Variation Of Volatile Organic Compounds Research Articles

GC–IMS facilitates identification of carbapenem-resistant Klebsiella pneumoniae in simulated blood cultures

This study aimed to identify carbapenem-resistant Klebsiella pneumoniae (CRKP) based on changes in levels of its volatile organic compounds (VOCs) in simulated blood cultures (BCs) using the gas chromatography–ion mobility spectrometry (GC–IMS) technique. A comprehensive analysis of volatile metabolites produced by Klebsiella pneumoniae (K. pneumoniae) in BC bottles was conducted using GC–IMS. Subsequently, the released VOCs were analyzed to examine differences in VOC release between CRKP and carbapenem-susceptible Klebsiella pneumoniae (CSKP). A total of 54 VOCs were detected, of which 18 (6 VOCs found in both monomer and dimer forms) were successfully identified. The VOCs produced by K. pneumoniae in BC bottles (BacT/ALERT® SA) were primarily composed of organic acids, alcohols, esters, and ketones. The content of certain VOCs was significantly different between CRKP and CSKP after the addition of imipenem (IPM). Moreover, the inclusion of carbapenemase inhibitors facilitated the identification of carbapenemase-producing K. pneumoniae based on the variations in VOCs. This study demonstrates the utility of GC–IMS technology in identifying CRKP, and reveals that changes in VOCs are closely related to the growth and metabolism of K. pneumoniae, indicating that they can be leveraged to promote early identification of CRKP bacteremia. However, further in-depth studies and experiments are needed to validate our findings.

Assessment of seasonal variations of volatile organic compounds in raw and treated wastewater in Kuwait

This study assesses the seasonal variations of volatile organic compounds (VOCs) in raw and treated wastewater from one of the largest treatment plants in Kuwait. Samples from the influent and effluent of the treatment plant were collected weekly and analyzed for toluene, benzene, xylene, 1, 3, 5 trimethylbenzene, 1, 4 dichlorobenzene, dichloromethane, chloroform, and tetrachloroethene. The results showed that the median concentrations of all VOCs measured in raw wastewater were higher during the winter season than during the summer season. The concentrations of VOCs during winter were higher by 4 to 5 times than in the summer season. However, there was no significant difference between winter and summer concentrations of all the VOCs in treated wastewater. A significant difference in Dichloromethane and Toluene removal efficiencies was noticed between the summer and winter seasons, as higher removal efficiency was achieved in summer.

Roles of photochemical consumption of VOCs on regional background O3 concentration and atmospheric reactivity over the pearl river estuary, Southern China

Understanding of the photochemical ozone (O3) pollution over the Pearl River Estuary (PRE) of southern China remains limited. We performed an in-depth analysis of volatile organic compounds (VOCs) data collected on an island (i.e., the Da Wan Shan Island, DWS) located at the downwind of Pearl River Delta (PRD) from 26 November to 15 December 2021. Abundances of O3 and its precursors were measured when the air masses originated from the inland PRD. We observed that the VOCs levels at the DWS site were lower, while the mixing ratio of O3 was higher, compared to those reported at inland PRD, indicating the occurrence of photochemical consumption of VOCs during the air masses transport, which was further confirmed by the composition and diurnal variations of VOCs, as well as ratios of specific VOCs. The simulation results from a photochemical box model showed that the O3 level in the outflow air masses of inland PRD (O3(out-flow)) was the dominant factor leading to the intensification of O3 pollution and the enhancement of atmospheric radical concentrations (ARC) over PRE, which was mainly contributed by the O3 production via photochemical consumption of VOCs during air masses transport. Overall, our findings provided direct quantitative evidence for the roles of outflow O3 and its precursors from inland PRD on O3 abundance and ARC over the PRE area, highlighting that alleviation of O3 pollution over PRE should focus on the impact of photochemical loss of VOCs in the outflow air masses from inland PRD.

