Air pollution is killing about 1.6 million people every year in China, or nearly 4,400 people every day, accounting for seventeen percent of all the country's deaths, a new study has found.

Researchers from the University of California, Berkeley found the sources of pollution to be widespread, but particularly intense in a corridor extending from Shanghai to Beijing. The paper, which has been accepted for publication in the journal PLOS ONE, analyzed hourly pollution measurements for a period of four months from April 5, 2014 to August 5, 2014. Data was collected from 1,500 sites.

Thirty-eight percent of the Chinese population was exposed to unhealthy levels of pollution, according to the standards defined by the US Environmental Protection Agency,the researchers concluded.

"Air pollution is the greatest environmental disaster in the world today," Richard Muller, study author and the scientific director of Berkeley Earth, told VICE News. "We listen to the news reports of the explosion in Tianjin and we hear of maybe hundreds dying, but that same day more than 4,000 people are going to die of air pollution."

The study also found out what makes China's pollution so deadly. The scientists found that really small particles — measuring just 2.5 microns, which is about 30 times smaller than the diameter of human hair — were present in especially high concentrations. Being so small in size, these particles are able to penetrate deep into lungs and can trigger heart attacks, stroke, and lung cancer, among many other conditions.

Muller believes PM2.5 poses such acute human health hazards that it will become as much of a public health concern as other major epidemics, like AIDS. Worldwide, diseases linked to exposure to air pollution now kill over three million people per year — more than AIDS, malaria, diabetes, or tuberculosis, according to World Health Organization data.

Sources of China's pollution include power plants, industrial facilities, and automobiles with the main culprit being any source that relies on coal burning. Muller and his colleagues focused on six types of particles — PM2.5, PM10, which is up to 10 microns in diameter, sulfur dioxide, nitrogen dioxide, ozone, and carbon monoxide.

The study also sheds light on how polluting particles move around, which could help identify methods for protecting public health. While industrial zones were found to be the most dirty, the pollution spread very rapidly because of a high concentration of the tiny PM2.5 particles that can be easily carried by wind.

"PM2.5 is found over most of China, even in places where it is not produced," Muller said. "Chinese people are not really aware of this pollution and they think it is confined to cities and basins… but it is actually spread out all over."

The severe pollution levels in China, the world's biggest producer and consumer of coal, could impact some of it's national ambitions, notably the 2022 Winter Olympics, which it is hosting.

And given that the pollution does not stay localised and instead travel around, mitigation will be time consuming.

Greenpeace is optimistic about government efforts — already underway — to address the nation's poor air quality.

"If the coal consumption reductions and improvements in enforcement of emission standards that we have seen in the past 12 months continue, we could see a substantially less polluted China by 2022," Lauri Myllyvirta, a senior global campaigner on coal for Greenpeace, told VICE News.

But, she emphasized, comprehensive environmental policies are needed to ensure the Olympics doesn't counteract those advances.

"This is not to say that there aren't a lot of challenges and open questions around the Olympics — for example, withdrawing enough water for all the artificial snow required for the event could be a major issue in the area that is already grappling with water scarcity," she said.

Decommissioning coal-burning power plants, improving energy efficiency, and developing cleaner energy resources were several solutions proposed by the study authors. And, as international pressure mounts on all big economies to cut greenhouse gas emissions ahead of UN climate negotiations in Paris later this year, action needs to happen sooner, rather than later, they sa

"Many of the same solutions that mitigate air pollution will simultaneously reduce China's contribution to global warming. We can save lives today and tomorrow," Elizabeth Muller, executive director of Berkeley Earth, said.

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