Ambient biomass smoke and cardio-respiratory hospital admissions in Darwin, Australia.

Fay H Johnston,Louis S Pilotto,Ross S Bailie,Ivan C Hanigan

doi:10.1186/1471-2458-7-240

Fay H Johnston, Louis S Pilotto + Show 2 more

Open Access

https://doi.org/10.1186/1471-2458-7-240

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Abstract

BackgroundIncreasing severe vegetation fires worldwide has been attributed to both global environmental change and land management practices. However there is little evidence concerning the population health effects of outdoor air pollution derived from biomass fires. Frequent seasonal bushfires near Darwin, Australia provide an opportunity to examine this issue. We examined the relationship between atmospheric particle loadings <10 microns in diameter (PM10), and emergency hospital admissions for cardio-respiratory conditions over the three fire seasons of 2000, 2004 and 2005. In addition we examined the differential impacts on Indigenous Australians, a high risk population subgroup.MethodsWe conducted a case-crossover analysis of emergency hospital admissions with principal ICD10 diagnosis codes J00–J99 and I00–I99. Conditional logistic regression models were used to calculate odds ratios for admission with 10 μg/m3 rises in PM10. These were adjusted for weekly influenza rates, same day mean temperature and humidity, the mean temperature and humidity of the previous three days, days with rainfall > 5 mm, public holidays and holiday periods.ResultsPM10 ranged from 6.4 – 70.0 μg/m3 (mean 19.1). 2466 admissions were examined of which 23% were for Indigenous people. There was a positive relationship between PM10 and admissions for all respiratory conditions (OR 1.08 95%CI 0.98–1.18) with a larger magnitude in the Indigenous subpopulation (OR1.17 95% CI 0.98–1.40). While there was no relationship between PM10 and cardiovascular admissions overall, there was a positive association with ischaemic heart disease in Indigenous people, greatest at a lag of 3 days (OR 1.71 95%CI 1.14–2.55).ConclusionPM10 derived from vegetation fires was predominantly associated with respiratory rather than cardiovascular admissions. This outcome is consistent with the few available studies of ambient biomass smoke pollution. Indigenous people appear to be at higher risk of cardio-respiratory hospital admissions associated with exposure to PM10.

Highlights

Increasing severe vegetation fires worldwide has been attributed to both global environmental change and land management practices
The relationship between hospital admissions and PM10 for the same day and lags up to three days are presented in Figures 1, 2, 3, 4, 5, 6
Admissions for all respiratory conditions were positively associated with 10 μg/m3 increases in PM10 from bushfires with a larger magnitude in Indigenous people alone (OR1.17 95% confidence intervals (CI) 0.98–1.40)

Summary

Introduction

Increasing severe vegetation fires worldwide has been attributed to both global environmental change and land management practices. Short term associations between cardiovascular and respiratory hospital admissions and particulate air pollution have been demonstrated in many settings around the world, including multi-city studies in Europe, North America and Australia [1,2,3,4,5]. In most of these settings the (page number not for citation purposes). While it has been argued that deliberate population exposure to smoke from management fires is justifiable to prevent large wild fires, there is an immediate need for evidence concerning the public health risks or potential benefits of various burning regimes [14]

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