An innovative approach for analysing and evaluating enteric diseases in poultry farm

Volatile organic compounds (VOCs) produced by pathogens, host-pathogen interactions and biochemical pathways are present everywhere such as in blood, breath, faeces, sweat, skin, urine, and vaginal fluids. Their qualitative and quantitative composition is influenced by pathophysiological responses to infections, toxins, or endogenous metabolic pathway perturbations. In poultry, VOCs analysis has been explored to evaluate air quality in sheds, but they have never been monitored to determine if birds were affected by enteric diseases. The enteric disorders represent one of the most important groups of diseases that affect poultry and cause illness, mortality, and economic losses. For this reason, monitoring the health status of broilers and the early detection of any health problem is of great importance in intensive farming, especially nowadays that antibiotics are banned. Precision Livestock Farming, through the combination of cheap technologies and specific algorithms, can provide valuable information for farmers starting from the huge amount of data collected in real time at farm level. This study was aimed to the application of a PLF diagnostic tool, sensible to the variation of volatile organic compounds, to promptly recognize enteric problems recognize enteric problems (as coccidiosis and necrotic enteritis) in intensive farming, supporting veterinarians and enabling specific treatments in case of disease.

Laboratory benchmark of low-cost portable gas and particle analysers at the source of smouldering wildfires

Background Smouldering wildfires emit large amounts of carbon, toxic gases and particulate matter (PM), posing health and environmental hazards. It is challenging to conduct field measurements on wildfire emissions, and available instruments are limited by high cost and low mobility. Aim Here, we contribute to solving this challenge by studying three commercial low-cost and portable air quality analysers (KANE101, SDS011 and FLOW) and comparing them with research-grade instruments (FTIR, PM Cascade Impactor and DustTrak). Methods A series of laboratory experiments on peat smouldering were conducted including the stages of ignition, spread and burnout to provide conditions of emission measurements near the source. Key results The gas analyser KANE101 accurately measured CO2 and allowed calculation of modified combustion efficiency (MCE). The FLOW air pollution sensor was found unsuitable for PM measurements near fire sources because of its narrow range. FLOW captured the variation of volatile organic compounds (VOCs), but measurements did not correlate well with NO2 measurements. The SDS011 PM sensor responded well in measuring PM10 in this study. Conclusions KANE101 and SDS011 can be used in the field after calibration to measure CO2/CO and PM. Implications This work provides a better understanding of how low-cost and portable emission sensors can be of use for wildfire measurements in the field.

Characterization, source apportionment, and risk assessment of ambient volatile organic compounds in urban and background regions of Hainan Island, China

The pollution characteristics of volatile organic compounds (VOCs) in urban and background regions in Hainan province, China, were determined based on field measurements of CO, NO, NO2, O3, VOCs, and meteorological parameters conducted at Haikou (HK, an urban site) and Wuzhishan (WZS, a background site) in 2019. The annual average concentration of VOCs at HK was 13.1 ppb, which was 2.2 times higher than that at WZS (6.0 ppb). VOC concentrations at HK were higher in winter, whereas there was no significant monthly variation at WZS. Diurnal variations in VOCs were characterized by two peaks at HK, attributable to emissions during morning and evening rush-hour traffic. At WZS, the diurnal variations of VOCs were characterized by one peak at 13:00–16:00, corresponding to the high temperature and intense sunlight in the afternoon. The total O3 formation potential of ambient VOCs was 135.1 g g−1 at HK and 80.6 g g−1 at WZS, with the O3 formation potential of alkenes accounting for 53.4% and 47.2%, respectively. The potential source region of VOCs at both sites was likely the southeastern ocean region of China (i.e., Guangdong, Guangxi, Hunan, and Jiangxi provinces) and Vietnam, Cambodia, and Thailand. Using on an empirical kinetic modeling approach, O3 formation at HK occurred under a mixed-limited region, and at WZS under a NOx-limited region. Traffic emissions were the largest contributor to VOCs at HK, accounting for 38.7%, followed by solvents (19.6%), combustion (15.2%), industrial sources (15.0%), and plant sources (11.5%). At WZS, traffic accounted for 39.6% of VOCs, similar to HK, whereas the contribution of industrial sources (22.1%) was higher. Although there are few vehicles and little industry around WZS, the long-distance transport of VOCs emitted elsewhere by these sources had a significant influence on the region's VOCs. The contribution of plant sources of VOCs was 1.5 times higher at WZS (17.0%) than at HK. None of the VOC species posed significant non-carcinogenic or carcinogenic risks at either HK or WZS.

