Volatile organic compounds (VOCs) are the organic compounds having a minimum vapor pressure of 0.13 kPa at standard temperature and pressure (293 K, 101 kPa). Being used as a solvent for organic and ...inorganic compounds, they have a wide range of applications. Most of the VOCs are non-biodegradable and very easily become component of the environment and deplete its purity. It also deteriorates the water quality index of the water bodies, impairs the physiology of living beings, enters the food chain by bio-magnification and degrades, decomposes and manipulates the physiology of living organisms. To unveil the adverse impacts of volatile organic compounds (VOCs) and their rapid eruption and interference in the living world, a review has been designed. This review presents an insight into the currently available VOCs, their sources, applications, sampling methods, analytic procedures, imposition on the health of aquatic and terrestrial communities and their contamination of the environment. Elaboration has been done on representation of toxicological effects of VOCs on vertebrates, invertebrates, and birds. Subsequently, the role of environmental agencies in the protection of environment has also been illustrated.
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•VOCs are used as a solvent for organic and inorganic compounds; they have a wide range of applications.•Most of the VOCs are non-biodegradable and very easily become component of the environment and deplete itspurity.•VOCs deteriorate the water quality index of the water bodies and shows biomagnification in food chain.•Most of the VOCs impairs the physiology of living organisms.
In recent years, ozone (O3) is often the major pollutant during summertime in China. In order to better understand this problem, a long-term measurement of ozone (from 2006 to 2015) and its ...precursors (NOx and VOCs) as well as the photochemical parameter (UV radiation) in a mega city of China (Shanghai) is analyzed. The focus of this study is to investigate the trend of O3 and the causes of the O3 trend in large cities in China. In order to understand the relationship between the O3 precursors and O3 formation, two distinguished different sites of measurements are selected in the study, including an urbanization site (XJH-Xujiahui) and a remote site (DT-Dongtan). At the XJH site, there are high local emissions of ozone precursors (such as VOCs and NOx), which is suitable to study the effect of O3 precursors on O3 formation. In contrast, at the DT site, where there are low local emissions, the measured result can be used to analyze the background conditions nearby the city of Shanghai. The analysis shows that there were long-term trends of O3 and NOx concentrations at the urban site (XJH) from 2006 to 2015 (O3 increasing 67% and NOx decreasing 38%), while there were very small trends of O3 and NOx concentrations at the background site (DT). The analysis for causing the O3 trend suggests that (1) the large O3 increase at the urban area (XJH) was not due to the regional transport of O3; (2) the measurement of solar radiation had not significant trend during the period, and was not the major cause for the long-term O3 trend; (3) the measurement of VOCs had small change during the same period, suggesting that the trend in NOx concentrations at the urban site (XJH) was a major factor for causing the long-term change of O3 at the urban area of Shanghai. As a result, the O3 and NOx concentrations from 2006 to 2015 at the urban area of Shanghai were strongly anti-correlated, suggesting that the extremely high NOx concentration in the urban area depressed the O3 concentrations. It is interesting to note that the anti-correlation between O3 and NOx was in an un-linearly relationship. Under high O3 concentration condition, the ratio of ΔO3/ΔNOx was as large as −1.5. In contrast, under low O3 concentrations, the ratio of ΔO3/ΔNOx was only −0.2. This result suggested that when O3 concentration was high, it was more sensitive to NOx concentration, while when O3 concentration was low, it was less sensitive to NOx concentration. This study provides useful insights for better understanding the causes of the long-term-trend of regional O3 pollution nearby Shanghai, and has important implication for air pollution control in large cities in China. Due to the fact that NOx and VOCs are not only precursors for O3, but also are important precursors for particular matter (PM). If reduction of NOx leads to decrease in PM, but increase in O3, the NOx emission control become a very complicated issue and need to carefully design a comprehensive control method.
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•There are insignificant trends of O3 and NOx from 2006 to 2015 in a mega city (Shanghai).•The trends between O3 and NOx are strongly anti-correlated, indicating that the O3 is strongly depressed by high NOx.•The study suggests that the reduction of NOx can reduce PM2.5, while causes O3 to increase.•The NOx emission control becomes a very complicated issue and needs to carefully design a comprehensive control method.
