Figure illustrates the detection coverage ratio, the proportion of detected emission scenarios out of the total emission scenarios generated in Step 1, achieved with the optimal sensor placement for each budget. The blue lines show the coverage ratio associated with the optimal sensor placements derived by the PORSS algorithm in this setting. The observed trend indicates diminishing returns in terms of detection coverage with increasing sensor budgets. This type of analysis enables us to determine the minimum number of sensors required for a desired detection coverage. Additionally, we compared the results under two different detection amplitude thresholds: 0.5 ppm and 5 ppm representing high and low end sensors, respectively. Low-end sensors generally exhibit larger background variation compared to high-end sensors and hence require higher detection thresholds. The analysis shows that to achieve a specific detection coverage ratio, more low-end sensors are needed.