Study Of Volatile Organic Compounds Research Articles

A longitudinal study of volatile organic compounds from cooking under ventilation and purification intervention: Health risk assessment and odor nuisance control

Cooking oil fumes (COFs) expose occupants to hazardous air pollutants and nuisance odors, hence the real controlling effects of different intervention methods deserve to be explored. This longitudinal study conducted year-round field measurements in 10 apartments to explore the synergistic effects of dual ventilation and purification interventions on the exposure level, odor intensity, and health risk control of gaseous organic compounds during cooking. Gas chromatography-mass spectrometry (GC‒MS) and high performance liquid chromatography (HPLC) were used for quantification of volatile organic compounds (VOCs) and carbonyls. A total of 59 VOCs were detected during cooking, and the average ΣVOC concentrations in summer, the transition seasons, and winter were 483.16 μg/m3, 233.97 μg/m3, and 282.82 μg/m3, respectively, and the proportion of aldehydes was approximately 50 %. The small temperature differences between the indoors and outdoors led to a 24 % reduction in the effective air changes per hour (ACH) in the summer compared with that in other seasons. The average estimated carcinogenic risks of formaldehyde, acetaldehyde and benzene were 9.20 × 10−5, 1.11 × 10−5, and 6.05 × 10−6, respectively, for daily cooking conditions. It is difficult to guarantee a healthy cooking environment by mechanical ventilation alone. The inhalation carcinogenic risk of these 3 hazardous VOCs was reduced by approximately 130.9 % under air purification intervention but was still greater than 1E-6. The noncarcinogenic risk of acrolein under the different intervention modes ranged from 69.8 to 84.9. Moreover, acetaldehyde and hexanal were found to be the key odorants in kitchen. When the effective exhaust air rate was greater than 12 m3/min with air purifier in operation, the average inhalation health risk was 1.05–1.78 times that before cooking, and more than half of the users would not smell obvious odors during the cooking process. This study quantifies the effectiveness of the synergetic control strategy of independent purification modules combine with kitchen mechanical ventilation, with a view to implementing a healthy & comfortable living environment.

Study of Volatile Organic Compounds in Emission from Bottom Sediments of Three Lakes with Impact of Anthropopression Using the Proton Transfer Reaction Mass Spectrometry

Studies of volatile organic compounds (VOCs) emitted from the bottom sediments of three Pomeranian lakes in Poland: Łazienkowskie, Rychnowskie, and Jeleń were conducted. All three lakes are subject to anthropogenic pressure but to varying degrees. In 2021, bottom sediment samples were taken from the lakes studied and an analysis of the emission of 20 volatile organic compounds was carried out using a proton transfer reaction mass spectrophotometer (PTR-MS). Concentrations in emissions from the bottom sediments of VOCs with the following mass–charge ratio (m/z) were analyzed: 57, 61, 63, 69, 75, 81, 83, 85, 87, 95, 97, 99, 101, 109, 111, 127, 129, 137, 149, and 157. The obtained data were analyzed by performing statistical tests and multivariate cluster and PCA analysis. The analysis shows that the lowest concentrations of VOCs were observed from bottom sediments in Lake Jeleń, which is subject to the lowest anthropopressure among the studied lakes. The analysis shows that the lowest concentrations of VOCs were observed from bottom sediments in Lake Jeleń, which is subject to lower anthropopressure among the studied lakes. With the help of cluster analysis, it was possible to collect data on the VOC concentrations into clusters, which resulted in demonstrating similarities between Łazienkowskie and Rychnowskie lakes—lakes connected by an isthmus, and the different characteristics of Lake Jeleń. PCA analysis leads to similar observations. The tested m/z VOCs can be identified using additional analytical methods.

Health risk assessment of volatile organic compounds (VOCs) in a refinery in the southwest of Iran using SQRA method.

