Airborne pollutants from China caused about 40 percent of deaths related to PM 2.5 in the rest of the East Asian region, according to a recent study.

The study examined 2.52 million deaths worldwide in 2007 caused by PM 2.5 from production activities in the industrial, energy, transportation, residential and agricultural sectors in various countries and regions.

Of 76,231 such deaths in East Asia, including Japan and the two Koreas, about 30,900, or 40.5 percent, were associated with particles originating from China, the researchers said.

PM 2.5 is an airborne particle or droplet measuring 2.5 microns or less, small enough to make its way through the air tract and into the lungs. When outdoor levels of the pollutant are high enough, the air appears hazy, known as smog. A pollen grain is about 30 to 50 microns.

The study also identified India as a major polluter of its neighbors, with 26 percent of PM-2.5 related deaths in the rest of Asia associated with fine particles attributable to Indian sources.

Globally, about 12 percent of PM 2.5-related deaths in the year were estimated to be caused by contaminants carried by the wind from out-of-country sources.

The researchers then flipped the data on its head, shifting the focus from where the emissions were produced, to the regions in which the produced goods were consumed.

Taking this “consumption-based perspective”, they found that the biggest culprits were western Europe, the United States and the rest of Asia.

“Chinese exports embody a greater number of deaths than do exports from any other region. By contrast, net imports to the USA and western Europe embody the greatest number of deaths,” the researchers proffered.

“Our findings quantify the extent to which air pollution is a global problem,” they added.

The study concluded with a call for improving pollution controls in the major emissions-producing countries, saying it would have a disproportionately significant effect.