Every year over half-a-million people die in Asia from breathing air loaded with pollutants that are far in excess of World Health Organisation (WHO) guidelines for air quality, experts warn.

The premature deaths in Asia account for half of all deaths caused by air dirtied by industrial activity and vehicular emissions said Michal Kryzanoski, regional advisor of air quality and health at WHO, warned at an international workshop on air quality which ended in this tourist city on Friday. The main aerial pollutants that Asians are exposed to are sulphur dioxide, nitrogen dioxide, ozone, carbon monoxide, and particles such as soot and dust.

Of special concern are China, where levels of soot or ‘black carbon' released by its industries continue to remain high, and India, which may emerge as a ‘‘hotspot for ozone pollution'' in the coming decades, Surabi Menon, scientist at the Lawrence Berkeley Laboratory in the United States, told IPS. Ozone found in the upper air layer called stratosphere is the ‘good' ozone that blocks harmful ultraviolet rays of the sun, which damage skin and eyes, from reaching the earth. But ozone found in lower layers, released by vehicle exhausts and aircraft emissions, is ‘bad' ozone that affects the eyes and skin and is the main component of the winter smog that chokes many parts of Asia. In many Asian cities the average annual levels of coarse polluting particles, of sizes of 10 micrometers diameters (a micrometer is one-millionth of a metre), are more than three times the WHO guidelines.