Loss of life expectancy from PM_2.5 in Brazil: A national study from 2010 to 2018

Long-term exposure to PM_2.5 is proved to be linked with mortality. However, limited studies have estimated the PM_2.5 related loss of life expectancy (LLE) and its changing trends. How much life expectancy would be improved if PM_2.5 pollution is reduced to the new WHO air quality guideline (AQG) level is unclear.

Data on deaths from all-causes, cancer, cardiovascular and respiratory diseases were collected from 5,565 Brazilian municipalities during 2010-2018. A difference-in-differences approach with quasi-Poisson regression was applied to examine the PM_2.5-years of life lost (YLL) associations and PM_2.5 associated LLE.

The annual PM_2.5 concentration in each municipality from 2010 to 2018 was 7.7 µg/m³ in Brazil. Nationally, with each 10 μg/m³ increase in five-year-average (current and previous four years) concentrations of PM_2.5, the relative risks (RRs) were 1.18 (95% CI: 1.15-1.21) for YLL from all-causes, 1.22 (1.16-1.28) from cancer, 1.12 (1.08-1.17) from cardiovascular and 1.17 (1.10-1.25) from respiratory diseases. Life expectancy could be improved by 1.09 (95% CI: 0.92-1.25) years by limiting PM_2.5 concentration to the national lowest level (2.9 µg/m³), specifically, 0.20 (0.15-0.24) years for cancer, 0.16 (0.11-0.22) years for cardiovascular and 0.09 (0.05-0.13) years for respiratory diseases, with significant disparities across regions and municipalities. Life expectancy would be improved by 0.78 (0.66-0.90) years by setting the new WHO AQG PM_2.5 concentration level of 5 μg/m³ as an acceptable threshold.

Using nationwide death records in Brazil, we found that long-term exposure to PM_2.5 was associated with reduced life expectancy from all-causes, cancer, cardiovascular and respiratory diseases with regional inequalities and different trends. PM_2.5 pollution abatement to below the WHO AQG level would improve this loss of life expectancy in Brazil.