Coal-mine fire-related fine particulate matter and medical-service utilization in Australia: A time-series analysis from the Hazelwood Health Study

Background: This study assessed the association between coal-mine-fire-related fine particulate matter (PM_2.5) and medical-service utilization, following a 6-week coal-mine fire in Australia, in 2014. Areas in the immediate vicinity of the mine experienced hourly mine-fire-related PM_2.5 concentrations of up to 3700 μg/m³. Methods: Data on medical-service utilization were collected from the Medicare Benefits Schedule - a national database of payment for medical services. PM_2.5 concentrations were modelled using atmospheric chemical transport modelling. Quasi-Poisson interrupted distributed lag time-series analysis examined the association between daily mine-fire-related PM_2.5 concentrations and medical-service utilization, including General Practitioner (GP) consultations and respiratory, cardiovascular and mental health services. Confounders included seasonality, long-term trend, day of the week, maximum daily temperature and public holidays. Gender and age stratification were conducted. Results: A 10-μg/m³ increase in PM_2.5 was associated with an increased relative risk of service usage for all long and short GP consultations [11% (95% confidence interval: 7 to 15%)] and respiratory services [22% (4 to 43%)] in both men and women. Sex stratification found an increased relative risk in mental health consultations in men [32% (2 to 72%)] but not women. No associations were found for cardiovascular services in men or women. Conclusions: Coal-mine-fire-related PM_2.5 exposure was associated with increased use of medical services for GP consultations and respiratory services in men and women and mental health consultations in men. These findings can inform the development of future public-health-policy responses in the event of major air-pollution episodes.