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 PM2.5 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 PM2.5 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.