Identification and biotransformation analysis of volatile markers during the early stage of Salmonella contamination in chicken

Salmonella is one of the most prevalent foodborne pathogens in poultry and its products. Its rapid detection based on volatile organic compounds (VOC) has been widely accepted. However, the variation in the VOCs of Salmonella-contaminated chicken during the early stage (48 h) remains uncertain. Headspace-SPME-gas chromatography-mass spectrometry (HS-SPME-GC–MS) and headspace-gas chromatography-ion migration spectroscopy (HS-GC-IMS) were used to identify VOCs and their variations after the chicken meat was contaminated with Salmonella. Chemometric and KEGG enrichment analyses were performed to identify VOC markers and their potential metabolic pathways. A total of 64 volatile compounds were detected using HS-GC-IMS, which showed a better differentiation than HS-SPME-GC–MS (45 volatile compounds) based on principal component analysis (PCA) and orthogonal partial least squares-discriminant analysis (OPLS-DA). Fatty acid degradation was the main cause of VOC variation. 2-Propanol, hexadecane, 3-methylbutanol, acetic acid, propyl acetate, acetic acid methyl ester, and 3-butenenitrile were identified as VOC markers in the middle stage of decomposition, and 1-octen-3-ol was recognized as a VOC marker of Salmonella-contaminated chicken during the first 48 h of contamination. This provides a theoretical basis for the study of Salmonella contamination VOC markers in poultry meat.

Variation in Volatile Organic Compounds in native, synanthropic accessions and cultivars of the musk strawberry (Fragaria moschata Duchesne ex Weston).

Prior to the world-wide dominance of F. ×ananassa in strawberry production, native species had been cultivated in European gardens for centuries. Especially the musk strawberry (F. moschata) had been highly appreciated due to its fruit size and extraordinary aroma. Detailed studies on the diversity of the species' fruit aroma are lacking, although breeding aims to improve strawberry aroma by complex crossings during recent years. Today a few cultivars, abandoned synanthropic occurrences and native populations of this species exist in Germany. Here we characterised aroma profiles of F. moschata accessions by analysing Volatile Organic Compounds. In particular, differences between native and cultivated accessions as well as the diversity in aroma profiles of native populations were investigated. Profiles of Volatile Organic Compounds were analysed by immersion stir bar sorptive extraction-gas chromatography-quadrupol mass spectrometry (imm-SBSE-GC-qMS). These data were compared with a genetic characterisation of samples based on eight microsatellite loci using univariate and multivariate statistical analyses. High amounts of furanones and the key compound methyl anthranilate were characteristic for the aroma profile of F. moschata. We detected a considerable diversity of Volatile Organic Compounds among accessions of F. moschata, particularly among genetically distinct samples from the same population. Native accessions contained more terpenoids but less esters and were moderately differentiated from cultivated samples. The observed patterns of Volatile Organic Compounds indicate that cultivated accessions had been selected for favourable aroma profiles and thus showing traces of domestication. Moreover, native populations harbour a great diversity of Volatile Organic Compounds, which could be also considered for future breeding efforts.

