Are urban water bodies really cooling?

Small urban water bodies, like ponds or canals, are often assumed to cool their surroundings during hot periods, when water bodies remain cooler than air during daytime. However, during the night they may be warmer. Sufficient fetch is required for thermal effects to reach a height of 1–2 m, relevant for humans. In the ‘Really cooling water bodies in cities’ (REALCOOL) project thermal effects of typical Dutch urban water bodies were explored, using ENVI-met 4.1.3. This model version enables users to specify intensity of turbulent mixing and light absorption of the water, offering improved water temperature simulations. Local thermal effects near individual water bodies were assessed as differences in air temperature and Physiological Equivalent Temperature (PET). The simulations suggest that local thermal effects of small water bodies can be considered negligible in design practice. Afternoon air temperatures in surrounding spaces were reduced by typically 0.2 °C and the maximum cooling effect was 0.6 °C. Typical PET reduction was 0.6 °C, with a maximum of 1.9 °C. Night-time warming effects are even smaller. However, the immediate surroundings of small water bodies can become cooler by means of shading from trees, fountains or water mists, and natural ventilation. Such interventions induce favorable changes in daytime PET.</p

Creating prototypes for cooling urban water bodies

When addressing urban heat problems, climateconsciousurban design has been assumingthat urban water bodies such as canals, ditchesor ponds cool down their surroundings. Recentresearch shows that this is not necessarily thecase and that urban water bodies may actuallyhave a warming e!ect, particularly during latesummer season nights. There are howeverindications that water can have a coolingpotential if brought together with the rightshading, evaporation and ventilation strategies.Yet, it is not clear how this should be achieved.Knowledge on such spatial configurations shouldthus be developed and made available to designpractice. This challenge is directly addressed bythe “REALCOOL” project, a research aiming todefine design prototypes showing the physicalprocesses behind the e!ective cooling potentialof urban water bodies, that design professionalscan take as conceptual design frameworks

EXPERIMENTS WITH AN HOURLY STREET CANYON DISPERSION MODEL

Based on wind tunnel experiments and the yearly average calculating CAR model (Jonkers 2007) a new hourly average calculating street canyon dispersion model is derived. With this hourly model, dispersion can be calculated for different types of street configurations, varying in aspect ratio and building configuration. The model outcome is compared with measured concentrations from the TRAPOS campaign. After applying linear regression, a correlation coefficient between the hourly measured and the hourly modelled concentrations of 0.64 was found, the systematic error was 1.13

High resolution exposure modelling of heat and air pollution and the impact on mortality

Background Elevated temperature and air pollution have been associated with increased mortality. Exposure to heat and air pollution, as well as the density of vulnerable groups varies within cities. The objective was to investigate the extent of neighbourhood differences in mortality risk due to heat and air pollution in a city with a temperate maritime climate. Methods A case-crossover design was used to study associations between heat, air pollution and mortality. Different thermal indicators and air pollutants (PM10, NO2, O3) were reconstructed at high spatial resolution to improve exposure classification. Daily exposures were linked to individual mortality cases over a 15 year period. Results Significant interaction between maximum air temperature (Tamax) and PM10 was observed. During “summer smog” days (Tamax > 25 °C and PM10 > 50 μg/m3), the mortality risk at lag 2 was 7% higher compared to the reference (Tamax 15 °C and PM10 15 μg/m3). Persons above age 85 living alone were at highest risk. Conclusion We found significant synergistic effects of high temperatures and air pollution on mortality. Single living elderly were the most vulnerable group. Due to spatial differences in temperature and air pollution, mortality risks varied substantially between neighbourhoods, with a difference up to 7%

Magnetic Resonance Direct Thrombus Imaging (MRDTI) Can Distinguish Between Old and New Thrombosis in the Abdominal Aorta: a Case Report

A 43-year-old man complaining of abdominal angina for several months showed a large suprarenal aneurysm of the abdominal aorta with extensive circumferential wall thrombosis, complete occlusion of the right renal artery and a critically stenosed left renal artery on CT angiography. He suffered from severe hypertension and renal failure. A percutaneous transluminal angioplasty (PTA) was planned. After the PTA procedure, which was complicated by the development of left renal artery occlusion, successful rescue revascularization surgery was performed. Since we were hesitant to start anticoagulant treatment because of a high bleeding risk, magnetic resonance direct thrombus imaging was performed to assess the age of the extensive arterial thrombosis. The aortic thrombus showed a low signal intensity, which is indicative of chronic rather than acute thrombosis. Therefore, oral anticoagulant treatment was not started. The patient recovered without major complications

Urotherapy in children with dysfunctional voiding and the responsiveness of two condition-specific questionnaires

