Climate change, air pollution and public health in India: impact assessment and adaptation strategies

Abstract

Climate change has brought into sharp focus two key environmental health concerns for Indian cities - outdoor air pollution and climate change related temperature extremes. This research explores exposure-response relationships between air pollution, temperature and their interactions on daily all-cause mortality. Ahmedabad, Bangalore, Hyderabad, Mumbai and Shimla are primarily studied, each representing a different climactic zone. Future temperature related mortality projections for these cities are carried out until 2080s under alternate climate scenarios and subsequently extended to fifty two cities with million plus population. In addition, effectiveness of air pollution control policies is assessed using the GAINS model. The relative health benefits of pollution reduction are highest for Shimla (1.36% decrease in mortality risk for every 10 μg/m3 PM10 decrease), and results for other cities are comparable to similar international studies. Current policies to curb pollution are inadequate and will not achieve national ambient air quality standards even by 2030, therefore additional policies are required. Heat related mortality effects are highest for Shimla (8.11%) and cold related effects for Ahmedabad (7.09%). This may be indicative of population acclimatization to normal temperature ranges over time. Additional mortality risks as a consequence of heat and cold waves or temperature-pollution interactions are not significant for the cities studied. Significant increases (p<0.05) in heat related mortality are observed in the short (2020s), medium (2050s) and long term (2080s) under RCP 4.5 and 8.5 scenarios. Moreover, we find that increases in heat related mortality will overshadow declines in cold related mortality. Urban areas of Delhi, Ahmedabad, Kolkata, Mumbai and Bangalore are projected to exhibit highest increases in heat related mortality in 2080s under the RCP 8.5. We provide a consistent framework for public health adaptation to mitigate temperature related mortality effects in the future.