In this study, PM monitoring was performed by biomagnetic analysis of roadside plant leaves of Azadirachta indica A. Juss (neem tree) in the arid desert region of Jodhpur in western Rajasthan, India. This study used the remanent magnetisation of PM10 deposited on neem leaves as a proxy for PM biomonitoring. The saturation isothermal remanent magnetisation (SIRM) showed a strong linear relationship (Pearson's r = 0.9340, p = 0.006) with PM10 data from the low-cost PM sensor. Among six sampling sites, the highest PM10 concentration (88.8 ± 9.8 μg/m³) and SIRM value (7231.2 mA) were observed in the Basni industrial area, confirming the signficance of vehicular and industrial emissions. Conversely, the IIT Jodhpur campus, isolated from anthropogenic sources, still exhibited high SIRM values (1904.4 mA), attributed to magnetite-type minerals transported via aeolian processes from the Thar Desert. SEM-EDS analysis further confirmed the presence of crustal minerals (Al, Si) alongside anthropogenic elements (Fe, K, Ca, Mg). A comparative financial study revealed that biomagnetic monitoring (~50,000 INR for ten sites) is significantly more economical than conventional CAAQMS (~110 million INR for ten stations). These findings demonstrate that biomagnetic monitoring offers a robust, low-cost proxy for PM10 mapping in arid desert regions, with strong implications for public health and environmental management.