Lower Greenhouse Gas Emissions Research Articles

Cu-Supported ZnO under Conditions of CO2 Reduction to Methanol: Why 0.2 ML Coverage?

By hydrogenating carbon dioxide to value-added products such as methanol, heterogeneous catalysts can lower greenhouse gas emissions and generate alternative liquid fuels. The most common commercial catalyst for the reduction of CO2 to methanol is Cu/ZnO/Al2O3, where ZnO improves conversion and selectivity toward methanol. The structure of this catalyst is thought to be Zn oxy(hydroxyl) overlayers on the nanometer scale on Cu. In the presence of CO2 and H2 under reaction conditions, the Cu substrate itself can be restructured and/or partially oxidized at its interface with ZnO, or the Zn might be reduced, possibly completely to a CuZn alloy, making the exact structure and stoichiometry of the active site a topic of active debate. In this study, we examine Zn3 clusters on Cu(100) and Cu(111), as a subnano model of the catalyst. We use a grand canonical genetic algorithm to sample the system structure and stoichiometry under catalytic conditions: T of 550 K, initial partial pressures of H2 of 4.5 atm and CO2 of 0.5 atm, and 1% conversion. We uncover a strong dependence of the catalyst stoichiometry on the surface coverage. At the optimal 0.2 ML surface coverage, chains of Zn(OH) form on both Cu surfaces. On Cu(100), the catalyst has many thermally accessible metastable minima, whereas on Cu(111), it does not. No oxidation or reconstruction of the Cu is found. However, at a lower coverage of Zn, Zn3 clusters take on a metallic form on Cu(100), and slightly oxidized Zn3O on Cu(111), while the surface uptakes H to form a variety of low hydrides of Cu. We thus hypothesize that the 0.2 ML Zn coverage is optimal, as found experimentally, because of the stronger yet incomplete oxidation afforded by Zn at this coverage.

Climate Smart Agriculture: Innovating Sustainable Practices for a Changing Climate

Climate Smart Agriculture (CSA) is a strategy aimed at lowering greenhouse gas emissions, strengthen climate change resilience, raising crop production and incomes significantly. In a variety of agro-ecological zones, the implementation of climate smart agriculture methods has significantly improved the availability of food, adaptability to fluctuations in the climate, and emissions reduction. One of the key benefits of CSA is its ability to improve agricultural productivity and stabilize food security, particularly for small-scale farmers in developing nations who are most vulnerable to climate change. By integrating sustainable techniques such as conservation agriculture, crop diversification, and agroforestry, CSA helps ensure stable yields, even amid erratic weather patterns. Enhanced soil fertility, enhanced irrigation practices and the use of varieties of crops that are climate resilient all contribute to sustained productivity, mitigating the risks of crop failure and food shortages. CSA also strengthens agricultural systems' resilience to climate impacts by promoting practices like zero tillage, residue management, and efficient irrigation, which improve soil health and water retention, making crops more resistant to droughts and floods. In addition to boosting resilience, CSA contributes to climate change mitigation by reducing agriculture's carbon footprint. Precision farming, organic agriculture, and other low-emission practices help curb greenhouse gas emissions from farming activities. Mobile technology is also emerging as a key driver of CSA by providing real-time information, decision-making support, and access to essential resources, further enhancing the adaptability and sustainability of farming systems. The significance of CSA as a strategic solution to the threats that climate change poses to food security and agricultural sustainability is being more widely acknowledged by governments. As a result, numerous initiatives have been launched at national, regional, and international levels to encourage the widespread adoption of CSA practices. In order to achieve sustainable agricultural development and ensure food security in the face of climate change, CSA must be scaled up around the world.

Industrial Symbiosis Practices: A Case Study of Türkiye and Denmark

The term "industrial symbiosis (IS)" refers to a cooperative strategy where industrial actors share services and exchange physical resources. This method improves resource efficiency and lessens the environmental effects of industrial operations within the network. It is a cooperative method in which businesses trade and reuse physical resources such as by-products, water, and energy, as well as share services such as waste management and infrastructure. It has several advantages, such as (i) lowering greenhouse gas emissions through energy, process, input, disposal, and transportation savings, as well as fuel substitution; (ii) cutting energy expenses; (iii) diverting waste from landfills; (iv) avoiding the use of virgin materials; (v) lowering transportation and logistics costs; (vi) lowering pollution to land, water, and air; (vii) lowering industrial water use; (viii) lowering hazardous waste; (ix) creating economic value from waste material; and (x) simplifying environmental legislation and regulation compliance. In Türkiye and Denmark, the number of industrial companies is rapidly increasing. These industries consume many resources (such as raw materials, water, electricity, natural gas, coal, etc.) and generate a large amount of solid, liquid, and gaseous waste. IS is gaining popularity as an approach for improving the sustainability of industrial systems. The efforts to develop IS have emerged as a critical issue over the last decade in these two European countries. The paper presents the current implementation of IS in Türkiye and Denmark’s process sectors, focusing on well-known IS practices.

