Volatile Organic Compounds Emissions Research Articles

Strengthening biopolymer adhesives through ureolysis-induced calcium carbonate precipitation

Common adhesives for nonstructural applications are manufactured using petrochemicals and synthetic solvents. These adhesives are associated with environmental and health concerns because of their release of volatile organic compounds (VOCs). Biopolymer adhesives are an attractive alternative because of lower VOC emissions, but their strength is often insufficient. Existing mineral fillers can improve the strength of biopolymer adhesives but require the use of crosslinkers that lower process sustainability. This work introduces a novel approach to strengthen biopolymer adhesives through calcium carbonate biomineralization, which avoids the need for crosslinkers. Biomineral fillers produced by either microbially or enzymatically induced calcium carbonate precipitation (MICP and EICP, respectively) were precipitated within guar gum and soy protein biopolymers. Both, MICP and EICP, increased the strength of the biopolymer adhesives. The strength was further improved by optimizing the concentrations of bacteria, urease enzyme, and calcium. The highest strengths achieved were on par with current commercially available nonstructural adhesives. This study demonstrates the feasibility of using calcium carbonate biomineralization to improve the properties of biopolymer adhesives, which increases their potential viability as more sustainable adhesives.

Thermal‐Oxidative Aging Behavior and Factors of Polystyrene‐Based Thermoplastic Elastomers‐Based Automotive Interior Skin

ABSTRACTCompared to traditional polyvinyl chloride (PVC), polyurethane (PU), and thermoplastic olefin (TPO) materials, thermoplastic elastomers (TPEs) offer advantages of complete recyclability, absence of plasticizers and solvents, superior mechanical properties, pleasing tactile characteristics, low volatile organic compounds (VOCs) emissions, and cost‐effective processing. Making it an exceptional choice for environmentally friendly automotive skin materials. The automotive skin is frequently subjected to harsh conditions, such as high temperatures and oxygen exposure during use, presenting a significant durability challenge. Therefore, this study focuses on polystyrene (PS)‐based thermoplastic elastomers (TPE‐S) as the subject and investigates the influence of molecular weight, PS content, and chain structure in the blend on the mechanical properties of TPE‐S using an accelerated thermal‐oxidative aging method. Meanwhile, the changes of TPE‐S during the aging process are discussed via molecular weight, crystalline structure, molecular chain structure, microphase separation structure, and tactile sensation, providing a scientific foundation for guiding the selection of TPE‐S in automobile skin and heat oxidative aging resistance ability.

Particulate Matter and Volatile Organic Compounds Emissions and Their Health Impact: Spotlight on Solid Fuel Combustion

Solid fuel combustion, while a crucial source of energy in many regions around the world, remains one of the primary contributors to air pollution, with significant implications for human health [...]

Citrus Yellow Vein Clearing Virus Infection in Lemon Influences Host Preference of the Citrus Whitefly by Affecting the Host Metabolite Composition.

Plant viruses have been known to alter host metabolites that influence the attraction of insect vectors. Our study investigated whether Citrus yellow vein clearing virus (CYVCV) infection influences vector attractiveness, focusing on the citrus whitefly, Dialeurodes citri (Ashmead). Free choice assays showed that citrus whiteflies exhibited a preference for settling on CYVCV-infected lemon plants versus healthy control plants. Using chromatography techniques, we found that the levels of sugars were similar in leaves and stems of both plant groups, while the contents of several amino acids in leaf or stem samples and non-volatile phenolic compounds in the leaf samples of CYVCV-infected and healthy plants differ drastically. In addition, volatile terpenes/terpenoids decreased significantly in virus-infected plants compared to healthy controls. Several of the identified volatile compounds such as α-phellandrene, α-terpinolene, p-cymene, linalool, and citral are known for their whitefly repellent properties. Further Y-tube olfactometer bioassays revealed that emissions of volatile organic compounds (VOCs) from infected plants attracted more citrus whiteflies, but not alate spirea aphids, Aphis spiraecola Patch, than those from healthy plants, suggesting that the VOCs released from CYVCV-infected lemon plants may specifically affect citrus whiteflies. Therefore, we suggest that, in addition to the visual cue of yellow vein symptoms, the preference of citrus whiteflies that settled on CYVCV-infected lemon plants was attributed to a reduction in the levels of repellent volatile compounds.

