'Filthy glamour': could polluted Marylebone Road help fix London's air?

Marylebone Road has the odd distinction of being the world's most studied road in terms of air pollution - yet remains a chief culprit in London's 'shameful' air quality. Now it's home to a series of new experiments

Daybreak in the capital and on the pavement opposite Great Portland Street underground station runners cut virtuous paths through a crisp, cold winter's morning. To one side of them lies Regent's Park, deep green beneath a perfect frost. On the other roars a source of contamination so severe that the health of these runners might have been better served staying indoors.

Marylebone Road, one of London's main east-west streets, illustrates with filthy glamour why the city suffers from stubbornly poor air quality - with recent record-breaking pollution levels having caused particular concern.