Effects of temperature and air pollution on emergency ambulance dispatches: a time series analysis in a medium-sized city in Germany

Management of adverse health related effects from heat waves requires comprehensive and accessible sources of information. This paper examines the effects of temperature and air pollution on human health and identifies areas with increased occurrence of emergency ambulance dispatches in the city of Würzburg, Bavaria, Germany and discusses the applicability for health care interventions and urban planning. An over-dispersed Poisson generalized additive model was used to examine and predict the association and potential lag of exposure between temperature, air pollution and three types of emergency ambulance dispatches during the study period from 2011-2019. A linear model was used to estimate heat-wave effects. A line density function was used to identify areas with increased occurrence of dispatches. Significant effects of temperature were detected for non-traumatic and cardiovascular diseases after exceeding a threshold temperature. The exposure-response relationships showed an increased relative risk up to two days after exposure for non-traumatic and cardiovascular diseases. Results indicate a significant association between presence of heat waves and cardiovascular diseases with up to 17% (CI 95%: 5.9% -30.0%) increased relative risk on a heat wave day compared to a non-heat wave day. Dispatches for cardiovascular diseases occur more often in areas with a high population and building density, especially in summer. The analyses identified hotspots of heat-related dispatches in areas with increased population and building density and provides baseline information for interventions in future urban planning and public health care management based on data commonly available even in small cities.