Use of an unmanned aircraft system to quantify NO<sub><i>x</i></sub> emissions from a natural gas boiler

Abstract

Abstract. Aerial emission sampling of four natural gas boiler stack plumes was conducted using an unmanned aerial system (UAS) equipped with a lightweight sensor–sampling system (the “Kolibri”) for measurement of nitrogen oxide (NO), and nitrogen dioxide (NO2), carbon dioxide (CO2), and carbon monoxide (CO). Flights (n = 22) ranged from 11 to 24 min in duration at two different sites. The UAS was maneuvered into the plumes with the aid of real-time CO2 telemetry to the ground operators and, at one location, a second UAS equipped with an infrared–visible camera. Concentrations were collected and recorded at 1 Hz. The maximum CO2, CO, NO, and NO2 concentrations in the plume measured were 10 000, 7, 27, and 1.5 ppm, respectively. Comparison of the NOx emissions between the stack continuous emission monitoring systems and the UAS–Kolibri for three boiler sets showed an average of 5.6 % and 3.5 % relative difference for the run-weighted and carbon-weighted average emissions, respectively. To our knowledge, this is the first evidence of the accuracy performance of UAS-based emission factors against a source of known strength.

Effects of UAS Rotor Wash on Air Quality Measurements

“…Measurements of concentration ratios, where one concentration is compared to another, are also less likely to be affected when mixing does not result in preferential displacement of one species from the other. This is particularly important when emission ratios are used to determine emission factors, such as in Gullett et al [16].…”

“…The CO 2 and CO detection ranges were 0-10,000 ppm and 1-300 ppm with a resolution of 1 ppm, respectively. A full description of the Kolibri and further details on the CO 2 and CO sensors has been described elsewhere [16,25,26]. Due to microcontroller board limitations, the two CO 2 sensor signals were read differently: one was digital (sensor set 1 used for the body measurements) and one was analog (sensor set 2 used for the arm measurements).…”

“…This is particularly noted for sensing applications in which the UASs fly close to point or surface emitters. Nonetheless, Gullett et al [16] found that body-mounted gas sensors on a UAS determined plume-averaged gas emission factors from a natural gas boiler within 4-6% of the stack sample emission rate, and Arroyo et al [17], in comparing stationary versus UAS gas measurements, achieved an R 2 of 0.67 and 0.68 for NO and NO 2 , respectively, with a horizontal sampling tube extended only a few centimeters beyond the propeller radius.…”

Eyes in the Sky: Drones Applications in the Built Environment under Climate Change Challenges

“…In the domain of emission monitoring, researchers have used UAV-based methane detection and quantification to track wetland emissions and offshore gas seeps [135]. Moreover, multiple studies have utilized UAVs to measure carbon dioxide concentrations and fluxes in complex urban environments [136][137][138]. Such flexible aerial sampling can improve emissions inventories and our understanding of climate feedback.…”