Oil industries, such as oil refineries, are important sources of volatile organic compound production. These compounds have significant health effects on human health. In this study, a health risk assessment is carried out on volatile organic compounds (VOCs) in the recovery oil plant (ROP) unit of a refinery in southwest Iran. It was performed using the SQRA1 method including respiratory risk for chronic daily intake (CDI) of VOCs and cancer risk and non-cancer risk indices. Five locations in the area of oil effluents and five locations in the refinery area (control samples) were considered for evaluation. The sampling was done according to the standard NIOSH-1501 and SKC pumps. The gas chromatography/flame ionization detector (GC/FID) method was used to extract VOCs. The cancer slope factor (CSF) and respiratory reference dose (RFC) were calculated in addition to the respiratory risk (CDI). The end result shows that a significant difference was observed between the concentrations of volatile organic compounds in the two groups of air (P < 0.05). The SQRA risk assessment showed that the risk levels of benzene for workers in the pit area were very high (4–5). Health hazard levels were also evaluated as high levels for toluene (2–4) and moderate levels for xylene and paraxylene (1–3). The cancer risk assessment of volatile organic compounds recorded the highest level of cancer risk for benzene in the range of petroleum effluents (>1). Also, a non-cancer risk (HQ) assessment revealed that benzene had a significant health risk in the range of oil pits (2–3). Based on the results, petroleum industries, including refineries, should conduct health risk assessment studies of volatile organic compounds. The units that are directly related to the high level of VOCs should be considered sensitive groups, and their employees should be under special management to reduce the level of exposure to these compounds and other hazardous compounds.

Study of Volatile Organic Compounds of Two Table Grapes (cv. Italia and Bronx Seedless) along Ripening in Vines Established in the Aegean Region (Turkey).

(1) Background: Italia is a seeded grape variety widely cultivated in the Aegean Region in Turkey, whereas Bronx Seedless is a seedless grape variety, preferred by consumers due to its pink berries and interesting flavor. The goal was to study the volatile compounds of these table grapes throughout berry ripeness. (2) Methods: The volatile compounds were analyzed by GC-MS in six different phenological stages (3) Results: Bronx Seedless grapes presented a higher content of seven terpenes, three aldehydes, one fatty acid, three alcohols, one C6 compound, total aldehydes and total alcohols, and a lower content of eleven terpenes, one fatty acid, four esters, one alcohol, four C6 compounds and its total content than Italia table grapes. The concentration of most of the volatile compounds analyzed increased from “begin of berry touch” to “berries ripe for harvest” stages. Terpenes content in both varieties at harvest was lower than 1.0 mg L−1. β-ionone presented the highest odor activity value (OAV) in both varieties. Bronx Seedless grapes presented higher OAV for (Z)-3-hexenal and cedrol, and lower hexanal to (E)-2-hexenal ratio than Italia grapes. (4) Conclusions: Both varieties could be classified as neutral aromatical varieties and it is probable that to achieve a better aromatic quality, Bronx Seedless should be harvested later than Italia.

A study on propane depletion by surface dielectric barrier discharges

A study of volatile organic compounds (VOCs) depletion using a plasma system based on a surface dielectric barrier discharge SDBD has been carried out. The analysis of the temporal evolution of VOCs permitted to estimate the corresponding dissociation rates as a function of the relevant parameters and to demonstrate the ability of SDBD in the abatement of large VOC concentrations up to 9,300 ppm. The depletion rate increases as a function of plasma power and concentration for propane, pentane and acetone. The efficiency evaluated as quantity of propane per unit of energy takes values between 2 and 7.5 g/kWh. A comparison between propane, pentane and acetone, exploits that propane efficiency is higher than of those pentane and acetone. On the basis of this study SDBD is a promising plasma source for VOCs abatement at high concentrations.

A comprehensive study of volatile organic compounds from the actual emission of Chinese cooking.

China's current perspective for big cities was filled with great population, great number of restaurants, growing gaseous pollutants, and great pollution. Volatile organic compounds (VOCs) were the main components of catering industry gaseous pollutants. In this study, we collected and analyzed VOCs from home cooking (HC), Sichuan and Hunan cuisine (S&H), Shandong cuisine (SD), Anhui cuisine (AH), Beijing cuisine (BJ), and barbecue (BBQ). The result showed that BBQ gave the highest VOC concentration (6287.61 μg m-3), followed by HC (1806.11 ± 2401.85 μg m-3), SD (2238.55 ± 2413.53 μg m-3), AH (1745.89 μg m-3), S&H (1373.58 ± 1457.45 μg m-3), and BJ (288.81 μg m-3). The abundance of alkane was higher among BBQ, Anhui cuisine, and HC with the proportion from 33 to 71%. SD contained higher halohydrocarbons proportion (33%). BJ was characterized by high-oxygenated volatile organic compounds proportion (50%). The ozone formation potential (OFP) of BBQ was much greater than other cuisines. The degree of stench pollution from cooking VOCs of HC was 17.51 ± 16.95, followed by S&H (15.77 ± 16.85), SD (15.12 ± 14.17), AH (16.29), BBQ (2.58), and BJ (1.81). Benzene had the highest life cancer risk (LCR) in SD (2.11×10-5 ± 3.12×10-5), following HC (4.50×10-6 ± 3.83×10-6) and S&H (4.08×10-6 ± 4.49×10-6). Acrolein had a high hazard index (HI) in HC (789.81 ± 768.77), following AH (728.78), S&H (689.89 ± 776.07), SD (664.29 ± 648.77), BBQ (65.93), and BJ (62.84).

