부산대학교 도서관

Determination of trace gas emissions from sources is critical for understanding and regulating air quality and climate change. Here, we demonstrate a method for rapid quantification of the emission rate of multiple gases from simple and complex sources using a mass balance approach with a spatially scannable open-path sensor – in this case, an open-path dual-comb spectrometer. The open-path spectrometer measures the total column density of gases between the spectrometer and a retroreflector mounted on an uncrewed aerial vehicle (UAV). By measuring slant columns at multiple UAV altitudes downwind of a source (or sink), the total emission rate can be rapidly determined without the need for an atmospheric dispersion model. Here, we demonstrate this technique using controlled releases of CH 4 and C 2 H 2. We show an emission rate determination to within 56 % of the known flux with a single 10 min flight and within 15 % of the known flux after 12 flights. Furthermore, we estimate the detection limit for CH 4 emissions to be 0.03 g CH 4 s -1. This detection limit is approximately the same as the emissions from 25 head of beef cattle and is less than the average emissions from a small oil field pneumatic controller. Other gases including CO 2 , NH 3 , HDO, ethane, formaldehyde (HCHO), CO, and N 2 O can be measured by simply changing the dual-comb spectrometer. [ABSTRACT FROM AUTHOR]