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Journal articleChen A, Wang J, Toumi R, et al., 2025,
Impact of tropical cyclone precipitation on fluvial discharge in the Lancang‒Mekong river basin
, Geophysical Research Letters, Vol: 52, ISSN: 0094-8276Tropical cyclone precipitation (TCP) and associated floods have caused widespread damage globally. Despite growing evidence of significant changes in the activity of tropical cyclones (TCs) in recent decades, the influence of TCs on regional flooding remains poorly understood. Here, we distinguish the role of TCs in fluvial discharge by explicitly simulating discharge with and without observed TCP in the Lancang‒Mekong River Basin, a vulnerable TC hotspot. Our results show that TCs typically contributed approximately 30% of annual maximum discharge during 1967–2015. However, for rare and high-magnitude floods (long return periods), TCs are the dominant driver of extreme discharge events. Moreover, spatial changes in TC-induced discharge are closely related to changes in TCP and TC tracks, showing increasing trends upstream but decreasing trends downstream. This study reveals significant spatiotemporal differences in TC-induced discharges and provides a methodology for quantifying the role of TCs in fluvial discharge.
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ReportKimutai J, Dieudonne Nsadisa F, Ayabagabo P, et al., 2025,
High vulnerability and exposure main driver behind Kinshasa’s deadly floods following heavy, but not unusual rainfall
, Publisher: Centre for Environmental Policy -
ReportClarke B, Otto F, Barnes C, et al., 2025,
Extraordinary March heatwave in Central Asia up to 10°C hotter in a warming climate
, Publisher: Centre for Environmental Policy -
ReportZachariah M, Rivera JA, Sörensson AA, et al., 2025,
Consecutive extreme heat and flooding events in Argentina highlight the risk of managing increasingly frequent and intense hazards in a warming climate
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OtherLefauve A, Bassett C, Plotnick D, et al., 2025,
The structure of stratified mixing by shear instability in baroclinically forced shear flows
<jats:p>We present observational data from the mouth of the Connecticut River, a shallow salt-wedge estuary characterised by intense interfacial mixing. The motivation is to better understand, and ultimately predict, density-stratified turbulent mixing driven by shear instabilities at high Reynolds numbers (Re > 10^5). Such processes span an immense turbulent energy cascade across eight orders of magnitude, from coherent instabilities at kilometre scales to the smallest mixing eddies at micrometre scales. Using multi-beam echo-sounding imagery, we reveal the spatial structure and temporal evolution of turbulent mixing with unprecedented detail. During the flood tide, large-scale topography and hydraulics cause the pycnocline to slope, which triggers, through baroclinic forcing, primary shear instabilities in the form of long trains of Kelvin-Helmholtz billows. Our data demonstrate that at Re ~ 5x10^5, mixing occurs primarily by turbulence in the braids connecting the cores of the billows rather than within the cores themselves. This secondary 'braid turbulence' is continuously forced by the secondary baroclinic generation of shear within the sloping braids. This finding challenges the prevailing paradigm built upon direct numerical simulations (DNS) at lower Reynolds numbers (Re ~ 10^3-10^4), where mixing is thought to occur primarily by overturning in the billow cores. This distinction is a significant shift in understanding the high-Re turbulent cascade in mixing hotspots, with potential implications for mixing parameterisations in the coastal ocean.</jats:p>
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OtherTheokritoff E, Sparks N, Otto F, et al., 2025,
Building a global and rapid event impact attribution framework
<jats:p>While event attribution has made considerable progress in the last two decades, event impact attribution, which calculates the attributable share of impacts from extreme weather events, remains challenging. Impacts result from the interaction between the intensity of hazards, the exposure of affected areas and the vulnerability of individuals, infrastructures and the environment. Across different types of extreme weather events, impacts and world regions, a wide range of datasets and approaches need to be considered to tackle this complex and interdisciplinary field of research.Here, we aim to develop simple methods that can be deployed rapidly and globally to estimate attributable impacts in the aftermath of extreme weather events. We will present initial work on attributing direct economic impacts from tropical cyclones and on an updated global physical asset database used in this context.This initiative produces near-real-time results that can be communicated in a timely manner to a broad audience, raising awareness about the impacts of extreme weather and the role of climate change. It ultimately seeks to provide valuable information on losses and damages and levels of adaptation, which can be instrumental for policymaking, climate justice and preparing societies for future extremes.</jats:p>
