FOUR new man-made gases that contribute to destruction of the ozone layer have been identified by scientists.

An estimated 74,000 tonnes of three chlorofluorocarbons (CFCs) and one hydrochlorofluorocarbon (HCFC) have been released into the atmosphere within recent decades, the research led by the University of East Anglia (UEA) found.

All four gases started to enter the atmosphere in the 1960s, suggesting they were entirely man-made, and two were significantly increasing, the research revealed.

Emission increases on this scale have not been seen for other types of CFCs - the main cause of the hole in the ozone layer discovered above Antarctica - since controls on the gases were introduced in the 1990s, the scientists said.

But they are nowhere near the peak emissions of CFCs of around a million tonnes a year seen in the 1980s, before action was taken to tackle the problem.

Dr Johannes Laube, from UEA's School of Environmental Sciences, said: "The identification of these four new gases is very worrying as they will contribute to the destruction of the ozone layer."