Gas Source Research Articles

A Comprehensive Review of CO2 Mineral Sequestration Methods Using Coal Fly Ash for Carbon Capture, Utilisation, and Storage (CCUS) Technology

CO2 emissions from fossil fuel combustion are the main source of anthropogenic greenhouse gases (GHGs). A method of reducing CO2 emissions is CCUS (carbon capture, utilisation, and storage) technology. One part of CCUS technology involves mineral sequestration as its final stage, utilisation, which can be carried out using natural raw materials or waste. This is a particularly interesting option for power and CHP plants that use coal as their primary fuel. Combustion processes produce fly ash as a waste by-product, which has a high potential for CO2 sequestration. Calcium fly ash from lignite combustion and fly ash from fluidised bed boilers have particularly high potential due to their high CaO content. Fly ash can be used in the mineral sequestration of CO2 via direct and indirect carbonation. Both methods use CO2 and flue gases. Studies conducted so far have analysed the influence of factors such as temperature, pressure, and the liquid-to-solid (L/S) ratio on the carbonation process, which have shown different effects depending on the ash used and the form of the process. Due to the large differences found in the properties of fly ash, related primarily to the type of fuel and boiler used, the process of mineral CO2 sequestration requires much research into its feasibility on an industrial scale. However, the method is promising for industrial applications due to the possibility of reducing CO2 emissions and, at the same time, recovering waste.

The Gas Generation Process and Modeling of the Source Rock from the Yacheng Formation in the Yanan Depression, South China Sea

The research on deepwater oil and gas exploration areas is relatively limited, and sample collection is difficult. A drilled coal sample from Yanan Depression was used to investigate the hydrocarbon generation process, and the potential, by a gold tube thermal simulation experiment. The results show that the total gas yield was much higher than the oil yield. According to an analysis of the gas pyrolysis data, as represented by ln(C1/C2) and ln(C2/C3), the gas generation process consisted of two forms, namely, primary gas with ~1.33% Ro and secondary gas that occurred at levels greater than 1.33% Ro. The primary gas from kerogen was generated at ~1.33% Ro, which coincided with the %Ro value of the maximum oil yield. The activation energy distribution of the C1–C5 generation processes ranged from 54 to 72 kcal/mol, with a frequency factor of 6.686 × 1014 s−1 for the coal sample. We constructed the history of gas generation on the basis of the process and kinetic parameters, combined with data on the sedimentary burial and thermal history. The extrapolation of the gas history revealed that the gas has been generated from 5 Ma to the present, with a maximum yield of 178.5 mg/gTOC. This history suggests that the coal has good primary gas generation potential and provides favorable gas source conditions for the formation of gas fields. This study provides a favorable basis for expanding the effective source rock areas.

Implementation Status and Suggestions of “Coal-to-gas” Policy in Beijing-Tianjin-Hebei Region of China

With the acceleration of industrialization for the past few years, the level of air pollution has also increased significantly. The Beijing-Tianjin-Hebei region is one of the regions that need to be improved urgently. The air pollutants produced by coal burning are the main source of pollution in this region, so it is of great practical necessity for the Beijing-Tianjin-Hebei region to replace coal burning with clean energy. At present, the status of the "coal-to-gas" policy of the Beijing-Tianjin-Hebei region has achieved remarkable results. With the strong support of the government, air pollution has been effectively improved. However, there are still many problems such as "one-size-fits-all" policy, imperfect financial subsidy mechanism, tight gas source, differentiated scope of policy implementation, and hidden dangers of rural equipment safety. For these reasons, the government should formulate differentiated policies according to local conditions, implement "coal-to-gas" and "coal-to-electricity" synchronously, improve the subsidy mechanism, strengthen technical and equipment support, enhance gas supply security, stabilize gas price and strengthen publicity and training.

