Predominant Volatile Organic Compounds Research Articles

Database of emission factors of volatile organic compound (VOC) species in motor vehicle exhaust in China

The synergistic strategy for fine particulate matter (PM2.5) and O3 pollution prevention and control has emerged as a pivotal approach in combating air pollution. Volatile organic compounds (VOCs) serve as crucial precursors to both O3 and secondary organic aerosols (SOAs), with motor vehicles representing one of their significant sources. In this study, a standard for establishing a database of VOC species emission factors for motor vehicles was developed, and a database containing 134 VOC species was constructed through field tests and literature surveys. The VOC emissions of light-duty gasoline passenger vehicles (LDGPVs) comprised primarily alkanes and aromatics. The VOC emissions of light-duty diesel trucks (LDDTs) comprised mostly alkanes. Regarding low-speed trucks, 3-wheel vehicles, medium-duty diesel trucks (MDDTs) and heavy-duty diesel trucks (HDDTs), their VOC emissions comprised mainly oxygenated volatile organic compounds (OVOCs). The update of emission standards resulted in a reduction in VOC species emission factors while altering the composition of VOCs. Attention should be directed toward isopentane, benzene and dichloromethane emitted by LDGPVs, dodecane, undecane, ethene and propene emitted by LDDTs, and acetaldehyde emitted by HDDTs. VOC species originating from LDGPVs were more dispersed than those originating from LDDTs and HDDTs. In addition, variations in VOC species were observed among motor vehicles with different fuel types. Toluene, ethene, benzene, m,p-xylene, isopentane, hexanal, ethyne and 1,2,4-trimethylbenzene were the predominant VOC species emitted by gasoline vehicles. Diesel vehicles emitted mainly dodecane, formaldehyde, propene, undecane, acetaldehyde, ethene, decane and benzene. The results could enhance our comprehension of the emission characteristics of VOC species originating from motor vehicles and provide data support and a scientific foundation for achieving synergistic PM2.5 and O3 pollution prevention and control.

Volatile Organic Compounds in Disposable Diapers and Baby Wipes in the US: A Survey of Products and Health Risks.

Many thousands of diapers are worn by young children and the elderly, who have thin and sensitive skin that is highly vulnerable to chemicals, including volatile organic compounds (VOCs) that may be ingredients of these products or present as inadvertent or residual components. The levels and potential health risks of VOCs in diapers have not been reported previously. In this study, we collected 31 disposable hygiene products in the US market based on market share and analyzed 98 target VOCs using purge and trap sampling and thermal desorption/gas chromatography/mass spectrometer analysis. Exposures and risks were modeled using reasonable upper level exposure scenarios. Adult diapers contained the highest total target VOC concentration (median level of 23.5 μg/g), and the predominant VOCs were alkanes. In some diapers, the estimated noncancer risk from these VOCs was sometimes very large (hazard quotient of 1609) due to n-heptane. Baby diapers contained several known or suspected carcinogens, including benzene and 1,4-dioxane, and the lifetime cancer risk from some diapers approached 1 per million under a worst-case scenario. Store-brand products had higher levels of VOCs than generic brands, and products labeled "organic" or "for sensitive skin" did not necessarily have lower levels. Our results show that toxic VOCs were found in all tested disposable diapers and wipes at trace levels, and risks from using some diapers in high use exposure scenarios are high enough to warrant additional attention and possibly corrective measures. We recommend eliminating and monitoring toxic ingredients and disclosing all chemicals that may be in these products.

Salt-Induced Stress Impacts the Phytochemical Composition and Aromatic Profile of Three Types of Basil in a Genotype-Dependent Mode.

