Changes In Emissions Research Articles

Cooperative Strategies in Transboundary Water Pollution Control: A Differential Game Approach

This paper, based on differential game theory, examines governance models and cooperative strategies for managing cross-border water pollution in regions with uneven economic development. To address cross-regional water pollution, three differential game models are constructed under different scenarios: the Nash noncooperative mechanism, the pollution control cost compensation mechanism, and the collaborative cooperation mechanism. This study analyzes the dynamic changes in pollution emissions, governance investments, and economic returns within each model. The results indicate that the collaborative cooperation mechanism is the most effective, as it significantly reduces pollution emissions, maximizes overall regional benefits, and achieves Pareto optimality. In comparison, the pollution control cost compensation mechanism is suboptimal under certain conditions, while the Nash noncooperative mechanism is the least efficient, resulting in the highest pollution emissions. Furthermore, the research explores the influence of cooperation costs on the selection of governance models. It finds that high cooperation costs reduce local governments’ willingness to engage in collaborative cooperation. However, an appropriate compensation mechanism can effectively encourage less-developed regions to participate. Numerical analysis confirms the dynamic evolution of pollution stocks and economic returns under different models, and provides corresponding policy recommendations. This paper offers theoretical insights and practical guidance for cross-regional water pollution management, highlighting the importance of regional cooperation and cost-sharing in environmental governance.

Historical Insights into CO2 Emission Dynamics in Urban Daily Mobility: A Case Study of Lyon’s Agglomeration

CO2 emissions from urban daily mobility play a major role in both environmental degradation, rising economic costs, and sustainability. Reducing these emissions not only advances environmental sustainability but also fosters economic development by enhancing public health, lowering energy consumption, and alleviating the financial strain caused by climate change. Understanding the dynamics of CO2 emissions from urban daily mobility provides valuable historical insights into environmental impacts and economic costs tied to urban development. This study takes a historical perspective, examining changes in CO2 emissions associated with daily mobility in the Lyon agglomeration across two decades, drawing on data from the 1995 and 2006 household travel surveys. Our findings reveal that individual factors such as gender, age, employment status, and income significantly influence CO2 emissions, with males and full-time workers exhibiting higher emissions. Furthermore, household characteristics, including size and vehicle ownership, are critical in shaping emission levels, while urban form variables such as population density and mixed land use demonstrate a negative correlation with emissions, highlighting the importance of urban planning in mitigating CO2 output. The analysis emphasizes that greater accessibility and proximity to essential services are vital in reducing individual emissions. Based on these insights, we discuss the implications for policy design, suggesting targeted strategies to enhance urban mobility, improve public transport accessibility, and promote sustainable urban development. Finally, we outline directions for future research to further explore the intricate relationship between urban characteristics and emissions, ultimately aiming to contribute to the development of effective climate policies.

Unexpectedly strong heat stress induction of monoterpene, methylbutenol, and other volatile emissions for conifers in the cypress family (Cupressaceae)

We investigated the biogenic volatile organic compound (BVOC) emission rates and composition of Cupressaceae species and how the emissions change in response to moderate warming and more severe heat stress. A total of 8 species from 7 distinct Cupressaceae genera were targeted in this study and exposed to laboratory-simulated heatwaves. Each plant was enclosed in a temperature-controlled glass chamber and allowed to equilibrate at 30 °C for 24 h. The temperature was then increased stepwise from 33 °C to 43 °C in 2 °C increments, with each step lasting 2 h, and was finally kept at 45 °C for 12 h. The BVOC emissions were measured periodically using an automated air sampler coupled to a gas chromatograph.Most of the sampled Cupressaceae species (6 out of 8) were low BVOC emitters (<0.3 μgC g−1 h−1) at 30 °C. However, the BVOC emissions of all 8 species increased strongly with temperature, and in most species (5 out of 8), the emissions continued to increase with longer exposure times to heat stress. The largest increase was observed in Thuja occidentalis and Chamaecyparis thyoides, which reached maximum emissions of 350 and 190 μgC g−1 h−1, respectively. Of the different BVOCs, monoterpenes responded most strongly to heat stress, with Q10 temperature coefficients typically ranging between 7.6 and 22, which were significantly greater than the model-predicted value of 2.7. Other BVOCs including sesquiterpenes, C9 aromatics (only detected in Calocedrus decurrens), methylbutenols, and other C5 oxygenates were also induced by heat stress, but generally at a lower magnitude than monoterpenes.Our results indicate that Cupressaceae are a large but typically dormant source of reactive volatile hydrocarbons (mostly monoterpenes) whose emissions can be activated by heat stress. This phenomenon could have important implications for ozone and aerosol formation, air quality, and human health, particularly in urban areas that are prone to heatwaves.

