What's New?

This third annual State of Global Air report presents the latest information on worldwide air pollution exposures and health impacts. It draws from the most recent evidence as part of the Global Burden of Disease (GBD) project of the Institute for Health Metrics and Evaluation (IHME).

 

Reflecting the Latest Science

This year’s State of Global Air report presents updated information for all of the indicators addressed in previous reports, including:

  • Exposure to fine particles (PM2.5), ozone, and household air pollution
  • Illnesses and deaths that are attributed to air pollution
  • Patterns and trends since 1990
  • Sociodemographic patterns

 

New Considerations and Methods for this Year

As the science continues to advance, the GBD project has incorporated new data and methodology into its air pollution and health assessments. This new methodology may result in differences among assessments from this and previous years because the numbers were calculated in a different way. However, the trends in air pollution and health burden over time are recalculated with each GBD update to ensure the findings are internally consistent within each report.

  • Assessing impacts on life expectancy. This year, the State of Global Air features an analysis of how much air pollution exposure reduces life expectancy in countries around the world. 
  • Accounting for risks from type 2 diabetes. In light of recent evidence indicating that air pollution contributes to development of type 2 diabetes, GBD and the State of Global Air now include estimates of the health burden related to type 2 diabetes.
  • Eliminating double counting. This year’s report analyzes the burden of disease from ambient air pollution independently from that of household air pollution. Past estimates had the potential for some double counting of the disease burden in populations exposed to both ambient and household air pollution.
  • New methods for analyzing health impacts from air pollution exposures. The mathematical methods for analyzing how exposure to pollution relates to specific health risks (known as exposure-response functions) have been updated. The new methods reflect data from recent epidemiological studies on the impacts of ambient PM2.5, household air pollution, and secondhand smoke, and from updated literature reviews on the impacts of active smoking.
  • New methods for assessing ozone. The method for estimating ozone levels has been revised, incorporating for the first time an extensive database of ground-level ozone measurements. In addition, the ozone exposure metric was changed to an 8-hour daily maximum level to align with more recent epidemiological analyses. 
  • Inclusion of more PM2.5 measurements. The database of ground measurements of PM2.5 has been expanded from approximately 6,000 to 9,960 sites. Including more measurements in the models used to calibrate satellite-based estimates results in finer-grained estimates of PM2.5 concentrations that vary more smoothly over space and time. In addition, estimates of PM2.5 exposure now directly incorporate uncertainty distributions from the calibration model.  

 

Learn more about How We Estimate Pollution Exposures and How We Estimate Burden of Disease.