Characterization of aroma profiles of chinese four most famous traditional red-cooked chickens using GC–MS, GC-IMS, and E-nose

The aroma profile of the four most popular types of red-cooked chickens in China was analyzed using a combination of gas chromatography-mass spectrometry (GC–MS), gas chromatography-ion mobility spectrometry (GC-IMS), and electronic nose (E-nose). Principal component analysis (PCA) demonstrated that the E-nose could successfully distinguish between the four types of red-cooked chickens. Additionally, a fingerprint was created using GC-IMS to examine the variations in volatile organic compounds (VOCs) distribution in the four chicken types. A total number of 84 and 62 VOCs were identified in the four types of red-cooked chickens using GC–MS and GC-IMS, respectively. Odor activity value (OAV) showed that 1-octen-3-ol, heptanal, hexanal, nonanal, octanal, eugenol, dimethyl trisulfide, anethole, anisaldehyde, estragole, and eucalyptol were the key volatile components in all samples. Furthermore, partial least squares-discriminant analysis (PLS-DA) demonstrated that (E, E)-2,4-decadienal, dimethyl trisulfide, octanal, eugenol, hexanal, (E)-2-nonenal, 1-octen-3-ol, butanal, ethyl acetate, ethyl acetate (D), nonanal, and heptanal could be used as markers to distinguish aroma of the four types of red-cooked chickens. Also, it is worth noting that levels of VOCs varied between chicken breast muscle and skin. The obtained results offer theoretical and technological support for flavor identification and control in red-cooked chickens to enhance their quality and encourage consumer consumption, which will be advantageous for the red-cooked chicken production chain.

Identification of multiple symptoms of huanglongbing by electronic nose based on the variability of volatile organic compounds

AbstractHuanglongbing (HLB) is highly contagious and cannot be cured, resulting in a decrease in the commercial value of citrus. Timely detection and removal of diseased trees is an effective way to reduce losses. Complex symptoms of HLB, such as nutrient deficiencies often accompany HLB; as a result effective and accurate identification of HLB remains a challenge. In this study, 175 volatile organic compounds (VOCs) were detected in three categories (healthy, HLB, and Zn‐deficiency) of samples using headspace solid‐phase microextraction gas chromatography–mass spectrometry (HS‐SPME‐GC/MS), highlighting the variability of VOCs present in different categories of samples. In order to simplify the testing steps and reduce the cost in practical agricultural production, a method based on electronic nose technology to collect VOCs from citrus leaves for HLB detection was proposed. Among them, limiting value features and linear discriminant analysis were identified as the best combination of feature extraction and pattern recognition methods. Multiple sets of comparison experiments were set up and the collection conditions of VOCs were optimized. The results showed that the best classification performance was achieved for a 0.2 g sample at a collection time of 20 min when the collection temperature was 40°C and the headspace volume was 200 mL. Four types of samples (healthy, HLB‐positive, Zn‐deficiency, Zn‐deficiency and HLB‐positive) were used for model reliability validation, with an accuracy of 97.79% for HLB samples for multiple symptoms (including HLB‐positive and Zn‐deficiency and HLB‐positive) identification. In addition, the accuracy of samples with a combined effect of Zn‐deficiency and HLB was 96.43%. The results show that the E‐nose‐based HLB detection method is conducive to suppressing the spread of HLB, which can ensure the quality of citrus products and reduce the economic loss to horticulturists, and has good practical value.

Emission Ratios and Diurnal Variability of Volatile Organic Compounds and Influence of Industrial Emissions in Two Texas Cities

Changing urban emission landscapes and increasing population make it imperative to understand the driving forces for air quality in growing urban areas. Recent field studies in an industrial area in Houston and a semiurban area in San Antonio reveal unique emission signatures for these two growing Texas cities. A comparison of benzene, toluene, xylenes, isoprene, and methyl ethyl ketone (MEK) was conducted for these two Texas locations and previous studies in other megacities. It was found that San Antonio had similar emission ratios as these megacities for benzene, toluene, and xylenes (1.10, 4.57, and 3.60 pptv ppbv−1 of CO, respectively), likely indicating a similar traffic emission source. Isoprene and MEK were of biogenic origin in San Antonio. However, analysis of emission ratios, diurnal trends, and comparison with emission inventories indicated that benzene, toluene, and MEK were likely associated with fugitive and stack emissions in the industrial corridor in Houston. Isoprene in Houston appeared to have mixed fugitive and biogenic sources in Houston, based on diurnal trends and emission ratio. The peak nighttime concentrations for benzene, toluene, xylene, isoprene, and MEK observed during the campaign were 66, 533, 21, 138, and 731 ppbv, respectively, in the Houston site. The emission ratio for xylenes (3.37 pptv ppbv−1 of CO) for the Houston site was similar to Paris, London, and Mexico City, despite emission inventories indicating high fugitive and stack emissions. The conditional probability function (CPF) analysis closely matched the direction of the industrial sources with the highest recorded emission levels as listed in the emission inventory for the Houston site. The estimated ozone production efficiency (OPE) for the industrial area in Houston indicated volatile organic compound (VOC)–limited conditions in the morning, which transitioned to nitrogen oxide (NOx)–limited conditions in the afternoon. Texas cities have complex emission scenarios, and future efforts to mitigate ozone and particulate matter may have to consider a variety of emission reduction strategies.

