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Abstract
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Fires that burn countryside - whether as bushfires, wildfires, prescribed burning, land clearing, regeneration burning - occur across the globe and emit 'smoke' that can significantly impact human populations and their health and safety, even those distant from the actual fires. Models of global warming impacts predict more frequent and more severe bushfires/wildfires in many countries,1 and prescribed burning (fuel reduction) now occurs more frequently to mitigate these events and their disastrous impacts on lives and property (though still with smoke impacts).
In Australia, accidental bushfires have been part of the environment since before human settlement and much flora and fauna have evolved to coexist and regenerate with bushfires. Aboriginal arrival to Australia resulted in an increased frequency in the incidence of bushfires since 'firestick farming' was used to manage the terrain. This frequency increased further with European settlement.2,3 Some examples of very significant bushfire events in Australia (Table 1) show the severe impacts on life, land and property. Notably, two epidemiological studies following the 2003 and 2006 events in Victoria found increased hospital emergency admissions (respiratory) and out-of-hospital cardiac arrests associated with the bushfires.4,5
Large efforts are being made to mitigate these impacts (e.g. fire bans and warnings, improved fire-fighting practices, public education, building standards for bushfire prone locations). However, accidental fires and fire events in cooler weather (such as prescribed burning) can lead to extensive regions being blanketed in 'smoke' for many days to several weeks.6-8 These regions may be rural or urban depending on the events, but with increasing building activities in Australia's major cities at the rural-urban interface, significant public exposure to bushfire 'smoke' is a growing matter of concern.6-8 And not just in Australia - in the USA, the wildland-urban interface contains 45 million housing units, representing 39% of all houses.9
Unless building occupants are evacuated for their physical safety, they may remain in smoke-blanketed regions and be exposed to bushfire smoke. This smoke may contain a wide variety of air pollutants as particulates, droplets, vapours and gases.7 For example, bushfire/biomass smoke may contain: particles from 'respirable' particles down to fine particles (PM1, PM2.5), aldehydes such as formaldehyde and acetaldehyde, volatile organic compounds such as benzene, and inorganic gases such as carbon monoxide, all with potential to impact the health of building occupants, especially those 'at-risk' and with pre-existing illnesses.10
Fire, health and environment agencies commonly recommend that during fire events, residents should remain indoors to reduce their exposures to smoke. While there is sense in this strategy where the building has external windows/doors that are closed and outside air infiltrates to the inside at a low air exchange rate, it provides a level of protection dependent on the duration of the external smoke event...
Language: en |