An Experimental Study on the Effect of Nano Zinc Oxide on Reflective Coatings and Building Roof Temperatures

Most roofs on Earth are made of dark materials. Dark roof surfaces can retain heat better than light ones; in Iraq, summer time temperatures on the roofs of dark buildings reached 70–80 degrees Celsius in July and August. The effects of this temperature rise are detrimental to cooling and energy consumption. To lessen heat transfer into the building, use reflective surfaces that can reflect infrared radiation waves. Cool roofs have both short-term and long-term advantages. They can reduce a building's annual air conditioning energy consumption by up to 15%, extend the life of the roof and its service life, improve the energy efficiency of roofs particularly those with inadequate insulation at the front of the roof improve thermal comfort in buildings without air conditioning, and lower greenhouse gas emissions and air pollution. Solar heat is one of the main factors affecting the durability of roofing membranes, according to research and real-world experience with the deterioration of these materials over time. High solar reflectance materials can reflect more sunlight and maintain their coolness in the sun. This study examines a low-cost composite cool coating that uses 60% calcium carbonate and demonstrates a 15°C drop in surface concrete temperature for roof buildings when compared to an uncoated surface. Additionally, compared to 30%wt CaCO3, the effect of 60%CaCO3 in composite coating reduces adhesion strength. According to the study, the weight of CaCO3 in the composite coating increases while adhesion strength, surface roughness, and particle homogeneity distribution decrease. Conversely, the maximum weight of CaCO360% weight percent exhibits good IR reflectance and less tribological properties. While preserving good infrared reflectance, adding 10% ZnO to the coating solution (60% CaCO3/PVac) improves tribological properties. The adhesion strength of the 60% calcium carbonate polymer composite paint increased from 10.9 MPa to 40.2 MPa when the nanomaterial was present, while this material maintained the superior optical qualities of infrared reflection. The coefficient of thermal expansion varies between concrete and coating solutions. For instance, the coating that has 10% weight added ZnO has a peel resistance coefficient of 8*10-6 1/K. The 60%CaCO3/10%ZnO/PVac coating effectively lowers the temperature by 15–12 °C when applied to a building roof.

Mitigation of phosphorus contamination from livestock farms with La-containing hydrochar adsorbent

Phosphorus releases from livestock and poultry farms cause environmental contamination that must be mitigated through robust and effective recycle technologies. Lanthanum-modified hydrochars (La-HCN) prepared via mechanochemical modification had 96.8 mg g−1 phosphorus adsorption capacities and unprecedented fast uptake rates (half-maximum absorption capacity in 1.5 min). Presence of nitrogen in the hydrochars enhanced ion electrostatic interactions between lanthanum and carbon and accelerated phosphorus adsorption, which was confirmed theoretically with density functional theory calculations. Life cycle assessment (LCA) on a one-animal one-year basis revealed that production of La-containing hydrochar required fewer resources, had lower greenhouse gas emissions (171 kg CO2) and lower environmental impact than comparable adsorbent materials. Phosphorus removal levels achieved using the La-HCN adsorbent on actual wastewater from livestock and poultry breeding farms reached an adsorption rate of 93.6 %, exceeded sewage effluent standards of China, US EPA and EU, thus, demonstrate the practicality and scope of the developed technology.