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OtherTheokritoff E, Sparks N, Otto F, et al., 2025,
Tracking losses and damages from extreme weather events
<jats:p>While the field of event impact attribution is still relatively nascent, diverse methodologies and datasets are starting to be used to put numbers on the share of additional impacts that occur due to climate change during extreme weather events. The growth of this body of evidence has implications for climate litigation as these studies can be starting points for legal cases centred around specific climate change impacts, such as heat-related mortality or economic costs of extreme weather.As we work towards operationalising a tracker that will provide timely estimates of losses and damages from extreme weather events globally, we aim to present results from our initial rapid studies conducted over the past year. We will reflect on the potential implications of the increasing availability of loss and damage information and the broader need for communication and awareness raising around these issues. We also plan to highlight prevailing methodological challenges and areas of research to be advanced in the near future that are relevant for legal efforts.</jats:p>
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OtherLinden P, Atoufi A, Lefauve A, et al., 2025,
Hydraulic control, turbulence and mixing in stratified buoyancy-driven exchange flows
<jats:p>Buoyancy-driven exchange flows in geophysical contexts, such as flows through straits, often create a partially-mixed intermediate layer through mixing between the two stratified counterflowing turbulent layers. We present a three-layer hydraulic analysis of such flows, highlighting the dynamical importance of the intermediate layer. Our model is based on the viscous, shallow water, Boussinesq equations and includes the effects of mixing as a non-hydrostatic pressure forcing. We apply this shallow-water formulation to direct numerical simulations of stratified inclined duct (SID) exchange flows where turbulence is controlled by a modest slope of the duct. We show that the nonlinear characteristics of the three-layer model correspond to linear long waves perturbing the three-layer mean flow, and predict, in agreement with recent experimental observations in SID, hydraulically-controlled regions in the middle of the duct, linked to the onset of instability and turbulence. We also provide the first evidence of long-wave resonance, as well as resonance between long and short waves, and their connection to transitions from intermittent to fully developed turbulence. These results challenge current parameterisations for turbulent transport in stratified exchange flows, which typically overlook long waves and internal hydraulics induced by streamwise variations of the flow.</jats:p>
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OtherLefauve A, Zhu L, Jiang X, et al., 2025,
New insights into experimental stratified flows obtained through a physics-informed neural network
<jats:p>We develop a physics-informed neural network (PINN) to significantly augment state-of-the-art experimental data of stratified flows. A fully connected deep neural network is trained using experimental data in a salt-stratified inclined duct (SID) experiment. SID sustains a buoyancy-driven exchange flow for long time periods, much like an infinite gravity current. The data consist of time-resolved, three-component velocity fields and density fields measured simultaneously in three dimensions at Reynolds number= O(10^3) and at Prandtl or Schmidt number = 700 [1]. The PINN enforces incompressibility, the governing equations for momentum and buoyancy, and the boundary conditions at the duct walls. These physics-constrained, augmented data are output at an increased spatio-temporal resolution and demonstrate five key results: (i) the elimination of measurement noise; (ii) the correction of distortion caused by the scanning measurement technique; (iii) the identification of weak but dynamically important three-dimensional vortices of Holmboe waves; (iv) the revision of turbulent energy budgets and mixing efficiency; and (v) the prediction of the latent pressure field and its role in the observed asymmetric Holmboe wave dynamics. These results mark a significant step forward in furthering the reach of fluid mechanics experiments, especially in the context of stratified turbulence, where accurately computing three-dimensional gradients and resolving small scales remain enduring challenges.References[1] L. Zhu, X. Jiang, A. Lefauve, R. R. Kerswell, and P. F. Linden. New insights into experimentalstratified flows obtained through physics-informed neural networks. J. Fluid Mech., 981:R1, 2024.</jats:p>
