Evaluation of life expectancy loss associated with submicron and fine particulate matter (PM 1 and PM 2.5 ) air pollution in Nanjing, China

Particulate matters with an aerodynamic diameter ≤1 μm (PM 1 ) significantly increased mortality risk, and the effect of PM 1 was even greater than that of PM 2.5 (aerodynamic diameter ≤2.5 μm). But the quantitative impact of PM 1 on life expectancy was unknown. We aim to examine the extent to which that people’s life expectancy was shortened by PM 1 and PM 2.5 . We obtained daily data on deaths, PM 1 and PM 2.5 records, and weather variables during 2016–2017 in Nanjing, China. Years of life lost (YLLs) were calculated by matching each decedent’s age and sex to the Chinese life table. The fitted nonlinear dose-response associations of YLLs with PM 1 and PM 2.5 were estimated by utilizing a generalized additive model with a Gaussian link that controlled for confounding factors including meteorological variables, day of week, and long-term trend and seasonality. The effect estimates were presented as the YLLs when PM 1 and PM 2.5 concentrations fell in different ranges. Life expectancy losses attributable to PM 1 and PM 2.5 were calculated. Stratified analyses were also performed by age, sex, and death causes. Significant PM-YLL associations were observed, with greater increases in YLLs associated with PM 1 (68.9 thousand). PM 1 was estimated to reduce life expectancy, which was greater than PM 2.5 (PM 1 : 1.67 years; PM 2.5 : 1.55 years). For PM 1 , greater years of loss in PM-related life expectancy were found in the female group, ≥65 years group, and cardiovascular disease group. Exposure to PM 1 had a greater impact on life expectancy loss than did PM 2.5 . Constant efforts are urgently needed to control PM 1 air pollution to improve people’s longevity.