The next challenge in emissions control for heavy-duty diesel vehicles: From NOx to N2O

Vehicle emissions are a major source of greenhouse gases globally. Dual selective catalytic reduction (SCR), an advanced version of single SCR, is crucial under stricter nitrogen oxide (NOx) emission standards for heavy-duty diesel vehicles (HDDVs). However, the emission characteristics of nitrous oxide (N2O), a byproduct of SCR and a potent greenhouse gas, remain unclear. This study investigates the N2O emissions from HDDVs equipped with single or dual SCR systems using heavy-duty chassis dynamometers under various ambient temperatures, altitudes, and loading masses. The results showed that the brake-specific emissions (EFb) of N2O from HDDVs with single and dual SCRs were 76.28–269.65 mg/kWh and 147.50–170.22 mg/kWh, respectively. Notably, the dual SCR-equipped HDDV emitted 6–22 times more N2O than NOx under all tested conditions. As ambient temperature increased from −10 °C to 25 °C and from 25 °C to 40 °C, the average distance-based emission factors (EFd) of N2O for the single SCR-equipped HDDV increased by 87.73% and 48.26%, respectively. However, the variation was not significant for the dual SCR-equipped HDDV. Under half- and full-load conditions, the average EFd of N2O for the single SCR-equipped HDDV increased by 47.57% and 110.92%, respectively, compared to those without loading. Similarly, N2O emissions for dual SCR-equipped HDDV increased by 41.40% and 65.37% under the same loading variations. As altitude increased from 0 m to 3000 m, the average EFd of N2O for the single SCR-equipped HDDV decreased by 64.31%. Additionally, N2O emissions were significantly affected by SCR temperature, engine power, and nitric oxide (NO)/nitrogen dioxide (NO2) ratio. These findings are crucial for setting future greenhouse gas limits of HDDVs and informing carbon reduction strategies.

Synchronous photocatalytic benzimidazole formation and olefin reduction by magnetic separable visible-light-driven Pd-g-C3N4-Vanillin@γ-Fe2O3-TiO2 Nanocomposite

A visible light-responsive magnetically separable photocatalyst Pd-g-C3N4-Vanillin@γ-Fe2O3-TiO2 is fabricated using vanillin as a natural junction under ultrasonic agitation. Structural, morphological, optical, thermal, and magnetic assessments of the as-prepared catalyst are carried out. The photocatalyst successfully drives the simultaneous benzimidazole formation, and olefin hydrogenation with high atom economy under blue LED light and mild conditions. The photocatalytic activity of Pd-g-C3N4-Vanillin@γ-Fe2O3-TiO2 is significantly affected by the γ-Fe2O3:TiO2 weight ratio. PL spectra revealed the effective separation of carriers in the fabricated catalyst promoting its photocatalytic activity. The action spectra using the apparent quantum efficiency (AQE) exhibited the maximum AQEs at 520 and 750 nm in which the highest performance for styrene hydrogenation is observed. The title magnetically separable heterogeneous photocatalyst provides high yields of products under perfectly safe visible light, produces low/zero waste, and avoids using an external high-pressure hydrogen gas source, harmful solvents, undesirable additives, and reducing agents rendering green conditions for chemical reactions.

Study on the effect pattern of moisture on the oxidized combustion of ventilation air methane

AbstractVentilation air methane (VAM) is one of the main greenhouse gas sources. Owing to the characteristics of low concentration of ventilation air methane and high moisture content, we build an experimental platform and take the oxidative combustion temperature and methane conversion rate as the research indexes, and the systematic research finds that the inhibitory effect of moisture on the oxidative combustion of ultra‐low concentration of methane (<1%) is a nonlinear polynomial law. In the meantime, we constructed OH(H2O)n+CH4 and studied its reaction potential energy surface using quantum chemical calculations, which used the most significant primitive reaction of methane combustion, OH+CH4→H2O+CH3, as the theoretical basis. We found that as moisture content increased, so did its reaction energy barrier, making the reactants more stable, strengthening the three‐body collision effect, and reducing the number of free radicals, all of which hindered the methane chain reaction. The study aimed to validate the experimental finding that moisture inhibits the oxidative combustion of ventilation air methane by examining the internal mechanism of methane oxidation. © 2024 Society of Chemical Industry and John Wiley & Sons, Ltd.