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ReportClarke B, Zachariah M, Pinto I, et al., 2025,
Increasing extreme rainfall and rapid urbanisation major drivers behind Gaborone’s deadly floods
, Publisher: Centre for Environmental Policy -
ReportKew S, Pinto I, Philip S, et al., 2025,
Women and girls continue to bear disproportionate impacts of heatwaves in South Sudan that have become a constant threat
, Publisher: Centre for Environmental Policy -
Journal articleLefauve A, Cheung YHM, Jiang X, et al., 2025,
Routes to stratified turbulence and temporal intermittency revealed by a cluster-based network model of experimental data
, Europhysics Letters, Vol: 149, ISSN: 0295-5075Modelling fluid turbulence using a "skeleton" of coherent structures has traditionally progressed by focusing on a few canonical laboratory experiments such as pipe flow and Taylor-Couette flow. We here consider the stratified inclined duct, a sustained shear flow whose density stratification allows for the exploration of a wealth of new coherent and intermittent states at significantly higher Reynolds numbers than in unstratified flows. We automatically identify the underlying turbulent skeleton of this experiment with a data-driven method combining dimensionality reduction and unsupervised clustering of shadowgraph visualisations. We demonstrate the existence of multiple types of turbulence across parameter space and intermittent cycling between them, revealing distinct transition pathways. With a cluster-based network model of intermittency we uncover patterns in the transition probabilities and residence times under increasing levels of turbulent dissipation. Our method and results pave the way for new reduced-order models of multi-physics turbulence.
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Journal articleHe S, Tong Z, Tong S, et al., 2025,
Collaborative optimization of turbo-expander impellers and guide vanes to mitigate flow-induced vibrations
, Physics of Fluids, Vol: 37, ISSN: 1070-6631When subjected to a high-flow gas impact, the impeller and guide vane are prone to vibration, jeopardizing equipment safety and stability. This study presents a collaborative optimization strategy for reducing the flow-induced vibration of the turbo-expander's impeller and guide vane. Parametric modeling of the impeller and guide vane profiles is conducted, followed by dimensionality reduction of parameters based on geometric characteristics. Flow-induced vibration arises from the complex interactions between the impeller and guide vane, where adjustments to one component inevitably influence the other due to intricate coupling. Traditional heuristic algorithms, constrained by numerous interacting design parameters, typically optimize individual structures rather than addressing the overall system performance. To overcome this limitation, this paper integrates tent chaotic mapping into the conventional particle swarm optimization algorithm, leveraging it to initialize the search space. This approach broadens the optimization scope for both components, enhances global search coverage, and improves system-wide performance. Moreover, through extensive optimization comparisons within collaborative optimization, the introduction of an adaptive t-distribution effectively balances the exploration of uncharted domains with the exploitation of known information, enabling more robust solutions to complex coupled problems. The proposed optimization framework allows for direct parameter model updates, minimizing errors associated with surrogate models and significantly improving optimization accuracy. Results demonstrate that the method successfully avoids premature convergence while maintaining efficient execution performance. Notably, the pressure pulsation amplitudes in the impeller and guide vane runners of the turbo expander were reduced by 50.5% and 37.3%, respectively, while the radial vibration acceleration amplitude of the impeller decreased by 74.3%.
