Only 0.001% of the world’s population breathe air considered safe.
A recent peer-reviewed study published in Lancet Planetary Health reveals that air pollution is a major global problem. The study found that almost all of the global land area, about 99.82%, is exposed to unsafe levels of particulate matter 2.5 (PM2.5) – tiny particles that have been linked to lung cancer and heart disease. Only 0.001% of the world’s population breathe air considered safe.
The study, conducted by scientists in Australia and China, found that over 70% of days in 2019 had PM2.5 concentrations exceeding the WHO-recommended daily limit of 15 micrograms of gaseous pollutant per cubic metre. Air quality is particularly concerning in southern Asia and eastern Asia, where more than 90% of days had PM2.5 concentrations above the 15 microgram threshold.
While scientists and regulators are usually more concerned about chronic exposure to PM2.5, the study emphasizes the significant health risks associated with short-term exposure, particularly sudden increases. Air pollution kills 6.7 million people annually, with nearly two-thirds of premature deaths caused by fine particulate matter. The study utilized ground-based air pollution measurements collected from over 5,000 monitoring stations worldwide, machine learning simulations, meteorological data, and geographical factors to estimate global daily PM2.5 concentrations.
The study also found that the highest annual PM2.5 concentrations occurred in eastern Asia, followed by southern Asia and northern Africa. Residents of Australia and New Zealand faced the lowest threat from fine particulate matter.
The researchers also examined how air pollution changed over the two decades leading up to 2019. Most areas in Asia, northern and sub-Saharan Africa, Oceania, and Latin America and the Caribbean experienced an increase in PM2.5 concentrations over the 20 years, driven in part by intensified wildfires. In contrast, annual PM2.5 concentrations and high PM2.5 days in Europe and northern America decreased due to stricter regulations.
Furthermore, the study reveals how the levels of fine particulate matter vary depending on the season, influenced by human activities that accelerate air pollution. For example, northeast China and north India record higher PM2.5 concentrations from December to February, likely linked to increased use of fossil fuel-burning heat generators during the winter months. South American countries such as Brazil had increased concentrations between August and September, probably connected to slash-and-burn cultivation in the summer.
Overall, the study emphasizes the urgent need for more comprehensive measures to address the global air pollution crisis.