Air pollution shortens people's lives worldwide on a much larger scale than smoking, HIV/AIDS, and diseases such as malaria, a new study has found.

According to German researchers who led the study, as many as five-and-a-half million deaths related to air pollution are potentially avoidable every year.

The researchers used a new method of modeling the effects of different sources of air pollution on death rates. From this, they were able to estimate that in 2015, air pollution caused an extra 8.8 million premature deaths around the world.

This represents an average shortening of life expectancy of almost three years among all people globally.

In comparison, smoking shortens life expectancy by an average of 2.2 years (7.2 million deaths), while HIV/AIDS shortens it by 0.7 years (one million deaths).

Meanwhile diseases that are carried by parasites, insects, ticks and fleas, such as malaria, shorten life expectancy by 0.6 years (600,000 deaths), while all forms of violence, including wars, shorten it by 0.3 years (530,000 deaths).

The study found that air pollution has a greater impact on older people. Globally, three-quarters of air pollution deaths occur in people over the age of 60.

As part of the study, the researchers looked at the impact of air pollution on six categories of disease - lower respiratory tract infection, chronic obstructive pulmonary disease (COPD), lung cancer, heart disease, cerebrovascular disease leading to stroke, and other non-communicable diseases, such as high blood pressure and diabetes.

They found that cardiovascular diseases (heart disease and cerebrovascular disease combined) are responsible for the greatest proportion of shortened lives from air pollution - 43% of the loss in life expectancy globally.

"It is remarkable that both the number of deaths and the loss in life expectancy from air pollution rival the effects of tobacco smoking and are much higher than other causes of death. Air pollution exceeds malaria as a global cause of premature death by a factor of 19; it exceeds violence by a factor of 16, HIV/AIDS by a factor of nine, alcohol by a factor of 45, and drug abuse by a factor of 60," explained one of the lead researchers, Prof Jos Lelieveld of the University Medical Centre Mainz in Germany.

Meanwhile according to the study's co-lead researcher, Prof Thomas Münzel, also of University Medical Centre Mainz, policy makers and the medical community "should be paying much more attention to this".

"Since the impact of air pollution on public health overall is much larger than expected, and is a worldwide phenomenon, we believe our results show there is an ‘air pollution pandemic'. Both air pollution and smoking are preventable, but over the past decades, much less attention has been paid to air pollution than to smoking, especially among cardiologists," he noted.

He pointed out that this research distinguishes between avoidable, human-made air pollution and pollution from natural sources, such as wildfire emissions, which cannot be avoided.

"We show that about two-thirds of premature deaths are attributable to human-made air pollution, mainly from fossil fuel use. This goes up to 80% in high-income countries. Five and a half million deaths worldwide a year are potentially avoidable.

"It is important that policy-makers and the medical community realise that air pollution is an important risk factor for heart and blood vessel disease. It should be included as a risk factor, along with smoking, diabetes and high blood pressure and cholesterol, in the guidelines of the European Society of Cardiology and the American Heart Association on the prevention of acute and chronic heart syndromes and heart failure," Prof Münzel said.

Air pollution causes damage to the blood vessels as a result of increased oxidative stress, which leads to increases in blood pressure, heart attacks, heart failure, stroke and diabetes.

Details of these findings are published in the journal, Cardiovascular Research.