ISPRA, Italy (AFP) - The internal combustion engine contributes massively to global warming, kills around 1.2 million people a year in road accidents and, scientists now warn, is costing billions of dollars in crop damage each year.

The villain is a molecule of oxygen called ozone.

Way up in the stratosphere, the wafer-thin ozone layer exists naturally as a protector of life, filtering out ultra-violet sunlight that would otherwise slice and corrupt human DNA.

At ground level, though, ozone can be dangerous. Formed by a reaction between nitrogen oxides and volatile organic compounds emitted by road traffic, ozone smog can be a life-shortening problem for people with bad respiratory problems.

Another fast-emerging picture is that this pollution is also inflicting a rising bill in damage to food plants, especially in regions where hot, sunny, windless conditions favour ozone formation.

»news.yahoo.com/s/afp/20060711/sc···ollution