Sources and exploration potential of Ordovician subsalt natural gas in Ordos Basin, China

With the continuous increase in exploration efforts in new zones and new strata, significant breakthroughs have been made in the natural gas exploration of the O1m56 to O1m4 formations in the Ordos Basin. Thus, the origin and exploration potential of subsalt natural gas have attracted much attention and urgently need to be addressed. On the basis of certain geochemical characteristics, genetic types, and sources of natural gas, a comprehensive study on the sedimentary environment, organic geochemical characteristics, and spatial distribution scale of source rocks are conducted in this paper by using geological and geochemical methods. The study shows that: (1) The Ordovician subsalt natural gas is mainly “pyrolysis dry gas,” among which the δ13C1 of Ordovician subsalt low sulfur (sulfur-free) natural gas is lighter, with an average value of −39.6‰; the δ13C2 ranges more largely from −35.6‰ to −25.8‰. In contrast, both δ13C1 and δ13C2 values are heavier in high-sulfur natural gas, revealing that different Thermochemical Sulfate Reduction (TSR) reaction stages have different degrees of influence on natural gas components and carbon isotope composition. (2) Subsalt natural gas is classified as “oil-type gas,” which is self-generated and self-accumulated, whose source rocks are mainly Ordovician subsalt marine deposits. (3) Three types of marine source rocks are developed in Ordovician subsalt, including black argillaceous rock, dark argillaceous dolomite (dolomitic mudstone), and dark micrite (bioclastic) limestone. In addition to micrite limestone, these rocks were mainly formed in a confined lagoon sedimentary environment with high salinity and anoxia. Sedimentary water was significantly stratified and the environment was highly reduced. The organic matter content of the source rocks is relatively high, with an average TOC value of 0.45%. The hydrocarbon-generating parent materials are mainly composed of bacteria and algae, and the organic matter evolution reaches high-over maturity stage. The total gas generation amount of the marine source rocks in Ordovician subsalt is approximately 43.8×1012 m3, which can provide hydrocarbons and accumulate for the subsalt favorable reservoir facies located far from Upper Paleozoic gas sources.

Pore formation and evolution mechanisms during hydrocarbon generation in organic-rich marl

Marine organic-rich marl is not only a high-quality hydrocarbon source of conventional oil and gas, but also a new type and field of unconventional oil and gas exploration. An understanding of its pore structure evolution characteristics during a hydrocarbon generation process is theoretically significant and has application prospects for the exploration and development of this special type of natural gas reservoirs. This study conducted thermal simulation of hydrocarbon generation under near-geological conditions during a whole process for cylinder samples of low mature marine organic-rich marl in the Middle Devonian of Luquan, Yunnan Province, China. During this process, hydrocarbon products at different evolution stages were quantified and corresponding geochemical properties were analyzed. Simultaneously, field emission scanning electron microscopy (FE-SEM) and low-pressure gas adsorption (CO2, N2) tests were applied to the corresponding cylinder residue samples to reveal the mechanisms of different types of pore formation and evolution, and clarify the dynamic evolution processes of their pore systems. The results show that with an increase in temperature and pressure, the total oil yield peaks at an equivalent vitrinite reflectance (VRo) of 1.03% and is at the maximum retention stage of liquid hydrocarbons, which are 367.51 mg/g TOC and 211.67 mg/g TOC, respectively. The hydrocarbon gas yield increases continuously with an increase in maturity. The high retained oil rate at the peak of oil generation provides an abundant material basis for gas formation at high maturity and over-maturity stage. The lower limit of VRo for organic matter (OM) pore mass development is about 1.6%, and bitumen pores, organic-clay complex pores together with intergranular pores, grain edge seams and dissolution pores constitute a complicated pore-seam-network system, which is the main reservoir space for unconventional carbonate gas. Pore formation and evolution are controlled synergistically by hydrocarbon generation, diagenesis and organic-inorganic interactions, and the pattern of pore structure evolution can be divided into four stages. A pore volume (PV) and a specific surface area (SSA) are at their highest values within the maturity range of 1.9% to 2.5%, which is conducive to exploring unconventional natural gas.