Health and air pollutant emission impacts of net zero CO2 by 2050 scenarios from the energy modeling forum 37 study

Carbon dioxide and non-greenhouse gas air pollutants are emitted from many of the same sources. Decarbonization actions thus typically yield air pollutant emission reductions, resulting in significant air quality benefits. Although several studies have highlighted this connection, including in the context of net zero carbon emission targets, substantial uncertainty remains regarding how alternative technological pathways to this goal will affect the spatial distribution and magnitude of air pollutants. Comprehensive multi-model and multi-scenario analyzes are needed to explore the relative impacts of alternative pathways. Our study begins to address this gap by leveraging the results from the recent Energy Modeling Forum 37 inter-model comparison exercise on U.S. decarbonization pathways. Comparing the results of the six teams who submitted air pollutant emissions suggests that strategies that target net zero U.S. carbon emissions would yield significant reductions in many air pollutants, and that this finding is generally robust across pathways. However, some energy sources, such as biomass and fossil fuels with carbon capture, will emit air pollutants and can potentially influence the magnitude, spatial distribution, and even sign of localized air pollutant emission changes. In the second part of this analysis, a simplified air quality and health impacts screening model is used to evaluate the air quality impacts in 2035 of sectoral emission changes from the three models that provided sectoral detail. Relative to a reference scenario, a net zero pathway is estimated to reduce fine particulate matter concentrations across the contiguous U.S., with health benefits from reduced mortality ranging from $65 billion to $250 billion in 2035 alone (2023$s). These benefits would be expected to grow over time as the net zero trajectory becomes more stringent. Both the magnitude of potential benefits and the substantial variation of the projections across models underscore the need for an EMF-like inter-model comparison exercise focused on air quality.

Evaluating the effects of meteorology and emission changes on ozone in different regions over China based on machine learning

Systematically understanding the impact of meteorological conditions on regional ozone pollution helps to retrieve ozone dataset and evaluate emission changes on ozone variation. Here, more air-quality observation sites were collected, and Random Forest algorithm was applied to retrieve daily maximum 8 h average (MDA8) O3 concentrations at 1 km resolution in 2019-2020 in China. The region-season model and whole-retrieved model were established to compare the contributions of meteorological variables to ozone variations on spatiotemporal scale. The former model outperformed the latter for retrieval capability, but the predictive ability of the latter was slight stronger. This may be associated with the spatiotemporal heterogeneity of meteorological influence. Daily ozone variability in China was mainly influenced by meteorology, especially in North China Plain in autumn. The key factors were temperature, ultraviolet radiation and relative humidity over the whole country, but varied significantly in different regions and seasons. The effects of meteorology and emission sources on ozone were separated by weather normalization technique. Meteorological conditions were particularly favorable for increasing ozone concentrations in spring, but particularly unfavorable in winter. During the COVID-19 lockdown, the increases in ozone in spring and winter of 2020 were the contribution of the combination of meteorology and emissions; while the decreases in ozone in summer and autumn of 2020 were mainly due to the changes of emission sources, although meteorological conditions were unfavorable to ozone mitigation in heavily polluted areas. Our findings provide scientific basis for the prevention and control of ozone pollution for the regional scale in China.

