Assessment of Ambient Multipollutant Exposure and Health Impacts Over India Using the Novel Satellite‐Based Multi‐Pollutant Index

Ambient air pollutants are reported to have adverse health impacts, which could be better assessed by examining human exposure to multiple criteria pollutants or through a multi-pollutant Air Quality Index (AQI). As compared to AQIs developed using in situ measurements of pollutants across sparse monitoring stations, satellite-based products such as ambient PM_2.5 or NO₂ provide better spatiotemporal patterns. Here, we examine the long-term (2005-2019) air pollution exposure and health impacts over India with the novel Satellite-Based Multi-Pollutant Index (SMPI). The high spatial resolution (1 km × 1 km) SMPI over India reveals pollution exposure hotspots in most states and districts over the Indo-Gangetic Plain (IGP) and eastern states. The spatiotemporal patterns in SMPI exposure and its urban-rural heterogeneity were different from either PM_2.5 or NO₂, highlighting the importance of multi-pollutant indices to comprehensively assess air quality. Furthermore, we found a strong association (1.05, 95% UI: 1.025-1.075) between SMPI and odds of Chronic Obstructive Pulmonary Disease (COPD), which increased with increasing co-pollutant exposures [1.03 (1.018-1.042) to 1.184 (1.156-2.212)]. The SMPI-COPD association was significantly higher among males, middle class, tribes, and older sub-populations, highlighting the need for future environmental policies prioritized for vulnerable population subgroups for larger health benefits.