Air pollution linked to over 2 million deaths each year: study

(Xinhua) -- U.S. researchers claimed Friday that human-caused outdoor air pollution may be responsible for over two million deaths worldwide each year.

The study, published in the journal Environmental Research Letters, estimated that around 470,000 people die each year because of human-caused increases in ozone.

It also estimated that around 2.1 million deaths are caused each year by human-caused increases in fine particulate matter, tiny particles suspended in the air that can penetrate deep into the lungs, causing cancer and other respiratory disease.

"Our estimates make outdoor air pollution among the most important environmental risk factors for health," co-author of the study, Jason West, from the University of North Carolina, said in a statement. "Many of these deaths are estimated to occur in East Asia and South Asia, where population is high and air pollution is severe."