Key effects contributing to changes in energy imports in the EU-27 between 2000 and 2020: A decomposition analysis based on the Sankey diagram

The aim of this paper is to analyse the key effects contributing to changes in energy imports in the European Union (EU-27) in the period 2000–2020. Using the Logarithmic Mean Divisia Index (LMDI), the analysis examines the effect of changes in six factors—energy structure, energy dependence, energy transformation efficiency, energy yield after transformation, energy efficiency and activity—on imports of oil, natural gas and other sources of energy. The results of the analysis reveal that the decarbonisation process has fostered the abandonment of the most polluting fossil fuel sources; however, there has been an increase in energy dependence on less polluting sources that are not produced domestically. In contrast, there has been an opportunity for change through improved energy efficiency, which has made it possible to reduce energy requirements per unit produced. In short, in order to achieve a sustainable and secure energy future, it is crucial to implement policies and actions that promote both the diversification of the energy mix—particularly renewable energies—and efficiency in consumption. Doing so will enable countries to move towards true decarbonisation and minimise vulnerability in their energy supply.

Identification and prevention of gas source in goaf: Stable carbon hydrogen isotope tracer method and numerical simulation of gas flow field

Identification and prevention of gas source in goaf: Stable carbon hydrogen isotope tracer method and numerical simulation of gas flow field

A novel hybrid information-based PF-WOA algorithm for gas source localization in 3D space

Abstract In recent years, dangerous gas leakage events occur frequently. Rapid and accurate location of gas leakage sources by mobile robots is the key to avoid the expansion of disasters. In order to solve the problem of discontinuous gas concentration gradient and sparse gas environment in three-dimensional space, particle filter, and whale swarm optimization algorithm are integrated to locate gas source. Firstly, the Z-shape search and comb search are used to locate the plume, and then, the particle filter algorithm is combined with the whale optimization method to guide the particle movement, and the random inertial disturbance term is designed to improve the convergence speed and search accuracy of the algorithm. Experimental results in three-dimensional environment show that the proposed information-driven particle filter whale optimization hybrid algorithm effectively guides the robot in localizing gas source within a certain range, significantly enhancing both the efficiency and accuracy of localization compared to other algorithms.

COCCON Measurements of XCO2, XCH4 and XCO over Coal Mine Aggregation Areas in Shanxi, China, and Comparison to TROPOMI and CAMS Datasets

This study presents the first column-averaged dry-air mole fractions of carbon dioxide (XCO2), methane (XCH4) and carbon monoxide (XCO) in the coal mine aggregation area in Shanxi, China, using two portable Fourier transform infrared spectrometers (EM27/SUNs), in the framework of the Collaborative Carbon Column Observing Network (COCCON). The measurements, collected over two months, were analyzed. Significant daily variations were observed, particularly in XCH4, which highlight the impact of coal mining emissions as a major CH4 source in the region. This study also compares COCCON XCO with measurements from the TROPOspheric Monitoring Instrument (TROPOMI) onboard the Sentinel-5P satellite, revealing good agreement, with a mean bias of 7.15 ± 9.49 ppb. Additionally, comparisons were made between COCCON XCO2 and XCH4 data and analytical data from the Copernicus Atmosphere Monitoring Service (CAMS). The mean biases between COCCON and CAMS were −6.43 ± 1.75 ppm for XCO2 and 15.40 ± 31.60 ppb for XCH4. The findings affirm the stability and accuracy of the COCCON instruments for validating satellite observations and detecting local greenhouse gas sources. Operating COCCON spectrometers in coal mining areas offers valuable insights into emissions from these high-impact sources.