Two years of volatile organic compound online in situ measurements at the Site Instrumental de Recherche par Télédétection Atmosphérique (Paris region, France) using proton-transfer-reaction mass spectrometry

Abstract. Volatile organic compounds (VOCs) have direct influences on air quality and climate. They indeed play a key role in atmospheric chemistry as precursors of secondary pollutants, such as ozone (O3) and secondary organic aerosols (SOA). In this respect, long-term datasets of in situ atmospheric measurements are crucial for characterizing the variability of atmospheric chemical composition, its sources, and trends. The ongoing establishment of the Aerosols, Cloud, and Trace gases Research InfraStructure (ACTRIS) allows implementation of the collection and provision of such high-quality datasets. In this context, online and continuous measurements of O3, nitrogen oxides (NOx), and aerosols have been carried out since 2012 at the SIRTA (Site Instrumental de Recherche par Télédétection Atmosphérique) observatory, located in the Paris region, France. Within the last decade, VOC measurements were conducted offline at SIRTA, until the implementation of real-time monitoring which started in January 2020 using a proton-transfer-reaction quadrupole mass spectrometer (PTR-Q-MS). The dataset acquired during the first 2 years of online VOC measurements provides insights into their seasonal and diurnal variabilities. The additional long-term datasets obtained from co-located measurements (NOx, aerosol physical and chemical properties, meteorological parameters) are used to better characterize the atmospheric conditions and to further interpret the obtained results. Results also include insights into VOC main sources and the influence of meteorological conditions and air mass origin on their levels in the Paris region. Due to the COVID-19 pandemic, the year 2020 notably saw a quasi-total lockdown in France in spring and a lighter one in autumn. Therefore, the focus is placed on the impact of these lockdowns on the VOC variability and sources. A change in the behaviour of VOC markers for anthropogenic sources was observed during the first lockdown, reflecting a change in human activities. A comparison with gas chromatography data from the Paris city centre consolidates the regional representativity of the SIRTA station for benzene, while differences are observed for shorter-lived compounds with a notable impact of their local sources. This dataset could be further used as input for atmospheric models and can be found at https://doi.org/10.14768/f8c46735-e6c3-45e2-8f6f-26c6d67c4723 (Simon et al., 2022a).

[Characteristics and Source Apportionment of Volatile Organic Compounds in Zhanjiang in Summer].

