emission and vehicular exhaust were both the major sources for ozone formation. Through the Observation-Based Model (OBM) simulation, the daytime average net ozone production rate was 4.1 ppb/h and the ozone production pathway was dominated by the reaction of HO2 + NO. This study shows that local emission and long-range transport of air pollutants should be taken into account for developing the science-based air pollution control strategies at Mt. Wudang.

Adjunctive Therapeutic Effects of Cinnamomum Camphora Forest Environment on Elderly Patients with Hypertension

Background: Many studies have demonstrated the beneficial effects of the mixed forest environment on human health. However, few studied the effect of the single tree species forest on human health. This study was explored the effect of C. camphora forest environment on elderly patients with hypertension (HTN). Methods: 31 elderly patients with essential HTN were randomly divided into two groups. Blood pressure (BP), pulse oxygen saturation (SpO_2%), heart rate (HR), heart rate variability (HRV) and levels of plasma high-sensitivity C-reactive protein (hs-CRP), as well as profile of mood states (POMS) test, were measured. Environment factors of two experimental sites were monitored. Categorical variables and continuous data were analyzed by Chi-square and t-test, respectively. Results: After forest bathing, subjects in the forest group showed significantly lower levels of diastolic blood pressure (DBP), low frequency (LF), the ratio of low frequency and high frequency (LF/HF) and hs-CRP, and greatly higher levels of SpO_2% and high frequency (HF) than that of in control group. Furthermore, negative mood subscale scores of POMS were significantly lower following forest bathing, while the positive score was much higher. However, the main components of volatile organic compounds (VOCs) in the two experimental sites were obviously different. Conclusion: C. Camphora environment significantly decreased the DBP and inflammatory level, balanced the autonomic activity and improved the mood state of participates, which might be associated with the biological effectiveness of terpenes, implying that C. Camphora environment might be an adjunctive therapy for HTN patients.

Investigation of health risk assessment and odor pollution of volatile organic compounds from industrial activities in the Yangtze River Delta region, China

To investigate composition characteristics and assess occupational health risks and odor pollution of volatile organic compounds (VOCs) from industrial activities in the Yangtze River Delta (YRD) region, China, one-year field measurements of VOCs were conducted simultaneously at an iron and steel industrial park (ISP), one chemical industrial park (CMP) and one petrochemical industrial park (PCP) from September, 2018 to August, 2019. The concentrations of VOCs were 80.2 ± 67.9 ppbv, 28.1 ± 27.2 ppbv and 144 ± 378 ppbv for ISP, CMP and PCP, respectively. Aromatics, alkanes and alkenes were the major components of VOCs at ISP, CMP and PCP, respectively. Moreover, the toluene to benzene ratios were 0.330 ± 0.302, 4.31 ± 6.48 and 1.84 ± 3.34, which generally showed the characteristics of combustion source for ISP, industrial activities for CMP and petrochemical industry for PCP, respectively. The hazard index values were 0.752 ± 0.438, 0.108 ± 0.248 and 0.090 ± 0.260 at ISP, CMP and PCP, which were generally lower than threshold limit value, suggesting a low noncarcinogenic risk for workers. Meanwhile, the 95th percentile LCR values of VOCs were 8.76 × 10−5, 1.15 × 10−5 and 1.00 × 10−5 at ISP, CMP and PCP, respectively, which were also under acceptable risk level, indicating a low carcinogenic risk. Benzene and 1,3-butadiene were main harmful substances for both noncarcinogenic and carcinogenic risks of VOCs. The odor levels of VOCs were 2.12 ± 4.21, 12.5 ± 28.7 and 1.01 ± 7.84 at ISP, CMP and PCP, respectively. Aromatics for ISP and sulfide compounds for CMP and PCP were primary pollutants for odor pollution. This work could improve the understanding of risk levels and odor characteristics of VOCs and benefit policy development on alleviating odor complaints and health risks for workers in YRD region, China.

Emission Inventory of VOCs Components in Zhengzhou and Their Ozone Formation Potential

In this study, according to the activity levels of volatile organic compounds (VOCs) sources and source profiles, a 2016-based inventory of the speciation emission of the VOCs was established and the ozone formation potential (OFP) were estimated in Zhengzhou. The results showed that the total VOCs emission in Zhengzhou in 2016 was 96215.3 t. The highest emission source was on-road mobile source (29.7%) followed by solvent use sources (28.1%). The species that contributed the highest emission was alkanes (29.8%) followed by aromatics (29.0%). The OFP in Zhengzhou in 2016 was 341291.0 t with the highest contributing source as on-road mobile (30.5%) followed by solvent use source (28.8%). Moreover, the light duty gasoline vehicle, use of interior wall coatings, vehicle surface coating, gas station loading and unloading, and manufacture of non-metallic mineral were the major secondary emission sources of OFP, which needed to be controlled for reducing ozone pollution in Zhengzhou. For VOCs species group, the higher contribution groups were aromatics (42.8%) and alkenes (38.9%). The sources that produced m/p-xylene, propylene, ethylene, and other species should be paid more attention.

Abatement of n-Butane by Catalytic Combustion over Co-ZSM-5 Catalysts

Catalytic combustion has become a promising technology to address the accelerating volatile organic compounds (VOCs) emissions. In this work, cobalt modified ZSM-5 zeolite catalysts (3–18 wt % Co) were prepared to investigate the combustion of n-butane (one typical model component of VOCs). The performances of catalysts were evaluated by conducting experiments in a flow tube reactor. XRD, BET, FT-IR, and XPS were also utilized to characterize their physicochemical properties. A significant enhancement of the catalytic activity was demonstrated in terms of the cobalt supported over ZSM-5, with an optimal cobalt loading of 7 wt %. The excellent catalytic activity of 7 wt % Co-ZSM-5 is mainly attributed to a higher concentration of active surface Co3+ species. Furthermore, DFT calculations indicated that the role of Co can enhance the activity by decreasing the activation barriers for C–H bond cleavage. In addition, the primary reaction mechanism of n-butane combustion on Co-ZSM-5 was also revealed.