Basil (Ocimum basilicum L.) is among the most widely used aromatic plants of Lamiaceae, often grown in areas where salinity is an adverse factor. Most studies on the effect of salinity on basil focused on the influence of salt stress on productive traits, while few reported on how it affects the phytochemical composition and the aroma profile. Three basil cultivars (Dark Opal, Italiano Classico, and Purple Ruffles) were grown hydroponically for 34 days with two nutrient solutions that differed in NaCl concentration [no NaCl (Control) and 60 mM NaCl]. Yield, secondary metabolite concentration (β-carotene and lutein), antioxidant activity [1,1-diphenyl-2-picrylhydrazyl (DPPH) and ferric reduction antioxidant power (FRAP)], and aroma profile based on composition of volatile organic compounds (VOCs) were appraised in response to salinity applications. Salt stress significantly reduced fresh yield in Italiano Classico and Dark Opal by 43.34 and 31.69%, respectively, while no effect was observed in Purple Ruffles. Furthermore, the salt-stress treatment increased β-carotene and lutein concentrations, DPPH, and FRAP activities, and the total nitrogen content of the latter cultivar. CG-MS analysis revealed significant differences in VOCs composition of the basil cultivars, with Italiano Classico and Dark Opal characterized by the predominance of linalool (average 37.52%), which, however, was negatively affected by salinity. In Purple Ruffles, the predominant VOC compound, estragole (79.50%), was not affected by the deleterious effects of NaCl-induced stress.

The Use of Carbon Dioxide as a Green Approach to Recover Bioactive Compounds from Spent Coffee Grounds.

Spent coffee grounds (SCG) contain bioactive compounds. In this work, given the increasing demand to valorize waste and use green technologies, SCG were submitted to extraction by carbon dioxide (CO2) in supercritical and liquid conditions. The extraction parameters were varied to obtain the maximum yield with the maximum antioxidant activity. The use of supercritical and liquid CO2 with 5% ethanol for 1 h provided yields (15 and 16%, respectively) comparable to those obtained by control methods for 5 h and extracts with high total polyphenolic contents (970 and 857 mg GAE/100 g oil, respectively). It also provided extracts with DPPH (3089 and 3136 μmol TE/100 g oil, respectively) and FRAP (4383 and 4324 μmol TE/100 g oil, respectively) antioxidant activity levels higher than those of hexane extracts (372 and 2758 μmol TE/100 g oil, respectively) and comparable to those of ethanol (3492 and 4408 μmol TE/100 g oil, respectively). The SCG extracts exhibited linoleic, palmitic, oleic, and stearic acids (predominant fatty acids) and furans and phenols (predominant volatile organic compounds). They were also characterized by caffeine and individual phenolic acids (chlorogenic, caffeic, ferulic, and 3,4-dihydroxybenzoic acids) with well-known antioxidant and antimicrobial properties; therefore, they could be used in the cosmetic, pharmaceutical, and food sectors.

Biological Control Efficacy of Indigenous Antagonistic Bacteria Isolated from the Rhizosphere of Cabbage Grown in Biofumigated Soil against Pythium aphanidermatum Damping-Off of Cucumber

Soil biofumigation is a widely used farming practice for soil-borne disease management in vegetable crops. Soil biofumigation is the practice of the incorporation of fresh plant materials from the members of the Brassicaceae family into the soil which release antimicrobial volatile organic compounds (VOCs), namely glucosinolates and their hydrolysis products. However, the VOCs may affect non-target beneficial soil biota including microbial biocontrol agents (MBAs) due to their broad-spectrum toxicity. In this study, native antagonistic rhizobacteria were isolated from cabbage plants grown in biofumigated fields and their potential in the management of Pythium aphanidermatum cucumber damping-off was evaluated with and also without biofumigation using cabbage leaf residue. A total of 20 morphologically distinct, culturable bacterial strains were recovered from the rhizosphere soil of cabbage cultivated in a biofumigated field, with the largest fraction of the isolates belonging to the genus Bacillus. The other bacterial genera isolated were Pseudomonas, Serratia, Stenotrophomonas, Microbacterium and Priestia. Of the 20 bacterial isolates, Pseudomonas aeruginosa B1-SQU, Pseudomonas indica B2-SQU, Serratia marcescens B3-SQU and Pseudomonas brenneri B4-SQU exhibited inhibitory activity against P. aphanidermatum in a co-culture assay. The deformation and shrinkage of P. aphanidermatum hyphae due to diffusible antimicrobial compounds from these bacterial strains were witnessed through scanning electron microscopy. A biofilm was formed by these bacterial strains in vitro and they exhibited compatibility with each other; however, they had no significant plant growth promotion effect on cucumber. These bacterial strains significantly reduced damping-off in cucumber under greenhouse conditions when applied to soil singly, but failed to show a significant effect when combined with biofumigation treatment, though the bacterial population in the soil was maintained at higher levels. Soil biofumigation alone was also not effective in suppressing the damping-off of cucumber. Gas chromatography–mass spectrometry analysis revealed that 1-butanol, n-butyl butyrate and butyl acetate were the predominant VOCs in the soil amended with cabbage leaf residue. The results suggest that soil biofumigation with cabbage leaf residue has no significant effect on P. aphanidermatum under high inoculum levels; furthermore, it affects the efficiency of the bacterial antagonists in controlling damping-off in cucumber.

