Science Inventory

Field determination of multipollutant, open area combustion source emission factors with a hexacopter unmanned aerial vehicle

Citation:

Aurell, J., Bill Mitchell, V. Chirayath, J. Jonsson, D. Tabor, AND B. Gullett. Field determination of multipollutant, open area combustion source emission factors with a hexacopter unmanned aerial vehicle. ATMOSPHERIC ENVIRONMENT. Elsevier Science Ltd, New York, NY, 166:433-440, (2017). https://doi.org/10.1016/j.atmosenv.2017.07.046

Impact/Purpose:

This paper details the most extensive application to date of a small, lightweight sensor/sampler system to the measurement of combustion pollutants using an unmanned aerial system. The purpose of the work was to demonstrate the efficacy of this new sampling technique for determining lofted emission factors. The significance of the results is the agreement with published emission factors and good reproducibility of measurements. The UAS/sampler presents a significant advance in emission characterization capabilities for open area sources, safely and effectively making measurements heretofore deemed too hazardous for personnel or beyond the reach of land-based samplers. This tool will prove useful to state and regional air quality personnel as well as industrial sources.

Description:

An emission sensor/sampler system was coupled to a NASA hexacopter unmanned aerial system (UAS) to characterize gases and particles in the plume emitted from open burning of military ordnance. The UAS/sampler was tested at two field sites resulting in 33 flights at Radford, VA and 51 flights during two campaigns at McAlester, OK. Flight sampling time amounted to 16 hours of flight time (7 ½ from Radford and 8 ½ from McAlester). The UAS was remotely maneuvered into the plumes at distances from the pilot of up to 1,500 m at Radford and 360 m at McAlester and altitudes of up to 12l m (Radford) and 119 m (McAlester) above the ground. Flight durations prior to battery change were dependent on the type of sampler payload (from 3.2 kg to 4.6 kg), flight paths, and meteorological conditions, ranging from 5 to 12 min at Radford and 4 to 12 min at McAlester. Load/duration tests indicated that the UAS with the 3.2 kg payload had a flight duration of 13.5 min until the preset first safety warning, 40% battery charge remaining, was reached. Measurements determined emission factors for particulate matter, metals, chloride, perchlorate, volatile organic compounds, chlorinated dioxins/furans, and nitrogen-based organics. Gas sensors were selected based on their applicable concentration range, light weight, freedom from interferents, and response/recovery times. Samplers were designed, constructed, and operated based on EPA methods and quality control criteria. Results show agreement with published emission factors and good reproducibility (e.g., 26% relative standard deviation for PM2.5). The UAS/sampler presents a significant advance in emission characterization capabilities for open area sources, safely and effectively making measurements heretofore deemed too hazardous for personnel or beyond the reach of land-based samplers.