Background Bushfire smoke contains a range of air toxics. To prevent inhalation of these toxics, fire fighters use respiratory equipment. Yet, little is known about the effectiveness of the equipment on the fire ground. Experimental trials in a smoke chamber demonstrated that, the particulate/organic vapor/formaldehyde (POVF) filter performed best under simulated conditions. This article reports on the field validation trials during prescribed burns in Western Australia. Methods Sixty-seven career fire fighters from the Fire and Emergency Services Authority of Western Australia were allocated one of the three types of filters. Spirometry, oximetry, self-reported symptom, and personal air sampling data were collected before, during and after exposure to bushfire smoke from prescribed burns. Results Declines in FEV1 and SaO2 were demonstrated after 60 and 120 min exposure. A significant higher number of participants in the P filter group reported increases in respiratory symptoms after the exposure. Air sampling inside the respirators demonstrated formaldehyde levels significantly higher in the P filter group compared to the POV and the POVF filter group. Conclusions The field validation trials during prescribed burns supported the findings from the controlled exposure trials in the smoke chamber. Testing the effectiveness of three types of different filters under bushfire smoke conditions in the field for up to 2 hr demonstrated that the P filter is ineffective in filtering out respiratory irritants. The performance of the POV and the POVF filter appears to be equally effective after 2 hr bushfire smoke exposure in the field. Am. J. Ind. Med. 52:76-87, 2009.
Annemarie J.B.M. De Vos MPH RN ICCert1 * Angus Cook PhD MBChB(NZ) VATGP1 Brian Devine BAppSc1 Philip J. Thompson MBBS FRACP FCCP MRACMA2 Philip Weinstein PhD MBBS MAppEpi BSc FAFPHM3
School of Population Health M431, The University of Western Australia, Crawley, Western Australia, Australia;Lung Institute of Western Australia, Sir Charles Gairdner Hospital, Nedlands, Western Australia, Australia;School of Population Health, University of Queensland, Herston Road, Herston, Queensland, Australia