Multi-component ppm level adsorption of VOCs on the ZIF-8 and UiO-66 MOFs: Breakthrough analysis with selected ion flow tube mass spectrometry

In the recent years, Metal-Organic Frameworks (MOFs) emerged at a high and increasing pace and have been widely studied in the frame of applications such as gas storage, mixtures separation and heterogeneous catalysis. Nevertheless, the study of Volatile Organic Compounds (VOCs) adsorption on Metal-Organic Frameworks (MOFs) is still lagging behind compared to zeolites and other conventional adsorbent materials. The selection of an optimal adsorbent for the trapping of environmental VOCs, only present at ppmv levels, strongly relies on its low-coverage adsorption properties, which are often challenging to evaluate through conventional experimental methods. In this work, adsorption of VOCs on Metal-Organic Frameworks (MOFs) was investigated using a novel experimental methodology to measure breakthrough adsorption at ultra-low concentration amid 4–12 ppmv. Multicomponent breakthrough curves of a mixture of ethanol, ethyl acetate, 2-butanone and 2,3-butanedione were measured in anhydrous condition at 25 °C and 6 °C on two highly stable MOFs, namely ZIF-8 and UiO-66, using Selected Ions Flow Tube Mass Spectrometry (SIFT-MS) for monitoring. Furthermore, adsorption experiments were carried out at 6 °C and 90% RH to evaluate the effect of humidity on the VOCs uptake onto the selected MOFs. While ZIF-8 adsorption capacities were ranging between 0.3 and 1.8 mg g−1, UiO-66 exhibited significantly higher uptake towards the target compounds, with a concentration comprised between 1.8 and 51.9 mg g−1. Despite this relevant discrepancy, both MOFs shared a pronounced preferentiality towards the most hydrophobic molecules. Very large enrichment factors (between 100 and 5000) showed that these materials can increase many-fold the adsorbed phase over gas phase concentration, even when present at ppmv levels, which is crucial for the good operation of sensors based on affinity layers. Furthermore, VOCs adsorption on UiO-66 unveils intricate competitive mechanisms, leading to multiple steps of ethanol displacement while simultaneous adsorption of ethyl acetate, 2-butanon and 2,3-butanedione occurs.

Diagnosis of Clostridioides difficile infection by analysis of volatile organic compounds in breath, plasma, and stool: A cross-sectional proof-of-concept study.

Clostridioides difficile infection (CDI) is an important infectious cause of antibiotic-associated diarrhea, with significant morbidity and mortality. Current diagnostic algorithms are based on identifying toxin by enzyme immunoassay (EIA) and toxin gene by real-time polymerase chain reaction (PCR) in patients with diarrhea. EIA's sensitivity is poor, and PCR, although highly sensitive and specific, cannot differentiate infection from colonization. An ideal test that incorporates microbial factors, host factors, and host-microbe interaction might characterize true infection, and assess prognosis and recurrence. The study of volatile organic compounds (VOCs) has the potential to be an ideal diagnostic test. The presence of VOCs accounts for the characteristic odor of stool in CDI but their presence in breath and plasma has not been studied yet. A cross-sectional proof-of-concept study analyzing VOCs using selected ion flow tube mass spectrometry (SIFT-MS) was done on breath, stool, and plasma of patients with clinical features and positive PCR for CDI (cases) and compared with patients with clinical features but a negative PCR (control). Our results showed that VOC patterns in breath, stool, and plasma, had good accuracy [area under the receiver operating characteristic curve (ROC) 93%, 86%, and 91%, respectively] for identifying patients with CDI.