Engineering a fluorescent probe for the visual and wearable detection of N2H4 in foods, environment samples and biological imaging

Hydrazine (N2H4), as an important chemical raw material widely used in many fields, caused serious harm to human, food and environment. Therefore, a smart fluorescent probe TPC-N2H4 with intramolecular charge transfer (ICT) process was fabricated for colorimetric and fluorescent differentiating of N2H4 in many samples. When TPC-N2H4 met N2H4, blue emission at 451 nm was obviously observed attributed to the interruption of ICT process, resulting in the formation of the hydrazone structure. Additionally, smartphone-assisted colorimetric and fluorescent sensing platforms had been developed for real-time monitoring of N2H4. Importantly, TPC-N2H4 with low toxicity revealed its ability to image N2H4 in HeLa cells, onion and Arabidopsis thaliana. Interestingly, a hydrogel-coated cotton swab sensor was developed with TPC-N2H4 as recognition unit, which showed obvious color and emission changes after N2H4 fumigation with fast response speed. Flexible fluorescent TPC-N2H4-glove was constructed for wearable N2H4 detection and used to monitor N2H4 in food and environment samples. In brief, the TPC-N2H4 probe not only showed great potential in N2H4 detection for environmental and food safety, but also provided a new method for wearable tracking platforms in toxic substance detection.

Pathways to innovation: How city pilots leverage digital technology to reduce carbon emissions

Technological innovation through various pathways is crucial for achieving carbon neutrality and peak carbon emissions. The Innovative City Pilot (ICP) initiative, a key effort to promote national innovation, has garnered increasing attention. However, most studies have not examined the effects of ICP on carbon emissions through diverse digital technologies. Using city-level data from 2000 to 2022, we constructed a staggered difference-in-differences (DID) model to analyze changes in carbon emissions before and after the ICP period in both ICP and non-ICP areas. The carbon emission reduction pathway of the ICP influences various forms of digital technology, which then empower local green product innovation, market-oriented innovation, and industrial innovation. The impact of ICP emission reduction through digital technology is more significant in western, first- and second-tier, sub-provincial, populous, and coastal cities. In conclusion, policymakers should tailor policies according to the action pathways of digital technology and specific city characteristics. We outline the specific pathways of green product innovation, market-oriented innovation, and industrial innovation enabled by digital technologies and provide policy recommendations for the sustainable development of China.

Changes in source contribution to particle number concentrations during the 2022 COVID-19 Lockdown on southern edge of North China Plain

The COVID-19 lockdown was a typical example of extreme emission reduction, providing an opportunity to study the impact of lockdown measures on air pollution. Particle number concentrations (PNC) originate from direct emissions or through new particle formation events. However, their variations during the lockdown period are under investigation. This study focuses on Luohe, a city on the southern edge of the North China Plain, analyzing the changes in PNC and its sources before, during, and after the COVID-19 lockdown. From March 25th to May 31st, 2022, real-time PNC measurements were conducted using a Scanning Mobility Particle Sizer for particle size. Results showed an 11.2 % decrease in PNC during the lockdown compared to pre-lockdown and a 3.6 % decrease compared to post-lockdown, indicating reduced local emissions and weakened regional transportation during the lockdown. Positive Matrix Factorization analysis identified six sources contributing to the total PNC, including photochemical nucleation, aged photochemical nucleation, gasoline vehicle emissions, diesel vehicle emissions, coal and biomass combustion, and secondary aerosols. The significant changes in source emissions indicate a substantially reduced traffic volume after the implementation of lockdown measures (2644.8 #/cm³, 2202.2 #/cm³, 2792.7#/cm³). Concurrently, photochemical nucleation (310.1 #/cm³, 306.3 #/cm³, 393.1 #/cm³) and photochemical nucleation aging (592.8 #/cm³, 744.1 #/cm³, 810.7 #/cm³) exhibited increasing trends, while coal/biomass combustion (1656.6 #/cm³, 1586.2 #/cm³, 980.0 #/cm³) and secondary sources (999.4 #/cm³, 791.1 #/cm³, 804.1 #/cm³) showed decreasing trends. In summary, the contributions of traffic emissions to PNC highlight the potential for targeted traffic management strategies to improve urban air quality.

