In-situ burning (ISB) is an efficient and important response tool in a wide range of conditions from open water and very open drift ice (herders) to consolidated ice (self-contained). Herding agents provide a means to thicken and then burn uncontained slicks that would otherwise be too thin to ignite. In this project we assessed the impacts on ambient air quality in the vicinity of the location following ISB tests on crude oil herded and ignited from the air in a large purpose built test pond outside of Fairbanks Alaska. We measured downwind and in-the-smoke-plume, concentrations of respirable particulate matter sizes (PM2.5) and seven different combustion gases (CO, CO2, NO, NO2, NOx, SO2, & VOCs) during five ISB tests, with sampling instruments placed 6–12 m away from the source area. It was also investigated if the herding agent was detectable in the air borne plume. Although in this study we did not use instrument and methods specifically approved by the Occupational Safety and Health Administration (OSHA) and the National Institute for Occupational Safety and Health (NIOSH), to provide a context the study results were compared with exposure limits provided by these agencies. From our results downwind, in the smoke plume, concentrations of particulate matter and SO2 were found to significantly exceed (P <0.01) NIOSH and OSHA exposure limits, while the remaining compounds measured were significantly below (P <0.01) established NIOSH and OSHA exposure limits. In addition, GC/MS Analysis of aerosol samples collected utilizing a flow meter and carbon sorbent tubes in the smoke plume, the silicone based functional group of the applied OP-40 herding agent was not detected in the collected samples. The concentrations measured in this study in the vicinity of the ISB site, lasted for less than ten minutes, before drifting downwind and becoming greatly diluted. These results provide information which might be helpful towards developing guidelines for worker safety in spill response situations.
