Science

Air pollution, a bigger killer than tobacco

T V Jayan New Delhi | Updated on March 12, 2019 Published on March 12, 2019

The number of deaths from cardiovascular disease that can be attributed to air pollution is much higher than expected. File Photo   -  The Hindu

Fine particulate matter causes 8.8 m extra deaths worldwide: Study

Air pollution is killing more people than tobacco and the number of deaths associated with the fine particulate matter in the atmosphere globally is around 8.8 million, twice more than that has been estimated previously, said researchers in a study published on Tuesday.

Using a new method of modelling the effects of various sources of outdoor air pollution on death rates, the researchers found that it caused an estimated 8.8 million extra deaths globally rather than the previously estimated 4.5 million, according to the study which appeared in the European Health Journal.

“To put this into perspective, this means that air pollution causes more extra deaths a year than tobacco smoking, which the World Health Organization (WHO) estimates was responsible for an extra 7.2 million deaths in 2015. Smoking is avoidable but air pollution is not,” said Thomas Münzel, a co-author and cardiology professor at the University Medical Centre Mainz in Germany, in a statement said.

The number of deaths from cardiovascular disease that can be attributed to air pollution is much higher than expected. In Europe alone, the excess number of deaths is nearly 800,000 a year and each of these deaths represents an average reduction in life expectancy of more than two years, he said.

The researchers used exposure data from a model that simulates atmospheric chemical processes and the way they interact with land, sea and chemicals emitted from natural and man-made 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 WHO, which included information on population density, geographical locations, ages, risk factors for several diseases and causes of death. They focused particularly on levels of polluting fine particles that are less than or equal to 2.5 microns in diameter – known as PM2.5 – and ozone.

Global numbers

Worldwide, they found that air pollution is responsible for 120 extra deaths per year per 100,000 of the population. In Europe and the EU-28, it was even higher, causing 133 and 129 extra deaths a year per 100,000 people, respectively. In eastern Europe, however, it is over 200 deaths per 100,000 annually.

“The high number of extra deaths caused by air pollution in Europe is explained by the combination of poor air quality and dense population, which leads to exposure that is among the highest in the world. Although air pollution in eastern Europe is not much worse than in western Europe, the number of excess deaths it caused was higher. We think this may be explained by more advanced health care in western Europe, where life expectancy is generally higher,” said co-author Jos Lelieveld of the Max-Plank Institute for Chemistry in Mainz and the Cyprus Institute Nicosia, Cyprus.

The researchers said national governments and international agencies must take urgent action to reduce air pollution, including re-evaluating legislation on air quality and lowering the EU’s current limits on the annual average levels of air pollution to match the WHO guidelines.

Currently, the average annual limit for PM2.5 in the EU is 25 μg/m3 (micrograms per cubic metre), which is 2.5 times higher than the WHO guideline of 10 μg/m3. Even at this level, several European countries regularly exceed the limit. “The current limit of 25 μg/m3 should be adjusted downwards to the WHO guideline of 10 μg/m3. Many other countries, such as Canada, the USA and Australia use the WHO guideline; the EU is lagging a long way behind in this respect. Indeed, new evidence may lead to a further lowering of the WHO guideline in the near future,” Münzel said.

The link between air pollution and cardiovascular disease, as well as respiratory diseases, is well established. It causes damage to the blood vessels through increased oxidative stress, which then leads to increases in blood pressure, diabetes, stroke, heart attacks and heart failure. The scientists, however, were candid to admit that there could be statistical uncertainty surrounding the estimates and this may exaggerate or downplay the effect of air pollution on deaths.

Published on March 12, 2019
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