OSA2.4

Heatwaves have been increasing in frequency, duration, and intensity. They have been the deadliest hydro-meteorology hazard globally for the last 5 years according to the world meteorological organisation. In addition, they are not constrained by geography in the same sense as many other hazards and as such they are borderless. They however receive less attention, research, and funding internationally than other hazards such as floods and storms, effecting how we perceive their risk and their reporting. Here we consider the impact of heatwaves by making use of the Universal Thermal Climate Index (UTCI) for indicating heat stress. The UTCI is a biometeorological index that computes thermal stress using the parameters of 2m temperature, wind speed, mean radiant temperature and relative humidity and a body model, making it a human-centric approach to assessing thermal stress and is skilful for both indicating and forecasting heat hazards. Further a comparison to how heat impacts are reported in EM-DAT (an international disasters database) and international meteorological organisation reports, supplemented by English news media reports is made to assess whether heat impacts are sufficiently reported. In addition, we refer to specific case studies of the United Kingdom, Ghana, and Uganda to further explore impacts, risk perception and policy at a country level, because although heat is borderless impacts occur on a local scale. All this together, will provide the evidence for the development a potentially global early warning system and the implementation of climate change adaptation on a local level to build adaptive capacity and resilience to the growing risk of heat stress internationally. 

How to cite: Brimicombe, C., Di Napoli, C., Cornforth, R., Pappenberger, F., Petty, C., and Cloke, H.: Borderless Heat Stress, EMS Annual Meeting 2021, online, 6–10 Sep 2021, EMS2021-28, https://doi.org/10.5194/ems2021-28, 2021.

Ultraviolet (UV) radiation is essential for many biological processes even its intensity near the surface is weak in comparison with visible and infrared sun radiation. Plants, animals and humans adopted to common UV radiation intensity. However higher doses pose an increased risk for all organisms. The UV index (UVI) defined in early 90s is recently used to express possible harm to the human body.

The UVI is computed from the spectral intensity of UV–B radiation. Its magnitude is thus related to sun elevation, cloud cover, stratospheric ozone concentration, altitude and air pollution. Important factor is also snow cover which increases the UVI due to high reflectivity. The UVI usually attains values between 0 and 9 in middle latitudes; the higher value of the UVI indicates a higher risk of the human body harm. The highest values are generally reached in sunny days around the noon in June and July in mid-latitudes. The cloudiness usually decreases the UVI and the Cloud modification factor defined for the UV-B radiation reduction is usually applied for the UVI forecast.

The aim of the contribution is to quantify effect of clouds on the UVI and revise the values of the CMF for the UVI. Different types of clouds, the base height and cloud structure are considered. The study is based on station measurement of the UVI, global radiation and sun duration in 10 minutes intervals from four stations in the Czechia during the period 2011–2017. The parameters of clouds were extracted from the SYNOP reports from the nearest stations. The results show a weak effect of high- level clouds on the UVI (decrease of 15 %) even under cover 8/8. The mid- and low-level clouds reduce the UVI with factor 0,7 to 0,35 according to its amount. However, clouds with vertical evolution (cumulus and cumulonimbus) cause in specific cases even increase of the UVI. Complete table of cloud effect on the UVI for the sun elevation between 35° and 50° will be introduced in presentation.

How to cite: Pokorná, L. and Tomanová, H.: Cloud effect on the Ultraviolet index, EMS Annual Meeting 2021, online, 6–10 Sep 2021, EMS2021-57, https://doi.org/10.5194/ems2021-57, 2021.

Air pollution and heat events present two major health risks, both already independently posing a significant threat to human health and life. High levels of ground-level ozone (O₃) and air temperature often coincide due to the underlying physical relationships between both variables. The most severe health outcome is in general associated with the co-occurrence of both hazards (e.g. Hertig et al. 2020), since concurrent elevated levels of temperature and ozone concentrations represent a twofold exposure and can lead to a risk beyond the sum of the individual effects. Consequently, in the current contribution, a compound approach considering both hazards simultaneously as so-called ozone-temperature (o-t-)events is chosen by jointly analyzing elevated ground-level ozone concentrations and air temperature levels in Europe.

Previous studies already point to the fact that the relationship of underlying synoptic and meteorological drivers with one or both of these health stressors as well as the correlation between both variables vary with the location of sites and seasons (e.g. Otero et al. 2016; Jahn, Hertig 2020). Therefore, a hierarchical clustering analysis is applied to objectively divide the study domain in regions of homogeneous, similar ground-level ozone and temperature characteristics (o-t-regions). Statistical models to assess the synoptic and large-scale meteorological mechanisms which represent main drivers of concurrent o-t-events are developed for each identified o-t-region.