Ozone pollution is intensifying in China, and its related studies are weak in non-focus regions and non-focus cities. Here, we investigated the characteristics and sources of volatile organic compounds (VOCs) at three sampling sites in Zhanjiang. We analyzed 101 VOCs using a gas chromatography-mass spectrometry/hydrogen ion flame detector (GC-MS/FID) and high-performance liquid chromatography (HPLC) using a Summa canister and DNPH adsorption tube. We calculated the ozone formation potential (OFP) of VOCs and used the positive matrix factorization (PMF) model for source apportionment. The results showed that the mean φ(TVOCs) was 1.28×10-7, and the dominant contributors were OVOCs (52%), followed by alkanes (36%), alkenes (7%), halogenated hydrocarbons (2.42%), aromatic hydrocarbons (1.61%), and alkynes (0.78%). The diurnal variation in VOCs was influenced by photochemical reactions; the ratio of aromatic hydrocarbons and alkanes was high in the morning and evening and low at noon, whereas OVOCs had a low ratio in the morning and noon and high in the evening, influenced by primary emissions and the upwind transport of pollutants. The OFP was 3.28×10-7, and the dominant species were formaldehyde, butene, n-butane, butanone, and acetaldehyde.The analysis of X/E values (characterizing the aging degree of air masses) and backward trajectories of air masses showed that during the sampling, when influenced by air masses from the south or southwest, X/E was small, and the aging degree of air masses was high, indicating the influence of regional transport; when influenced by air masses from the east or southeast direction, X/E was large, and the air masses were fresh, and VOCs were mainly from local emissions. Six emission sources of VOCs, including industrial emissions, gasoline vehicle exhaust and gasoline evaporation, regional background and transport sources, biomass combustion, diesel vehicles and marine shipping emissions, and solvent use emission sources, were resolved using the PMF model, with contributions of 36.05%, 28.99%, 13.84%, 10.13%, 7.05%, and 3.95%, respectively.Zhanjiang should strengthen the supervision of formaldehyde, butene, n-butane and butanone, industry sources, and mobile sources as the focus of control.

Vertical evolution of the concentrations and sources of volatile organic compounds in the lower boundary layer in urban Beijing in summer

Exploring the vertical variations in volatile organic compounds (VOCs) in the atmosphere and quantifying the sources of VOCs at different heights can help control atmospheric photochemical pollution in summer. Here, VOCs were vertically detected at three heights (47 m, 200 m and 320 m) along a 325 m tower of the Institute of Atmospheric Physics, Chinese Academy of Sciences, Beijing, in the mornings (8:00) and afternoons (15:00) from May 19 to June 18, 2021. The VOC concentrations in Beijing in summer were 16.2 ± 5.6 ppbv, 14.7 ± 2.5 ppbv and 14.9 ± 3.8 ppbv at 47 m, 200 m and 320 m, respectively, and alkanes accounted for the largest proportion at all heights (>56%). The vertical gradients of the VOC concentrations and components did not significantly change, which was consistent with the summer observations of other stations in North China in recent years, but these results significantly differed from observations from more than a decade ago. To determine the reason for this, a classification based on atmospheric stability was performed, revealing that the vertical distribution of VOCs was uniform in convective and stable conditions and decreased with increasing height in neutral condition. With the transition of atmospheric stability from neutral to convective to stable, the contributions of fuel combustion sources and solvent use sources gradually increased, while those of biogenic sources and background sources gradually decreased. With increasing height, the contributions of background sources increased, those of biogenic sources, solvent use and gasoline vehicular emissions decreased, and those of fuel combustion and industrial emissions remained basically unchanged. The above results indicated that with air pollution treatment, the potential for reducing emissions of VOCs in Beijing has decreased. Therefore, regional joint prevention and control are the main ways to control VOC pollution in Beijing.

[Variation Characteristics and Ozone Formation Potential of Ambient VOCs in Urban Beijing in Summer].

To further understand the effect of volatile organic compounds (VOCs) on ozone (O3) formation in seasons when ozone (O3) pollution occurs frequently, the variation in VOCs, chemical composition characteristics, and ozone formation potential (OFP) were studied, using high-resolution online monitoring data obtained in an urban site of Beijing in the summer of 2019. The results showed that the averaged total mixing ratio of VOCs was (25.12±10.11)×10-9, with alkanes as the most abundant group (40.41%), followed by oxygenated volatile organic compounds (OVOCs) (25.28%) and alkenes/alkynes (12.90%). The diurnal variation in VOCs concentration showed a bimodal pattern with the morning peak appearing from 06:00 to 08:00, when the proportion of alkenes/alkynes increased significantly,indicating that the vehicle exhaust contributed more to VOCs. The VOCs concentration decreased in the afternoon when the proportion of OVOCs showed an upward trend, and the photochemical reaction and meteorological factors had great influences on VOCs concentration and composition.The OFP in urban Beijing in summer was 154.64 μg·m-3; aromatics, OVOCs, and alkenes/alkynes played dominant roles in OFP; and hexanal, ethylene, and m/p-xylene were the key species. The results suggested the need for the control of vehicle and solvent use and restaurants emissions to reduce the high level of O3in urban Beijing in summer. The diurnal variations in ethane/acetylene (E/E) and m/p-xylene/ethylbenzene (X/E) showed that the photochemical-aging of the air masses was obvious, which was jointly affected by photochemical reactions and regional transport. The back-trajectory results indicated a high contribution of southeastern and southwestern air masses to atmospheric alkanes and OVOCs concentration; moreover, aromatics and alkenes were mainly from local sources.