Dependence of thermal desorption method for profiling volatile organic compound (VOC) emissions from soil

The study of volatile organic compounds (VOCs) in soil and other complex substrates is a rapidly developing field. VOCs in soils originate from a wide variety of biological sources; bacterial, fungal, mesofaunal, and plant. They are vital to inter- and intra-species interaction and soil health, and therefore offer a potential reactive, functional diagnostic tool to determine soil quality. The standard methodology for untargeted VOC profiling in environmental samples has been headspace solid phase microextraction (HS-SPME), avoiding the need for solvent extraction procedures used in many biological soil tests. However, this technique can suffer from a lack of sensitivity due to competition between individual VOCs on the solid phases used for VOC recovery. Other common techniques used to monitor the VOC fingerprints from soils include high capacity sorptive extraction (HCSE). This study presents a novel SPME-trap-enrichment method using an automated, cryogen-free, focusing and pre-concentration trap method to reduce phase competition and increase sensitivity of analysis. This method was evaluated against single-SPME-trap and HCSE methods for sensitivity and number of compounds identified using a range of induced soil qualities (good, medium and poor). Results showed that SPME-trap-enrichment was able to identify 71% and 7% more compounds than single-SPME-trap and HCSE, respectively, using a software-based data processing approach, as well as increased total peak areas. The VOC profile was substantially affected by the extraction method used. The samples within the ‘poor’ treatment produced a larger number of aromatic, carboxylic acid and sulphur containing compound groups, while the ‘good’ and ‘medium’ groups were largely characterised by ketones and aldehydes. The potential ecological significance of the compounds identified were also explored. Of those tested, SPME-trap-enrichment represented the most robust and sensitive technique for VOC analysis, offering the potential to better elucidate the multifaceted interactions of VOCs within plant-microbial-soil systems.

Characterization of Volatile Organic Compounds in ‘Rossa di Tropea’ Onion by Means of Headspace Solid-Phase Microextraction Gas Chromatography–Mass Spectrometry (HS/SPME GC–MS) and Sensory Analysis

Background: Plant viral infections induce changes in the host plant, which can potentially impact composition, organoleptic properties, and storability characteristics of plant products. In particular, onion odor and flavor are determined mainly by volatile organic compounds, and changes upon infection with onion yellow dwarf virus may deeply influence these characters. Methods: A time-course study of volatile organic compounds in onion yellow dwarf virus-infected versus healthy ‘Rossa di Tropea’ onion bulbs was performed using headspace solid-phase microextraction gas chromatography–mass spectrometry; sensory analysis performed at marketability stage of onion production was used to correlate such changes to the taste characteristics perceived by consumers. Results: Volatile organic compounds regulated in infection conditions were identified, mainly belonging to mono- and poly-sulfides classes. The most abundant compounds in the analyzed samples were propyl disulfide, allyl-isopropyl disulfide, and propanethiol; significantly different concentrations were observed for 7 out of 11 VOCs in virus-infected compared to healthy bulbs. Statistical analysis based on a partial least squares discriminant analysis model and hierarchical cluster analysis allowed us to cluster samples based on phytosanitary status and storage time and to identify the most responsible compounds for such classification. Conclusions: Onion yellow dwarf virus infection induces changes in volatile organic compounds in onion during storage. The impact of such regulated compounds on ‘Rossa di Tropea’ onion odor and flavor and correlation with sensory analysis are discussed.

Unraveling the Extracellular Metabolism of Immortalized Hippocampal Neurons Under Normal Growth Conditions.

Metabolomic profiling of cell lines has shown many potential applications and advantages compared to animal models and human subjects, and an accurate cellular metabolite analysis is critical to understanding both the intracellular and extracellular environments in cell culture. This study provides a fast protocol to investigate in vitro metabolites of immortalized hippocampal neurons HN9.10e with minimal perturbation of the cell system using a targeted approach. HN9.10e neurons represent a reliable model of one of the most vulnerable regions of the central nervous system. Here, the assessment of their extracellular metabolic profile was performed by studying the cell culture medium before and after cell growth under standard conditions. The targeted analysis was performed by a direct, easy, high-throughput reversed-phase liquid chromatography with diode array detector (RP-HPLC-DAD) method and by headspace solid-phase microextraction–gas chromatography–mass spectrometry (HS-SPME-GC-MS) for the study of volatile organic compounds (VOCs). The analysis of six different batches of cells has allowed to investigate the metabolic reproducibility of neuronal cells and to describe the metabolic “starting” conditions that are mandatory for a well-grounded interpretation of the results of any following cellular treatment. An accurate study of the metabolic profile of the HN9.10e cell line has never been performed before, and it could represent a quality parameter before any other targeting assay or further exploration.

