Air pollution is the world’s leading cause of mortality as it reduces a person’s lifespan by three years on average, according to a study published on Tuesday (3 March), Euractiv’s partner Le Journal de l’Environment reports.

While air pollution is a well-established factor in global mortality, it remains largely underestimated.

While the World Health Organisation (WHO) estimated that it had killed 4.2 million people in 2016, researchers have concluded that this figure could actually be closer to 8.8 million people. This is according to Jos Lelieveld of the Max Planck Institute for Chemistry in Mainz (Germany) and his colleagues, who published a study on Tuesday in Cardiovascular Research, the journal of the European Society of Cardiology (ESC).

The researchers cross-referenced global data on the exposure to fine particle matter (PM2.5; smaller than 2.5 microns in size) together with ozone exposure data by using the Global Exposure Mortality Model, a tool published in 2018 that allows for a better calculation of air pollution’s impact on human health.

In addition to cardiovascular and pulmonary effects, the team has for the first time evaluated the effect on other non-communicable diseases, including diabetes and hypertension. Air pollution is thus proving to be the main risk factor for mortality worldwide, even surpassing both active and passive smoking, which accounts for 7.2 million deaths per year.