Temporal variations of volatile organic compounds inside the cabin of a new electric vehicle under different operation modes during winter using proton transfer reaction time-of-flight mass spectrometry

Transportation is globally becoming more vehicle-dependent as public awareness towards the health risks caused by cabin-emitted volatile organic compounds (VOCs) increases. Therefore, the need for quantifying their concentration increases as well. This study measured the real-time VOCs in a new mini-truck-type electric vehicle cabin using a proton transfer reaction time-of-flight mass spectrometry under varying cabin heating conditions during winter. A total of 246 ions were detected between m/z 30 and 250, 82 of which were quantified. The total ion count in the cabin was double that of the ambient air. Morning-to-noon concentration of total VOCs increased 2.5 times in the cabin under solar exposure (164.47–405.92 µg·m−3). Additionally, 12 VOCs that either had higher indoor-to-outdoor ratios or globally regulated chosen to investigate the effects of cabin air conditions. Heater operation immediately increased concentrations of some VOCs by 54.62%. Furthermore, blocking solar exposure from windows reduced VOC emissions during heater off and on scenarios by 35.49% and 65.42%, respectively, indicating that window coverage also provided insulation against heat loss. Finally, the fresh air reduced cabin VOCs by 62.83% due to ambient air inflow. However, cabin concentrations remained higher than those of ambient air.

Comparative Study on Chemical Constituents of Ginseng Flowers with Four Consecutive Cultivation Age.

The harvest period of cultivated ginseng is generally 4-6 years. Ginseng flowers (GFs), the nonmedicinal parts, are usually removed every autumn, in which components are generally believed to stay unchanged with the increasing cultivation age. Recently, few documents were reported on the variation of volatile organic compounds (VOCs) and other components about ginseng flowers. This study had an insight into the variation of the chemical constituents with the cultivation ages through the comparison of the volatile organic compounds, gross ginsenosides, crude polysaccharide, and gross proteins of ginseng flowers from 3-, 4-, 5-, and 6-yr-old (GF3, GF4, GF5, and GF6) which were conducted by headspace solid-phase microextraction-gas chromatography-triple quadrupole mass spectrometry (HS-SPME-GC-QQQ/MS) and spectroscopic analysis combined with multivariate statistical analysis, including one-way ANOVA analysis and T test. The results indicated that the crude polysaccharide contents raised significantly depending on cultivation age except 6-yr-old, whereas the gross ginsenosides and the gross protein content were indistinctive. According to the peak intensity of determined VOCs, the contents of most differential compounds arranged in an order from high to low are GF3, GF4, GF5, and GF6, such as the compounds 2-15, 17-19, 22, and 25-26, therefore, they can be inferred that they are important markers to identify the age of GFs. 461 common differential compounds were gained and 26 common volatile organic compounds were identified with RSI >800 and RI and RIx no more than 30, including alcohols (such as 11, 12, and 15), sesquiterpenes (such as 2, 3, and 4), esters (such as 1 and 26), naphthalene and naphthol (such as 7 and 20), which had potential effects on curing Alzheimer's disease, inflammatory diseases, and prostate cancer based on network pharmacology analysis. This paper firstly revealed the variation rules of constitutions of GFs, which may provide a reference for the harvest and making rational application.