Artificial humic acid promotes carbon sequestration in rice-soil system

Artificial humic acid (AHA) is a new exogenous organic material with enormous carbon sequestration potential. However, the effects and mechanisms of applying AHA under different irrigation regimes on carbon sequestration in rice-soil systems still need to be clarified. This study applied carbon isotope labeling technology to analyze the photosynthetic carbon sequestration capacity, the carbon transport capacity of the root, and greenhouse gas emission flux in the rice-soil system under different irrigation regimes and AHA application conditions. The results showed that as the amount of AHA applied increased, the leaf area and chlorophyll concentration gradually increased, the Rubisco activity first increased and then decreased under two irrigation regimes. In alternate wetting and drying irrigation with 300 mg kg-1 AHA treatment (DWI3), the photosynthetic carbon fixation ability was the highest, with Pn, Fv/Fm, and qP increasing by 65.35%, 214.85%, and 43.15% compared to alternate wetting and drying irrigation without applying AHA treatment (DWI0), respectively. Meanwhile, during DWI3 treatment, the organic acid concentration in root exudates, root biomass, root length, root surface area, and root length density were also the highest. In summary, among all treatments in this study, the content of 13C in soil under DWI3 treatment was highest, closely related to the strongest photosynthetic carbon fixation and root transport capacity under this treatment, as well as the lower greenhouse gas emission flux. Therefore, it is recommended to apply 300 mg kg-1 AHA with alternate wetting and drying irrigation for carbon sequestration, water conservation, and sustainable agricultural development.

Impact of biogas adoption on household energy use and livelihood improvement in Kenya: an overview on a roadmap toward sustainability

Purpose This study assesses the impact of biogas adoption on household energy use and livelihood improvement. Also, this study aims to clarify the benefits of biogas adoption as a pathway to sustainable household energy. Design/methodology/approach The study explored the benefits of adopting biogas uptake. Fourteen sustainability indicators were identified, validated and categorized. Findings Adopting biogas technology provides numerous benefits, including better air quality, reduced deforestation and lower greenhouse gas emissions. Households can replace up to 4.5 tons of wood fuel, cutting CO2 emissions by around 6.75 tons annually. This shift saves approximately US$25 (Ksh.3223) monthly and frees up 45.5 h per week, enabling families to pursue additional income-generating activities. Biogas also produces digestate, a natural fertilizer that improves soil fertility, water retention and reduces erosion while minimizing the need for chemical fertilizers. Integrating biogas in livestock housing reduces odors, pathogens and methane emissions. Research limitations/implications The findings demonstrate numerous social, economic and environmental implications of biogas use. Social implications Health benefits include lower exposure to smoke and particulate matter, particularly benefiting women and children by reducing respiratory issues, improving lighting and enhancing educational opportunities. Biogas further improves hygiene, promotes cleanliness, strengthens energy security and alleviates energy poverty. In addition, the construction, operation and maintenance of biogas systems create jobs, and the use of digestate enhances agricultural productivity. Originality/value This study provides a unique and thorough analysis of the benefits of biogas, offering valuable insights and outlining a sustainable approach.

Enhancing Environmental Conservation through the Implementation of GMOs

The rapid advancements in genetic engineering have opened new frontiers in agriculture, medicine, and environmental conservation. Among these, the potential of genetically modified organisms (GMOs) in preserving biodiversity and combating environmental challenges has garnered significant attention. This article delves into how GMOs contribute to conservation efforts by bolstering species resilience and curbing biodiversity decline. For instance, the case of ash trees in North America facing the threat of emerald ash borers showcases how genetic modification can aid in rescuing endangered species. The discussion also delves into measures overseeing GMO releases into environments highlighting approaches taken by countries such as the U.S. And China to mitigate risks such as diminished genetic diversity and ecological disturbances. While GMOs offer advantages like lowering greenhouse gas emissions and aiding in toxin breakdown, there are concerns about drawbacks such as displacing species or causing unintended ecological consequences. To address these issues innovative solutions are proposed—like using GMOs that self-terminate after their intended purpose or creating GMOs that establish symbiotic relationships with species.

Concretes meeting the requirements of sustainable construction

The article concerns the production of lightweight geopolymer concretes based on raw materials from alkali-activated waste, which is consistent with the doctrine of sustainable construction. Fly ash, which is the main component of these geopolymer composites, constitutes energy waste and causes lower emissions of greenhouse gases and other pollutants than traditional cement. The article presents the optimisation of the geopolymer concrete recipe with different dosages of fly ash (200, 300, 400, 500, 600 and 700 kg/m3) and two recipes, the first of which is based on the use of fly ash aggregate, the largest fraction of which was subjected to surface impregnation, and the second one is based on the use of aggregate without any impregnation. Both recipes use an alkaline solution for alkaline activation with a concentration of 6 mol/dm3. Compressive strength tests and apparent density were carried out on the samples. The adequacy of the use of surface impregnation has been demonstrated in the case of low fly ash content (<500 kg/m3), and the optimal recipe based on fly ash in the amount of 600 kg/m3 was indicated.

