Temperature-dependent health risks from short-term ozone exposure: spatial variation across urbanisation levels

This study assessed health risks associated with short-term exposure to ground level-ozone and its interaction with ambient temperature in Baden-Wurttemberg, Germany (2013–2022), using a spatio-temporal case-crossover study design with Distributed Lag Non-Linear Models (DLNM). Despite compliance with EU and WHO air pollution standards, significant effect modification by temperature and urbanisation characteristics was observed. Due to inflated health risks during the COVID-19 period, analyses focused on pre-pandemic years (2013-2019). Ozone exposure was significantly associated with increased hospital admissions and sick leave notes, especially under extreme temperature conditions, but not with all-cause mortality. Risk patterns varied by lag structure, with delayed effects at low temperatures and immediate effects at high temperatures. Suburban districts showed elevated mortality risk, whereas higher relative risk of hospital admissions and sick leave notes was observed across all levels of urbanisation. In conclusion, the study reveals complex interactions between air pollution and temperature on health outcomes, with distinct urban-suburban-rural disparities in relative risks.