Volatile compounds reveal age: a study of volatile organic compounds released by Chrysomya rufifacies immatures.

Age determination of insects collected from vertebrate remains is an essential step in estimating time since colonization as related to the post-mortem interval. Long-established methods for making such estimates rely on determining age related to stage of development at the time of collection in relation to conditions experienced. However, such estimates are based on the completion of a stage of development. Methods allowing for more precise estimates of age (i.e., within a stage of development) are sorely needed. This study examined the potential of volatile organic compounds emitted by blow fly, Ch. rufifacies (Macquart), immatures to determine stage of development, which could potentially be used to estimate the age. Volatile organic compounds (VOCs) from the larval and pupal stages of Ch. rufifacies were collected by headspace solid-phase micro-extraction followed by gas chromatography-mass spectrometry (GC-MS). Analyses indicated 37 compounds shift quantitatively, as well as qualitatively, as the larvae and pupae age. Furthermore, compounds, such as 2-ethyl-1-hexanol, phenol, butanoic acid, hexadecanoic acid, octadecanoic acid, 2-methyl propanamide, and 2-methyl butanoic acid, serve as indicator compounds of specific stages within Ch. rufifacies development. This information could be important to determine if these compounds can be used in the field to predict the presence of certain developmental stages, in order to determine the potential of using volatile markers to estimate time of colonization.

In vitro study of volatile organic compounds produced by the mutualistic fungus of leaf-cutter ants and the antagonist Escovopsis

Occasionally, the symbiosis of the fungus-growing ants is threatened by ascomycetous fungi mainly by species in the genus Escovopsis. GC-MS analyses were conducted to investigate the volatile organic compounds (VOCs) produced by Escovopsis and the mutualistic Leucocoprinus gongylophorus during dual-culture. In dual-culture Escovopsis' development was faster. Hexadecanoic acid (palmitic acid) and VOCs such as the sesquiterpenes α-cedrene, β-cedrene, thujopsene, α-santalene, α-selinene, cedrene, (+)-cuparene and δ-cadinene secreted by L. gongylophorus may be responsible for speeding the germination of Escovopsis’ conidia as well as for the faster hyphal development. Based on this study and available literature we infer that the relationship between these two species is mediated by hyphal interference (HI). Additional studies should unveil if the biological activity of some compounds produced by these fungi is attractive, repellent or toxic to the ants and inhibitory to other fungi.

The year-round variations of VOC mixing ratios and their sources in Kuytun City (northwestern China), near oilfields

Few studies of volatile organic compounds (VOCs) near oilfields have been performed. Continuous online measurements of 102 VOC species were made for 1 year in Kuytun city (northwestern China), near the Karamay and Tuha oilfields. The total VOC (TVOC) concentrations were high (mean 45.6 ppbv, range 21.9–86.1 ppbv). Alkanes, alkenes, nitrogen- and oxygen-containing VOCs, acetylene, halohydrocarbons, and aromatic compounds contributed 46.6%, 23.7%, 12.9%, 11.8%, 11.4%, and 5.3%, respectively, of TVOC concentrations. TVOC concentration varied markedly by season, and decreased in the order winter, spring, summer, fall. The dominant 11 VOCs (in decreasing concentration order) were acetylene, ethane, propane, carbon tetrachloride, isopentane, ethylene, n-butane, acetone, isobutane, methyl tert-butyl ether, and n-pentane, which contributed 68% of TVOC concentrations. The acetone, acetylene, chloroethylene, ethane, ethylene and benzene concentrations were higher on more-polluted than less-polluted days but the n-butane, carbon tetrachloride, isobutane, isopentane, methyl tert-butyl ether, n-pentane, and propane concentrations were always lower on more-polluted than less-polluted days. A positive matrix factorization model indicated that acetylene was the main VOC emitted through combustion during the heating period but acetylene, halohydrocarbons, and oxygen-containing VOCs emitted by industrial plants were dominant during the non-heating period. Carbon tetrachloride, methyl tert-butyl ether, and propane were the dominant VOCs emitted by petrochemical plants, gasoline-powered vehicles and liquefied petroleum gas, respectively. Air mass back trajectories (72 h) indicated that VOCs were mainly supplied by local and regional sources but clean air from Kazakhstan decreased VOC concentrations when wind came from the northwest at wind speeds higher than scale 5.