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Journal articleWang T, Iriawan H, Peng J, et al., 2025,
Confined Water for Catalysis: Thermodynamic Properties and Reaction Kinetics
, CHEMICAL REVIEWS, Vol: 125, Pages: 1420-1467, ISSN: 0009-2665- Cite
- Citations: 9
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Journal articleYang WW, Tang XY, Ma X, et al., 2025,
Synergistic intensification of palladium-based membrane reactors for hydrogen production: A review
, Energy Conversion and Management, Vol: 325, ISSN: 0196-8904Hydrogen is a clean, zero-carbon energy carrier that is critical in the transition to a renewable energy system. Hydrogen production membrane reactors are based on membrane technology for process intensification, allowing simultaneous reaction enhancement and hydrogen purification. However, concentration polarization creates mismatch between reaction and separation processes, limiting the performance. To further develop and increase the hydrogen production efficiency in membrane reactors, this review first provides advances in membrane reactor research from several perspectives, including membrane materials, performance metrics, and evaluation tools. Subsequently, the effects of operating conditions and structural design on the performance enhancement of membrane reactors are organized and analyzed. The review focuses on summarizing the mechanisms for improving membrane reactor design performance, proposing four methods: shortening distance, increasing routes, smoothing paths, and multi-product removal. Additionally, it is suggested to draw on membrane surface pattern designs to guide the disruption of concentration boundary layers. The review finds that enhancement ways primarily revolve around mitigating concentration polarization. Various ways have the potential to achieve low-cost and higher performance by complementing each other's strengths, such as minimizing the use of precious metals and employing low-cost multi-product separation. Moreover, there is a lack of corresponding evaluation standards for membrane reactors, which hinders the subsequent commercialization development. Finally, this review combines existing challenges and research progress to provide perspectives for the future development of membrane reactors. The major goal is to introduce new research methods to further promote the application of membrane reactors in greater depth.
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Journal articleJiang J, Chen Y, Zhang R, et al., 2025,
New insights on the impact of light, photoperiod and temperature on the reproduction of green algae <i>Ulva prolifera</i> via transcriptomics and physiological analyses
, MARINE POLLUTION BULLETIN, Vol: 211, ISSN: 0025-326X -
ReportBarnes C, Keeping T, Madakumbura G, et al., 2025,
Climate change increased the likelihood of wildfire disaster in highly exposed Los Angeles area
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Journal articleMonerie P-A, Feng X, Hodges K, et al., 2025,
High prediction skill of decadal tropical cyclone variability in the North Atlantic and East Pacific in the met office decadal prediction system DePreSys4
, npj Climate and Atmospheric Science, Vol: 8, ISSN: 2397-3722The UK Met Office decadal prediction system DePreSys4 shows skill in predicting the number of tropical cyclones (TCs) and TC track density over the eastern Pacific and tropical Atlantic Ocean on the decadal timescale (up to ACC = 0.93 and ACC = 0.83, respectively, as measured by the anomaly correlation coefficient—ACC). The high skill in predicting the number of TCs is related to the simulation of the externally forced response, with internal climate variability also allowing the improvement in prediction skill. The Skill is due to the model’s ability to predict the temporal evolution of surface temperature and vertical wind shear over the eastern Pacific and tropical Atlantic Ocean. We apply a signal-to-noise calibration framework and show that DePreSys4 predicts an increase in the number of TCs over the eastern Pacific and the tropical Atlantic Ocean in the next decade (2023–2030), potentially leading to high economic losses.
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OtherTheokritoff E, Yesil B, Menke I, et al., 2025,
How can overshoot risks be included in long-term adaptation planning?
<jats:p>As climate change intensifies, it is essential to take a wide range of climate scenarios and their consequential impacts into account for adaptation planning. Overshoot scenarios, during which global warming will temporarily exceed the 1.5&#176;C Paris Agreement target before it is brought down again in the following decades, are increasingly likely under current emissions trajectories. They would result in complex risks such as limits to adaptation and irreversible impacts and stress the need to prepare long-term adaptation plans under deep uncertainty.Here, we introduce the latest version of the Overshooting Proofing Methodology, a self-assessment tool designed to guide adaptation planners and policy-makers to integrate overshoot risks into planning processes, and present novel insights from its application with key stakeholders at city and regional levels. We also reflect on how adaptation pathways can allow to adequately plan a sequence of adaptation measures over time based on information collected through this tool. Its initial implementation in selected cities/regions reflects its applicability in varied climatic settings together with a range of climate related challenges. This work provides insights on key data gaps, capacity building needs and avenues for future adaptation planning, policy-making and research.</jats:p>
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ReportJennings N, Paterson P, Whitmarsh L, et al., 2025,
How have the UK public been affected by extreme heat and what do they think about the risks that it poses in the future?