Influencing Factors and Model of Shallow Gas Enrichment in the Quaternary Sediments of the Qiongdongnan Basin, South China Sea

Investigating the primary influencing factors that regulate the enrichment of shallow gas not only deepens our understanding of the rules governing shallow gas enrichment in deep-ocean environments but also has the potential to enhance the success rate of locating shallow gas reservoirs. Recent drilling activities in the LS36 gas field located in the central Qiongdongnan Basin have revealed a substantial shallow gas reserve within the sediments of the Quaternary Ledong Formation, marking it as the first shallow gas reservoir discovered in the offshore region of China with confirmed natural gas geological reserves surpassing 100 billion cubic meters. However, the formation mechanism and influencing factors of shallow gas enrichment remain elusive due to the limited availability of 3D seismic and well data. This study employs seismic interpretation and digital simulation to decipher the dynamics of shallow gas accumulation and utilizes the carbon isotope composition of methane to ascertain the origin of the shallow gas. Our results show that the shallow gas is primarily concentrated within a large-scale submarine fan, covering a distribution region of up to 2800 km2, situated in the deep-sea plain. The δ13 C1 methane carbon isotope data ranges from −69.7‰ to −45.2‰ and all δ13 C2 values are above −28‰, suggesting that the shallow gas within the Ledong Formation is derived from a mix of biogenic gas produced in shallow strata and thermogenic gas generated in deeper source rocks. The results of gas sources, seismic profiles, and digital simulations suggest that thermogenic gas originating from the Lingshui and Beijiao sags was transported to the Quaternary submarine fan via a complex system that includes faults, gas chimneys, and channel sands. The mass-transported deposits (MTDs) in the upper reaches of the submarine fan have effectively acted as a seal, preventing the escape of shallow gas from the fan. Therefore, the factors contributing to the enrichment of shallow gas in the Qiongdongnan Basin include the presence of favorable submarine fan reservoirs, the availability of two distinct gas sources, the effective sealing of MTDs, and the presence of two efficient transport pathways. A conceptual model for the accumulation of shallow gas is developed, illuminating the complex formation–migration–accumulation process. This study underscores the importance of aligning multiple influencing factors in the process of shallow gas accumulation, and the suggested accumulation model may be pertinent to shallow gas exploration in other marginal sea basins.

Monitoring of the inertization of cargo tanks of LNG class vessels

The results of monitoring the inertization of cargo tanks of vessels intended for the transportation of liquefied natural gas are given. It is determined that the mandatory stage of cargo operations in the port of unloading of liquefied natural gas is the inertization of tanks. It is noted that on gas-carrying vessels, the following sources of inert gases can be: flue gases of vessel's auxiliary boilers; gases generated in the inert gas generator during the burning of liquid fuel in them; directly chemically pure inert gas (usually nitrogen). It is also stated that the inertization of cargo tanks is carried out by one of two methods: either dilution of the gas atmosphere (which is the process of mixing two environments), or replacement of the gas atmosphere (in which the gases supplied to the tank form a dividing layer and gradually displace the residual vapors cargo). The stability and integrity of the dividing layer determines the inertization quality of cargo tanks. Control of the state of the dividing layer in the cargo tank is impossible with optical or visual means of control, which is caused by the opaque environment inside the tank. In this regard, it is proposed to determine the integrity of the separating layer, as well as the level at which it is located in the cargo tank, by measuring the concentration of inert gas in the volume of the tank. Research was carried out on a gas carrier with a cargo capacity of 42,563 m3. Inertization of the vessel's cargo tanks was ensured with the help of nitrogen, which was generated by an inert gas generator using the Pressure Swing Adsorption technology. Nitrogen concentration monitoring in the volume of the cargo tank was performed at levels corresponding to 5 %, 20 %, 50 %, 80 % and 95 % of the tank depth. Research on determining the effect of nitrogen pressure entering the cargo tanks for their inertization on the stability and integrity of the dividing layer was carried out in the range of 0.95–1.05 MPa. The duration of the experiment was 210 minutes, fixation of nitrogen concentration values was performed every 30 minutes. As a result, optimal pressure values were established, according to which the inertization is ensured in the minimum time. The critical pressure values at which the separation layer breaks down were also determined.

