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During volcanic eruptions, aviation stakeholders require an assessment of the volcanic ash hazard. Operators and regulators are required to make fast decisions based on deterministic forecasts, which are subject to various sources of uncertainty. For a robust decision to be made, a measure of the uncertainty of the hazard should be considered, but this can lead to added complexity preventing fast decision‐making. A proof‐of‐concept risk‐matrix approach is presented that combines uncertainty estimation and volcanic ash hazard forecasting into a simple warning system for aviation. To demonstrate the methodology, an ensemble of 600 dispersion model simulations is used to characterize uncertainty (due to eruption source parameters, meteorology and internal model parameters) in ash dosages and concentrations for a hypothetical Icelandic eruption. To simulate aircraft encounters with volcanic ash, trans‐Atlantic air routes between New York (JFK) and London (LHR) are generated using time‐optimal routing software. This approach was developed in collaboration with operators, regulators and engine manufacturers; it demonstrates how an assessment of ash dosage and concentration risk can be used to make fast and robust flight‐planning decisions, even when the model uncertainty spans several orders of magnitude. The results highlight the benefit of using an ensemble over a deterministic forecast and a new method for visualizing dosage risk along flight paths. The risk‐matrix approach is applicable to other aviation hazards such as sulphur dioxide (SO2) dosages, desert dust, aircraft icing and clear‐air turbulence, and is expected to aid flight‐planning decisions by improving the communication of ensemble‐based forecasts to aviation. The methodology described in the present paper shows how a dispersion model ensemble can be used to make fast and robust flight‐planning decisions during volcanic eruptions. It was found that agreement between ensemble member simulations can be used to visualize confidence in ash concentration and dosage forecasts. The risk‐matrix approach allows for fast decision‐making, even when there is significant spread within the ensemble. Ash concentration and dosage risk are visualized along air routes for the first time. [ABSTRACT FROM AUTHOR]

• Role of corridors in the overheating of multi-residential dwellings was assessed. • Three TM59 compliant corridors/flat scenarios were compared to monitored data. • Propensity of corridors to overheat and exacerbate overheating in flats is nuanced. • Discretisation of flat/corridor boundary conditions may be masking dominant effects. • A new method is proposed for the consistent and replicable modelling of corridors. Prolonged overheating can have serious cumulative effects on human health, resulting in heat exhaustion, heatstroke and even death. The frequency and severity of heatwaves will increase considerably in the future as a result of accelerating climatic changes compounded by increasing urbanisation. A recent overheating risk-assessment methodology, Technical Memorandum (TM)59: 2017 was developed by the Chartered Institution of Building Services Engineers (CIBSE) to address this problem, by providing a consistent framework for the evaluation of overheating risks in new homes. TM59 has for the first time highlighted the importance of including corridor heat transfer effects in the dynamic modelling of multi-residential dwellings. This paper investigates the strengths and limitations of current approaches to the modelling of corridors, based on a case study of three energy-efficient flats located in London. The results of modelling in accordance with TM59 guidance are compared with alternative approaches, using more realistic occupancy and weather information, and compared to empirically measured data. The findings of this study indicate that current practices in Building Performance Simulation (BPS) are likely to under-estimate the actual air temperatures in corridors. This study highlights the need for further research into the way in which corridors, flats and their interconnecting ventilation and heat transfer networks are commonly discretised in BPS models. [ABSTRACT FROM AUTHOR]

Commercial London wants new air capacity. Is expansion the very least that should be done, or are the environmental costs too much to pay? The article presents views from both sides of the table. One of the view is that immediate expansion in aviation sector is necessary, but is only an interim solution to a wider problem that requires the full exploitation of cutting edge technology. On the other side it is debated that environmental problems associated with air transport expansion are growing faster than the technical solutions, creating a sustainability gap. [ABSTRACT FROM AUTHOR]