Measurement report: Volatile organic compound characteristics of the different land-use types in Shanghai: spatiotemporal variation, source apportionment and impact on secondary formations of ozone and aerosol

Abstract. Volatile organic compounds (VOCs) have important impacts on air quality, atmospheric chemistry and human health. In order to identify the spatiotemporal variations, sources and ozone (O3) and secondary organic aerosol (SOA) formation potentials of the atmospheric VOCs, a concurrent multi-site observation campaign was performed at the supersites of Shanghai, East China, in the first three months of 2019. The sampling sites are located at the different land-use types, including an industrial district (the Jinshan site: JS), residential and commercial mixed districts (the Pudong site: PD) and a background district (the Qingpu site: QP) of Shanghai. During the observation period, the average VOC concentrations were sensitive to the land-use types in the order of the JS (21.88 ± 12.58 ppb) > PD (21.36 ± 8.58 ppb) > QP (11.93 ± 6.33 ppb) sites. The predominant VOC category was alkanes (49.32 %–71.48 %), followed by aromatics (10.70 %–21.00 %), alkenes (10.13 %–15.30 %) and alkynes (7.69 %–14.80 %) at the studied sites. There were distinct diurnal variations and “weekend effects” of VOCs at the sampling sites. The VOC concentrations increased by 27.15 %, 32.85 % and 22.42 % during the haze events relative to the clean days. Vehicle exhaust was determined as the predominant VOC source. The second-largest VOC contributor was identified as industrial production at the JS and PD sites, while it proved to be fuel production and evaporation at the QP site. The industrial emission and biomass burning showed slight contributions to VOC concentrations at the QP and JS/PD sites, respectively. This was consistent with the regional characteristics of anthropogenic activities dominated by land-use types. High potential source contribution function (PSCF) values primarily appeared in the northeastern and northern areas surrounding sampling sites, suggesting strong local emissions. The ozone formation potential (OFP) values of each land-use type were in the order of the JS (50.89 ± 2.63 ppb) > PD (33.94 ± 1.52 ppb) > QP (24.26 ± 1.43 ppb) sites, with alkenes and aromatics being the predominant contributors. Secondary organic aerosol formation potential (SOAFP), mainly contributed by the aromatics, was highest at the JS site (1.00 ± 2.03 µg m−3), followed by the PD (0.46 ± 0.88 µg m−3) and QP (0.41 ± 0.58 µg m−3) sites. The VOC–PM2.5 sensitivity analysis showed that VOCs at the QP site displayed a more rapid increment along with the increase in PM2.5 values relative to the other two sites. Alkenes and aromatics are both the key concerns in controlling the VOC-related pollution of O3 and SOA in Shanghai. These findings provide more information on accurate air-quality control at a city level in China. The results shown herein highlight that the simultaneous multi-site measurements with the different land-use types in a megacity or city cluster could be more appropriate for fully understanding the VOC characteristics relative to a single-site measurement performed normally.

Engineered Stone Fabrication Work Releases Volatile Organic Compounds Classified as Lung Irritants.

