Premature deaths from air pollution will rise to 4.5 million unless changes are made to the way the world uses and produces energy, the International Energy Agency (IEA) said on Monday.

Around 6.5 million deaths globally are attributed each year to poor air quality inside and outside, making it the world's fourth-largest threat to human health. Tiny particulate matter can cause lung cancer, strokes and heart disease as well as trigger symptoms such as heart attacks. The release of these pollutants is mainly due to the unregulated or inefficient production and use of energy.

Without action, premature deaths attributable to outdoor air pollution will increase to 4.5 million in 2040 from around 3 million currently. Premature deaths due to household air pollution, however, should fall to 2.9 million from 3.5 million.

Asia will account for almost 90 percent of the rise in deaths.

Even though global emissions are forecast to decline overall to 2040, existing and planned energy policies will not be enough to improve air quality, the report said.

"Without changes to the way that the world produces and uses energy, the ruinous toll from air pollution on human life is set to rise," the IEA said.