Integrated risk analysis for urban flooding under changing climates

Urban flooding poses significant threats to human lives and urban development worldwide, while the impact of climate change on urban flooding remains unclear. To systematically analyze the variabilities of hydrological patterns and urban flooding under changing climates, this study coupled the downscaled general circulation model (GCM) projection with hydrologic-hydraulic modeling, with consideration of both the low-greenhouse gas (GHG) emission scenario of SSP1–2.6 and the high-GHG emission scenario of SSP5–8.5. Results demonstrated that the original GCM projection effectively captured the changing trend of rainfall patterns in the given area, with an overestimation of rainfall peaks. The GCM downscaling through the k-nearest neighbors (kNN)-based analog method significantly improved the model accuracy. Scenario analysis indicated that climate change significantly affected the regional hydrology, with the precipitation, surface runoff, and floods increasing by a maximum value of 17.10%, 12.66%, and 63.26%, respectively. The interannual comparison demonstrated that the temporal variability in precipitation and flood intensified with the increase in GHG emissions during 2025–2100, suggesting the uncertainty of long-term climate forecasts. According to flood risk analysis, long-term and short-term floods exhibit varied changing trends across climate scenarios, despite the strong correlations between precipitation and runoff, implying the complexity of flood generation mechanisms. The methods and findings herein provide valuable insights for policymakers and practitioners, to cope with the increasing urban flood risk within the context of evolving environment.

Metal Imidazole-Modified Covalent Organic Frameworks as Electrocatalysts for Alkaline Oxygen Evolution Reaction.

Since the product contains no carbon-based substances and can be driven by non-carbon-based electricity, electrocatalytic water splitting is considered to be among the most effective strategies for alleviating the energy crisis and environmental pollution. This process helps lower greenhouse gas emissions while also supporting the shift toward renewable energy sources. The anodic oxygen evolution reaction (OER) involves a more complex multi-electron transfer process, which is the principal limiting factor in overall water splitting. Extensive research has demonstrated that the controlled design of effective electrocatalysts can address this limitation. In this study, a previously unreported covalent organic framework material (COF-IM) was synthesized via a post-synthetic modification strategy. Notably, COF-IM contains imidazole nitrogen metal active sites. Transition metal-coordinated COF-IM@Co can function as a highly effective electrocatalyst, exhibiting a lower overpotential (403.8 mV@10 mA cm-2) in alkaline electrolytes, thereby highlighting its potential for practical applications in energy conversion technologies. This study offers new perspectives on the design and synthesis of COFs, while also making substantial contributions to the advancement and application of OER electrocatalysts.

ICE to EV Conversion in Thailand: Evaluating Feasibility, Benefits, and Challenges

Abstract: The shift to electric vehicles (EVs) is vital for reducing greenhouse gas (GHG) emissions, but Thailand faces challenges in adopting new EVs due to high costs and limited infrastructure. This study investigates the feasibility of converting internal combustion engine (ICE) vehicles to EVs over the next decade, examining the economic, environmental, and social impacts. Findings show that EV conversions can reduce operational costs by 40-50% and lower GHG emissions by up to 70%, even when accounting for electricity-related emissions. In addition, the transition could significantly improve air quality, leading to public health benefits. However, barriers such as high upfront conversion costs, limited access to conversion kits, and the need for skilled labor remain. Addressing these challenges through government incentives, infrastructure development, and workforce training will be essential for scaling up EV conversions, enabling Thailand to accelerate its shift toward sustainable transportation and meet its climate goals.

Effects of GroMore® Program on Rice Yield and GHG Emissions in a Korean Paddy Rice

The agronomic benefits of pesticides combined with amino acid application to increase rice production have been recognized, but they are still not well-known for greenhouse gas (GHG) emissions and mitigation in irrigated paddy fields. Thus, this study was conducted to investigate the combined effects of pesticide and amino acid application on rice yield and methane (CH4) emissions in a Korean rice paddy. A field experiment was conducted with five levels: none (no pesticide application, T1), different conventional practices (combined application of insecticides and fungicide, T2 and T3), and GroMore® programs (combined application of insecticides, fungicides, and amino acids, T4 and T5). Rice grain yield and yield components were obtained using agronomic measurements. To determine the greenhouse gas intensity (GHGI) of each treatment, CH4 emissions were measured throughout the rice growing period. Results showed that the chemical applications in combination with amino acids in T4 obtained a higher grain yield and number of panicles per plant compared to T1, T2, and T3, while T4 and T5 showed no difference on filled spikelets except for T2. T3 and T5 showed lower respective cumulative CH4 emissions by 30% and 32% during the entire rice growing season, compared to no chemical application (T1). Meanwhile, N2O emissions were negligible in all treatments because the paddy field was flooded most of the growing season. The results of the impact of GroMore® programs on relatively higher grain yield and lower GHG emissions are presented. In conclusion, the application of pesticides combined with amino acids obtained lower GHGI values.