Engineered stones are often characterized for their crystalline silica content. Their organic composition, particularly that of the emissions generated during fabrication work using hand-held power tools, is relatively unexplored. We forensically screened the emissions from dry-cutting 12 engineered stone products in a test chamber for their organic composition by pyrolysis-gas chromatography-mass spectrometry (GC-MS) plus selected traditional capture and analysis techniques. Phthalic anhydride, which has a Respiratory Sensitization (RSEN) Notation by the American Conference of Governmental Industrial Hygienists (ACGIH), was the most common and abundant compound, at 26-85% of the total organic composition of engineered stone emissions. Benzaldehyde and styrene were also present in all twelve samples. During active cutting, the predominant volatile organic compound (VOC) emitted was styrene, with phthalic anhydride, benzene, ethylbenzene, and toluene also detected. These results have important health implications as styrene and phthalic anhydride are irritants to the respiratory tract. This study suggests a risk of concurrent exposure to high levels of respirable crystalline silica and organic lung irritants during engineered stone fabrication work.

Characteristics and sources analysis of ambient volatile organic compounds in a typical industrial park: Implications for ozone formation in 2022 Asian Games

In this study, volatile organic compounds (VOCs) at a major industrial park in Yangtze River Delta Region, China, along with an urban site had been investigated for three years (2018–2020). The daily-mean concentration of total 97 VOCs in the industrial park (224.3 ± 139.1 μg/m3) was about twice that of urban site (112.0 ± 64.2 μg/m3). Halohydrocarbons were predominant VOCs species at both sites accounting for 39.0 % and 32.2 % in industrial and urban sites, respectively. Annual-average concentrations of total VOCs slowed down gradually in industrial park, while that of the urban site increased annually. Evident seasonal and diurnal variations were observed for VOCs concentration in both sites. Higher VOCs concentrations appeared in summer for industrial park, and high concentrations generally appeared at 8:00 and 19:00–20:00 in two sites. Diagnostic ratios of m/p-xylene to ethylbenzene indicated vehicle emissions and solvent volatilization were main sources of VOCs in industrial site during winter. Further positive matrix factorization identified fuel usage and industry source as major sources in industrial park and urban site, respectively. Ozone formation potential calculations showed aromatics contributed most to ozone formation, and benzyl chloride was a key species when its concentration was high. Further empirical kinetic modeling approach revealed ozone formation in industrial park was in VOCs-limited regime. Through air mass trajectory analysis, air pollutants especially ozone from industrial park will be transported to stadiums by northeast wind during the 2022 Asian Games. The reductions in VOCs emissions from industrials are highly recommended for ozone control in 2022 Asian Games.

Characteristics, Sources, and SOAP of VOCs During Winter in Jiyuan

Haze pollution events often occur in the heavy industry city of Jiyuan. Volatile organic compounds (VOCs) are the precursors of secondary organic aerosol (SOA), which accounts for 15%-20% of particulate matter (PM2.5). Here, PM2.5, O3, VOCs, and trace gases were monitored by using online instruments in Jiyuan from December 1st to 31st. The characteristics, sources, and secondary organic aerosol potential (SOAP) of VOCs were analyzed. The mean concentrations of TVOC were (54.3±27.5)×10-9. Alkanes, halocarbons, and alkynes were the predominant VOCs. The positive matrix factorization model was used to identify and apportion VOCs sources. Eight major sources of VOCs were identified, which included liquefied petroleum gas (LPG) or natural gas (NG), the polyvinyl chloride (PVC) industry, vehicular exhaust, the coking industry, solvent usage, industry, technological process, and fuel evaporation. The SOAP of aromatics was the largest. Among them, BTEXs were the dominant contributors to SOAP.

