Dataset Information

Synergies between Urban Heat Island and Heat Waves in Athens (Greece), during an extremely hot summer (2012).

ABSTRACT: Heat waves (HWs) are recognized as a serious threat for human health worldwide, with urban areas being more vulnerable due to the urban heat island (UHI) effect and population density. Yet, in the climate change context, HWs are becoming more frequent, stronger and longer, which, coupled with intensifying urbanization exacerbates thermal risk for urban residents. Despite the profound impact of this global phenomenon there is no clear consensus so far on possible synergies between UHIs and HWs. The study sheds light on the complex synergies between UHIs and HWs focusing on coastal sites. A quite challenging period comprising five HW episodes during summer 2012 in Athens (Greece) was selected for analysis. A positive feedback between UHIs and HWs was found, with intensification of the average UHI magnitude by up to 3.5?°C during HWs, compared to summer background conditions. Our results contribute significantly to understanding synergies between UHIs and HWs that may strongly increase thermal risk in cities and vulnerability of urban population.

SUBMITTER: Founda D

PROVIDER: S-EPMC5591211 | biostudies-literature | 2017 Sep

REPOSITORIES: biostudies-literature

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Synergies between Urban Heat Island and Heat Waves in Athens (Greece), during an extremely hot summer (2012).

Founda Dimitra D Santamouris Mattheos M

Scientific reports 20170908 1

Heat waves (HWs) are recognized as a serious threat for human health worldwide, with urban areas being more vulnerable due to the urban heat island (UHI) effect and population density. Yet, in the climate change context, HWs are becoming more frequent, stronger and longer, which, coupled with intensifying urbanization exacerbates thermal risk for urban residents. Despite the profound impact of this global phenomenon there is no clear consensus so far on possible synergies between UHIs and HWs. T ...[more]

PMID: 28887502

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Project description:Abstract At present, understanding the synergies between the Surface Urban Heat Island (SUHI) phenomenon and extreme climatic events entailing high mortality, i.e., heat waves, is a great challenge that must be faced to improve the quality of life in urban zones. The implementation of new mitigation and resilience measures in cities would serve to lessen the effects of heat waves and the economic cost they entail. In this research, the Land Surface Temperature (LST) and the SUHI were determined through Sentinel-3A and 3B images of the eight capitals of Andalusia (southern Spain) during the months of July and August of years 2019 and 2020. The objective was to determine possible synergies or interaction between the LST and SUHI, as well as between SUHI and heat waves, in a region classified as highly vulnerable to the effects of climate change. For each Andalusian city, the atmospheric variables of ambient temperature, solar radiation, wind speed and direction were obtained from stations of the Spanish State Meteorological Agency (AEMET); the data were quantified and classified both in periods of normal environmental conditions and during heat waves. By means of Data Panel statistical analysis, the multivariate relationships were derived, determining which ones statistically influence the SUHI during heat wave periods. The results indicate that the LST and the mean SUHI obtained are statistically interacted and intensify under heat wave conditions. The greatest increases in daytime temperatures were seen for Sentinel-3A in cities by the coast (LST = 3.90 °C, SUHI = 1.44 °C) and for Sentinel-3B in cities located inland (LST = 2.85 °C, SUHI = 0.52 °C). The existence of statistically significant positive relationships above 99% (p < 0.000) between the SUHI and solar radiation, and between the SUHI and the direction of the wind, intensified in periods of heat wave, could be verified. An increase in the urban area affected by the SUHI under heat wave conditions is reported. Graphical Abstract Supplementary Information The online version contains supplementary material available at 10.1007/s41748-021-00268-9.

Project description:The main objective of this study was chemical characterization and source apportionment of the oxidative potential of ambient PM2.5 samples collected in an urban background area in Athens, Greece. Ambient PM2.5 samples were collected during the summer (June-September) of 2017 and winter (February-March) of 2018 at a residential, urban background site in the outlying neighborhood of the Demokritos National Laboratory in Athens, Greece. The collected PM samples were analyzed for their chemical constituents including metals and trace elements, water-soluble organic carbon (WSOC), elemental and organic carbon (EC/OC), and marker of biomass burning (i.e., levoglucosan). In addition, the DCFH in vitro assay was performed to determine the oxidative potential of the PM2.5 samples. We performed a series of statistical analyses, including Spearman rank-order correlation analysis, principal component analysis (PCA), and multi linear regression (MLR) to determine the most significant species (as source tracers) contributing to the oxidative potential of PM2.5. Our findings revealed that the intrinsic (per PM mass) and extrinsic (per m3 of air volume) oxidative potentials of the collected ambient PM2.5 samples were significantly higher than those measured in many urban areas around the world. The results of the MLR analyses indicated that the major pollution sources contributing to the oxidative potential of ambient PM2.5 were vehicular emissions (characterized by EC) (44%), followed by secondary organic aerosol (SOA) formation (characterized by WSOC) (16%), and biomass burning (characterized by levoglucosan) (9%). The oxidative potential of the collected ambient PM2.5 samples was also higher in summer compared to the winter, mainly due to higher concentrations of EC and WSOC during this season. Results from this study corroborate the impact of traffic and SOA on the oxidative potential of ambient PM2.5 in greater Athens area, and can be helpful in adopting appropriate public health policies regarding detrimental outcomes of exposure to PM2.5.

Project description:BackgroundWe sought to perform a study to record and evaluate patients' views of the way surgeons communicate informed consent (IC) in Greece.Methodology/principal findingsA prospective pilot study was carried out in Athens from 9/2007 to 4/2008. The study sample was extracted from patients, operated by eight different surgeons, who volunteered to fill in a post-surgery self-report questionnaire on IC. A composite delivered information index and a patient-physician relationship index were constructed for the purposes of the analysis. In total, 77 patients (42 males) volunteered to respond to the questionnaire. The delivered information index scores ranged from 3 to 10, the mean score was 8, and the standard deviation (SD) was 1.9. All patients were aware of their underlying diagnosis and reason for surgery. However, a considerable proportion of the respondents (14.3%) achieved a score below or equal to 5. The patient-physician relationship scores ranged from 0 to 20, the mean score was 16 and the standard deviation (SD) was 4.3. The better the patient-physician relationship, the more information was finally delivered to the patient from the physician (Spearman's rank-order correlation coefficient was 0.4 and p<0.001). Delivered information index was significantly higher among participants who comprehended the right to informed consent, compared to participants who did not (p<0.001), and among participants who were given information regarding other possible therapeutic options (p = 0.001). 43% of the respondents answered that less than 10 minutes were spent on the consent process, 58.4% of patients stated that they had not been informed about other possible therapeutic choices and 28.6% did not really comprehend their legal rights to IC.ConclusionsDespite the inherent limitations and the small sample size that do not permit to draw any firm conclusions, results indicate that a successful IC process may be associated with specific elements such as the patient-physician relationship, the time spent by the physician to inform the patient, a participant's comprehension of the right to IC and the provision of information regarding other possible therapeutic options.

Dataset Information

Synergies between Urban Heat Island and Heat Waves in Athens (Greece), during an extremely hot summer (2012).

Publications

Synergies between Urban Heat Island and Heat Waves in Athens (Greece), during an extremely hot summer (2012).

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