Comparison of volatile organic compound profiles in exhaled breath versus plasma headspace in different diseases

Breath analysis is the study of volatile organic compounds (VOC’s) in exhaled breath. This analysis provides information on the body’s condition. In this study we investigated the relationship between 22 VOC’s detected in exhaled breath and plasma headspace using a selected ion flow tube mass spectrometer (SYFT-MS). We compared pairs of exhaled breath and plasma samples from patients with pulmonary hypertension inflammatory bowel disease (IBD), and IBD patients after J-pouch surgery (pouch group). Half of the measured VOC’s from exhaled breath were significantly associated with the VOC’s from plasma headspace. Interestingly, six breath VOC’s (trimethyl amine (FDR p = 0.02), hydrogen sulfide (FDR p = 7.64 × 10−30), ethanol (FDR p = 1.56 × 10−4), dimethyl sulfide (FDR p = 5.70 × 10−19), benzene (FDR p = 8.40 × 10−27), and acetaldehyde (FDR p = 4.27 × 10−17)) and two plasma headspace VOC’s (1-Octene (FDR p = 0.02) and 2-propanol (FDR p = 2.47 × 10−9)) were able to differentiate between the three groups. Breath and plasma headspace share a similar signature with significant association in half of the measured VOCs. The disease discriminatory capacity of breath and plasma headspace appear to be different. Therefore, using the VOC’s print from both breath and plasma headspace may better help diagnose patients.

Low-cost FloPump for regulated air sampling of volatile organic compounds.

PremiseWe present a low‐cost, battery‐operated, portable pump, “FloPump,” which allows regulated air sampling for the study of volatile organic compounds (VOCs). VOCs are routinely investigated in applications such as atmospheric chemistry, agriculture, and fragrance biology.Methods and ResultsWe compared the performance of FloPump with the Supelco pump in collecting VOCs using two test samples: guava fruit (Psidium guajava) and a perfume. The sampling and identification of volatiles was carried out using a dynamic headspace sampling method followed by gas chromatography–mass spectrometry. We show that the sampling efficiency of FloPump is comparable to the commercial pump, and at an affordable cost of ~US$115 (~86% cheaper), it provides a viable option for researchers interested in sampling volatiles on a constrained budget.ConclusionsAccurate air sampling is critical for the study of VOCs. We propose that FloPump will make air sampling more affordable, thus encouraging studies of VOCs.

Characteristics of Volatile Organic Compounds in Nanjing and Suzhou, Two Urban Sites in the Yangtze River Delta, China.

A field measurement study of volatile organic compounds (VOCs) was performed in January 2015 in the urban areas of two of the most important cities of the Yangtze River Delta: Nanjing and Suzhou. The objectives of this study included comparing the characteristics of VOC concentrations, comparing the impacts of emissions on VOCs, using species ratios to assess air mass age, and evaluating ozone formation potential (OFP) and secondary organic aerosol formation potential (SOAP) in air masses. The VOC concentrations in Nanjing (34.6 ± 5.8 ppbv) were higher than those of Suzhou (28.1 ± 5.6 ppbv). The most abundant VOC measured was ethane (6.6 ppbv in Nanjing and 3.6 ppbv in Suzhou). Relevant analysis shows that motor vehicle emissions in Suzhou were dominant, whereas industrial emissions in Nanjing also contributed to VOCs. During rush hour, the VOC concentrations in Nanjing were the highest (35.3 ppbv). The T/B ratio (0.92-1.79) for the two sites was observed to be relatively low in the other studied cities, indicating the source impact of traffic emissions in the two sites. Indicators X/B (0.26-0.39) and X/E (0.33-0.66) also confirmed an aging air mass was transported at the two sampling sites. According to principal component factor analysis results, vehicle emissions (44.8% in Nanjing and 30.6% in Suzhou) were the most important contribution to the two sites. Industrial sites were not only likely to experience industrial emissions but were affected by traffic emissions. Using the OFP method, both sites showed the largest percentage of alkenes (59.9% in Nanjing and 62.0% in Suzhou). When comparing SOAP, both sites showed an absolute majority of aromatics (97.6% in Nanjing and 98.3% in Suzhou). To control the formation of O3 and SOA in the two sites, it is necessary to reduce the concentration of alkenes and aromatics, respectively. By CPF analysis, pollutants transported from the SE and NE have significant effects on the Nanjing site. In the Suzhou, roads and industrial parks in the SE and S of Suzhou have significant impacts on the site.

