Response of the FLIR Airtec Monitor to Airborne Coal Dust
Emily Sarver, Virginia Tech; Cigdem Keles, Virginia Tech; Emanuele Cauda, CDC/NIOSH; Kent Phillips, Utah Department of Oil, Gas and Mining
Diesel particulate matter (DPM) exposures are a serious occupational health hazard in underground mines. While the complex nature of DPM makes direct analysis difficult, its primary component, elemental carbon (EC), can be used as surrogate. The near real-time FLIR Airtec monitor measures EC mass based on laser extinction. It was developed for use in underground metal/non-metal mines, and calibrated to the NIOSH 5040 Standard Method. Its effectiveness has not been demonstrated in coal mines, however, where coal-sourced EC could produce analytical interference. To gain preliminary insights regarding the Airtecs performance in the presence of coal dust, experiments were conducted in a controlled laboratory chamber. The Airtec EC results consistently underestimated NIOSH 5040 EC for both respirable-sized and submicron coal dusts. While underestimation of coal-sourced EC bodes well for limiting coal interference for DPM measurement, one key reason for the observed trend was non-uniform coal particle deposition on the Airtec filter. This may be problematic in coal mines where DPM and coal dust occur together in the instance that DPM deposition is also non-uniform.