Biogenic and anthropogenic organic vapors are crucial precursors of ozone and secondary organic aerosol (SOA) in the atmosphere. Here we conducted real-time measurements of gaseous organic compounds ...using a Vocus proton-transfer-reaction mass spectrometer (Vocus PTR-MS) at the Shanghuang mountain site (1128 m a.s.l.) in southeastern China during November 2022. Our results revealed a substantial impact of mixed biogenic and anthropogenic compounds at the mountain site, with oxygenated volatile organic compounds (OVOCs) comprising 74 % of the organic vapors. Two distinct periods, characterized by sunny days (P1) and persistent cloud events (P2), were observed. P1 exhibited higher concentrations of biogenic-related emissions compared to P2. For instance, isoprene, monoterpenes, and sesquiterpenes during P1 were 2.4–2.9 times higher than those during P2. OVOCs such as acetaldehyde, MVK + MACR, acetone, and MEK also showed higher concentrations during P1, indicating a dominant source from the photochemical oxidation of biogenic VOCs. Anthropogenic-related VOCs like benzene and toluene had higher concentrations during P2, displaying different diurnal cycles compared to P1. Our analysis identified four biogenic-related factors dominated by isoprene and sesquiterpene oxidation products, and two anthropogenic-related factors. During P1, biogenic sources contributed approximately 80 % to total organic compounds, while during P2, anthropogenic sources, particularly the aromatic-related factor, increased from 16 % to 35 %. Furthermore, a unique factor characterized by C2 amines and C3 amides and periodic plumes indicated the influence of industrial emissions from regional transport. The study highlights the significant variations in sources and compositions of gaseous organic compounds at regional mountain sites due to changes in meteorology and photochemical processing, potentially impacting regional ozone and SOA formation.
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•Organic vapors at a mountain site in southeastern China were first characterized by a Vocus PTR-MS.•Organic vapors at the regional background site comprised mainly oxygenated volatile organic compounds (74 %).•Largely different influences of biogenic and anthropogenic emissions between sunny and cloudy days.
The development of highly efficient and stable monolithic catalysts is essential for the removal of volatile organic compounds (VOCs). Copper foam (CF) is a potential ideal carrier for monolithic ...catalysts, but its low surface area is not conducive to dispersion of active species, thus reducing the interface interaction with active species. Herein, a vertically oriented Cu(OH)2 nanorod was in situ grown on the CF, which acted as the template and precursor to synthesize CoCu-MOF. The optimized catalyst (12CoCu-R) delivers excellent performance for acetone oxidation with a T90 of 195 °C. Impressively, the catalyst demonstrated satisfactory stability in long-term, cycle, water resistance, and high airspeed tests. Therefore, the present study provides a novel strategy for rationally designing efficient monolithic catalysts for VOC oxidation and other environmental applications.
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•A new method for investigating the role of ROS during VOCs removal was developed.••OH radicals played a key free radical in o-xylene and styrene elimination.••O2− species acted as ...the dominant active species during acetaldehyde decomposition.••OH radicals played a leading role in the ring-opening process of benzene ring.••O2− played a crucial role in the formation of acids during acetaldehyde degradation.
To identify the distinctive role of reactive oxygen species (ROS) and trace the intermediates not only help to decompose the pollutants in high efficiency but also for avoiding more harmful intermediates formed. Here, we developed a new method to generate different ROSs by controlling the atmosphere to distinguish their role in the degradation of flowing gas-phase VOCs, including o-xylene, styrene, and acetaldehyde. This method is in good agreement with the traditional sacrificial agent capture experiment. The results show that •OH radicals play a dominant role in the degradation of o-xylene and styrene, while •O2− radicals primarily take part in the acetaldehyde degradation. Additionally, we distinguish the role of holes, •OH and •O2− played during the VOCs photo-oxidation through the radical trapping, in situ DRIFTS, and GC-MS analysis. Under the attack of •O2− radicals, aromatic VOCs were photo-oxidized to intermediates containing benzene rings and ketones (i.e., toluene and butanone), while carbon chain compounds (i.e., 3-methylfuran and ethanol) tend to form under the action of •OH and holes. This can be associated with the different reaction paths initiated by ROS. For acetaldehyde removal, •O2− species facilitate the formation of acids (i.e., acetic acid) while the •OH species and holes lead to the production of ketones (i.e., acetone). This work provides deep understanding on the role of various ROS in the photocatalytic oxidation of VOCs, which can guide the design of efficient photocatalysts, selective formation of intermediates to be easily decomposed or as raw materials for further application.
Volatile compounds are usually associated with an appearance/presence in the atmosphere. Recent advances, however, indicated that the soil is a huge reservoir and source of biogenic volatile organic ...compounds (bVOCs), which are formed from decomposing litter and dead organic material or are synthesized by underground living organism or organs and tissues of plants. This review summarizes the scarce available data on the exchange of VOCs between soil and atmosphere and the features of the soil and particle structure allowing diffusion of volatiles in the soil, which is the prerequisite for biological VOC‐based interactions. In fact, soil may function either as a sink or as a source of bVOCs. Soil VOC emissions to the atmosphere are often 1–2 (0–3) orders of magnitude lower than those from aboveground vegetation. Microorganisms and the plant root system are the major sources for bVOCs. The current methodology to detect belowground volatiles is described as well as the metabolic capabilities resulting in the wealth of microbial and root VOC emissions. Furthermore, VOC profiles are discussed as non‐destructive fingerprints for the detection of organisms. In the last chapter, belowground volatile‐based bi‐ and multi‐trophic interactions between microorganisms, plants and invertebrates in the soil are discussed.
