Future health impacts of long-term exposure to fine particulate matter under climate change, demographic change and urbanisation in India

Abstract

Background: Rapid socio-economic development in India has been accompanied by gains in life expectancy and improvements in a range of health outcomes. However, it is uncertain how the fast pace of urbanisation, the aging of the population, and climate change will alter this trend in the future. This study estimates dynamically over time the health co-benefits from projected changes in exposure to ambient fine particulate matter (PM2.5) in India up to 2050 under alternative climate change mitigation and air pollution abatement scenarios, considering future demographic change, urbanisation trends and changes in disease burdens. Methods: We use outputs from an integrated assessment model and a multi-dimensional cohort-component projection model to explore dynamically over time the range of potential health impacts across urban and rural areas in all states of India. Results: We show that pursuit of the aspirational climate change mitigation targets can bring clear co-benefits from cleaner air by averting up to 7.9 million deaths and adding up to 0.8 years to average life expectancy at birth in 2050 compared to business-as-usual. Combining these targets with policy measures that target air pollution explicitly can double human health benefits. Across the population, the largest health gains from PM2.5 reduction will occur for those living in rural areas, as well as for males and the elderly. Future health co-benefits differ substantially between states, with the highest potential gains observed in the regions around the Indo-Gangetic Plain, where high population density and low baseline life expectancy coincide with high PM2.5 levels. Conclusions: Our analysis helps reduce one of the main uncertainties in future health impact assessments (changes in the size, structure, disease burden, and distribution of the population), demonstrates the impact of different PM2.5 pathways on survival and highlights the important synergies between climate change mitigation and air quality control.