Compound elevated ozone concentration and air temperature events are expected to become more frequent due to climate change in many parts of Europe (e.g. Jahn, Hertig 2020; Hertig 2020). Statistical projections of potential frequency shifts of compound o-t-events until the end of the twenty-first century are assessed using the output of Earth System Models (ESMs) from the sixth phase of the Coupled Model Intercomparison Project (CMIP6).

Hertig, E. (2020) Health-relevant ground-level ozone and temperature events under future climate change using the example of Bavaria, Southern Germany. Air Qual. Atmos. Health. doi: 10.1007/s11869-020-00811-z

Hertig, E., Russo, A., Trigo, R. (2020) Heat and ozone pollution waves in Central and South Europe- characteristics, weather types, and association with mortality. Atmosphere. doi: 10.3390/atmos11121271

Jahn, S., Hertig, E. (2020) Modeling and projecting health‐relevant combined ozone and temperature events in present and future Central European climate. Air Qual. Atmos. Health. doi: 10.1007/s11869‐020‐009610

Otero N., Sillmann J., Schnell J.L., Rust H.W., Butler T. (2016) Synoptic and meteorological drivers of extreme ozone concentrations over Europe. Environ Res Lett. doi: 10.1088/ 1748-9326/11/2/024005

How to cite: Jahn, S. and Hertig, E.: Current and future occurrences of health-relevant, compound heat and ozone pollution events in six European ozone-temperature regions, EMS Annual Meeting 2021, online, 6–10 Sep 2021, EMS2021-61, https://doi.org/10.5194/ems2021-61, 2021.

The effects of green areas and shading strategies have been identified as an effective means to reduce urban risk factors such as the Urban Heat Island (UHI) effect. Even though the importance of shaded outdoor spaces and thermal comfort have been well documented in the existing literature; there is still limited research on how these spaces can influence thermal adaptability and cognitive performance in primary school children.

As a result, the aim of the study is twofold: (1) to evaluate the effect of outdoor shaded spaces upon thermal comfort; and, (2) link such results upon the cognitive performance of primary school students in a classroom environment with natural ventilation. A case study shall be conducted with primary school students between the ages of 8-10 in the Bilkent Primary School in Ankara during the month of September.

The quantitative thermal microclimatic conditions of unshaded/shaded areas of the schoolyard and indoor classrooms are obtained through the Physiologically Equivalent Temperature (PET) index. The qualitative evaluation of thermal comfort is undertaken by using both the adaptive model, and a complementary thermal sensation survey. As a result, both human physiological and psychological attributes of thermal comfort adaptation shall be evaluated and cross-examined in the study. Attention and memory tasks are given to the respondents in order to measure the cognitive performance of the students that are subjected to different experiences of outdoor shading levels.

The outcome of this individual study shall pinpoint the contributions of shaded outdoor green spaces upon the thermal adaptability and cognitive performance of children within classroom settings.

How to cite: Gündoğdu, B., Santos Nouri, A., and Afacan, Y.: Investigating the impacts of shaded outdoor spaces on thermal adaptation and cognitive performance of children in classroom environments, EMS Annual Meeting 2021, online, 6–10 Sep 2021, EMS2021-95, https://doi.org/10.5194/ems2021-95, 2021.

Background: Pollen information is crucial for effective preventive behaviour of pollen allergy sufferers. In addition to the results of pollen monitoring and weather conditions, feedback from allergic people plays an important role in generating information for the public. A useful tool that gives us an insight into the burden of pollen allergy is the patient’s hay fever diary (PHD), developed by the Vienna Medical University. PHD is freely available online, users enter their location, general well-being, pollen symptoms and medication use.

Methods: This study is based on two databases: 1- PHD data for symptom load index (SLI) calculations, only daily entries from Slovenia were used; 2- National pollen database for three measuring stations: Ljubljana, Maribor and Izola. A five-year period (2014-2018) was analysed. We reviewed the number of monthly entries as an indicator of the time span when most people need pollen information. The focus was on three high allergenic pollen types; birch (Betula), grass (Poaceae) and ragweed (Ambrosia). Annual pollen load (APL) allows us to compare results between years.

Results: 60 % of yearly entries were recorded from March to May, when users reported the most problems with pollen-induced symptoms. In parallel the monthly pollen totals were high. Birch pollen season typically occurs from late March to end of April with May marked by grass pollen season. The highest SLI values were calculated for birch pollen (4,79 – 7,68), with the maximum in the year 2016 when the highest APL was also recorded. SLI for grass pollen season varied from 3,92 to 4,80 and is mostly lower than SLI for birch. SLI slowly decreased after May and rose again in August and September, when ragweed pollen occurs. Results for this non-native species show that SLI was increasing from 2,48 (2014) to 4,55 (2018).

