LAUSR

BACKGROUND Little is known about the long-term health effects of coalmine fire smoke exposure. The 2014 Hazelwood coalmine fire event in southeast Australia released smoke into surrounding areas for 6 weeks. OBJECTIVES We aimed to investigate whether individual-level exposure to coalmine fire-related PM2.5 was associated with a long-term increase in ambulance attendances following a coalmine fire event. METHODS A total of 2223 residents from the most exposed town of Morwell were assessed for ambulance attendances after the Hazelwood event from April 1, 2014 to December 31, 2017. PM2.5 exposure was estimated for each individual using participant self-reported location diary data during the event and modelled PM2.5 concentrations. Recurrent event survival analysis was used to evaluate the relationship between PM2.5 exposure and ambulance attendances. RESULTS For each 10 μg/m3 increase in mean coalmine fire-related PM2.5 exposure, there was a 10% (adjusted hazard ratio [HR]:1.10, 95%CI:1.03-1.17) increase in the overall risk of ambulance attendances within 3.5 years after the coalmine fire. Exposure to PM2.5 was also associated with increased risk of respiratory (HR: 1.21, 95%CI: 1.02-1.44) and cardiovascular (HR: 1.13, 95%CI: 1.01-1.28) related ambulance attendances. CONCLUSION These results demonstrate that exposure to coalmine fire smoke during the Hazelwood event was associated with a long-term health risk post the fire event, specifically for respiratory and cardiovascular conditions. These findings are important for effective implementation of health care services following future extended coalmine fire PM2.5 events.