Unmanned aerial vehicles (UAVs) are being explored by researchers to measure concentrations of gas emissions in situations where such measurements are otherwise extremely difficult to obtain, such as NO and NO₂ (NOx) emissions from surface mine blasting. Recently, countries have imposed or are planning to impose surface blasting gas pollution regulations, which creates a need for an improved understanding of UAV-based gas measuring systems. The experiments detailed in this paper were performed to determine if airflow generated by the rotors, also known as downwash, unnaturally alters concentration measurements. Downwash turbulence could create locations of varying pressure, which could affect concentration. A UAV fitted with gas sensors was attached to a stand in a controlled environment containing a mixture of NOx. The gas sensor measuring points were placed at various distances on and from the UAV body to evaluate downwash effects on gas concentration. Results show that the presence of downwash turbulence causes no statistically significant changes to concentration measurements at any distance or direction from the UAV. Based on these results, it is possible to use a UAV-mounted gas monitor to measure concentrations without concern for downwash interference, provided the UAV and measuring point are entirely contained within the gas cloud.

研究人员正在探索无人驾驶飞行器 (UAV)，以在极难获得此类测量值（例如 NO 和 NO _2）的情况下测量气体排放浓度露天矿爆破产生的 (NOx) 排放。最近，各国已实施或计划实施表面爆破气体污染法规，这就需要更好地了解基于无人机的气体测量系统。本文中详述的实验旨在确定转子产生的气流（也称为下洗）是否会不自然地改变浓度测量值。下洗湍流可能会产生不同压力的位置，这可能会影响浓度。在含有氮氧化物混合物的受控环境中，将装有气体传感器的无人机连接到支架上。气体传感器测量点放置在无人机机身上和距离无人机机身的不同距离处，以评估下洗气流对气体浓度的影响。结果表明，下洗湍流的存在不会对距无人机任何距离或方向的浓度测量值造成统计上的显着变化。基于这些结果，只要无人机和测量点完全包含在气体云中，就可以使用安装在无人机上的气体监测器来测量浓度，而不必担心下洗干扰。