AIR pollution linked to damage to unborn children worsened dramatically in North-East towns in last summer's heatwave, Government figures have revealed.

People living in Redcar suffered 80 days last year when pollution was "moderate or higher", compared to only 54 in 2002.

There were similar big leaps in both Middlesbrough (29 days to 78) and in Stockton (13 days to 35).

Only this week, the World Health Organisation (WHO) warned that air pollution can damage the lungs of children even before they are born.

The WHO said pollutants - in particular soot from vehicle exhausts - impaired lung growth in the womb and demanded urgent action to protect foetuses.

Pollution can also be harmful for people suffering from asthma or chest illnesses, such as bronchitis.

The Department for the Environment figures show that Redcar and Middlesbrough were hit by moderate or higher pollution on far more days last year than Newcastle (30).

And their totals were higher than many other big cities, including Sheffield (49), Leeds (46) and Manchester (44).

Environment Minister Elliott Morley said high levels of ozone, caused by high temperatures last summer, were mainly to blame.

Research suggested that air pollution may have contributed to 20-40 per cent of the extra deaths during the heatwave, he said.

However, a significant amount of the poor air quality was caused by pollution blown into Britain from abroad.

Mr Morley also insisted the increase in the number of days of moderate or higher air pollution last year bucked a ten-year trend of significant improvement in air quality.

But the Department for the Environment admitted it was impossible to tell if the rise was "a short-term blip or part of a long term trend".

As well as ozone, harmful gases which increased last summer included sulphur dioxide, nitrogen dioxide and carbon monoxide.