Opposing response of biogenic volatile organic compound and CO2 emissions to nitrogen addition during decomposition of two litter species

Opposing response of biogenic volatile organic compound and CO2 emissions to nitrogen addition during decomposition of two litter species

Computational Study of the 1,3-Dipolar Cycloaddition between Criegee Intermediates and Linalool: Atmospheric Implications.

In this research, we investigated the essential role of biogenic volatile organic compound emissions in regulating tropospheric ozone levels, atmospheric chemistry, and climate dynamics. We explored linalool ozonolysis and secondary organic aerosol formation mechanisms, providing key insights into atmospheric processes. Computational techniques, such as density functional theory calculations and molecular dynamics simulations, were employed for the analysis. Our study delves into the energetic and mechanistic aspects of the 1,3-dipolar cycloadditions involving linalool and its ozonolysis byproducts, known as Criegee intermediates. A total of 24 reactions were analyzed from the three possible Criegee intermediates formed, resulting from different reactant orientations and their endo/exo isomers. We found that only four of these reactions exhibit large rate constants that can compete with tropospheric reactions. This reactivity pattern was characterized by analyzing reactivity indices from conceptual density functional theory and determining that electron flux originates from linalool to the Criegee intermediates. Greater electrophilicity in the Criegee intermediates results in a lower reaction activation energy, confirmed by the global electrophilicity index. Furthermore, using the activation strain model and energy decomposition analysis, we found that differences in activation energies were primarily driven by nonorbital energy factors. Finally, molecular dynamics simulations showed that the final cycloaddition adducts of the most favorable 1,3-dipolar cycloaddition interact favorably with water molecules in an exergonic process, adsorbing up to 92% of the water molecules after 20 ns. Our findings provide insights that enhance our understanding of the interactions between natural emissions and atmospheric constituents.

The active layer soils of Greenlandic permafrost areas can function as important sinks for volatile organic compounds

Permafrost is a considerable carbon reservoir harboring up to 1700 petagrams of carbon accumulated over millennia, which can be mobilized as permafrost thaws under global warming. Recent studies have highlighted that a fraction of this carbon can be transformed to atmospheric volatile organic compounds, which can affect the atmospheric oxidizing capacity and contribute to the formation of secondary organic aerosols. In this study, active layer soils from the seasonally unfrozen layer above the permafrost were collected from two distinct locations of the Greenlandic permafrost and incubated to explore their roles in the soil-atmosphere exchange of volatile organic compounds. Results show that these soils can actively function as sinks of these compounds, despite their different physiochemical properties. Upper active layer possessed relatively higher uptake capacities; factors including soil moisture, organic matter, and microbial biomass carbon were identified as the main factors correlating with the uptake rates. Additionally, uptake coefficients for several compounds were calculated for their potential use in future model development. Correlation analysis and the varying coefficients indicate that the sink was likely biotic. The development of a deeper active layer under climate change may enhance the sink capacity and reduce the net emissions of volatile organic compounds from permafrost thaw.

Emissions of Biogenic Volatile Organic Compounds from Plants: Impacts of Air Pollutants and Environmental Variables

Emissions of Biogenic Volatile Organic Compounds from Plants: Impacts of Air Pollutants and Environmental Variables

Application of Space-Based Glyoxal Observation for Estimating Global Nonmethane Volatile Organic Compounds Emissions from Urban Sources and Biomass Burning

Application of Space-Based Glyoxal Observation for Estimating Global Nonmethane Volatile Organic Compounds Emissions from Urban Sources and Biomass Burning

Emission Characteristics and Health Risk Assessment of Volatile Organic Compounds in Key Industries: A Case Study in the Central Plains of China

Volatile organic compounds (VOCs), the precursors of ozone and fine particulate matter, are one of the atmospheric pollutants harmful to human health. The emission characteristics of VOCs in Anyang, a typical industrial city in the Central Plains of China, are unclear. To determine the emission level and composition of local VOCs, this study conducted on-site sampling of 20 factories in eight key industries. A total of 105 VOC species in seven categories were observed. The concentration of total VOCs emitted from the eight industries in order from large to small was as follows: packaging and printing > pharmaceutical > paint manufacturing > industrial coating > chemical industry > metal smelting > furniture manufacturing > textile printing and dyeing. In addition to industrial coating, the total VOCs and their corresponding ozone formation potential of organized emissions in seven industries (1.44–87.64, 1.52–181.61 mg/m3) were higher than those of unorganized emissions (0.38–24.17, 0.38–125.55 mg/m3). The VOC emissions were concentrated in the central, south-central, and south-eastern parts of the city, mainly from the factories in the packaging and printing, pharmaceutical, paint, and coating industries. The furniture manufacturing (4.55 × 10−3) and pharmaceutical (1.66 × 10−3) industries in organized emissions were at high risk of carcinogenesis, while the pharmaceutical industry in unorganized emissions (3.61 × 10−4) was at moderate risk of carcinogenesis. Naphthalene was the main high-risk compound. In terms of non-carcinogenic risk, the packaging and printing industry in organized emissions (228.51) and the metal smelting industry in unorganized emissions (16.16) had the highest risk, and the main high-risk compound was ethyl acetate.

