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Effects of UAS Rotor Wash on Air Quality Measurements
Citation:
Aurell, J. AND B. Gullett. Effects of UAS Rotor Wash on Air Quality Measurements. Drones. MDPI, Basel, Switzerland, , 0, (2024).
Impact/Purpose:
This work assessed the potential effects of rotor wash from unmanned aircraft systems (UAS) on air quality measurements. Field tests examined the potential for UAS rotor wash effects on gas and particle measurements from a biomass combustion source. Tests compared simultaneous placement of two sets of CO and CO2 gas sensors and PM2.5 instruments on a UAS body and on a vertical or horizontal extension arm beyond the rotors. Evaluation of PM2.5 emission factors with single factor ANOVA analyses showed no significant differences between the values derived from the arm, either vertical or horizontal, and those from the body. These findings are important as the results suggest that UAS-based sensors and samplers can be expected to provide accurate measurements even in the presence of rotor wash. While applied to biomass combustion, these results are applicable to a wide variety of open area sources and so would be of interest to anyone conducting air quality measurements.
Description:
Laboratory and field tests examined the potential for unmanned aircraft system (UAS) rotor wash effects on gas and particle measurements from a biomass combustion source. Tests compared simultaneous placement of two sets of CO and CO2 gas sensors and PM2.5 instruments on a UAS body and on a vertical or horizontal extension arm beyond the rotors. For 1 Hz temporal concentration comparisons, correlations of body versus arm placement for the PM2.5 particle sensors yielded R2 = 0.85 and for both gas sensor pairs exceeded R2 of 0.90. Increasing the timestep to 10 s average concentrations throughout the burns improved the R2 value for the PM2.5 to 0.95 from 0.85. Finally, comparison of whole-test average concentrations further increased the correlations between body- and arm-mounted sensors, exceeding R2 of 0.98 for both gases and particle measurements. Evaluation of PM2.5 emission factors with single factor ANOVA analyses showed no significant differences between the values derived from the arm, either vertical or horizontal, and those from the body. These results suggest that rotor wash effects on body- and arm-mounted sensors are minimal in scenarios where short duration, time-averaged concentrations are used to calculate emission factors and whole-area flux values.