High contrast stimuli-responsive fluorescence emitters based on carbazole-cyanostilbene derivatives with aggregation induced emission properties

Due to the aggregation induced emission (AIE) materials exhibiting obvious fluorescent emission changes under the external stimuli of heat, solvent, force and so on, significant efforts have been directed toward developing AIE-active materials with high contrast stimuli-responsive fluorescence behaviors. Herein, three electron-donor(D)-electron-acceptor(A) and D-A-D type organic fluorescence emitters of Cz-DC-tBu, Cz-DC-CN and Cz-DC-OMe were facilely synthesized using carbazole group as D unit and cyano group as A unit. They showed typical AIE features and exhibited remarkable color changes under mechanical force and in different polarity solvents, respectively. The stimuli-responsive mechanism of the compounds were investigated by powder X-ray Diffraction (PXRD) and density functional theory calculations (DFT), which revealed that the mechanofluorochromic behaviors were associated with the molecular packing modes, and the solvatochromic effects were caused by the intramolecular charge-transfer transition (ICT) effect. Significantly, it was found that Cz-DC-tBu showed high contrast stimuli-responsive behaviors through adjusting the substituent groups on the cyanostilbene unit with CN, OMe, and tBu groups, respectively. This study provided a new strategy for the design of AIE-active stimuli-responsive fluorescence emitters, and made them possible using in stress sensors, chemical detection, memory storage, anti-counterfeiting applications.

Triple Pillar for Sustainability of Accounting Evaluation of Carbon Emissions and Climate Change

This study is among the first to address the relationship between accounting and adaptation to climate change. Aramco is a well-known company in the Middle East that produces oil, and it was used as a case study. This study examines the theoretical underpinnings of accounting assessment of carbon emissions arising from climate change and their influence on sustainability. The questionnaire was distributed to approximately 150 Saudi Arabian managers. The researcher used an analytical descriptive technique and the Statistical Packages Program for Social Sciences (SPSS) to assess the sample, fill out, tabulate, analyze the data, and test the hypotheses. The findings demonstrate that accounting for carbon emissions affects sustainable development in its three pillars-economic, social, and environmental. Further, the sub-hypothesis’s results indicate that accounting for carbon emissions statistically impacts sustainable development’s economic and environmental aspects. Accounting for carbon emissions has no discernible impact on sustainable development through the social component. The researcher advocated that the social aspect of sustainable development should be given attention. Large corporations are made aware of their significance in achieving environmental sustainability and that failing to adopt labor and human rights standards will result in companies being held accountable.

Improved nitrogen fertilizer management reduces nitrous oxide emissions in a northern Prairie cropland.

Arable croplands are a significant source of nitrous oxide (N2O) emissions, largely due to nitrogen (N) fertilizer applications to support crop production. Nevertheless, there is limited research on the N2O dynamics from canola-wheat rotations in the semi-arid northern Prairies, an important agricultural region. Here, we present micrometeorological N2O fluxes measured from January 2021 to April 2024 in Saskatchewan, Canada, to evaluate the impact of N fertilizer management on the year-round N2O emissions from a canola-wheat rotation. A combination of two 4R (Right Source, Right Rate, Right Time, Right Place) N management practices - a reduced N rate and an enhanced efficiency N fertilizer source - was compared to common fertilizer management practices for the region. Two periods at high risk for N2O flux events were identified, after N fertilizer applications and the following spring thaw, with the magnitude of emissions varying over the multi-year period. As for cumulative emissions, the growing season (GS) N2O emissions were 50 % of annual emissions, presenting an opportunity to mitigate N2O emissions through improved N fertilizer management. Indeed, the improved 4R N management reduced N2O emissions by 57 % over the entire study period without impacting yields. The reduction in GS N2O emissions resulted from the 4R N management lowering mean N2O flux at times of high WFPS (>50 %). The non-growing season (NGS) N2O accounted for 11-67 % of annual emissions. Fall soil nitrate levels were a strong explanatory variable of NGS emissions (r2 = 0.69, r2 = 0.39), but the rate of change and magnitude of NGS emissions depended on thawing conditions - lower for drier thaws, higher for wetter thaws. Ultimately, better N fertilizer management reduces cumulative N2O emissions from cropping systems when practiced for several years.