Manipulating stomatal aperture by silencing StSLAC1 affects potato plant-herbivore-parasitoid tritrophic interactions under drought stress.

The effects of drought stress on stomatal opening dynamics, plant volatile organic compound (VOC) emissions and plant-insect interactions have been well-documented individually, but how they interact mechanistically remains poorly studied. Here, we studied how drought-triggered stomatal closure affects VOC emission and plant-trophic interactions by combining RNAi silencing, molecular biological and chemical analyses (GC-MS) of a potato-tuber moth-egg parasitoid tritrophic system. Drought stress attenuated stomatal apertures and VOC emissions, which made the potato (Solanum tuberosum L.) plants more attractive to the herbivore but less attractive to the parasitoid. Stomatal aperture manipulations through StSLAC1 gene knockdown and chemicaltreatments (ABA and 5-aminolevulinic acid) consistently affected drought-triggered VOC emissions and plant-herbivore-parasitoid interactions, supporting aperture-dependent VOC emission. RNA-Seq analysis revealed that drought stress did not transcriptionally inhibitVOC biosynthesis. Collectively, our findings are consistent with the stomatal regulation of plant-insect interactions through the modulation of VOC emissions under drought stress. This highlights the intricate interplay between stomatal dynamics, VOC emission and plant-insect interactions.

Diurnal variations of NO2 tropospheric vertical column density over the Seoul metropolitan area from the Geostationary Environment Monitoring Spectrometer (GEMS): seasonal differences and the influence of the a priori NO2 profile

Abstract. The Geostationary Environment Monitoring Spectrometer (GEMS), launched in 2020, provides both temporally and spatially continuous air quality data from geostationary Earth orbit (GEO). This study first investigates the seasonal variations and diurnal behavior of nitrogen dioxide (NO2) tropospheric vertical column densities (TropVCDs) over the Seoul metropolitan area (SMA) using GEMS data, retrieved by the IUP-UB algorithm. We find that the magnitude of the NO2 TropVCDs and their diurnal behavior have significant seasonal dependences. In January, the highest NO2 TropVCD values in the range 27.5–28.9×1015 molec.cm-2 during the four seasons were observed at 15:00 local time (LT) and NO2 TropVCD increases from the first retrieved values at 10:00 LT. On the other hand, we find the lowest values (7.4–8.8×1015 molec.cm-2) are at ∼14:00 LT in July. The VCD values in July increased up to 10:00 LT and then decreased until 14:00 LT but then began to increase again. These different diurnal behaviors of the TropVCDs in the different seasons reflect the differences in photochemical and meteorological conditions as well as the emissions of NOx. Photochemical transformations are typically more rapid in July and slower in January. The absolute values and diurnal behavior of NO2 TropVCDs are significantly influenced by the wind speed, except in July. Moderate (wind speed ≥3 m s−1) or strong wind (wind speed >5 m s−1) reduced the magnitude of the diurnal behavior in January, implying that the NO2 plumes were transported downwind. Finally, we compared the retrieved NO2 TropVCDs by using different a priori NO2 data simulated by TM5 and WRF-Chem, calculated using the most recent emission inventories. Although simulated VCDs from WRF-Chem and TM5 show differences of up to a factor 2.75, retrieved NO2 TropVCDs using each a priori data have almost identical values and diurnal behaviors, except in July. Notably, the diurnal behavior of the retrieved NO2 TropVCDs is independent of that from the two chemical transport models, indicating that observations of slant column densities are the dominant factor in determining the diurnal behavior of NO2 TropVCDs. Changes in the model horizontal resolution and volatile organic compound (VOC) emission inventory do not significantly affect the retrieved NO2 TropVCDs in this study. However, when the a priori NO2 vertical profile was fixed as the values at 13:45 LT, the diurnal patterns of NO2 TropVCDs showed significant changes, with differences of up to −18.3 %.