Assessing Impacts of Additives on Particulate Matter and Volatile Organic Compounds Produced from the Grilling of Meat

Cooking fumes are an important source of volatile organic compounds (VOCs), particulate matter (PM), and carbonyl compounds. The additive is wildly applied in grilling meat for flavor improvement. However, the effects of additives on cooking fumes emissions, such as volatile organic compounds (VOCs), particulate matter (PM), and carbonyl compounds, in meat grilling have not been studied. The impact of four additives, including white pepper, salt, garlic powder, and compound marinade, on the emission characteristics of cooking fumes from the grilling meat was investigated. The concentrations of VOCs and carbonyl compounds in the cooking fumes were analyzed by TD-GC/MS and HPLC, respectively. The PM emission characteristics (mass concentration and size distribution) were measured by DustTrak DRX aerosol monitor in real-time. Results showed that the application of white pepper, salt, garlic powder, and mixed spices could significantly reduce the total particles mass concentration (TPM) emissions during meat-grilling by 65.07%, 47.86%, 32.87%, and 56.01%, respectively. The mass concentration of PM during meat-grilling reached maximum values ranging from 350 to 390 s and gradually fell at the final stages of grilling. The total concentration of 22 representative VOCs emitted from the grilling was significantly increased in grilling meat marinated with compound additives. Aromatic hydrocarbons were the predominant VOCs species, followed by ketone compounds. During the grilling process, formaldehyde, acetaldehyde, propionaldehyde, and acetone were major carbonyl compounds. The low molecular weight carbonyl compounds (C1–C3) in cooking fumes were dominant carbonyl compounds.

Evaluation of volatile aroma compounds from Chinese wild grape berries by headspace-SPME with GC-MS

Evaluation of volatile aroma compounds from Chinese wild grape species aimed to explore new grape species via fruit aroma. In this study, the volatile organic compounds (VOCs) from ten grape cultivars belonging to nine different grape species were detected, by using headspace solid-phase microextraction with GC-MS. Chinese wild grape species were studied along with table grape (Muscat Hamburg, Concord) and wine grape (Cabernet Sauvignon) cultivars belonging to different origins. Total forty-five volatile compounds were detected, upon which several VOCs including pentanoic acid, cyclobutyl ester, maltol, (+)-neoisomenthol, and 8-methyloctahydrocoumarin were detected in Chinese wild grapes that have not been detected in other Vitis species. The results revealed that C6 volatile compounds were pre-dominant VOCs. Esters were found abundant in V. labrusca (Concord) and terpenoids were dominant in V. vinafera (Hamburg Muscat). The principal component analysis showed that Chinese wild grape cultivars V. yeshanensis, V. facifolia, V. davidii, V. betulifolia V. heyneana, V. amurensis and V. adenoclada are correlated with wine grape cultivar ‘Cabernet Sauvignon’, while table grape cultivars are distributed separately. These results can provide a reference for the utilization of new germplasm for specific purposes.

Influence of Human Behavior on Indoor Air Quality in a Care Facility for the Elderly in Japan

Volatile organic compounds (VOCs), CO2, temperature, and humidity in a private room in a care facility for the elderly were measured and the behavior of a resident and staff were recorded in order to clarify the effects of the resident’s behavior, especially defecation, on indoor air quality. Average indoor concentrations of total VOCs (in μg m−3) in summer, autumn, and winter were 40.9, 16.7, and 18.8, respectively. Average indoor concentrations of CO2 in summer, autumn, and winter were 813, 761, and 1144 ppm, respectively, revealing a tendency for the concentrations of CO2 to be higher in winter, in contrast to the VOC concentration. The concentrations of VOCs and CO2 were 1.1 to 1.5 times higher when the resident was present in the room than when the resident was absent. This result suggests that one of the main sources of VOC and CO2 emissions in indoor air was the resident. Acetic acid, 1-butanol, propanoic acid, hexanoic acid, and phenol, which are contained in human sweat, exhaled air, and excrement, were the predominant VOCs in the air of the room regardless of the season, and these five components accounted for more than 90% of the total VOCs. The concentrations of these components were higher when the resident was present in the room, suggesting that the resident was the main source of these components. Based on the changes in the VOC and CO2 concentrations over time and the records of the resident and the staff, it was noted that VOC concentrations decreased, in some cases, before and after diaper changes. Our research suggests that certain aspects of the behavior of residents can be inferred by monitoring changes in indoor air quality.