The Intergovernmental Panel on Climate Change’s Sixth Assessment report concluded that the frequency and intensity of heatwaves and extreme heat has increased globally as a result of climate change. Such extremes of temperature negatively affect people’s physical and mental health.These slides summarise findings from a nationally representative sample (on the basis of age, gender and ethnicity) of 897 people who were asked to share their experience of heatwaves and very hot weather in the UK. The survey was conducted via the platform Prolific.com between 2-4 October 2024.
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Journal articlePfleiderer P, Frölicher TL, Kropf CM, et al., 2025,
Reversal of the impact chain for actionable climate information
, Nature Geoscience, Vol: 18, Pages: 10-19, ISSN: 1752-0894Escalating impacts of climate change underscore the risks posed by crossing potentially irreversible Earth and socioecological system thresholds and adaptation limits. However, limitations in the provision of actionable climate information may hinder an anticipatory response. Here we suggest a reversal of the traditional impact chain methodology as an end-user focused approach linking specific climate risk thresholds, including at the local level, to emissions pathways. We outline the socioeconomic and value judgement dimensions that can inform the identification of such risk thresholds. The applicability of the approach is highlighted by three examples that estimate the required CO2 emissions constraints to avoid critical levels of health-related heat risks in Berlin, fire weather in Portugal and glacier mass loss in High Mountain Asia. We argue that linking risk threshold exceedance directly to global emissions benchmarks can aid the understanding of the benefits of stringent emissions reductions for societies and local decision-makers.
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Journal articleWu J, Zhang Y, Jiang M, et al., 2025,
Onboard carbon capture, utilization, and storage
, Cell Reports Physical ScienceCarbon capture, utilization, and storage (CCUS) represents a key carbon-reduction strategy with significant potential to address global climate change. Current research primarily focuses on mitigation approaches for large-scale terrestrial emitters, such as power plants and petrochemical facilities, whereas comprehensive reviews in the maritime sector remain relatively scarce. In particular, there is a lack of studies that synthesize international development experiences or explore future trends aimed at meeting increasingly stringent carbon-reduction requirements in shipping. This paper reviews the current state of shipboard carbon-capture systems worldwide and emphasizes that real-time onboard CO<inf>2</inf> processing and utilization is likely to emerge as a critical pathway for decarbonizing the shipping industry. Given the distinct composition of marine exhaust gases and the challenges associated with integrating CCUS systems on vessels, future efforts should prioritize integrated system design. Moreover, dedicated technological development adapted to the maritime environment is essential to advance ship-based CCUS solutions.
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Journal articleSparks N, Toumi R, 2025,
Climate change attribution of Typhoon Haiyan with the Imperial College Storm Model
, Atmospheric Science Letters, Vol: 26, ISSN: 1530-261XIt is difficult to model changes in the likelihood of tropical cyclones under climate change to date. We do this, for the first time, by a applying a stochastic tropical cyclone event set generated by the Imperial College Storm Model to attribute the contribution of climate change to the case of Typhoon Haiyan in 2013. Compared to a pre-industrial baseline, we estimate that a typhoon with a landfall maximum wind speed like Haiyan was larger by +3.5 m/s. This is in good agreement with previous full physics numerical model estimates. A Haiyan type of event has a current return period of 850 years, and the fractional attributable risk due to climate change is 98%. Without climate change, this event was very unlikely. The type of information available from the IRIS model could inform subsidizing of catastrophe bond yield in the context of the loss and damage fund.
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Journal articleLai T, Toumi R, 2025,
Sensitivity of the energy conversion efficiency of tropical cyclones during intensification to sea surface temperature and static stability
, Quarterly Journal of the Royal Meteorological Society, Vol: 151, ISSN: 0035-9009It is projected that the sea surface temperature (SST) increases under climate change and enhances tropical cyclone (TC) intensification directly. An opposing expected feature of climate change is the strengthening atmospheric static stability, which may suppress intensification. The intensity and diabatic heating are closely related through the secondary circulation, but it has been unclear whether both will change at the same rate. Here we show that they respond differently to stability changes. The efficiency of converting diabatic heating to kinetic energy (KE) of TCs to SST and static stability during the intensification stage is examined. In a set of idealised simulations, the efficiency does not have a significant relation with the SST. However the efficiency is found to decrease with increasing static stability at a rate of about -5 % ⋅K‾¹. It is shown that the KE increment declines, while the diabatic heating in the eyewall remains unchanged with larger static stability. The decrease in KE gain at the eyewall is associated with an enhanced outward advection of absolute angular momentum. The combined effect of enhanced water‐vapour supply and the slightly reduced updraft at the eyewall keeps the diabatic heating steady with varying static stability. This study demonstrates the complex effects of enhanced static stability, which is expected to accompany surface warming, on tropical cyclones.
