Air pollution is shortening people’s lives by an average of three years, according to a study published in Cardiovascular Research on Tuesday. 

Researchers determined that air pollution is a severe global health risk that has a much higher loss of life expectancy than other major threats like smoking.

The study draws on previous research, which revealed that around 8.8 million people prematurely die from outdoor air pollution every year. 

The team of scientists, hailing from Europe and Saudi Arabia, also examined the impact PM2.5 particulate matter has on the human body. PM2.5 are toxic particles originating from fossil fuel emissions. Exposure to the fine particles caused 4.2 million deaths worldwide in 2015. 

Using this data, the team found that 2.9 years of life expectancy are lost to air pollution worldwide, a number greater than the loss of life expectancy from smoking, HIV/AIDS, parasitic diseases, and violence. 

While there are variations between countries, premature deaths from outdoor air pollution tend to increase with age.

Coronary heart disease accounts for the most number of premature deaths attributed to air pollution, followed closely by lung cancer and other respiratory infections and diseases. 

“Even [though] the lung is the primary target of air pollution, causing inflammation and therefore pneumonia, there will be a transmigration of particles into the bloodstream and into blood vessels,” wrote Professor Thomas Münzel of the University Medical Centre Mainz, co-author of the study. 

The study also showed that cutting back on fossil fuel emissions can help reverse this effect.

If fossil fuel emissions are cut to zero, the global life expectancy could increase by over a year and around 5.5 million premature deaths could be avoided every year.

“We need lower emission levels — 91% of the [world’s] population breathes polluted air as defined by the [World Health Organization]. We have incredibly high limits for Europe: those need to be reduced markedly,” Münzel said.