Extreme heat arrangements in South Australia: an assessment of trigger temperatures

Abstract

<h4>Issue addressed</h4>The high mortality and morbidity associated with the 2009 heat wave across South Eastern Australia highlighted the need for effective heat-related health promotion and preventive strategies. The adverse health effects of extreme heat are largely preventable, and heat-related health promotion can advise the public about the dangers of hot weather and how to reduce health risks. The South Australian State Emergency Service has outlined a co-ordinated response system in their Extreme Heat Arrangements for South Australia. This paper evaluates the health impacts at the temperature trigger levels incorporated in this plan.<h4>Methods</h4>Heat events in Adelaide between 1994 and 2009 were compared in terms of heat duration, heat intensity and their impact on mortality and ambulance call-outs.The health impacts for events meeting specific temperature triggers were estimated.<h4>Results</h4>Individual heat events varied in terms of estimated excess mortality and ambulance call-outs. Increased mortality was associated with heat events of 3 or more consecutive days with maximum temperature (T(max)) > or = 43 degrees C or average daily temperature (ADT) > or = 34 degrees C, while ambulance call-outs increased significantly at lower T(max) levels.The two events reaching the temperature triggers for an extreme heat warning were associated with a 44% (95% CI 26-63%) increase in mortality.<h4>Conclusions</h4>The results support the temperature trigger for an extreme heat warning within the Extreme Heat Arrangements for Adelaide, and indicate a limited health impact at lower temperature triggers.