Conclusion: Pollen information is most sought after in the spring, when the highest daily concentrations are recorded. Birch pollen seems to have the highest impact on allergy sufferers, followed by grasses. In the case of ragweed we have noticed that the impact on health was increasing during the analyzed period. A comparison of the calculated SLI with the level of exposure to different pollen types may explain the fluctuations in the occurrence of allergic disease during the course of pollen seasons. Preventive behaviour of allergic persons is only possible with quick and accurate pollen information. Therefore, we started releasing preliminary results with a three-color scale to keep the public informed about the current state of allergens in the atmosphere.  

How to cite: Simčič, A., Kofol Seliger, A., Koritnik, T., and Cegnar, T.: The Patient's Hay-fever diary: users feedback can improve pollen information, EMS Annual Meeting 2021, online, 6–10 Sep 2021, EMS2021-112, https://doi.org/10.5194/ems2021-112, 2021.

Within the existing literature, it is well established that thermal comfort thresholds play an integral part in sleep quality. For this reason and within consolidated urban environments that are continually witnessing increased vulnerability to heat stress as a result of urban densification and climate change, impediments upon sleep quality due to excess physiological heat stress is a growing concern. Such risk factors are particularly the case for older traditional building methods that depend on natural ventilation.  

Focused upon the capital city of Ankara, and through the application and modification of the WMO’s Expert Team on Climate Change Detection Monitoring Indices (ETCCDMI) to determine the effects of sleep quality during different heat stress events, three different conditions were respectively examined, during a: (1) typical summer day; (2) very hot day; and lastly, (3) heat wave event. Within this case study, the relationship between the indoor thermal thresholds and sleep quality shall be undertaken through the use of: (i) the Physiologically Equivalent Temperature (PET) calculated from climatic variables retrieved from the residential units at a 10 minute temporal resolution; (ii) questionnaires to acquire qualitative responses from local residents; and, (iii) local urban climatic data, retrieved from Ankara’s meteorological station (#17130) at an hourly temporal resolution.  

The outputs of the study address the growing need to identify and address the impact that urban augmenting temperatures have upon the sleep quality of occupants in more vulnerable construction typologies. Given that such vulnerabilities in urban settings are continually observing more frequent and intense heatwaves and hot days, the study highlights the need to strengthen the understanding between such outdoor events and sleep quality patterns in warming urban frameworks. 

How to cite: Ahan, M. and Nouri, A.: Investigating the relationship between outdoor heat events upon sleep quality in Ankara, EMS Annual Meeting 2021, online, 6–10 Sep 2021, EMS2021-177, https://doi.org/10.5194/ems2021-177, 2021.

Studies projecting the impacts of future climate change on temperature-mortality relationships suggest increasing heat-related mortality in most regions of the world. On the contrary, a reduced risk of heat-related mortality has been observed in many countries over the last decades, suggesting a positive effect of technological development and improved health care systems. However, most of the studies show that the decline in vulnerability of populations to heat has abated in the early 2000s and further decreasing trend is unlikely.

In this study, we analysed temperature-mortality relationships in Prague, Czech Republic during 1982–2019. The study was restricted to five warmest months (May–September). To investigate possible changes in the temperature–mortality relationship, the study period was divided in four decades (1980s to 2010s). Conditional Poisson Regression coupled with the Distributed Lag Non-Linear Model (DLNM) was run separately in each decade, to derive decade-specific temperature–mortality associations. A stratum indicator variable composed of year, month, and day of the week was used to control for long-term, seasonal trends and weekly effects. The DLNM approach was applied in order to analyse delayed effects of temperature on mortality. The attributable number of deaths (AD) and the attributable fraction (AF %) of total May–September deaths on hot days was calculated from the model’s outputs, separately for each decade. Hot days were defined as days with daily mean temperature larger than the 95th percentile of the decade-specific May–September distribution.

We observed a quadratic trend shape in the number of deaths attributable to heat; maximum in the 2010s and minimum in the 1990s. The total number of heat-attributable deaths increased from ≈500 to almost 900 per decade between the 1980s and the 2010s, which corresponds to the fraction of 0.90 and 1.75 %, respectively, of the total number of deaths in a warm season.

How to cite: Urban, A., Fonseca-Rodríguez, O., Di Napoli, C., Plavcová, E., and Kyselý, J.: Changes in heat-attributable deaths in Prague, Czech Republic, over 1982–2019, EMS Annual Meeting 2021, online, 6–10 Sep 2021, EMS2021-359, https://doi.org/10.5194/ems2021-359, 2021.