The smell of longevity: a combination of Volatile Organic Compounds (VOCs) can discriminate centenarians and their offspring from age-matched subjects and young controls.

Aging is characterized by dynamic changes at metabolic level that lead to modifications in the composition of the metabolome. Since the identification of biomarkers that can discriminate people of different age and health status has recently attracted a great interest, we wondered whether age-specific changes in the metabolome could be identified and serve as new and informative biomarkers of aging and longevity. In the last few years, a specific branch of metabonomics devoted to the study of volatile organic compounds (VOCs) has been developed. To date, little is known about the profile of specific VOCs in healthy aging and longevity in humans; therefore, we investigated the profile of VOCs in both urine and feces samples from 73 volunteers of different age including centenarians that represent useful "super-controls" to identify potential biomarkers of successful aging and footprints of longevity. To this purpose, we performed a discriminant analysis by which we were able to identify specific profiles of urinary and fecal VOCs. Such profiles can discriminate different age groups, from young to centenarians, and, even more interesting, centenarians' offspring from age-matched controls. Moreover, we were able to identify VOCs that are specific for the couples "centenarians - offspring" or the trios "centenarians - offspring - spouse," suggesting the possible existence of a familiar component also for VOCs profile.

An eight-city study of volatile organic compounds in Chinese residences: Compounds, concentrations, and characteristics

This study conducted on-site measurements of indoor volatile organic compounds (VOCs) in 251 occupied residences in China, with multiple visits throughout a whole year. Over 1000 samples were collected for measurement of VOCs in 8 cities, covering different climate regions. Overall, the concentrations of total VOCs (TVOCs) in occupied residences are in the range of 104–1151 μg/m3, with 20% of the samples over the Chinese standard of 600 μg/m3. A higher concentration was evident in the summer (mean = 705 μg/m3) compared to other seasons, especially winter (mean = 289 μg/m3). The TVOCs of residences in areas with central heating (severe cold regions and cold regions) are generally higher than those in areas without central heating. In winter, temperature was the dominant factor, whereas in summer, the building infiltration rate was the key factor influencing the indoor TVOC levels. The TVOCs concentration was also found to be directly proportional to the city economy level. Twenty-nine VOC species with a detection frequency higher than 40% were identified in all samples. Toluene is the most common VOC, with the highest detection rate (90%). The median concentration for a single VOC was between 1 and 14 μg/m3. Aldehydes were found to be the largest contributors to total VOCs in the Chinese residential buildings (mass proportion 22%), followed by benzene series (20%), alkenes (18%), and alkanes (15%). Aldehydes, especially long-chain saturated carbonyls, are likely to be the characteristic VOCs in the Chinese dwellings, with Chinese cooking as the major emission source. In addition, n-butane/i-butane showed maximum concentration in some residences (approximately 105 μg/m3 higher than other VOCs) owing to cooking fuel.

Adsorption studies of volatile organic compounds on germanene nanotube emitted from banana fruit for quality assessment – A density functional application

We report the density functional application of adsorption behavior of volatile organic compounds (VOCs) emitted from the different ripening stages of banana fruit on germanene nanotube (GNT). Initially, the geometric structural stability of GNT is ascertained and the tunable electronic properties lead to the application of GNT as a base material in order to know the adsorption features of VOCs. We further explored the adsorption behavior of VOCs on to GNT through charge transfer, adsorption energy and band gap variation. The energy band structure and density of states (DOS) spectrum shows a noteworthy variation upon adsorption of different VOCs on to the GNT. Also, the electron density variation is noticed upon adsorption of VOCs emitted from the banana on to the GNT base material. Besides, the difference in the energy band gap of GNT upon emission of VOCs from banana leads to the use of GNT as a chemiresistor to assess fruit freshness with adsorption studies. Moreover, we suggest the use of GNT to discriminate the fruit freshness of banana through the adsorption process of VOCs on to GNT.