Fingerprinting the emissions of volatile organic compounds emitted from the cooking of oils, herbs, and spices.

Emission rates for volatile organic compounds (VOCs) have been quantified from frying, spice and herb cooking, and cooking a chicken curry, using real-time selected-ion flow-tube mass spectrometry (SIFT-MS) for controlled, laboratory-based experiments in a semi-realistic kitchen. Emissions from 7 different cooking oils were investigated during the frying of wheat flatbread (puri). These emissions were dominated by ethanol, octane, nonane and a variety of aldehydes, including acetaldehyde, heptenal and hexanal, and the average concentration of acetaldehyde (0.059-0.296 mg m-3) and hexanal (0.059-0.307 mg m-3) measured during the frying was 2-10 times higher than the recommended limits for indoor environments. Total VOC emission rates were greatest for ghee (14 mg min-1), and lowest for groundnut oil (8 mg min-1). In a second series of experiments, 16 herbs and spices were individually shallow-fried in rapeseed oil. Over 100 VOCs were identified by offline gas chromatography-mass spectrometry (GC-MS), and absolute emission rates as well as oxidant reactivity for a subset of four spices were determined. These experiments allowed distinct indoor air quality profiles to be calculated for individual oils, herbs and spices, which were used to inform and interpret more realistic cooking experiments where a full recipe of chicken curry was prepared. Total-mass VOC emissions from chicken curry were dominated by methanol (62%), monoterpenes (13%) and ethanol (10%). Additionally, a clear relationship between the cooking events and the chemical classes of VOC was observed, e.g. heating the oil (aldehydes), frying spices (monoterpenes) and adding vegetables (alcohols).

Microbial inactivation and emission of volatile organic compounds in low-heat thermal treatment of infectious healthcare waste

Microbial inactivation and emission of volatile organic compounds in low-heat thermal treatment of infectious healthcare waste

The impact of surfaces on indoor air chemistry following cooking and cleaning.

Cooking and cleaning are common sources of indoor air pollutants, including volatile organic compounds (VOCs). The chemical fate of VOCs indoors is determined by both gas-phase and multi-phase chemistry, and can result in the formation of potentially hazardous secondary pollutants. Chemical interactions at the gas-surface boundary play an important role in indoor environments due to the characteristically high surface area to volume ratios (SAVs). This study first characterises the VOC emissions from a typical cooking and cleaning activity in a semi-realistic domestic kitchen, using real-time measurements. While cooking emitted a larger amount of VOCs overall, both cooking and cleaning were sources of chemically reactive monoterpenes (peak mixing ratios 7 ppb and 2 ppb, respectively). Chemical processing of the VOC emissions from sequential cooking and cleaning activities was then simulated in a kitchen using a detailed chemical model. Results showed that ozone (O3) deposition was most effective onto plastic and soft furnishings, while wooden surfaces were the most effective at producing formaldehyde following multi-phase chemistry. Subsequent modelling of cooking and cleaning emissions using a range of measured kitchen SAVs revealed that indoor oxidant levels and the subsequent chemistry, are strongly influenced by the total and material-specific SAV of the room. O3 mixing ratios ranged from 1.3-7.8 ppb across 9 simulated kitchens, with higher concentrations of secondary pollutants observed at higher O3 concentration. Increased room volume, decreased total SAV, decreased SAVs of plastic and soft furnishings, and increased wood SAV contributed to elevated formaldehyde and total peroxyacetyl nitrates (PANs) mixing ratios, of up to 1548 ppt and 643 ppt, respectively, following cooking and cleaning. Therefore, the size and material composition of indoor environments has the potential to impact the chemical processing of VOC emissions from common occupant activities.

Rapid detection of volatile organic compounds emitted from plants by multicapillary column-ion mobility spectrometry.

This study presents a novel rapid analytical method for the detection of volatile organic compounds (VOCs) emitted from blueberry leaves using the Tenax adsorbent followed by separation using a multicapillary column (MCC) and Ion Mobility Spectrometry (IMS) detection. The emitted VOCs including caryophyllene, benzene acetonitrile, linalool, ocimene, and methyl salicylate initiated by different stress factors including mechanical damage (punching), herbivore attack (aphids) and methyl jasmonate (MeJA) spraying were detected and quantified. Limits of Detection (LODs) for the VOCs were determined in the range of 8 to 33 ng. This new cost-efficient method provided a simple and direct detection of the emitted VOCs from plants without any sample pretreatment.