Decarbonizing Public Transportation: A Multi-Criteria Comparative Analysis of Battery Electric Buses and Fuel Cell Electric Buses

To combat global warming, many industrialized countries have announced plans to ban vehicles powered by fossil fuel in the near future. In alignment with this global initiative, many countries across the globe are committed to decarbonizing their public transportation sector, which significantly contributes to increased greenhouse gas emissions. A promising strategy to achieve this goal is the adoption of electric buses, specifically battery electric buses and fuel cell electric buses. Each technology offers distinct advantages and drawbacks, making the decision-making process complex. This research aims to answer two critical questions: What is the optimal choice for decarbonizing the bus transportation sector—electric battery buses or fuel cell electric buses? And what are the best energy carrier pathways for charging or refueling these buses? We propose a methodological framework based on multi-criteria decision-making to address these questions comprehensively. This framework utilizes the entropy weighting and the Technique for Order Preference by Similarity to the Ideal Solution (TOPSIS) methodologies to rank alternative bus technologies along with energy carrier pathways. The framework evaluates a range of criteria, including economic viability, energy demand, and environmental aspects. To illustrate the framework, we considered Qatar as a case study. Our results indicate that, with respect to economic viability and energy consumption, the operation of battery electric buses is favored over fuel cell electric buses, regardless of the energy pathway utilized during both the energy production and bus operation phases. However, from an environmental perspective, operating both bus alternatives using energy from green sources provides superior performance compared to when these buses are powered by natural gas sources.

CLOUDY modeling suggests a diversity of ionization mechanisms for diffuse extraplanar gas

Context. The ionization of diffuse gas located far above the energetic midplane OB stars poses a challenge to the commonly accepted notion that radiation from OB stars is the primary ionization source for gas in galaxies. Aims. We investigated the sources of ionizing radiation, specifically leaking midplane H II regions and/or in situ hot low-mass evolved stars (HOLMES), in extraplanar diffuse ionized gas (eDIG) in a sample of eight nearby (17−52 Mpc) edge-on disk galaxies observed with the Multi Unit Spectroscopic Explorer (MUSE). Methods. We constructed a model for the photoionization of eDIG clouds and the propagation of ionizing radiation through the eDIG using subsequent runs of CLOUDY photoionization code. Our model includes radiation originating both from midplane OB stars and in situ evolved stars and its dilution and processing as it propagates in the eDIG. Results. We fit the model to the data using the vertical line ratio profiles of our sample galaxies, and find that while the ionization by in situ evolved stars is insignificant for most of the galaxies in our sample, it may be able to explain the enhanced high-ionization lines in the eDIG of the green valley galaxy ESO 544−27. Conclusions. Our results show that while leaking radiation from midplane H II regions is the primary ionization source for eDIG, in situ evolved stars can play a significant part in ionizing extraplanar gas in galaxies with low star forming rates.

Inkjet-Printed Localized Surface Plasmon Resonance Subpixel Gas Sensor Array for Enhanced Identification and Visualization of Gas Spatial Distributions from Multiple Odor Sources

The visualization of the spatial distributions of gases from various sources is essential to understanding the composition, localization, and behavior of these gases. In this study, an inkjet-printed localized surface plasmon resonance (LSPR) subpixel gas sensor array was developed to visualize the spatial distributions of gases and to differentiate between acetic acid, geraniol, pentadecane, and cis-jasmone. The sensor array, which integrates gold nanoparticles (AuNPs), silver nanoparticles (AgNPs), and fluorescent pigments, was positioned 3 cm above the gas source. Hyperspectral imaging was used to capture the LSPR spectra across the sensor array, and these spectra were then used to construct gas information matrices. Principal component analysis (PCA) enabled effective classification of the gases and localization of their sources based on observed spectral differences. Heat maps that visualized the gas concentrations were generated using the mean squared error (MSE) between the sensor responses and reference spectra. The array identified and visualized the four gas sources successfully, thus demonstrating its potential for gas localization and detection applications. The study highlights a straightforward, cost-effective approach to gas sensing and visualization, and in future work, we intend to refine the sensor fabrication process and enhance the detection of complex gas mixtures.

