title: Extreme air pollution events from bushfires and dust storms and their association with mortality in Sydney, Australia 1994-2007.
abstract: BACKGROUND
  Extreme air pollution events due to bushfire smoke and dust storms are expected to increase as a consequence of climate change, yet little has been published about their population health impacts. We examined the association between air pollution events and mortality in Sydney from 1997 to 2004.
  
  
  METHODS
  Events were defined as days for which the 24h city-wide concentration of PM(10) exceeded the 99th percentile. All events were researched and categorised as being caused by either smoke or dust. We used a time-stratified case-crossover design with conditional logistic regression modelling adjusted for influenza epidemics, same day and lagged temperature and humidity. Reported odds ratios (OR) and 95% confidence intervals are for mortality on event days compared with non-event days. The contribution of elevated average temperatures to mortality during smoke events was explored.
  
  
  RESULTS
  There were 52 event days, 48 attributable to bushfire smoke, six to dust and two affected by both. Smoke events were associated with a 5% increase in non-accidental mortality at a lag of 1 day OR (95% confidence interval (CI)) 1.05 (95%CI: 1.00-1.10). When same day temperature was removed from the model, additional same day associations were observed with non-accidental mortality OR 1.05 (95%CI: 1.00-1.09), and with cardiovascular mortality OR (95%CI) 1.10 (95%CI: 1.00-1.20). Dust events were associated with a 15% increase in non-accidental mortality at a lag of 3 days, OR (95%CI) 1.16 (95%CI: 1.03-1.30).
  
  
  CONCLUSIONS
  The magnitude and temporal patterns of association with mortality were different for smoke and dust events. Public health advisories during bushfire smoke pollution episodes should include advice about hot weather in addition to air pollution.
authors: Menzies Research Institute, University of Tasmania, Private Bag 23, Hobart 7001, Tasmania, Australia. fay.johnston@utas.edu.au
authors: Fay
authors: F
authors: Johnston
authors: Ivan
authors: I
authors: Hanigan
authors: Sarah
authors: S
authors: Henderson
authors: Geoffrey
authors: G
authors: Morgan
authors: David
authors: D
authors: Bowman