Vegetation fires, particulate air pollution and asthma: A panel study in the Australian monsoon tropics

Abstract

We examined the relationship between particulate matter (PM) <10 and <2.5 microns in diameter (PM₁₀ and PM_2.5) generated by vegetation fires and daily health outcomes in 251 adults and children with asthma over a 7-month period. Data were analysed using generalized estimating equations adjusted for potential environmental confounders, autocorrelation, weekends and holidays. PM₁₀ ranged from 2.6 – 43.3 µg m⁻³and was significantly associated with onset of asthma symptoms, commencing oral steroid medication, the mean daily symptom count and the mean daily dose of reliever medication. Similar results were found for PM_2.5. No associations were found with the more severe outcomes of asthma attacks, increased health care attendances or missed school/work days. These results help fill a gap in the evidence about the population health impacts of lower levels of pollution characteristic of deliberate landscape burning to control fuel loads versus the better documented risks of more intense and severely polluting wildfires.

Keywords:

• Asthma
• air pollution
• particulate matter
• vegetation fires
• prescribed burning

Acknowledgements

Thanks are due to our research assistants Anne Myerscough, Judy Manning and Francoise Foti, and collaborators Michael Foley, Simon Haberle, David Bowman and John Gras. This study was funded by a linkage grant from the Australian Research Council with cash and in kind support from the Northern Territory Government, Bureau of Meteorology and Asthma NT.