Background: The ongoing climate change is exacerbating extreme weather events. Literature reports much evidence of the short-term effects of extreme climate on health. In contrast, the long-term effects of cumulative exposures to climatic extreme events remain understudied, with children being particularly vulnerable due to their developing respiratory system. 

Hypothesis: The study aims to delineate the effect of cumulative extreme events occuring in the first 6 years of life on children's respiratory health, assessed at age 7. 

Data: The study drew on the NINFEA cohort, a web-based birth cohort comprising 7500 mother-child pairs across Italy, recruited between 2005 and 2016. We calculated individual exposure by linking the residential history with the ERA5-land dataset provided by the Copernicus program of the European Centre for Medium-Range Weather Forecasts (ECMWF) for maximum (Tmax) and minimum (Tmin) temperature and cumulative precipitation (Pr) data. 

Respiratory health was collected at age 7 as wheezing symptoms in the last 12 months reported by the mothers.  

Method:Exposure to extreme weather events was identified as number of days in the 6 years of life above predetermined thresholds, defined with three  approaches: 

[a] The fixed value definition identifies the threshold using a value in the variable unit. 

[b] The percentile definition uses the location-specific normal series (1971-2000) to obtain the k-th percentile, allowing us to consider the geographical adaptation. 

[c] The day of the year (DOY) percentile definition uses the location-specific and day-specific normal series (1971-2000) to pick up the DOY-specific threshold; the extreme is located in a spatio-temporal definition addressing spatial and seasonal characteristics. 

Multiple thresholds were applied within each method to limit exposure's potential misclassification.

Analyses were adjusted for spatio-temporal confounders (macro-region, urban/rural classification, Koppen-Geiger climate zone, year of birth) and individual factors (maternal age, education, asthma).

Results: A consistent adverse effect of heat on respiratory health was captured using the fixed-value definition for both temperature extremes (OR= 1.011 for Tmax ≥35°C [C.I. 1.001-1.021]) and precipitation (OR= 1.006 for Pr ≥30mm [C.I. 1.001-1.011]). The percentiles analysis showed similar results, though with larger confidence intervals, reducing precision (OR= 1.007 for Tmax ≥95°[C.I. 0.999-1.015]; OR= 1.012 for Pr ≥95°[C.I. 0.998-1.025]). DOY percentile analysis,stratified by season, suggested clear effects of maximum temperatures in winter, spring, and autumn, but not in summer, and of minimum temperatures in summer, spring, and autumn, but not in winter. Stronger effects were detected with increasing threshold values, suggesting a threshold blurring or dose-response effect.

Conclusion: This study highlights the potential long-term impact of exposure to extreme weather events on children's respiratory health, emphasizing the need for mitigation measures against CC.

How to cite: Novaro, A., Maritano, S., Moirano, G., and Richiardi, L.: Effects of cumulative exposures to extreme weather events on children respiratory system, EMS Annual Meeting 2025, Ljubljana, Slovenia, 7–12 Sep 2025, EMS2025-576, https://doi.org/10.5194/ems2025-576, 2025.

The increase in thermal stress on human has been recently documented due to changing climatic conditions, mainly in the lowlands and the urban areas. The future evolution of the climate, as predicted by various scenarios, also proves that thermal stress on humans will further increase. Recently developed Aladin-Climate reanalysis for the broad area of Europe involves computation of the UTCI index (Universal Thermal Climate Index) at regular gridpoints. The advantage of the reanalysis is its resolution of 2.3 km and therefore the detailed orography mask, which is reflected in values of the UTCI, being substantially modulated by altitude. For separate seasons, the trends of UTCI are computed between 1991 and 2020. It has been shown that the most prominent increase is found in summer, mainly after 1990, probably due to rising temperatures. Insignificant increase of UTCI in autumn may be explained by increasing trends in cloudiness, affecting wind speed and the radiation balance on the surface. The UTCI trends are spatially inhomogeneous in separate seasons. Here, here we try to address factors causing discrepancies in the spatial distribution of the UTCI trends in individual seasons. For example, increasing thermal stress on human in northern and western parts of the country is detected in spring and autumn, whereas the increase in UTCI is concentrated in the lowlands in summer. The increasing temperature probably plays a major role, but changes in other factors associated with thermal stress, such as wind conditions and humidity, influence thermal stress as well. Those meteorological parameters are often tied to synoptic conditions, therefore, changes in surface pressure fields, front activity, etc. will be analyzed to uncover their influence on the spatial distribution of the UTCI trends.

How to cite: Hynčica, M., Novák, M., Došková, L., and Hrubý, J.: Explaining trends in UTCI in the Czechia between 1991 and 2020, EMS Annual Meeting 2025, Ljubljana, Slovenia, 7–12 Sep 2025, EMS2025-456, https://doi.org/10.5194/ems2025-456, 2025.

