The results indicate that mobile monitoring systems exhibit a substantially higher flex-ibility index than fixed monitoring stations. This difference reflects the inherent ability of mobile platforms to rapidly adapt monitoring strategies, cover multiple areas, and respond to emerging pollution events. Consequently, mobile stations provide a valua-ble complement to fixed monitoring networks, particularly for improving spatial rep-resentativeness and operational adaptability in urban air quality monitoring. 3.1.4. Analytical Cost Assumptions For comparative purposes, a 10-year analytical life-cycle horizon is considered. Fixed monitoring stations For a regulatory-grade fixed station, the following assumptions are used: • Initial equipment and installation cost: approximately €80,000 per station • Annual maintenance and calibration: approximately €8,000 • Annual operational and communication cost: approximately €2,000 This results in an estimated total life-cycle cost of: €180,000 per station over 10 years. For a configuration of 20 fixed stations, the total estimated cost is approximately: €3.6 million.

The findings show that mobile monitoring systems demonstrate significantly greater flexibility compared to stationary monitoring stations. This variation stems from mobile platforms' natural capacity to quickly adjust monitoring approaches, survey different locations, and react to new pollution incidents. As a result, mobile stations offer important support to established monitoring networks, especially for enhancing geographic coverage and operational flexibility in city air quality surveillance. 3.1.4. Cost Analysis Framework The comparison uses a 10-year operational lifespan for analysis purposes. Fixed monitoring stations The following estimates apply to regulatory-standard fixed stations: • Equipment and setup expenses: roughly €80,000 per station • Yearly maintenance and calibration fees: roughly €8,000 • Yearly operating and communication expenses: roughly €2,000 These figures produce a projected total operational cost of: €180,000 per station across 10 years. A network of 20 fixed stations would cost approximately: €3.6 million in total.