Estimating emissions of biogenic volatile organic compounds from urban green spaces and their contributions to secondary pollution

A 1 km spatial resolution of vegetation emission inventory.

POTENCIAL DE FORMAÇÃO DE OZÔNIO NA HOMOLOGAÇÃO VEICULAR NO BAIRRO DE BANGU, RIO DE JANEIRO

OZONE FORMING POTENTIAL FOR VEHICULAR HOMOLOGATION IN THE NEIGHBORHOOD OF BANGU, RIO DE JANEIRO. To control vehicle emissions, the new homologation process must be reported according to the California Maximum Incremental Reactivity (MIR) scale’s procedure to calculate the ozone forming potential (OFP) of each new vehicle. This work calculates an MIR scale suitable for the Brazilian reality. Meteorological and hourly pollutant data from the Bangu Automatic Air Quality Station was inventoried and processed from March to September 2020 to adjust OZIPR Lagrangean model and obtain the MIR scale by making small increments in the concentrations of each volatile organic compounds (VOC) and calculate the ozone increase/decrease. It was found that the VOC that had the greatest impact on ozone formation was 1,2,4-trimethylbenzene, with 2.06 ppb O3 ppbC–1 VOC. The OFP was calculated based on the VOC emissions of a vehicle and it was found a value of 9.421 mg O3 km–1, a much lower value when compared using the California MIR scale of 136.608 mg O3 km–1. It is concluded that meteorological conditions and VOC speciation data in the air mixture in the studied region directly affect the photochemical reactions of ozone formation.

Pyrolysis kinetics and pyrolysis-generated VOC emissions characteristics of thermally aged asphalt

ABSTRACT Styrene butadiene styrene (SBS) is widely used to enhance asphalt pavement performance. When road fires occur, asphalt quickly undergoes pyrolysis, releasing toxic volatile organic compounds (VOCs) that threaten life security. Many previous studies investigate the SBS modifier’s impact on mechanical characteristics, while quite rare of them address the pyrolysis kinetics with VOC formation of the SBS-modified asphalt, particularly when they experience thermally aged process. This study has applied the thermogravimetry-mass spectrometry technique (TG-MS) and distributed activation energy model (DAEM) to address these research gaps. Our analytical results present that the thermal stability of the SBS-modified asphalt (SBSMA) is significantly promoted with 5% higher activation energy (E) than that of unmodified asphalt (UMA), mainly attributed to the heat absorption of the SBS modifier which results in a slow temperature rise of asphalt. However, the VOC emissions of SBSMA are nearly 190% higher than those of UMA, which is owing to the thermal decomposition of the SBS modifier. Besides, thermally aged asphalt emits approximately 40% fewer VOCs than fresh asphalt, indicating that the organic-compositional loss occurs during the aging process. This work provides fundamental insights into asphalt combustion and alerts designers to re-design SBS-asphalt owing to its dramatic pyrolysis-generated VOC emissions.

Bioreactor contamination monitoring using off-gassed volatile organic compounds (VOCs).

Metabolically active cells emit volatile organic compounds (VOCs) that can be used in real time to non-invasively monitor the health of cell cultures. We utilized these naturally occurring VOCs in an adapted culture method to detect differences in culturing Chinese hamster ovary (CHO) cells with and without Staphylococcus epidermidis and Aspergillus fumigatus contaminations. The VOC emissions from the cell cultures were extracted and measured from the culture flask headspace using polydimethylsiloxane (PDMS)-coated Twisters, which were subjected to thermal desorption-gas chromatography-mass spectrometry (TD-GC-MS) analysis. In our initial time points of 1 and 2 h, we detected VOC signatures that differentiated the cultures earlier than traditional plating techniques or visualization methods. Partial least squares-discriminant analysis (PLS-DA) models were built to differentiate the analytes from the CHO cells and S. epidermidis- and A. fumigatus-inoculated CHO cultures. A total of 41 compounds with a variable importance in projection (VIP) score greater than 1 was obtained across the models. Similarly, based on the PLS regression analyses to predict the cell concentration of S. epidermidis (R2 = 0.891) and A. fumigatus (R2 = 0.375), 15 and 20 relevant compounds were putatively identified, respectively; two known compounds overlapped between the two microbes. Some of the compounds were unidentified and future studies will determine the relationship between the VOCs and the metabolic changes in contaminated cultures.