Over the past decade, human bio-meteorological research has increasingly examined the link between walkability and thermal comfort in urban environments. Traditional studies have focused on street-level thermal conditions, but recent research highlights how conventional methods misrepresent pedestrians’ actual exposure due to microclimatic variations along their walking route. Recently the concept of “thermal walks,” has been applied to examining pedestrians' dynamic thermal sensations as they move through the complex urban morphology.

This study examines (1) the relationship between urban morphology and pedestrians' dynamic thermal sensation in hot climates and (2) the impact of walking duration and distance on thermal perception. Field campaigns were conducted in Tel Aviv during both summer and winter across six street types: two commercial streets, two boulevards, and two side roads. Walking groups of 4 to 10 participants reported their thermal sensation votes (TSV) at four checkpoints along their routes, while simultaneous meteorological data—including air temperature, humidity, wind speed, and direction—were recorded using Kestrel 5400 Heat Stress Trackers. In total, 1,440 TSV responses were collected. PET and mPET thermal indices were calculated using RayMan Pro.

Results showed that mPET more accurately predicts thermal sensations during the thermal walk than PET. TSV varied significantly across different street types, increasing with walking distance. However, the relationship between TSV and objective thermal sensation weakened as walking distance increased, even with minor microclimate changes. Box plot analysis revealed that longer distances reduced TSV variability among participants.

These findings emphasize the need to incorporate dynamic thermal experiences into urban planning and bio-meteorological research, particularly in hot climates.

How to cite: Potchter, O., Cohen, P., Goldberg, A., Omer, I., and Matzarakis, A.: Assessment of Dynamic Thermal Sensation during thermal walk in a Mediterranean City, EMS Annual Meeting 2025, Ljubljana, Slovenia, 7–12 Sep 2025, EMS2025-575, https://doi.org/10.5194/ems2025-575, 2025.

Human health is directly affected by various environmental conditions associated with temperature, relative humidity, prevailing wind and incoming solar radiation. Among these climatic parameters, temperature and humidity have the greatest influence on human health and on thermal comfort sensation. In general, thermal comfort appears at air temperatures between 18^oC and 23^oC, relative humidity between 35% and 70%, with less or no air motion. Researchers have proposed various rational or empirical bioclimatic indices and models to assess human’s thermal comfort. These indices simplify the interpretation of the complex effects of prevailing atmospheric conditions on human comfort, allowing comparisons between different climatic regions. Two of the most widely accepted indices, are the ones of Humidex (HMDX) and Thom's Discomfort Index (TDI). HMDX represents the perception of heat in humid areas, while TDI indicates the contribution of temperature and humidity to thermal comfort.

For the city of Athens, a continuous urbanization process that started in the 1950s, with new high-rise buildings, and the subsequent appearance of the urban heat island phenomenon contributed to Athens basin’s local heating and modification of its climatic characteristics, especially during summers, characterized by long periods of sunshine, high temperatures and varying levels of humidity. At the same time, in recent decades (since the mid-1980s), Athens has experienced intense regional climate change.

The aim of the present study is to examine the temporal evolution of thermal sensation and discomfort, incorporating indices based on Temperature (T) and Relative Humidity (RH) records from NOA’s meteorological station on Thissio hill at the historic center of Athens (lat.: 37.972 N, log: 23.717 E, alt.: 107m), on an hourly basis , for the period between 1971 and 2005. In addition to the historical data, T and RH climate model projections up to 2100 are also used, after performing a bias correction procedure based on station data. HMDX and TDI were also estimated from 3-hourly T and RH projections (from a sub set of 3 regional climate models), for two different greenhouse gas emission scenarios the intermediate scenario - RCP 4.5 and the extreme with high emissions - RCP 8.5 (IPCC AR5). The analysis showed that, under the intermediate scenario an increase in the number of days of intense discomfort is expected in the city center of Athens by 15-20 days in the near future (up to 2060), and 25-30 days for the distant future (up to 2100). As for the extreme scenario, the corresponding increase in the number of days of intense discomfort reaches 25-30 days in the near and 60-65 days in the distant future, highlighting the expected heat exhaustion conditions and the need for urgent adaptation measures.

How to cite: Psiloglou, B., Gkinis, N., Kitsara, G., Machaira, P., and Giannakopoulos, C.: Discomfort Indices’ Variation in Athens, Greece: Present Status and Future Estimations., EMS Annual Meeting 2025, Ljubljana, Slovenia, 7–12 Sep 2025, EMS2025-475, https://doi.org/10.5194/ems2025-475, 2025.