Biological relevance of VOCs emanating from red onions infected with Erwinia (Pectobacterium) carotovora under different storage conditions

Volatile organic compounds (VOCs) are generated in different commodities through various biosynthetic pathways. They act as biomarkers for different infections and metabolisms and can be instrumental in the development of biosensors for monitoring the health of stored horticultural commodities. Healthy onions and samples infected with Pectobacter Erwinia carotovora were stored at different conditions (4 °C, 60 %; 8 °C, 65 %; 15 °C, 75 %; 25 °C, 60–80 %) for 4 weeks and the VOCs were mapped using SPME-GC–MS. The data were analyzed using multivariate data analysis techniques like Principal Component Analysis (PCA), and Partial Least-Squares Discriminant Analysis (PLS-DA), and visualized using a cluster heat map. The number of VOCs was higher in the infected samples, which increased over the storage duration. The predominant class of VOCs at 25 °C are mostly ester and sulfur; and at 15 °C, alkane and ketone groups of VOCs contributed more, during the initial phase of infection. At a lower temperature of 8 °C bacterial metabolic VOCs belonging to alcohol or aldehyde groups could be observed. On the other hand at 4 °C, since the microbial activity is retarded, no such compounds were found. With storage and extent of spoilage, the predominant VOCs belonged to acids and multi-functional group variants for lower temperatures. VOC profile was found to be correlated with storage conditions as well as periods that ultimately had an impact on Erwinia carotovora secondary metabolism. Except for the 4 °C storage temperature, PCA could distinguish and separate the VOCs into clusters for the classification of infected and non-infected samples; however, PLS-DA performed better separation and distinction of VOCs among the groups for all the storage conditions. The dominance of the VOCs with respect to sample type, storage condition, and storage duration was represented through the clustered heat maps.

VOCs concentrations and emission rates in hospital environment and the impact of sampling locations

In this study, volatile organic compounds (VOCs) were measured from 47 hospital rooms to determine the most suitable sampling location for VOCs indoors. Another goal was to find out the most predominant VOCs and their emission per floor area in a hospital environment. Three samples were taken from each room simultaneously: one from the center of the room, one from the floor near the wall, and one from the exhaust air terminal. Concentrations of the VOCs were relatively low in all the cases, and the most abundant compounds were decamethylcyclopentasiloxane, d-limonene, xylenes, and 2-methyl-2-propanol. The average emission rates of the main compounds per floor area varied between 49 and 81 µg/m2h. Statistical analyses showed that room area and volume affected differently the total volatile organic compounds (TVOC) concentrations among the sampling locations. Concentrations were higher at the exhaust air terminal than in samples at the floor and middle of the room. VOC levels were the same at the different sampling locations when the size of the room was below 10 m2. However, field measurements and statistical analyses showed that when the size of the room increased, the most evenly distributed VOCs can be measured most reliably in the vicinity of the exhaust terminal device or in the exhaust air.

Characteristics, sources and health risks assessment of VOCs in Zhengzhou, China during haze pollution season

Zhengzhou is one of the most haze-polluted cities in Central China with high organic carbon emission, which accounts for 15%-20% of particulate matter (PM2.5) in winter and causes significantly adverse health effects. Volatile organic compounds (VOCs) are the precursors of secondary PM2.5 and O3 formation. An investigation of characteristics, sources and health risks assessment of VOCs was carried out at the urban area of Zhengzhou from 1st to 31st December, 2019. The mean concentrations of total detected VOCs were 48.8 ± 23.0 ppbv. Alkanes (22.0 ± 10.4 ppbv), halocarbons (8.1 ± 3.9 ppbv) and aromatics (6.5 ± 3.9 ppbv) were the predominant VOC species, followed by alkenes (5.1 ± 3.3 ppbv), oxygenated VOCs (3.6 ± 1.8 ppbv), alkyne (3.5 ± 1.9, ppbv) and sulfide (0.5 ± 0.9 ppbv). The Positive Matrix Factorization model was used to identify and apportion VOCs sources. Five major sources of VOCs were identified as vehicular exhaust, industrial processes, combustion, fuel evaporation, and solvent use. The carcinogenic and non-carcinogenic risk values of species were calculated. The carcinogenic and non-carcinogenic risks of almost all air toxics increased during haze days. The total non-carcinogenic risks exceeded the acceptable ranges. Most VOC species posed no non-carcinogenic risk during three haze events. The carcinogenic risks of chloroform, 1,2-dichloroethane, 1,2-dibromoethane, benzyl chloride, hexachloro-1,3-butadiene, benzene and naphthalene were above the acceptable level (1.0 × 10−6) but below the tolerable risk level (1.0 × 10−4). Industrial emission was the major contributor to non-carcinogenic, and solvent use was the major contributor to carcinogenic risks.

