Summary

Air pollution of fine particulates (PM_2.5) is a leading cause of mortality worldwide. It is estimated that ambient PM_2.5 air pollution results in between 4.1 million and 8.9 million premature deaths annually. According to the World Bank, the health effects of ambient PM_2.5 air pollution had a cost of $6.4 trillion in purchasing power parity (PPP) adjusted dollars in 2019, equivalent to 4.8% of global gross domestic product (PPP adjusted) that year.

Estimating the health effects and cost of ambient PM_2.5 air pollution involves three steps: (1) estimating population exposure to pollution; (2) estimating the health effects of such exposure; and (3) assigning a monetary value to the illnesses and premature deaths caused by ambient air pollution.

Estimating population exposure to ambient PM_2,5 has gone from predominantly using ground level monitoring data mainly in larger cities to estimates of nationwide population weighted exposures based on satellite imagery and chemical transport models along with ground level monitoring data. The Global Burden of Disease 2010 (GBD 2010) provided for the first time national, regional and global estimates of exposures to ambient PM2.5. The GBD exposure estimates have also evolved substantially from 2010 to 2019, especially national estimates in South Asia, the Middle East and North Africa, Sub-Saharan Africa and Latin America and the Caribbean.

Estimation of health effects of ambient PM2.5 has also undergone substantial developments during the last two decades. These developments involve: i) going from largely estimating health effects associated with variations in daily exposures to estimating health effects of annual exposure; ii) going from estimating all-cause mortality or mortality from broad disease categories (i.e., cardiopulmonary diseases) to estimating mortality from specific diseases; and iii) being able to estimate health effects over a wide range of exposure that reflect ambient and household air pollution exposure levels in low- and middle-income countries.

As to monetary valuation of health effects of ambient air pollution, estimates in most low- and middle-income countries still rely on benefit transfer of values of statistical life (VSL) from high-income countries.