The Welsh valleys road with some of the UK's worst air pollution

Heavy traffic sees A472 at Crumlin record highest nitrogen dioxide outside London - and residents fear for children's health

The rush hour is not a good time to be out and about on the A472 as lorry after lorry climbs out of the south Wales valley town of Crumlin and heads up and over towards Pontypool.

"It's pretty terrible," said Deanna Harwick, a mother of two young children, who lives in a terrace lining one side of the heaving road. "We can't have the windows open because of the fumes so in the summer the house feels pretty airless. I don't let the children play outside, not just because of the risk of a road accident but because of the damage the air may cause to their health. I've been here 10 years and I'm keen to move."