Abstract
Airborne PM₁₀ poses significant respiratory and cardiovascular risks to the vulnerable population. In high-elevation urban zones like Gachibowli, Hyderabad, understanding the spatiotemporal behaviour of PM₁₀ spread is essential to develop targeted health advisories. This is not achievable solely by increasing the number of monitoring stations. The local topography, Land Use/Land Cover (LULC) patterns and mixing conditions must be understood to identify pollution sources and dispersal dynamics.
We estimated PM₁₀ concentrations based on Aerosol Optical Depth from two satellite sources - half-hourly, INSAT-3D geostationary satellite data at 11km; and daily polar-orbiting, MODIS Aqua data at 3km spatial resolution. By validating these PM₁₀ estimates against government-monitored Central Pollution Control Board (CPCB) sensors and low-cost academic AirIOT sensors of IIIT-Hyderabad, a near-continuous and hyperlocal PM₁₀ concentration estimate, near the ground surface, has been generated.
Among the 4 Machine learning models evaluated, Multiple Linear Regression technique offered the best results when temperature, humidity and ERA-5 Planetary Boundary Layer Height were used as predictors. While satellite-based PM₁₀ estimate averages ranged from 61–72 µg/m³, AirIOT and CPCB ranged 24–57 µg/m³ and 99–106 µg/m³ respectively, during colder months. While AirIOT sensors are spread across varied microenvironments, the CPCB node lies near a main road with partial green cover. Satellite-derived values provide frequent, broad-scale estimates of pollutant distribution, and AirIOT and CPCB give point measurements. This resolution gap drives our effort to bridge scales and produce PM₁₀ estimates at ~1–2 km resolution with temporal continuity, while also capturing sub-grid variability and dissipation patterns.
Thus, this integrated framework allows for hyperlocal pollution mapping for health-related early warning systems even in areas with sparse PM₁₀ sensor coverage. By correlating PM₁₀ subtypes with LULC and dispersion, health outcomes can be traced to specific exposure types. By extending this method across India, to megacities like New Delhi, a health risk classification can be developed along with guidelines for clinical response measures.