Characterizing sources and ozone formations of summertime volatile organic compounds observed in a medium-sized city in Yangtze River Delta region

Volatile organic compounds (VOCs) emitted from various sources into atmosphere could cause serious O3 pollution in urban areas. Although characterizations of ambient VOCs have been extensively studied in megacities, they are scarcely investigated in medium/small-sized cities, which could present different pollution characterizations due to the factors like emission sources and populations. Herein, field campaigns were conducted concurrently at six sites in a medium-sized city of Yangtze River Delta region to determine ambient levels, O3 formations and source contributions of summertime VOCs. During the observation period, the total VOC (TVOCs) mixing ratios ranged from 27.10 ± 3.35 to 39.09 ± 10.84 ppb at six sites. The ozone formation potential (OFP) results showed that alkenes, aromatics and oxygenated VOCs (OVOCs) were dominant contributors, together sharing 81.4% of total calculated OFPs. Ethene ranked the largest OFP contributor at all six sites. A high VOC site, KC, was selected as a case to detailed analyze diurnal variations of VOCs and its relationship with O3. Consequently, diurnal patterns varied with VOC groups, and TVOC concentrations were lowest during strong photochemical period (15:00–18:00 p.m.), opposite to the O3 peak. VOCs/NOx ratios and observation-based model (OBM) analysis revealed that O3 formation sensitivity was primarily in transition regime in summertime and that the reduction of VOCs rather than NOX would be more efficient to suppress O3 peak at KC during pollution episode. Additionally, source apportionment conducted with positive matrix factorization (PMF) indicated that industrial emission (29.2%–51.7%) and gasoline exhaust (22.4%–41.1%) were major sources for VOCs at all six sites, and that VOCs from industrial emissions and gasoline exhaust were the key precursors for ozone formation. Our results shed light on the importance of alkenes, aromatics and OVOCs in forming O3 and propose that preferentially reducing VOCs especially those from industrial emission and gasoline exhaust would benefit alleviating O3 pollution.

Salivary Volatile Organic Compound Analysis: An Optimised Methodology and Longitudinal Assessment Using Direct Injection Mass Spectrometry

Analysis of salivary volatile organic compounds (VOCs) may offer a novel noninvasive modality for disease detection. This study aims to optimise saliva headspace VOC analysis and assess longitudinal variation of salivary VOCs. Whole saliva from healthy participants was acquired in order to assess four methodological parameters: saliva collection, volume, dilution, and acidification. Saliva VOCs were analysed using untargeted proton transfer reaction time-of-flight mass spectrometry. Using the optimised method, five saliva samples collected over 3 weeks assessed the longitudinal VOC variability and reproducibility with targeted selected ion flow tube-mass spectrometry analysis. The method of saliva collection influenced VOC detection and was a source of contamination. An amount of 500 µL of whole saliva by passive drool yielded optimal VOCs. Longitudinal variation was negligible with target short chain fatty acids and aldehydes. However, certain compounds showed variability suggesting the influence of potential exogenous factors. Overall, there was an acceptable range of inter- and intraindividual VOC variability. Standardisation with morning sampling after a 6 h fast is recommended demonstrating minimal intersubject variability. Future studies should seek to establish salivary VOC levels in healthy and diseased populations.

Volatiles Emitted by Three Genovese Basil Cultivars in Different Growing Systems and Successive Harvests

The Genovese basil (Ocimum basilicum L.) is the essential ingredient in “pesto” sauce, and it has always had ample use in Mediterranean gastronomy. This horticultural type of basil is grown in the open field and harvested more than once during its cultivation cycle, but in recent decades it is increasingly grown using alternative cultivation methods (e.g., soilless cultivation) that guarantee higher and more uniform production. The dataset presented in this contribution refers to the analysis of the aroma profile by solid-phase microextraction and gas chromatography coupled with a mass spectrometer, of three different cultivars of Genovese basil (Aroma 2, Eleonora, and Italiano Classico) grown in the open field or floating raft system in two successive harvests. The data are a record of the variability of volatile organic compounds due to key agronomic factors, such as the genotype, the cultivation method, and the cut. They may be of interest for those concerned about the impact of different technical factors on the aroma and flavor of basil plants.