Characteristics and Source Apportionment of Atmospheric VOCs in the Nanjing Industrial Area in Autumn

Atmospheric volatile organic compounds (VOCs) were continuously monitored via an online GC-FID/MS system in Nanjing during the autumn of 2018 to analyze the chemical characteristics, ozone formation potential (OFP), and potential sources of VOCs in this industrial region. During the sampling period, the average concentration of atmospheric total VOCs (TVOCs) was (64.3±45.6)×10-9. Alkanes were the most predominant VOC compound, accounting for 33.1% of the TVOC mass, followed by oxygenated volatile organic compounds (OVOCs, 22.3%) and halogenated hydrocarbons (21.8%). The diurnal cycles of VOCs revealed "bimodal" distributions. The higher concentrations of VOCs observed at 06:00-07:00 and 18:00-20:00 were attributed to the intense traffic emissions and meteorological conditions. Furthermore, maximum incremental reaction (MIR) analysis was used to estimate OFP of VOCs. The results showed that the calculated OFP in Nanjing was 267.1 μg·m-3. Aromatic hydrocarbons and alkenes were the dominant contributors to OFPs, which accounted for 55.2% and 20.8% to the total OFPs, respectively. Finally, five potential sources of VOCs were quantified by the positive matrix factorization model, including traffic emissions (34%), industrial emissions (19%), liquefied petroleum gas (LPG) emissions (17%), usage of paints and solvents (16%), coal combustion, and biomass burning (14%). These findings suggested that control of vehicle emissions and industrial sources would be an important way to reduce VOC concentrations and improve air quality in Nanjing.

Emissions and health risks from the use of 3D printers in an occupational setting

ABSTRACTThe aim of this study was to determine concentrations of particulates and volatile organic compounds (VOCs) emitted from 3D printers using polylactic acid (PLA) filaments at a university workroom to assess exposure and health risks in an occupational setting. Under typical-case (one printer) and worst-case (three printers operating simultaneously) scenarios, particulate concentration (total and respirable), VOCs and formaldehyde were measured. Air samples were collected in the printing room and adjacent hallway. Size-resolved levels of nano-diameter particles were also collected in the printing room. Total particulate levels were higher in the worst-case scenario (0.7 mg/m3) vs. typical-case scenario (0.3 mg/m3). Respirable particulate and formaldehyde concentrations were similar between the two scenarios. Size-resolved measurements showed that most particles ranged from approximately 27 to 116 nm. Total VOC levels were approximately 6-fold higher during the worst-case scenario vs. typical situation with isopropyl alcohol being the predominant VOC. Airborne concentrations in the hallway were generally lower than inside the printing room. All measurements were below their respective occupational exposure limits. In summary, emissions of particulates and VOCs increased when multiple 3D printers were operating simultaneously. Airborne levels in the adjacent hallway were similar between the two scenarios. Overall, data suggest a low risk of significant and persistent adverse health effects. Nevertheless, the health effects attributed to 3D printing are not fully known and adherence to good hygiene principles is recommended during use of this technology.

