While governments are on the verge of declaring a coronavirus pandemic – an outbreak that is hogging daily media attention – another pervasive, growing cause of sickness and death is receiving a fraction of the attention it deserves.
Air pollution caused an extra 8.8 million premature deaths in 2015, shortening people’s life expectancy by an average of three years worldwide, according to a study published in the journal Cardiovascular Research.
These calculations are more than two times higher than previous estimates and surpass that of tobacco smoking, which causes 7.2 million premature deaths, write Jos Lelieveld, from the Max Planck Institute in Germany and co-authors.
Indeed, the diminished life spans are also far greater than wars and other forms of violence (530,000 deaths) and parasitic and vector-born diseases such as malaria and HIV/AIDS (600,000 deaths).
Lelieveld and senior author Thomas Munzel say the findings suggest the world is facing an air pollution ‘pandemic’.
“It is remarkable that both the number of deaths and the loss in life expectancy from air pollution rival the effect of tobacco smoking and are much higher than other causes of death,” says Lelieveld, proceeding to drive the shocking comparisons home.
“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.”
The most vulnerable age group, apart from children under five in low-income countries, was people over 60 who accounted for three-quarters of deaths.
The researchers used exposure data from a model that simulates atmospheric chemical processes and their interaction with land, sea and chemicals emitted from natural and human-caused sources such as energy generation, industry, traffic and agriculture.
They applied these to a new model of global exposure and death rates and to data from the Global Burden of Disease, estimating death rates and loss of life expectancy from different causes of air pollution compared to other causes.
Separating air pollution caused by humans and natural sources, including desert dust and wildfires, they found that around two-thirds of premature deaths are related to human-created air pollution – primarily from fossil fuels – and this increases to 80% in high income countries.
“Five and a half million deaths worldwide a year are potentially avoidable,” says Lelieveld.
A comparison of different diseases revealed that, along with smoking, air pollution’s greatest impact is on heart disease, which the authors say warrant its conclusion in the list of risk factors for this number one cause of global deaths.
“Air pollution causes damage to the blood vessels through increased oxidative stress,” explains Lelieveld, “which then leads to increases in blood pressure, diabetes, stroke, heart attacks and heart failure.”
The next greatest cause of lowered life expectancy came from lower respiratory infections. Others included chronic obstructive pulmonary disease, stroke and lung cancer.
The researchers estimate that reducing the air pollution caused by fossil fuel emissions would increase the average global life expectancy by more than a year, and eliminating all human-made emissions would boost it by nearly two years.
The degree and type of pollution does vary by region. East Asia has the highest loss of life expectancy due to avoidable air pollution, with three out of four lost years preventable, while at the other extreme, Africa’s pollution comes mainly from dust.