Outdoor air pollution is cutting almost three years of life expectancy of humans on average, researchers have found. The global survey finds the average figure to be higher than that caused by smoking tobacco.
The study reveals the life expectancy of more than a year could be received back if the emissions from fossil fuels are cut to zero along with all other controllable air pollution excluding particles from natural wildfires or wind-born dust. Global life expectancy could rise by 20 months and more with that.
“This corroborates that fossil fuel-generated air pollution qualifies as a major global health risk factor by itself,” the authors write.
The study based on the team’s previous research, according to which about 8.8m early deaths a year worldwide, has been confirmed are caused by outdoor air pollution, which is twice the figure from prior estimates. The new work is examining the issue for the whole world and also in detail, considering particular countries and regions.
“The loss of life expectancy from air pollution is much higher than many other risk factors, and even higher than smoking,” said co-author Prof Jos Lelieveld of the Max Planck Institute for Chemistry. “That was quite unexpected, I must say.”
The model of the impact of PM2.5, delicate particulate matter on the body, as well as a model for the effects of ozone, levels of exposure to these pollutants, and population and figures for 2015 mortality that are recently developed, the new study draws with the team’s previous work.
The team calculated the early deaths proportion from this data that could be attributed to outdoor air pollution across six categories in which unspecified non-communicable diseases encompassing conditions such as high blood pressure and diabetes is also included.
Globally the results reveal that outdoor air pollution has been a more significant toll for which life expectancy on average are lost 2.9 years than tobacco smoking (2.2 years lost), HIV/Aids (0.7 years lost), violence (0.3 years lost), and diseases spread by parasites and other vectors (0.6 years lost).
The team adds, should avoidable outdoor air pollution be cut, we could avoid more than 5.5m early deaths globally every year.
However, it varies between regions and countries: in East Asia, such a measure would save 2.4m early deaths a year and regain three out of the 3.9 years of life expectancy lost out of outdoor air pollution while in Africa only 230,000 premature deaths a year, air pollution cut would save just over eight months of the 3.1 years of life expectancy lost. The gains would be even smaller in Australia.
That is down to a variety of factors, the authors note, including Africa’s outdoor air pollution being dominated by wind-blown dust and air pollution policies are stricter in Australia than many other countries.
The premature deaths owing to air pollution generally increased with age, the team found. However, in some regions, including Africa and South Asia, there is also a high number of premature deaths among very young children.
The most significant number of extra deaths caused for any of the six categories was from coronary heart disease, at almost 2.8m a year worldwide, and made up the loss in life expectancy of 28% and more. By contrast, about 2.6m early deaths from outdoor air pollution a year caused by lung cancer, chronic obstructive lung diseases, and lower respiratory infections.
Prof Thomas Münzel, of the University Medical Centre Mainz in Germany and co-author of the study, said this was not surprising. “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,” he said, noting that will cause inflammation and, plaque will build up over time in the arteries.
According to Münzel, the findings underscore the significance of including air pollution as a risk factor for cardiovascular disease for such conditions in official guidelines.
However, there are several limitations in the study that looks at only two air pollutants and the chemical makeup of the particulate matter not considered. Among other factors, the team notes that as the models are based on data from a limited number of countries, there may be diseases that should be associated with the air pollution that are not currently included.
Therefore the team says there are large uncertainties in the findings. Nonetheless, Münzel said the study emphasizes the need for governments to act.
“We need lower emission levels – 91% of the [world’s] population breathes polluted air as defined by the [World Health Organization],” he said. “We have incredibly high limits for Europe: those need to be reduced markedly.”
The team notes life expectancy can also improve with the measures, including city planning and management, and with the improvements in healthcare. Münzel added that researching drugs could also mitigate the impacts of air pollution on health.
Prof Kevin McConway, emeritus professor of applied statistics at the Open University, said that due to uncertainty in the figures, it is still not clear whether air pollution is a bigger killer compared to tobacco, but that it certainly rivals it. He added that although smoking a packet of cigarettes per day is very dangerous, people in a higher proportion are inhaling air pollution than smoke from tobacco.
The work is published in the journal Cardiovascular Research.