Postharvest quality indices of different durian clones at ripening stage and their volatile organic compounds

The aim of the present work was to characterize the quality of durians at consumptions stage. Seven clones of durian namely “Musang King”, “D24″, “D88″, “IOI”, “XO”, “Red Prawn” and “Black Thorn” were characterized based on their physiochemical properties. The organic acid contents, sugar compositions and β-carotene of durian clones were measured by high-performance liquid chromatographic (HPLC), while the volatile organic compounds (VOCs) were analyzed using headspace solid phase microextraction (HS-SPME) coupled with gas chromatography-mass spectrometry (GCMS). There were significant differences on all the postharvest parameters in the selected durian clones. “Black Thorn” having orange pulp yieled the highest β-carotene content (4.55 × 10−5 kg/kg FW). The dominant sugars in the pulp of all durian clones were dominated by sucrose followed by glucose and fructose. Sulfur- and ester-containing compounds were the predominant VOCs found. Principal component analysis (PCA) allowed for the grouping of different durian clones based on VOCs.

Antifungal spectrum characterization and identification of strong volatile organic compounds produced by Bacillus pumilus TM-R

To obtain biocontrol agents for suppression of food-deteriorating fungi during storage of agricultural products, bacteria producing volatile organic compounds (VOCs) with strong antifungal activity were screened and isolated from various environmental samples. Among 136 bacterial isolates, strain TM-R showed the strongest and broadest antifungal activity. Based on physiological and genetical characterization, the bacterium was identified as Bacillus pumilus. The effects of VOCs produced by the bacterium, which was grown on four types of agar media (nutrient, Trypto-Soya, Luria–Bertani, and TM Enterprise), were examined against six species of fungi (Alternaria alternata, Aspergillus niger, Cladosporium cladosporioides, Curvularia lunata, Fusarium oxysporum, and Penicillium italicum) in both small- and large-scale tests (plate and 12-L tests, respectively). In the plate test, the bacterium markedly suppressed the mycelial growth of five fungi (Alternaria alternata, Cladosporium cladosporioides, Curvularia lunata, F. oxysporum, and P. italicum) but promoted the growth of Aspergillus niger. In the 12-L test, the degree of growth inhibitiondecreased; however, the bacterium grown on TMEA still exhibited the strongest inhibition, especially against P. italicum (growth inhibition rate of 93%). Surprisingly, the growth of Aspergillus niger was promoted even more strongly (−36%) by the bacterium on TMEA than in the plate test (−9%). Twenty-two of 32 VOCs detected by GC-MS were identified using three databases (NIST 2011, AromaOffice, and AroChemBase). The species and concentration of detected VOCs differed greatly among growth media. To identify causative antifungal VOCs, we estimated the correlation between growth inhibition of P. italicum by the bacterium grown on each of the four media vs. the relative abundance of individual VOCs. As a result, four VOCs (methyl isobutyl ketone, ethanol, 5-methyl-2-heptanone, and S-(−)-2-methylbutylamine) were determined to be the predominant antifungal VOCs. To the best of our knowledge, this study is the first to specify causative antifungal VOCs using such an approach.

A cool comparison of black and white pepper grades

Black pepper (BP) is globally the most widely used spice and is appreciated for its aroma and taste qualities. Its aroma is influenced by various factors. In the current study, we examined a reference set of 90 quality BP and 40 quality white pepper (WP) samples from the EU spice industry for their volatile organic compounds (VOC) by Proton Transfer Reaction - Mass Spectrometry, as well as 10 low-grade pepper (LG) samples (light berries, rejects, spent). Furthermore, 50 retail BP and 30 WP samples were compared with the reference set. The predominant VOC measured were terpenes. BP presented the most abundant VOC profiles, followed by the WP group, and - at some distance - by the LG pepper material. Reference BP exhibited significantly higher intensities for 41% of the masses compared to WP, and the LG group lower intensities than both BP and WP for 27% of the masses. When using mass 137, the monoterpenes marker, retail samples presented significantly lower VOC intensities than their reference counterparts in case of 42% of the retail BP and 70% of the WP samples. Those samples may have suffered from poor storage conditions during production or potential adulteration or substitution with LG material.