•Grafting methyl on the inner surface to enhance the water tolerance of HY.•Attachment of methyl leads to an enhancement of toluene adsorption capacity.•Outer surface silanization could not reduce ...the effect of water on toluene adsorption.•The adsorption behavior was investigated by adsorption kinetics and Y-N model.
Although Y zeolites are considered as a promising adsorbent for capturing volatile organic compounds (VOCs), its hydrophilic nature causes a significantly decrease in VOCs adsorption performance due to the pervasive water vapor in VOCs streams. Herein, a facile approach is proposed to significantly enhance the hydrophobicity by grafting methyl on the inner surface of Y zeolite. Attachment of methyl to the inner surface leads to a significant reduction in water affinity, resulting in a notable enhancement of toluene adsorption capacity in humid environment. The silanization process and the evolution of silane species are further elucidated through in-situ DRIFTS, NMR and TGA. Adsorption kinetics reveals that inner surface silanization reduces the adsorption rate constant of water by 50 %. However, the outer surface silanization with propyl is ineffective in mitigating the detrimental impact of water on the toluene adsorption. Moreover, Yoon-Nelson (Y-N) model analysis is applied to predict the breakthrough characteristics of fixed-bed adsorption and to evaluate the applicability in actual industry. In this work, this regioselective silanization approach could provide a facile strategy for controlling VOCs in humid environment.
Manganese oxide supported Pt single atoms (Pt1/MnOx) are prepared by the molten salt method. Catalytic oxidation of toluene and iso-hexane, typical emissions from furniture paints industry, is ...tested. Pt1/MnOx shows poor and high catalytic stability for toluene and iso-hexane oxidation, respectively. Enhancement in the catalytic stability for toluene oxidation is observed after the hydrogen reduction treatment of Pt1/MnOx at 200 °C. The hydrogen treated catalyst possesses the weaker Mn–O bonds and lower coordination number of PtO, with superior mobility of lattice oxygen and appropriate toluene adsorption. Balancing lattice oxygen mobility and volatile organic compounds adsorption is important for the catalytic stability of Pt1/MnOx. For the oxidation of toluene and iso-hexane mixture, owing to the competitive adsorption, iso-hexane oxidation is greatly inhibited, while toluene oxidation is not influenced. The present Pt1/MnOx catalyst holds promising prospect in furniture paints industry applications because of high catalytic stability and water resistance ability.
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•Single-atom Pt catalyst is synthesized via a novel one-pot molten salt strategy.•Simple H2 reduction treatment enhances the catalytic stability of single-atom Pt catalyst.•Balancing oxygen mobility and VOCs adsorption is the key for catalytic stability.•Single-atom Pt catalyst exhibits high performance for VOCs mixture removal in the presence of water.
Systemic propagation of immunity in plants Vlot, A. Corina; Sales, Jennifer H.; Lenk, Miriam ...
The New phytologist,
February 2021, 2021-02-00, 20210201, Letnik:
229, Številka:
3
Journal Article
Recenzirano
Odprti dostop
Summary
Systemic immunity triggered by local plant–microbe interactions is studied as systemic acquired resistance (SAR) or induced systemic resistance (ISR) depending on the site of induction and ...the lifestyle of the inducing microorganism. SAR is induced by pathogens interacting with leaves, whereas ISR is induced by beneficial microbes interacting with roots. Although salicylic acid (SA) is a central component of SAR, additional signals exclusively promote systemic and not local immunity. These signals cooperate in SAR‐ and possibly also ISR‐associated signaling networks that regulate systemic immunity. The non‐SA SAR pathway is driven by pipecolic acid or its presumed bioactive derivative N‐hydroxy‐pipecolic acid. This pathway further regulates inter‐plant defense propagation through volatile organic compounds that are emitted by SAR‐induced plants and recognized as defense cues by neighboring plants. Both SAR and ISR influence phytohormone crosstalk towards enhanced defense against pathogens, which at the same time affects the composition of the plant microbiome. This potentially leads to further changes in plant defense, plant–microbe, and plant–plant interactions. Therefore, we propose that such inter‐organismic interactions could be combined in potentially highly effective plant protection strategies.
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