Precision and uncertainty in natural gas calorific value estimation: advanced combinatorial predictive models for complex pipeline systems

Abstract In recent years, natural gas pipelines have been characterized by multiple intake points, the mixing of different gas sources, and significant variations in gas quality. The existing volumetric measurement system is no longer suitable for the development and operation of natural gas pipelines in China. To ensure accurate and equitable implementation of natural gas measurement, there is a gradual shift towards energy measurement. However, due to numerous measurement interfaces, installing chromatographs at all measurement stations would lead to substantial investment costs. Therefore, predicting the calorific value of natural gas is a key technology for energy measurement. In view of the issues existing in the current methods of obtaining natural gas calorific value, different prediction models of natural gas calorific value are constructed. According to the influencing factors of natural gas calorific value, the uncertainty evaluation is carried out, and the accuracy of different calorific value prediction models is analyzed by case data. The maximum error of regression equation (RE), response surface analysis (RSA), BP neural network and genetic algorithm (GA) prediction model is 2.29%, 0.43%, 0.59% and 0.45% respectively. However, the combined calorific value (CCV)prediction model is 0.41%. The results indicate that the predicted value calculated by the CCV prediction model is closer to the actual value and has higher prediction performance, which provides a new method for the calorific value prediction and measurement management of natural gas.

Detecting and sourcing GHGs and atmospheric trace gases in a municipal waste treatment plant using coupled chemistry and isotope compositions

Landfill operations and waste processing facilities are important and highly heterogeneous sources of both greenhouse gases (GHGs) and non-GHG air pollutants in the atmosphere. This arises the need for detailed apportionment of waste sources in order to locate and subsequently reduce emissions from landfills. Here, a time series of in situ measurements of atmospheric trace gases and spatial allocation of specific emission source types under different processing phases and environmental conditions were conducted in and in the surroundings of a Municipal Solid Waste Treatment Plant (MSWTP) in south-western Poland. Results revealed that several individual GHG sources dominated across the waste processing facility and that GHGs concentrations displayed spatial seasonality. An increase in the ground-level CH4 concentrations, from ∼ 30.3 to 56.3 ppmv, was observed close (∼5 – 10 m) to the major emission sources within the MSWTP. While hotspot areas generally yielded elevated CH4 concentrations near the soil surface, these were relatively low (2.4 to 8.9 ppmv) along the facility’s fence line. The study of the corresponding δ13C delineated the extent of dispersion plumes downwind emission hotspots, characterized by a 13C depletion (around 4.0 ‰) in the atmospheric CH4 and CO2. For CH4, emissions were isotopically discriminated between the extraction wells at active quarters/cells (δ13C = –58.3 ± 1.1 ‰) and biogas produced in the biological waste treatment installation (δ13C = –62.7 ± 0.7 ‰). Most of the trace compounds (non-methane hydrocarbons, halocarbons, oxygen-bearing organic gases, ketones, nitrogenous and sulphurous gases, and other admixture compounds) detected at the ground surface were linked to the CH4- and CO2-rich spots. Despite the relatively high variability in the concentrations of organic and inorganic compounds observed at the MSWTP active zones, our results suggest that they do not have a meaningful impact on the surrounding air quality.

Elucidation of Spartina dimethylsulfoniopropionate synthesis genes enables engineering of stress tolerant plants

The organosulfur compound dimethylsulfoniopropionate (DMSP) has key roles in stress protection, global carbon and sulfur cycling, chemotaxis, and is a major source of climate-active gases. Saltmarshes are global hotspots for DMSP cycling due to Spartina cordgrasses that produce exceptionally high concentrations of DMSP. Here, in Spartina anglica, we identify the plant genes that underpin high-level DMSP synthesis: methionine S-methyltransferase (MMT), S-methylmethionine decarboxylase (SDC) and DMSP-amine oxidase (DOX). Homologs of these enzymes are common in plants, but differences in expression and catalytic efficiency explain why S. anglica accumulates such high DMSP concentrations and other plants only accumulate low concentrations. Furthermore, DMSP accumulation in S. anglica is consistent with DMSP having a role in oxidative and osmotic stress protection. Importantly, administration of DMSP by root uptake or over-expression of Spartina DMSP synthesis genes confers plant tolerance to salinity and drought offering a route for future bioengineering for sustainable crop production.