Aims: We sought to establish the responsiveness of the Dutch Vancouver Symptom Score for Dysfunctional Elimination Syndrome (VSSDES) and Pediatric urinary incontinence Quality of life (PinQ) questionnaires. Secondary, we evaluated the outcome of urotherapy extended for children with dysfunctional voiding (DV). Methods: This cross-sectional multicenter study was done in one tertiary and two community hospitals. Children with DV were included, also when refractory to previous urotherapeutic treatment. The questionnaires were completed before and after urotherapy. The primary outcome measure was the responsiveness of the Dutch VSDESS and PinQ. Secondary outcome was the initial success (defined by the International Children's Continence Society) of extended urotherapy. Results: Between June 2014 and May 2016, 64 children (median age 7 years, IQR 6-10) received urotherapy (median 18 weeks, IQR 11-28). In contrast to the VSSDES, the PinQ showed good responsiveness. For children and parents, respectively, the area under the ROC-curve was 0.79 (P = 0.01) and 0.72 (P = 0.03) for the PinQ and 0.50 (P = 0.98) and 0.55 (P = 0.62) for the VSSDES. Fifty children received extended urotherapy, 27 had complete, and 14 had partial response. Sixteen children had been refractory to previous treatment; four showed complete, and six showed partial response. Conclusion: The PinQ is able to detect clinically important changes in continence-specific quality of life after treatment. We support the use of the VSSDES questionnaire in addition to the current diagnostics for the diagnosis of DV. Extended urotherapy showed to be a successful treatment for children with DV, also for those who had received previous unsuccessful treatment

The cooling effect of different water bodies in Amsterdam during hot days

Urban green and shading are adaptation measures that reduce urban heat. This is evident from meteorological measurements and investigations with surveys and has been described in many papers (e.g. Klemm et al., 2015). The cooling effect of these adaptation measures is reflected by lower air temperatures and an improved thermal comfort. Shading and urban green are also experienced as cooler than impervious urban spaces without vegetation or shading. However, the cooling effect of water bodies in cities, such as rivers, lakes, ponds, canals, fountains, is not clear yet (Steeneveld et al., 2014). Several studies show that the cooling effect of water bodies in cities is small, or can even be a source of heat during nighttime. The effect depends on the characteristics of the water body and the meteorological conditions. Nevertheless, water is often mentioned as an adaptation measure to reduce urban heat. To support urban professionals in designing cooler urban environments by using water bodies, we investigated in more detail how different water types in msterdam contribute to cooling the environment. During five summer days, we measured the cooling effect of five different water bodies: a pond, a fountain, a canal, and two rivers. We used measurements from mobile weather stations (air temperature, relative humidity, wind speed, global radiation and globe temperature) and collected almost 1000 surveys near the water bodies and a reference location. From these data, we could determine the effect of the water bodies on air temperature, thermal comfort and thermal sensation. The research question that we tried to answer with this study is: What is the cooling effect of different water types in the city of Amsterdam during hot days? The study has been carried out within the framework of a Dutch research project ‘Urban climate resilience – Turning climate adaptation into practice’ and supports urban professionals to decide on the right adaptation measures to reduce urban heat

Reasons to adapt to urban heat (in the Netherlands)

The future will be warmer with more tropical days, heat stress and related impacts for the healthy and liveable city. This is clear from many scientific studies and papers. Yet many local governments in the Netherlands claim to have insufficient understanding of the importance of these impacts in order to make the necessary step to climate adaptation and to take practical actions to manage the risks associated with rising heat levels. They struggle with defining the urgency of heat stress and finding good arguments for the need to adapt urban environments to rising temperatures. In order to provide urban professionals with reasons to adapt their urban environments to heat, we analyzed the potential impacts of urban heat from international policy reports and scientific literature. We summarized the impacts in a mind map. This map visualizes the large number and variety of heat-related risks. They can be subdivided into risks for health, open space, liveability, water and infrastructure networks. We believe that this mind map provides useful insight into the reasons to take heat adaptation actions. It can also be a helpful visual for urban professionals in outlining the reasons to take action for heat adaptation

Mindmap hitte in de stad: Interactieve tool om de gevolgen van extreme hitte in het bebouwde gebied in beeld te brengen Versie 2.0 (april 2019)

De mindmap ondersteunt gemeenten bij het verkennen van de problemen die door hitte kunnen optreden in bebouwd gebied en bij het voorbereiden van de risicodialoog over hitte. In totaal toont de mindmap 24 gevolgen van extreme hitte, verdeeld over vijf thema’s: gezondheid, netwerken, water, leefbaarheid en buitenruimte. In heldere tekst wordt ieder probleem uitgelegd, is beschreven op welke manier basiskaarten volgens de gestandaardiseerde stresstest het probleem inzichtelijk maken en welke aanvullende informatie gebruikt kan worden. Iedere tekst sluit af met mogelijke maatregelen en acties die het probleem voorkomen of verkleinen. Het kan zijn dat voor sommige situaties de mindmap niet compleet is en dat er nog andere hitteproblemen van belang zijn. Het is goed om hierbij stil te staan als de mindmap gebruikt gaat worden. De getoonde gevolgen zijn bovendien niet allemaal met ruimtelijke adaptatie op te lossen. Zorg voor medemens en aanpassingen aan gebouwen kunnen nodig of effectiever zijn