Sustainable Dietary Patterns and Alternative Food Sources

Sustainable nutrition ensures optimal dietary intake by evaluating the life cycle of foods and their environmental impacts, aiming to meet current needs without jeopardizing the ability of future generations to do the same. It is characterized by low greenhouse gas emissions, minimal water footprint, efficient energy and land use, and reduced food waste. Sustainable dietary models, which have become increasingly important in the face of rising food demand and climate change challenges, include the Mediterranean Diet, Nordic Diet, DASH Diet, Double Pyramid Model, Flexitarian Diet, EAT-Lancet Commission Reference Diet, and Vegetarian and Vegan diets. Alternative protein sources such as algae, insects, and cultured meat are also significant. Algae offer sustainability through ocean use but have unclear metabolic impacts. Insects are efficient and environmentally friendly but require safety assessments. Cultured meat promises environmental benefits but faces cost and acceptance hurdles. Promoting sustainable eating habits requires a collective effort and is a shared responsibility towards our planet and ourselves.

Facile synthesis of green graphite-based (Ni/Cu/N) MOF composite for a methanol oxidation reaction

Recently, direct methanol fuel cells (DMFCs) have been regarded as the greatest energy-producing owing to their low operating temperature, high production rate of methanol, and low greenhouse gas emission. However, the energy conversion efficiency of the DMFCs is still unsatisfactory due to the slow kinetics of the fuel oxidation reaction. So, an economic electrocatalyst with high efficiency and good stability is still needed. Herein, low-cost nanocomposites of (Ni/Cu/N) MOF and palm pollen-derived G-graphite were prepared with different ratios namely, (1:1), (1:2), and (2:1) through a solvothermal reaction. The nanocomposites were characterized via X-ray diffraction (XRD), Scanning electron Microscopy (SEM), Fourier transform infrared (FTIR), Thermal gravimetric analysis (TGA), and, (Brunauer–Emmett–Teller) technique (BET). Electrodes have been tested as electro-catalysts for methanol-oxidation reaction (MOR) in a basic medium. As revealed from the cyclic voltammetry measurements, all electrodes exhibit a good response to MOR, being the nanocomposite with the ratio between (Ni/Cu/N) MOF and G-graphite (2:1) is the best with an oxidation peak current density of 55 mA/cm2 at a scan rate of 50 mV/s, with an onset potential of 0.35 V, and stability reaches 96 %. The electrochemical impedance spectroscopy (EIS) test showed that the ratio (2:1) has the lowest charge transfer resistance, RCT, of 5.21 Ω which confirms its higher electrochemical activity. This superior performance of the (Ni/Cu/N) MOF and G-graphite (2:1) over other reported MOF-based electrocatalysts is attributed to the synergistic effect of the (Ni/Cu/N) MOF electrocatalyst, wherein Ni and Cu provide redox electrocatalytic active sites for MOR while the G-graphite contributes towards the chemical stability and electrical conductivity of the electrode, respectively. The good activity and stability of the prepared electrodes suggest the potential use of these electrodes as electrocatalysts for MOR in direct methanol fuel cells (DMFCs).This study opens the venue for valorizing the natural wastes derived graphitic material as stable supporting material in Mof based composites electrodes for MOR.

