Protection of firefighters against combustion aerosol particles: simulated workplace protection factor of a half-mask respirator (pilot study).

The present pilot study investigated the penetration of ultrafine particles originated by combustion of different materials into elastomeric half-mask respirators equipped with two P100 filters. We determined the Simulated Workplace Protection Factor (SWPF) for 11 firefighters wearing elastomeric half-mask respirators and performing activities simulating those conducted during fire overhaul operations. The tests were performed in a controlled laboratory setting. A newly-developed battery-operated Portable Aerosol Mobility Spectrometer (PAMS) was used to measure size-resolved aerosol particle concentrations outside (C(out)) and inside (Cin) of an air-purifying respirator donned on a firefighter, and the SWPF was calculated as C(out)/C(in). Based on the total aerosol concentration, the "total" SWPF ranged from 4,222 (minimum) to 35,534 (maximum) with values falling primarily in a range from 11,171 (25 percentile) to 26,604 (75 percentile) and a median value being ≈15,000. This is consistent with the recently reported fit factor (FF) data base.((1)) The size-resolved SWPF data revealed a dependency on the particle size. It was concluded that a portable device such as PAMS can be used on firefighters during overhaul operations (as well as on other workers wearing elastomeric half-mask respirators) to monitor the aerosol concentrations in real time and ultimately help prevent overexposure.