Dynamic Simulation of Carbon Emission Peak in City-Scale Building Sector: A Life-Cycle Approach Based on LEAP-SD Model

Systematically predicting carbon emissions in the building sector is crucial for formulating effective policies and plans. However, the timing and potential peak emissions from urban buildings remain unclear. This research integrates socio-economic, urban planning, building technology, and energy consumption factors to develop a LEAP-SD model using Shenzhen as a case study. The model considers the interrelationship between socio-economic development and energy consumption, providing more realistic scenario simulations to predict changes in carbon emissions within the urban building sector. The study investigates potential emission peaks and peak times of buildings under different population and building area development scenarios. The results indicate that achieving carbon peaking by 2030 is challenging under a business as usual (BAU) scenario. However, a 10% greater reduction in energy intensity compared to BAU could result in peaking around 2030. The simulation analysis highlights the significant impact of factors such as population growth rate, per capita residential building area, and energy consumption per unit building area and the need for a comprehensive analysis. It provides more realistic scenario simulations that not only enhance theories and models for predicting carbon emissions but also offer valuable insights for policymakers in establishing effective reduction targets and strategies.

Spatio-temporal variations of energy carbon emissions in Xinjiang based on DMSP-OLS and NPP-VIIRS nighttime light remote sensing data.

With the rapid economic development of Xinjiang Uygur Autonomous Region (Xinjiang), energy consumption became the primary source of carbon emissions. The growth trend in energy consumption and coal-dominated energy structure are unlikely to change significantly in the short term, meaning that carbon emissions are expected to continue rising. To clarify the changes in energy-related carbon emissions in Xinjiang over the past 15 years, this paper integrates DMSP/OLS and NPP/VIIRS data to generate long-term nighttime light remote sensing data from 2005 to 2020. The data is used to analyze the distribution characteristics of carbon emissions, spatial autocorrelation, frequency of changes, and the standard deviation ellipse. The results show that: (1) From 2005 to 2020, the total carbon emissions in Xinjiang continued to grow, with noticeable urban additions although the growth rate fluctuated. In spatial distribution, non-carbon emission areas were mainly located in the northwest; low-carbon emission areas mostly small and medium-sized towns; and high-carbon emission areas were concentrated around the provincial capital and urban agglomerations. (2) There were significant regional differences in carbon emissions, with clear spatial clustering of energy consumption. The clustering stabilized, showing distinct "high-high" and "low-low" patterns. (3) Carbon emissions in central urban areas remained stable, while higher frequencies of change were seen in the peripheral areas of provincial capitals and key cities. The center of carbon emissions shifted towards southeast but later showed a trend of moving northwest. (4) Temporal and spatial variations in carbon emissions were closely linked to energy consumption intensity, population size, and economic growth. These findings provided a basis for formulating differentiated carbon emission targets and strategies, optimizing energy structures, and promoting industrial transformation to achieve low-carbon economic development in Xinjiang.

Sensing the Small Change of Intermolecular Distance in Supramolecular Assembly by Using the Tunable Emission Wavelength of AIE-Active Luminogens.

The distinct molecular states - single molecule, assembly, and aggregate - of two ionic macromolecules, TPPE-APOSS and TPE-APOSS, are easily distinguishable through their tunable fluorescence emission wavelengths, which reflect variations in intermolecular distances. Both ionic macromolecules contain aggregation-induced emission (AIE) active moieties whose emission wavelengths are directly correlated to their mutual distances in solution: far away from each other as individual molecules, maintaining a tunable and relatively long distance in electrostatic interactions-controlled blackberry-type assemblies (microphase separation), or approaching van der Waals close distance in aggregates (macrophase separation). Furthermore, within the blackberry assemblies, the emission wavelength decreases monotonically with increasing assembly size, indicative of shorter intermolecular distances at nanoscale. The emission changes of TPPE-APOSS blackberry assemblies can even be visually distinguishable by eyes when their sizes and intermolecular distances are tuned. Molecular dynamics simulations further revealed that macromolecules are confined in various conformations by controllable intermolecular distances within the blackberry structure, thereby resulting in fluorescence emission with tunable wavelength.

