Long-term exposure to PM2.5 contributed to more than 4 million deaths in 2019.
In 2019, long-term exposure to PM2.5 pollution contributed to 4.14 million deaths worldwide (95% UI: 3.45 to 4.80), accounting for 62% of all air pollution attributable deaths. The number of deaths attributable to ambient PM2.5 increased by about 23% (95% UI: 13.9 to 34.4) globally over the past decade.
Among 69 risk factors that are considered to be potentially modifiable, ambient PM2.5 ranks 6th behind high blood pressure, smoking, and high blood sugar, among others. It is the leading risk factor among all environmental and occupational risks.
Asia and Africa see the highest burden of disease from PM2.5.
Countries in Asia and Africa experience the highest rates of death attributable to PM2.5. Given the combination of high death rates and large populations, China and India together account for 58% of the total global mortality burden. In 2019, there were 1.42 million deaths attributable to PM2.5 (95% UI: 1.17 to 1.69 million) in China, and 980,000 deaths attributable to PM2.5 (95% UI: 0.77 to 1.19 million) in India. The burden is far lower in countries in the GBD High-Income Region.
The burden is rising fastest in Asia. Over the past decade, South Asia and Southeast Asia, East Asia, and Oceania saw steep increases in total deaths attributable to PM2.5. More modest increases were seen in sub-Saharan Africa and in North Africa and the Middle East. Together, the increases in these regions vastly outweigh the modest decreases in the High-Income and the Central Europe, Eastern Europe, and Central Asia Regions.
Sixteen of the 20 most populous countries experienced increases in PM2.5-attributable deaths over the past decade.
Even as exposures level off or decline, the burden of disease rises as populations grow and age.
Many factors influence the burden of disease from PM2.5. Air pollution exposures can rise or fall. Changes in healthcare access or medical treatments can reduce the death rates for the diseases associated with air pollution. Shifts in a country’s level of socioeconomic development also influence the burden of disease over time.
Overall, changes in population size and age structure sometimes have the largest impacts on these trends. Even if exposures to air pollution are decreasing, the overall attributable burden of disease can increase if a population is growing faster than exposures are falling. By the same token, a population that is aging will likely face a higher burden of disease because older people are more vulnerable to diseases linked with air pollution.
Together, population growth and aging of the global population are estimated to account for more than half of the increased deaths attributed to PM2.5 exposure over the past decade.