Estimating potentially preventable ambient PM2.5-attributable adult deaths by improving air quality in Nepal

Abstract

Air pollution is an important global environmental health risk factor, with many Asian countries experiencing alarming levels in recent decades. Nepal, a South Asian country, has been facing severe degradation in air quality in recent years, where data are scarce on the health impact of air pollution, especially at sub-national levels. In this study, we investigated ambient fine particulate matter (PM2.5)-attributable adult (≥25 years) premature mortality in Nepal, analyzed its long-term trend, and estimated potentially preventable adult mortality under different improved air quality scenarios defined using the World Health Organization's (WHO) interim targets (IT) and the air quality goal (AQG). Leveraging an open-source high-resolution PM2.5 dataset and an age-specific population dataset, we employed the Global Exposure Mortality Model to estimate mean and 95% confidence intervals of PM2.5-attributable adult mortality using Monte Carlo simulations. We estimated the country-level NCD + LRI (non-communicable diseases and lower respiratory infections) adult deaths attributable to PM2.5 exposure as 48881 (95% CI: 37175−61470), and the PM2.5-attributable NCD + LRI adult mortality rate as 267 (95% CI: 203−335) per 100000 in 2019. The adult mortality burden consistently increased during 2000–2019. Moreover, improving air quality to the WHO ITs and AQG could prevent an estimated 9690 (95% CI: 7698−11812) to 39419 (95% CI: 30311−49277) premature adult deaths across the country in 2019. Our findings suggest that the adult mortality burden due to air pollution in Nepal is substantial, which offers an opportunity to prevent a considerable number of premature adult deaths by mitigating air pollution in the country.