Integrating Process Simulation and Life Cycle Assessment for Enhanced Process Efficiency and Reduced Environmental Impact in Ferromanganese Production

Process simulation was integrated with life cycle assessment to evaluate process efficiency and environmental impact of the production of manganese ferroalloys for various production modes and different ore mineralogies. Utilizing HSC Sim, the model was designed to evaluate the production process with or without a pretreatment step, where results for simulated cases using a four-zone ferromanganese furnace model were exported to openLCA for a complete life cycle assessment. Two main production scenarios were simulated: a closed ferromanganese furnace running on the duplex method and an open furnace running on the discard slag approach. The closed furnace scenario achieved a 17.5% reduction in energy consumption and a 16.2% decrease in direct CO2 emissions with CO-rich off-gas pretreatment. The open furnace scenario showed an 11.2% reduction in energy consumption with thermal solar energy pretreatment but no change in CO2 emissions.

An optimal global biochar application strategy based on matching biochar and soil properties to reduce global cropland greenhouse gas emissions: findings from a global meta-analysis and density functional theory calculation

Biochar has been extensively utilized to amend soil and mitigate greenhouse gas (GHG) emissions from croplands. However, the effectiveness of biochar application in reducing cropland GHG emissions remains uncertain due to variations in soil properties and environmental conditions across regions. In this study, the impact of biochar surface functional groups on soil GHG emissions was investigated using molecular model calculation. Machine learning (ML) technology was applied to predict the responses of soil GHG emissions and crop yields under different biochar feedstocks and application rates, aiming to determine the optimum biochar application strategies based on specific soil properties and environmental conditions on a global scale. The findings suggest that the functional groups play an essential role in determining biochar surface activity and the soil’s capacity for adsorbing GHGs. ML was an effective method in predicting the changes in soil GHG emissions and crop yield following biochar application. Moreover, poor-fertility soils exhibited greater changes in GHG emissions compared to fertile soil. Implementing an optimized global strategy for biochar application may result in a substantial reduction of 684.25 Tg year−1 CO2 equivalent (equivalent to 7.87% of global cropland GHG emissions) while simultaneously improving crop yields. This study improves our understanding of the interaction between biochar surface properties and soil GHG, confirming the potential of global biochar application strategies in mitigating cropland GHG emissions and addressing global climate degradation. Further research efforts are required to optimize such strategies.Graphical

Exploring resource-efficient urban mobility for sustainable low emission solutions: A case study of Ile-de-France, France

Urban areas and their associated mobility stocks exert substantial environmental impacts, necessitating urgent mitigation efforts. However, prevailing research predominantly concentrates on operational requirements for urban mobility. Few stock studies have quantified the embodied environmental requirements of mobility stocks. This study quantified both the embodied and operational environmental requirements and examined the stock-flow-service indicators to offer a new perspective on options for low emissions on urban mobility. Focusing on the mobility dynamics of the Ile-de-France region and its three sub-regional zones from 2010 to 2018, our findings reveal a pronounced imbalance in the utilization of materials within different mobility modes (car, public transport, motorized two-wheelers, cycling, and pedestrian) across Paris, Petite Couronne, and Grande Couronne.Local disparities in the stock of mobility modes and their capacity to facilitate movement are evident, particularly when considering various service metrics (person-trip, person-travel time, and person-kilometer). Furthermore, the different patterns of service-flow-stock indicators among mobility modes are investigated to find their impacts on regional carbon emissions changes from 2010 to 2018. Stock turnover rate and service demand were the main drivers of embodied emissions of public transportation and cycling, while operational carbon intensity showed a major impact on car operational emissions. This study enriches our comprehension of the intricate interplay between resource utilization and the provision of people's mobility, thereby promoting sustainable mobility in the Ile-de-France region.

