Exposure to fine particulate matter (PM2.5) air pollution is associated with large‐scale health consequences, but the ranges in estimates of global air pollution exposure and PM2.5‐related global premature mortality remain understudied. Using four model/observation‐based PM2.5 data sets and six Coupled Model Intercomparison Project Phase 6 (CMIP6) climate models, we compare ranges in current PM2.5‐related mortality estimates based on model/observation combinations to the range of projected emissions reductions and the resulting impacts on global health from CMIP6 models. Although estimates of current mortality are sensitive to the PM2.5 data set (6.54–9.23 million/year using the central estimate from the Global Exposure Mortality Model), the projected near‐term benefits of emissions reductions for reduced mortality are much more certain. Specifically, until the middle of the century, uncertainty ranges in projected avoided deaths are less than the magnitude of ranges in present‐day mortality estimates, even when projected future changing socio‐demographic factors are considered. Under a low‐emissions scenario, avoided cumulative early deaths could reach 275 million (range: 243–351 million) by 2100, assuming no future socio‐demographic changes. Avoided cumulative deaths could reach 124 million (range: 74–246 million) if changing future socio‐demographic factors are considered. As the global population ages and becomes more sensitive to breathing polluted air, there will be an increasing need for policies that both reduce air pollution and improve public health.
Plain Language Summary
Most people on Earth breathe polluted air. Breathing polluted air is associated with a variety of health problems, including early death. Despite the importance of breathing polluted air, global estimates of early death associated with breathing polluted air are often based on one observation‐based data set of global air pollution. Here we examine the ranges in estimates of global deaths from air pollution due to the choice of observation‐based data set. We find that estimates of recent global air pollution and associated deaths in recent years can vary substantially, depending on data set. We also use the latest climate model simulations to estimate how air pollution and associated deaths would change under a high‐emissions future and a low‐emissions future. We find that climate models agree that reducing fossil fuel emissions would lead to rapid, large‐scale reductions in the amount of polluted air people breathe, which leads to avoided future early deaths through at least the middle of the century. However, as the global population ages and becomes more sensitive to breathing polluted air, there will be an increasing need for policies that both reduce air pollution and improve public health.
Key Points
Estimates of recent global air pollution exposure and associated premature deaths are sensitive to the choice of observation‐based data set
The benefits of reduced fossil fuel emissions for future global health remain relatively well‐constrained until late in the century
Under aggressive emissions reductions, avoided cumulative premature deaths could reach 124 million by 2100