Paris (AFP)

China and India have the most cities affected by microparticle pollution, responsible for many premature deaths, according to a report released Tuesday by Greenpeace and the research arm of the Swiss company IQAir.

These two countries group together almost 90% of the 200 cities suffering from high levels of air pollution with fine PM2.5 particles (less than 2.5 micrometers), indicates this report, which is based on data from about 5,000 cities around the world. The remaining 10% is concentrated mainly in Pakistan and Indonesia, the report said.

Among the megalopolises of 10 million inhabitants and more, the Indian capital New Delhi was the most contaminated with fine PM2.5 particles in 2019, followed by Lahore in Pakistan, Dhaka in Bangladesh and Calcutta in India.

Taking into account the exposure of populations, Bangladesh is the country suffering the most from pollution with these fine particles, whose diameter corresponds to one thirtieth of a human hair. Their small size allows them to enter the blood system via the lungs, leading to asthma, lung cancer or heart disease.

Bangladesh is followed by Pakistan, Mongolia, Afghanistan and India. China ranks 11th.

The majority of the seven million premature deaths worldwide attributed by the World Health Organization (WHO) to air pollution are caused by PM2.5 particles, produced by sandstorms, forest fires , agriculture, industry and fossil fuel combustion.

- Coal, oil, gas -

The WHO recommends not to exceed a concentration of fine PM2.5 particles of 25 micrograms per cubic meter of air on a daily basis.

A study published in 2019 estimated that air pollution could be twice as deadly as we thought, with nearly 800,000 deaths per year in Europe, 2.8 million for China and 8.8 million in the world.

In a vast region from northern India to central China, meeting WHO standards would increase life expectancy by six to seven years, according to an index (Air Quality Life Index) developed by researchers from the Energy Policy Institute at the University of Chicago.

Among the 36 member countries of the Organization for Economic Co-operation and Development (OECD), South Korea is the country most polluted with fine PM2.5 particles, with 105 cities among the 1,000 lowest ranked. In Europe, Poland and Italy have 39 and 31 cities respectively.

It is more difficult to assess the situation in Africa and the Middle East for lack of data.

Africa has less than 100 measurement stations transmitting PM2.5 readings to the public in real time, compared to more than 1,000 in China.

Climate change has started to increase the health risks associated with these particles, with more intense forest fires and sandstorms compounded by desertification, according to this report.

Global warming and pollution with microparticles are accentuated by the same factor: the combustion of coal, oil and gas.

While the link between air pollution and lung cancer was already well established, a recent study shows that most premature deaths are caused by heart attacks, strokes and other types of cardiovascular disease .

© 2020 AFP