Abstract
Abstract. Hot weather episodes are globally associated with excess mortality rates. Elevated ozone concentrations occurring simultaneously also contribute to excess mortality rates during these episodes. However, the relative importance of both stressors for excess mortality rates is not yet known and assumed to vary from region to region. This study analyzes time series of daily observational data of air temperature and ozone concentrations for eight of the largest German cities during the years 2000 and 2017 with respect to the relative importance of both stressors for excess mortality rates in each city. By using an event-based risk approach, various thresholds for air temperature were explored for each city to detect hot weather episodes that are statistically associated with excess mortality rates. Multiple linear regressions were then calculated to investigate the relative contribution of variations in air temperature and ozone concentrations to the explained variance in mortality rates during these episodes, including the interaction of both predictors. In all cities hot weather episodes were detected that are related to excess mortality rates. Across the cities, a strong increase of this relation was observed around the 95th percentile of each city-specific air temperature distribution. Elevated ozone concentrations during hot weather episodes are also related to excess mortality rates in all cities. In general, the relative contribution of elevated ozone concentrations on mortality rates declines with increasing air temperature thresholds and occurs mainly as a statistically inseparable part of the air temperature impact. The specific strength of the impact of both stressors varies across the investigated cities. City-specific drivers such as background climate and vulnerability of the city population might lead to these differences and could be the subject of further research. These results underline strong regional differences in the importance of both stressors during hot weather episodes and could thus help in the development of city-specific heat–ozone–health warning systems to account for city-specific features.
Highlights
Hot weather episodes (HWEs) cause more human fatalities in Europe than any other natural hazard (EEA, 2019a)
This study investigated mortality rates during HWEs in eight cities in Germany from 2000 to 2017
HWEs were identified with a risk-based approach as a result of regressions between daily average air temperature above a threshold and mean mortality rates during these episodes
Summary
Hot weather episodes (HWEs) cause more human fatalities in Europe than any other natural hazard (EEA, 2019a). HWEs are typically characterized by elevated air temperature and can last for several days or weeks, depending on the respective threshold values that are used to identify such days. Numerous investigations found excess mortality rates during days of elevated air temperature (Curriero et al, 2002; Anderson and Bell, 2009; Gasparrini and Armstrong, 2011; Gasparrini et al, 2015). Hospital admissions and emergency calls are associated with elevated air temperatures (Bassil et al, 2009; Karlsson and Ziebarth, 2018). A. Krug et al.: The contribution of air temperature and ozone to mortality rates
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