Naked eye detection of anions: Dihydrazone receptor-based visual sensing

In this study, we designed and synthesized a novel colorimetric sensor for fluoride ions by integrating a thienodicarbohydrazide framework with salicylaldehyde, resulting in a unique bis-hydrazone-phenol receptor. This sensor exhibited exceptional selectivity for fluoride and acetate ions in nonaqueous environments, with detection visible to the naked eye. Upon interaction with fluoride ions, the receptor underwent a significant red shift in its UV–Visible absorption spectrum, moving from an absorption maximum at 332 nm–380 nm, signalling the recognition event. Acetate ions induced a similar shift. The binding interactions were thoroughly investigated, with a Jobs plot revealing a 1:1 receptor-anion complex formation with fluoride ions and a 1:2 complex with acetate ions. Further validation came from 1H NMR titration, which confirmed the presence of hydrogen bonding interactions between the receptor and the ions. The receptor demonstrated remarkable binding constants of 5.2 × 10⁴ M−2 for acetate and 1.6 × 10⁴ M−1 for fluoride ions, highlighting its strong and selective affinity. Fluorescence titrations further confirmed the receptor's potential as a chemo sensor, showing distinct emission changes in the presence of fluoride and acetate ions. This study not only underscores the receptor's capability for visual detection of fluoride ions in non-aqueous systems but also paves the way for its application in diverse analytical and environmental settings.

Impact of methane and other precursor emission reductions on surface ozone in Europe: scenario analysis using the European Monitoring and Evaluation Programme (EMEP) Meteorological Synthesizing Centre – West (MSC-W) model

Abstract. The impacts of future methane (CH4) and other precursor emission changes are investigated for surface ozone (O3) in the United Nations Economic Commission for Europe (UNECE) region excluding North America and Israel (the EMEP region, for European Monitoring and Evaluation Programme) for the year 2050. The analysis includes a current legislation (CLE) and maximum feasible technical reduction (MFR) scenario, as well as a scenario that combines MFRs with an additional dietary shift that also meets the Paris Agreement objectives with respect to greenhouse gas emissions (LOW). For each scenario, background CH4 concentrations are calculated using a probabilistic Earth system model emulator and combined with other precursor emissions in a three-dimensional Eulerian chemistry-transport model. While focus is placed on peak season maximum daily 8 h average (MDA8) O3 concentrations, a range of other indicators for health and vegetation impacts are also discussed. Our analysis shows that roughly one-third of the total peak season MDA8 reduction achieved between the 2050 CLE and MFR scenarios is attributable to CH4 reductions, resulting predominantly from CH4 emission reductions outside of the EMEP region. The impact of other precursor emission reductions is split nearly evenly between the reductions inside and outside of the EMEP region. However, the relative importance of CH4 and other precursor emission reductions is shown to depend on the choice of O3 indicator, though indicators sensitive to peak O3 show generally consistent results. The analysis also highlights the synergistic impacts of CH4 mitigation as reducing solely CH4 achieves, beyond air quality improvement, nearly two-thirds of the total global warming reduction calculated for the LOW scenario compared to the CLE case.

Multiple Energy Transfer Modes From o‐Carborane Dyad Induced by Synergetic Conformational Regulations and Intense Circularly Polarized Luminescence in Self‐Assembly Aggregates

AbstractPhotothermal modulated excited conformations in traditional optoelectronic materials have been extensively investigated for the manipulation of emissive properties. However, photoinduced molecular synergetic conformational changes, which are promising for controlling intramolecular energy transfer modes through molecular orbital breaking, are never been explored. Herein, a novel o‐carborane dyad composed of carbazole units as electron donors and triazine derivatives as electron acceptors is demonstrated to achieve conformation‐dependent emissions and abundant emissions via synergetic conformational changes. Notably, the resulting dyad exhibited multiple conformational changes that induced emissions through different energy transfer modes involved “through space” and “through bond.” Exactly, the electron spin from singlet to triplet state took a flip accompanied by molecular orbitals from π–π molecular orbitals in the space charge transfer style to π and σ molecular orbitals in the bond charge transfer mode. The circularly polarized luminescence (CPL) properties are systematically investigated, exhibiting intense CPL with large glum values. These results provide novel perspectives for elucidating the complicated emission changes in aggregated states, as well as unique perspectives on the relationship between molecular conformations, energy transfer modes, and molecular orbital breaking.