Patterns in acute aortic dissection and a connection to meteorological conditions in Germany.

Acute type A aortic dissection (ATAAD) is a dramatic emergency exhibiting a mortality of 50% within the first 48 hours if not operated. This study found an absolute value of cosine-like seasonal variation pattern for Germany with significantly fewer ATAAD events (Wilcoxon test) for the warm months of June, July, and August from 2005 to 2015. Many studies suspect a connection between ATAAD events and weather conditions. Using ERA5 reanalysis data and an objective weather type classification in a contingency table approach showed that for Germany, significantly more ATAAD events occurred during lower temperatures (by about 4.8 K), lower water vapor pressure (by about 2.6 hPa), and prevailing wind patterns from the northeast. In addition, we used data from a classification scheme for human-biometeorological weather conditions which was not used before in ATAAD studies. For the German region of Berlin and Brandenburg, for 2006 to 2019, the proportion of days with ATAAD events during weather conditions favoring hypertension (cold air advection, in the center of a cyclone, conditions with cold stress or thermal comfort) was significantly increased by 13% (Chi-squared test for difference of proportions). In contrast, the proportion was decreased by 19% for conditions associated with a higher risk for patients with hypotension and therefore a lower risk for patients with hypertension (warm air advection ahead of warm fronts, conditions with no thermal stress or heat stress, in the center of a cyclone with thermal stress). As many studies have shown that hypertension is a risk factor for ATAAD, our findings support the hypothesized relation between ATAAD and hypertension-favoring weather conditions.

[Thermal stress of urban dwellers during heat waves using the example of Freiburg (Breisgau)]. / Thermische Belastung von Bewohnern in Städten bei Hitzewellen am Beispiel von Freiburg (Breisgau).

BACKGROUND: As a result of climate change, people are increasingly affected by heat and the negative health effects of heat. Air temperature is often used as a measurement. However, in order to characterize the effects of heat on humans, other factors must be considered in addition to air temperature. OBJECTIVES: The aim of this paper is to characterize the thermal stress of urban dwellers by means of the perceived temperature during heat waves, compare it with rural dwellers, and highlight differences from air temperature. MATERIALS AND METHODS: Data from the year 2019 are used from two different German Weather Service (DWD) stations located within the city of Freiburg im Breisgau, Germany, and its surroundings (Freiburg Airport). Air temperature as well as other meteorological elements were taken to calculate the perceived temperature by means of the Klima-Michel model. Additionally, days with heat warnings as well as nightly indoor temperatures from the heat health warning system are presented. RESULTS: The perceived temperature exceeds the air temperature during heat waves by up to 10 °C. The classic heat-island effect is particularly evident in the difference in the nightly air temperature while the difference in the daily air temperature is small. In the case of perceived temperature, the difference is significantly higher not only at night but also during the day. CONCLUSIONS: In order to quantify negative impacts, not only the knowledge of air temperature is required, but also other factors that describe and control the thermal stress on humans. Urban-rural differences in air temperature and perceived temperature enable heat quantification. Adaptation measures taking into account the more intense conditions in cities are necessary.

Is Multidirectional UV Exposure Responsible for Increasing Melanoma Prevalence with Altitude? A Hypothesis Based on Calculations with a 3D-Human Exposure Model.

In a recent study, melanoma incidence rates for Austrian inhabitants living at higher altitudes were found to increase by as much as 30% per 100 m altitude. This strong increase cannot simply be explained by the known increase of erythemally-weighted irradiance with altitude, which ranges between 0.5% and 4% per 100 m. We assume that the discrepancy is partially explainable by upwelling UV radiation; e.g., reflected by snow-covered surfaces. Therefore, we present an approach where the human UV exposure is derived by integrating incident radiation over the 3D geometry of a human body, which enables us to take upwelling radiation into account. Calculating upwelling and downwelling radiance with a radiative transfer model for a snow-free valley and for snow-covered mountain terrain (with albedo of 0.6) yields an increase in UV exposure by 10% per 100 m altitude. The results imply that upwelling radiation plays a significant role in the increase of melanoma incidence with altitude.

A novel method to calculate solar UV exposure relevant to vitamin D production in humans.

We present a novel method to calculate vitamin D3 -weighted exposure by integrating the incident solar spectral radiance over all relevant parts of the human body. Earlier investigations are based on the irradiance on surfaces, whereas our calculated exposure of a voxel model of a human takes into account the complex geometry of the radiation field. Assuming that sufficient vitamin D3 (1000 international units) can be produced within the human body in one minute for a completely uncovered body in vertical posture in summer at midlatitudes (e.g. Rome, June 21, noon, UV index of 10), we calculate the exposure times needed in other situations or seasons to gain enough vitamin D3 . Our calculations show that the UV index is not a good indicator for the exposure which depends on the orientation of the body (e.g. vertical (standing) or horizontal (lying down) posture). Without clothing the exposure is dominated by diffuse sky radiation and it is nearly irrelevant how the body in vertical posture is oriented toward the sun. At the winter solstice (December 21, noon, cloudy) at least in central Europe sufficient vitamin D3 cannot be obtained with realistic clothing, even if the exposure were extended to all daylight hours.