LCA-based carbon footprint analysis of anaerobic digestion of coffee husk waste

While studies have shown that anaerobic digestion (AD) with energy generation of agricultural residues have many benefits, it is still unclear the extent to which this technology can reduce greenhouse gas (GHG) emissions, particularly in the context of coffee husk wastes. To address this knowledge gap, this work explored three scenarios of coffee husks as an energy source: 0) business-as-usual (landfilling); 1) AD with energy generation; 2) same as the previous one, adding a hydrothermal hydrolysis pre-treatment step. The study adopted a Life Cycle Assessment (LCA) methodology to estimate the environmental impacts of this technology in terms of GHG emissions. The results indicate that the main benefit of using AD is to avoid the impacts of landfilling, as the carbon footprint for the landfilling scenario was more than 13 times higher than the others. The emissions from digestate management were the main source of the overall emissions, accounting for 34 %. However, its use to replace chemical fertilizers affected the environmental performance positively. The inclusion of the pre-treatment was a key factor in making the bioenergy from coffee husks less carbon-intensive than natural gas and oil, although common renewable sources such as wind and hydropower tend to have lower GHG emissions. Sensitivity analyses indicate that this type of bioenergy can mitigate GHG emissions from energy generation in coffee-producing countries with fossil-based energy mixes. Overall, this work fills a knowledge gap by providing empirical evidence to the potential benefits of using coffee husks in the world's transition to a low-carbon economy.

The carbon footprint of vegetable imports into Aruba: A closer look at sea and air transport

This study aimed to give insights into low-carbon vegetable import strategies for Aruba, a Dutch Caribbean island. Our selected products were potatoes, lettuce, onions, tomatoes, and green beans. The products originated from 13 different countries, and 25 product-country combinations were identified. The system boundaries were from the farm until arrival at the supermarket. We identified actual maritime transport routes, and calculated greenhouse gas (GHG) emissions of passenger aircrafts flying from Amsterdam to Aruba. Vegetables imported by air had significantly higher GHG emissions (4.2–8.3 kg CO2eq per kg) than products imported by sea (0.4–2.3 kg CO2eq per kg). GHG emissions of road transport generally contributed more than those of other life cycle stages, except when products showed a high contribution of agriculture. Although sea transport was calculated with much detail, it usually did not contribute much to the GHG emissions. We recommend Life Cycle Practitioners to consider aircraft characteristics when calculating GHG emissions of air transport, and to include the weight of the 80 kg AKE container, used for cooled airfreight, when allocating impacts between passengers and freight. For this case study, GHG emissions of specific passenger aircrafts always resulted in lower GHG emissions compared to generic calculations.

Impact of a forage legume or nitrogen fertilizer application on ammonia volatilization and nitrous oxide emissions in Brachiaria pastures

ABSTRACT The largest proportion of greenhouse gas (GHG) emissions in the Agriculture sector of the Brazilian national GHG inventory is derived from the large (>200 million head) herd of cattle. The greatest contribution to these emissions comes from the enteric methane from cattle, but the direct and indirect emissions of nitrous oxide (N 2 O) from cattle excreta and N fertilizer are responsible for approximately 9 % of all national anthropogenic GHG emissions. Ammonia (NH 3 ) can be volatilized from N fertilizer and cattle excreta and deposited in sites remote from the source, constituting an indirect source of N 2 O. This study aimed to determine whether direct N 2 O emissions and NH 3 volatilization from N-fertilized pastures were greater than those derived from a mixed grass-legume pasture without N fertilizer addition. Emissions of N 2 O and NH 3 from excreta and N fertilizer from a Palisade grass (Urochloa brizantha cv. Marandu) monoculture fertilized with 2 × 60 kg N ha -1 yr -1 urea were compared to those from a mixed Palisade grass-forage peanut (Arachis pintoi) pasture. Dung and urine were collected from these cattle, and NH 3 losses and N 2 O emissions from the excreta and from N fertilizer were monitored using static chamber techniques. Volatilization of NH 3 and N 2 O emissions were found to be greater from urine than from dung. Ammonia losses from excreta and urea fertilizer were low, not exceeding 6.8, 1.1, and 4.7 % of the N applied as urine, dung, and fertilizer, respectively. The N 2 O emissions showed a tendency to be greater for the urine from the N-fertilized compared to the mixed grass-legume pasture, and the N 2 O emissions from the urine of the N-fertilized pasture ranged from 0.08 to 0.94 % of applied urine N. The N 2 O emission from the N fertilizer was at maximum 0.46 % of the applied N. The direct N 2 O emissions and the loss of NH 3 by volatilization (indirect N 2 O emission) from the excreta of cattle grazing the mixed grass-legume pasture were similar to, or lower than, the grazed grass monoculture fertilized with 120 kg N ha -1 yr -1 . As the mixed pasture received no N fertilizer and hence no GHG emission from its manufacture or application, introducing forage peanut to the Urochloa brizantha pastures shows potential to be responsible for lower GHG emissions than the N fertilized grass pasture.