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Journal articleLoureiro MD, Jennings N, Lawrance E, et al., 2025,
Cool Solutions in Hot Times: The Case for Digital Health in Heatwave Action Plans
, ONLINE JOURNAL OF PUBLIC HEALTH INFORMATICS, Vol: 17 -
ReportOtto F, Giguere J, Clarke B, et al., 2024,
When risks become reality: extreme weather in 2024
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Journal articleLi M, Toumi R, 2024,
On the temporal decay of tropical cyclones over the ocean
, Geophysical Research Letters, Vol: 51, ISSN: 0094-8276It is important to understand how tropical cyclones (TCs) decay over the ocean as this is a criticalpre‐landfall stage. A modified exponential decay model (β model) with two parameters α and β is proposed. Thescale parameter α defines the decay scale, while the shape parameter β determines whether the decay ratedecelerates or accelerates over time. Global fittings indicate that around 40% of TCs exhibit decelerating decay(β≤1), while the majority (about 60%) show accelerating decay (β>1). Correlation analysis reveals a strongnegative correlation between the scale parameter α and the initial Coriolis parameter (r = − 0.96) and a positivecorrelation between the shape parameter β and the meridional component of the initial translation velocity(r = 0.75). The β model provides a comprehensive understanding of how TCs decay with time and howenvironmental conditions affect the decay scale and evolution.
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ReportMerz N, Clarke B, Basconcillo J, et al., 2024,
Climate change supercharged late typhoon season in the Philippines, highlighting the need for resilience to consecutive events
, Publisher: Centre for Environmental Policy -
Journal articleXu Y, Han X, Cao XE, 2024,
Comprehensive performance evaluation of HVAC systems integrated with direct air capture of CO2 in various climate zones
, Building and Environment, Vol: 266, ISSN: 0360-1323Direct Air Capture (DAC) is a rapidly evolving technology that extracts CO<inf>2</inf> directly from ambient air. This study presents a comprehensive performance evaluation of integrating DAC in HVAC systems, which can reduce indoor CO<inf>2</inf> concentration and improve energy efficiency of HVAC systems. The DAC equipment is modeled in Modelica based on isotherm and thermodynamic equations, and pressure drop curves of the CO<inf>2</inf> sorbent described in literature. The model is validated with data from the literature, and then integrated into a typical HVAC system available in Modelica Buildings library. The HVAC system is a Variable Air Volume (VAV) with reheater system for a one-floor office building with standard ASHRAE 2006 control sequences. Demand control ventilation strategies are designed to reduce the outdoor air flowrates when indoor CO<inf>2</inf> concentrations are lower than the threshold, which is to maximize the benefits of integrating DAC. Four cases are proposed to assess the impacts of integrating DAC and DCV in HVAC systems in 8 different ASHRAE climate zones in the USA. The results show that by integrating DAC unit into the HVAC system, the average indoor CO<inf>2</inf> concentration can be significantly reduced by over 45 % against the baseline without a DAC unit. By integrating DCV, 0.39–21.66 % of annual energy savings and 226–9539 kg carbon emissions reduction are observed across different climate zones. The highest energy savings are found to be achieved with cold climatic conditions while the lowest energy savings occur with favorable weather.
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Journal articleBozigar M, Konstantinoudis G, Vieira CLZ, et al., 2024,
Domestic radon exposure and childhood cancer risk by site and sex in 727 counties in the United States, 2001-2018
, SCIENCE OF THE TOTAL ENVIRONMENT, Vol: 954, ISSN: 0048-9697
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