Impact of natural ventilation and outdoor environment on indoor air quality and occupant health in low-income tropical housing

Ventilation is pivotal in mitigating indoor pollutants and ensuring comfortable Indoor Air Quality (IAQ) levels globally. The outdoor environment and ventilation mechanisms significantly impact indoor air quality and occupant health. This research investigated the impact of natural ventilation (NV) and outdoor environment (OE) on indoor air quality (AQ) and occupant health (HI) in low-income housing in Kampala City, Uganda. The study followed a mixed methodology approach by employing self-administered questionnaires and statistical modeling using IBM® SPSS® Amos V24 to analyze the relationships between Natural Ventilation (NV), indoor Air Quality (AQ), Outdoor Environment (OE), and occupant health (HI). The research reveals a strong correlation (0.76) between NV and AQ. In contrast, correlations between AQ and OE (0.16) and NV and OE (0.08) are weak. Model comparative fit indices (CFI: 0.984, SRMR: 0.029, RMSEA: 0.053) indicate an excellent fit. Reliability is high with Cronbach's alpha (NV: 0.800, AQ: 0.862, OE: 0.782) and AVE values (NV: 0.832, AQ: 0.869, OE: 0.786). Significant positive relationships were found between NV and AQ and AQ and HI, highlighting the importance of natural ventilation in improving indoor air quality and occupant health. The study supports SDGs 3, 11, and 13, promoting sustainable building practices and promoting health, enhanced living conditions, and lower greenhouse gas emissions.

Greenhouse gas emissions during alfalfa cultivation: How do soil management and crop fertilisation of preceding maize impact emissions?

ContextThe use of alfalfa in rotation with intensive crops is common practice to mitigate the physical and chemical issues arising from intensive farming practices. However, there is a dearth of studies on this practice. Given the current concern regarding climate change and the significant impact agriculture has on greenhouse gas (GHG) emissions, understanding the emissions associated with this practice, as well as the most suitable soil and crop management techniques for their mitigation, is of paramount importance. ObjectiveThe present study aimed to (i) quantify emissions of N2O, CO2 and CH4 in an alfalfa crop following a maize cropping scenario; (ii) to determine which tillage system generates the lowest GHG emissions, and; (iii) to determine how N fertilisation from a preceding intensive maize crop affects GHG emissions during alfalfa cropping period. MethodsA three-year field experiment (2019, 2020 and 2021) was conducted to assess the emissions of N2O, CO2 and CH4 from alfalfa cultivation following a three-year period of irrigated maize. Two soil management practices (no-tillage and conventional tillage) were implemented during both the maize cropping period and the alfalfa establishment. Additionally, the nitrogen (N) fertilisation rates applied to the preceding maize crop were included as a treatment (0, 200, and 400 kg N ha⁻¹, corresponding to zero, medium, and high fertilisation levels, respectively) in a randomized block design with two factors. ResultsEmissions of N2O in alfalfa ranged from 0.05 to 0.32 mg N2O-N m⁻² day⁻¹, being significantly higher only during first month of sampling in the treatments that had received fertilisation. CO2 emissions ranged from 1158 to 4258 mg CO2-C m⁻² day⁻¹. Year-average CH4 fluxes were −0.27 g C ha⁻¹ day⁻¹. The average total dry matter produced by alfalfa was 17700 kg ha⁻¹ year⁻¹, being higher for the no-tillage treatment, though significantly so only during first month of sampling. ConclusionsUnder Mediterranean conditions, the tillage system and mineral N fertilizer rates have a relative effect on greenhouse gas emissions during the alfalfa cropping period. Plots without N fertilization initially produced lower N2O emissions and higher total dry matter, resulting in the lowest scaled emissions. For the tillage treatment, no significant differences were found in emission dynamics, which may be due to the fact that alfalfa does not involve soil disturbance, leading to a homogenization of the treatments. However, the NT treatment showed lower scaled emissions due to higher yields in the first year. Therefore, alfalfa cultivation is characterized by low GHG emissions, high yields, and a notable capacity to mitigate the negative effects of previous intensive crops. SignificanceThis study provides data on GHG emissions during alfalfa cropping in the typical Maize-alfalfa crop rotation under Mediterranean irrigated systems, which is useful for new agricultural policies aimed at reducing pollution in the agricultural sector. Additionally, it demonstrates the capability of this crop to mitigate adverse agronomic and environmental conditions caused by preceding intensive farming practices.